From 7a37a7c8228dfb7816e6367d3a37d3dd3177a3e9 Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Sat, 31 Jan 2026 10:08:33 +0100
Subject: [PATCH 01/46] feat: add PlasticShearStrengthIProfileCheck class for
 shear force resistance checks and enhance Report class with equation
 splitting functionality

---
 .../checks/eurocode/steel/shear_strength.py   | 190 ++++++++++++++++++
 blueprints/utils/report.py                    |  36 +++-
 2 files changed, 222 insertions(+), 4 deletions(-)
 create mode 100644 blueprints/checks/eurocode/steel/shear_strength.py

diff --git a/blueprints/checks/eurocode/steel/shear_strength.py b/blueprints/checks/eurocode/steel/shear_strength.py
new file mode 100644
index 000000000..2f735e3ef
--- /dev/null
+++ b/blueprints/checks/eurocode/steel/shear_strength.py
@@ -0,0 +1,190 @@
+"""Module for checking plastic shear force resistance of steel(Eurocode 3)."""
+
+from dataclasses import dataclass, field
+from typing import ClassVar, Literal
+
+from sectionproperties.post.post import SectionProperties
+
+from blueprints.checks.check_result import CheckResult
+from blueprints.codes.eurocode.en_1993_1_1_2005 import EN_1993_1_1_2005
+from blueprints.codes.eurocode.en_1993_1_1_2005.chapter_6_ultimate_limit_state import (
+    formula_6_17,
+    formula_6_18,
+    formula_6_18_sub_av,
+)
+from blueprints.codes.formula import Formula
+from blueprints.structural_sections.steel.profile_definitions.i_profile import IProfile
+from blueprints.structural_sections.steel.steel_cross_section import SteelCrossSection
+from blueprints.type_alias import DIMENSIONLESS, KN
+from blueprints.unit_conversion import KN_TO_N
+from blueprints.utils.report import Report
+
+
+@dataclass(frozen=True)
+class PlasticShearStrengthIProfileCheck:
+    """Class to perform plastic shear force resistance check for steel I-profiles (Eurocode 3).
+
+    Coordinate System:
+
+        z (vertical, usually strong axis)
+            ↑
+            |     x (longitudinal beam direction, into screen)
+            |    ↗
+            |   /
+            |  /
+            | /
+            |/
+      ←-----O
+       y (horizontal/side, usually weak axis)
+
+    Parameters
+    ----------
+    steel_cross_section : SteelCrossSection
+        The steel cross-section, of type I-profile, to check.
+    v : KN
+        The applied shear force (positive value, in kN).
+    axis : Literal["Vz", "Vy"]
+        Axis along which the shear force is applied. "Vz" (default) for z (vertical), "Vy" for y (horizontal).
+    gamma_m0 : DIMENSIONLESS, optional
+        Partial safety factor for resistance of cross-sections, default is 1.0.
+    section_properties : SectionProperties | None, optional
+        Pre-calculated section properties. If None, they will be calculated internally.
+
+    Example
+    -------
+    from blueprints.checks.eurocode.steel.shear_strength import PlasticShearStrengthIProfileCheck
+    from blueprints.materials.steel import SteelMaterial, SteelStrengthClass
+    from blueprints.structural_sections.steel.standard_profiles.heb import HEB
+
+    steel_material = SteelMaterial(steel_class=SteelStrengthClass.S355)
+    heb_300_profile = HEB.HEB300.with_corrosion(1.5)
+    v = 100  # Applied shear force in kN
+
+    heb_300_s355 = SteelCrossSection(profile=heb_300_profile, material=steel_material)
+    calc = PlasticShearStrengthIProfileCheck(heb_300_s355, v, axis="Vz", gamma_m0=1.0)
+    calc.report().to_word("shear_strength.docx", language="nl")
+
+    """
+
+    steel_cross_section: SteelCrossSection
+    v: KN = 0
+    axis: Literal["Vz", "Vy"] = "Vz"
+    gamma_m0: DIMENSIONLESS = 1.0
+    section_properties: SectionProperties | None = None
+    name: str = "Plastic shear strength check for steel I-profiles"
+    source_docs: ClassVar[list] = [EN_1993_1_1_2005]
+    _profile: IProfile = field(init=False, repr=False)
+
+    def __post_init__(self) -> None:
+        """Post-initialization to extract section properties and check profile type."""
+        if not isinstance(self.steel_cross_section.profile, IProfile):
+            raise TypeError("The provided profile is not an I-profile.")
+        object.__setattr__(self, "_profile", self.steel_cross_section.profile)
+        if self.section_properties is None:
+            section_properties = self.steel_cross_section.profile.section_properties()
+            object.__setattr__(self, "section_properties", section_properties)
+
+    def calculation_formula(self) -> dict[str, Formula]:
+        """Calculate plastic shear force resistance check.
+
+        Returns
+        -------
+        dict[str, Formula]
+            Calculation results keyed by formula number. Returns an empty dict if no shear force is applied.
+        """
+        if self.v == 0:
+            return {}
+
+        # Get parameters from profile, average top and bottom flange properties
+        a = self.section_properties.area
+        b = (self.steel_cross_section.profile.top_flange_width + self.steel_cross_section.profile.bottom_flange_width) / 2
+        tf = (self.steel_cross_section.profile.top_flange_thickness + self.steel_cross_section.profile.bottom_flange_thickness) / 2
+        tw = self.steel_cross_section.profile.web_thickness
+        hw = self.steel_cross_section.profile.total_height - (
+            self.steel_cross_section.profile.top_flange_thickness + self.steel_cross_section.profile.bottom_flange_thickness
+        )
+        r = (self.steel_cross_section.profile.top_radius + self.steel_cross_section.profile.bottom_radius) / 2
+
+        if self.axis == "Vz" and self.steel_cross_section.fabrication_method == "rolled":
+            av = formula_6_18_sub_av.Form6Dot18SubARolledIandHSection(a=a, b=b, hw=hw, r=r, tf=tf, tw=tw, eta=1.0)
+        elif self.axis == "Vz" and self.steel_cross_section.fabrication_method == "welded":
+            av = formula_6_18_sub_av.Form6Dot18SubDWeldedIHandBoxSection(hw_list=[hw], tw_list=[tw], eta=1.0)
+        else:  # axis == "Vy"
+            av = formula_6_18_sub_av.Form6Dot18SubEWeldedIHandBoxSection(a=a, hw_list=[hw], tw_list=[tw])
+
+        f_y = self.steel_cross_section.yield_strength
+        v_ed = abs(self.v) * KN_TO_N
+        v_pl_rd = formula_6_18.Form6Dot18DesignPlasticShearResistance(a_v=av, f_y=f_y, gamma_m0=self.gamma_m0)
+        check_shear = formula_6_17.Form6Dot17CheckShearForce(v_ed=v_ed, v_c_rd=v_pl_rd)
+        return {
+            "shear_area": av,
+            "shear_resistance": v_pl_rd,
+            "check": check_shear,
+        }
+
+    def result(self) -> CheckResult:
+        """Calculate result of plastic shear force resistance.
+
+        Returns
+        -------
+        CheckResult
+            True if the shear force check passes, False otherwise.
+        """
+        steps = self.calculation_formula()
+        if not steps:
+            return CheckResult(is_ok=True, unity_check=0.0)
+        provided = abs(self.v) * KN_TO_N
+        required = float(steps["shear_resistance"])
+        return CheckResult.from_comparison(provided=provided, required=required)
+
+    def report(self, n: int = 2) -> Report:
+        """Returns the report for the plastic shear force check.
+
+        Parameters
+        ----------
+        n : int, optional
+            Number of decimal places for numerical values in the report (default is 2).
+
+        Returns
+        -------
+        Report
+            Report of the plastic shear force check.
+        """
+        report = Report("Check: plastic shear force steel I-profile")
+        if self.v == 0:
+            report.add_paragraph("No shear force was applied; therefore, no shear force check is necessary.")
+            return report
+        axis_label = "(vertical) z" if self.axis == "Vz" else "(horizontal) y"
+        report.add_paragraph(
+            rf"Profile {self.steel_cross_section.profile.name} with steel quality {self.steel_cross_section.material.steel_class.name} "
+            rf"is loaded with a shear force of {abs(self.v):.{n}f} kN in the {axis_label}-direction. "
+            rf"The shear area $A_v$ is calculated as follows:"
+        )
+        formulas = self.calculation_formula()
+        report.add_formula(formulas["shear_area"], n=n, split_on=[[2, "="], [3, "="]])
+        report.add_paragraph("The shear resistance is calculated as follows:")
+        report.add_formula(formulas["shear_resistance"], n=n)
+        report.add_paragraph("The unity check is calculated as follows:")
+        report.add_formula(formulas["check"], n=n)
+        if self.result().is_ok:
+            report.add_paragraph("The check for plastic shear force satisfies the requirements.")
+        else:
+            report.add_paragraph("The check for plastic shear force does NOT satisfy the requirements.")
+        return report
+
+
+if __name__ == "__main__":
+    from blueprints.checks.eurocode.steel.shear_strength import PlasticShearStrengthIProfileCheck
+    from blueprints.materials.steel import SteelMaterial, SteelStrengthClass
+    from blueprints.structural_sections.steel.standard_profiles.heb import HEB
+
+    steel_material = SteelMaterial(steel_class=SteelStrengthClass.S355)
+    heb_300_profile = HEB.HEB300.with_corrosion(1.5)
+    v = 100  # Applied shear force in kN
+
+    heb_300_s355 = SteelCrossSection(profile=heb_300_profile, material=steel_material)
+    calc = PlasticShearStrengthIProfileCheck(heb_300_s355, v, axis="Vz", gamma_m0=1.0)
+    calc.report().to_pdf("shear_strength.pdf", language="en")
+    import os
+
+    os.startfile("shear_strength.pdf")
diff --git a/blueprints/utils/report.py b/blueprints/utils/report.py
index 3072102fe..48630081d 100644
--- a/blueprints/utils/report.py
+++ b/blueprints/utils/report.py
@@ -119,6 +119,7 @@ def add_equation(
         equation: str,
         tag: str | None = None,
         inline: bool = False,
+        split_on: list[tuple[int, str]] | None = None,
     ) -> Self:
         r"""Add an equation to the report. For adding Blueprints formulas, use add_formula instead.
 
@@ -130,6 +131,10 @@ def add_equation(
             Tag to label the equation (e.g., "6.83", "EN 1992-1-1:2004 6.6n", etc.).
         inline : bool, optional
             Whether to add the equation inline (meaning within text) or as a separate equation block. Default is False.
+        split_on: list[tuple[int, str]], optional
+            List of characters to split the equation line on for better readability.
+            e.g. a = b + c = 2 + 3 = 5 with split_on=[(2, "="), (2, "+")] will split after second "=" and second "+"
+            to give: a = b + c = \\ 2 + \\ 3 = 5. Default is None.
 
         Returns
         -------
@@ -145,12 +150,34 @@ def add_equation(
         >>> report.add_equation(r"\\frac{a}{b}", inline=True)
 
         """
+
+        def _split_equation(eq: str, split_on: list[tuple[int, str]] | None) -> str:
+            if not split_on:
+                return eq
+            eq_mod = eq
+            # Sort by decreasing index so insertion doesn't affect later positions
+            for n, char in sorted(split_on, reverse=True):
+                # Find nth occurrence of char
+                idx = -1
+                count = 0
+                for i, c in enumerate(eq_mod):
+                    if c == char:
+                        count += 1
+                        if count == n:
+                            idx = i
+                            break
+                if idx != -1:
+                    eq_mod = eq_mod[: idx + 1] + r" \\" + eq_mod[idx + 1 :]
+            return eq_mod
+
+        eq_to_use = _split_equation(equation, split_on)
+
         if inline:
-            self.content += r"\txt{ " + rf"${equation}$" + f"{f' ({tag})' if tag else ''}" + r" }"
+            self.content += r"\txt{ " + rf"${eq_to_use}$" + f"{f' ({tag})' if tag else ''}" + r" }"
         elif tag:
-            self.content += rf"\begin{{equation}} {equation} \tag{{{tag}}} \end{{equation}}"
+            self.content += rf"\begin{{multline}} {eq_to_use} \tag{{{tag}}} \end{{multline}}"
         else:
-            self.content += rf"\begin{{equation}} {equation} \notag \end{{equation}}"
+            self.content += rf"\begin{{multline}} {eq_to_use} \notag \end{{multline}}"
 
         # Add a newline for visual separation
         self.content += "\n"
@@ -165,6 +192,7 @@ def add_formula(
         include_source: bool = True,
         include_formula_number: bool = True,
         inline: bool = False,
+        split_on: list[tuple[int, str]] | None = None,
     ) -> Self:
         r"""Add a Blueprints formula to the report, for generic equations, use add_equation.
 
@@ -227,7 +255,7 @@ def add_formula(
                 tag_parts.append(formula.label)
         tag_str = " ".join(tag_parts).strip()
 
-        return self.add_equation(equation=equation_str, inline=inline, tag=tag_str or None)
+        return self.add_equation(equation=equation_str, inline=inline, tag=tag_str or None, split_on=split_on)
 
     def add_heading(self, text: str, level: int = 1) -> Self:
         """Add a heading to the report.

From ba289240d17f687a256e3af52d0101436919d51f Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Sat, 31 Jan 2026 11:07:20 +0100
Subject: [PATCH 02/46] feat: update equation handling in Report class to
 support multline environments and rename split_on to split_after for clarity

---
 .../checks/eurocode/steel/shear_strength.py   |  6 ++---
 blueprints/utils/_report_to_word.py           | 24 +++++++++++--------
 blueprints/utils/report.py                    | 22 ++++++++++-------
 3 files changed, 30 insertions(+), 22 deletions(-)

diff --git a/blueprints/checks/eurocode/steel/shear_strength.py b/blueprints/checks/eurocode/steel/shear_strength.py
index 2f735e3ef..1d7ec257c 100644
--- a/blueprints/checks/eurocode/steel/shear_strength.py
+++ b/blueprints/checks/eurocode/steel/shear_strength.py
@@ -161,7 +161,7 @@ def report(self, n: int = 2) -> Report:
             rf"The shear area $A_v$ is calculated as follows:"
         )
         formulas = self.calculation_formula()
-        report.add_formula(formulas["shear_area"], n=n, split_on=[[2, "="], [3, "="]])
+        report.add_formula(formulas["shear_area"], n=n, split_after=[[2, "="], [3, "="]])
         report.add_paragraph("The shear resistance is calculated as follows:")
         report.add_formula(formulas["shear_resistance"], n=n)
         report.add_paragraph("The unity check is calculated as follows:")
@@ -184,7 +184,7 @@ def report(self, n: int = 2) -> Report:
 
     heb_300_s355 = SteelCrossSection(profile=heb_300_profile, material=steel_material)
     calc = PlasticShearStrengthIProfileCheck(heb_300_s355, v, axis="Vz", gamma_m0=1.0)
-    calc.report().to_pdf("shear_strength.pdf", language="en")
+    calc.report().to_word("shear_strength.docx", language="en")
     import os
 
-    os.startfile("shear_strength.pdf")
+    os.startfile("shear_strength.docx")
diff --git a/blueprints/utils/_report_to_word.py b/blueprints/utils/_report_to_word.py
index 2b84fcf21..e7fd14df0 100644
--- a/blueprints/utils/_report_to_word.py
+++ b/blueprints/utils/_report_to_word.py
@@ -26,7 +26,7 @@ class _ReportToWordConverter:
 
     Limitations and Usage Notes:
     - Text blocks using \text{...} (can also be \textbf{...} and/or \textit{...} for bold/italic).
-    - Equations in \begin{equation}...\end{equation} environments (with optional \tag{...}).
+    - Equations in \begin{multline}...\end{multline} environments (with optional \tag{...}).
     - Titles, sections, subsections, and subsubsections using \title{...}, \section{...}, \subsection{...}, \subsubsection{...}.
     - Tables in \begin{table}...\end{table} environments with tabular content
     - Figures in \begin{figure}...\end{figure} environments with \includegraphics.
@@ -175,7 +175,7 @@ def _extract_structural_elements(content: str) -> list[dict[str, str | int]]:
             "figure": r"\\begin\{figure\}",
             "itemize": r"\\begin\{itemize\}",
             "enumerate": r"\\begin\{enumerate\}",
-            "equation": r"\\begin\{equation\}",
+            "equation": r"\\begin\{multline\}",
             "newline": r"\\newline",
         }
 
@@ -437,14 +437,18 @@ def _add_equation(self, doc: DocumentObject, content: str) -> None:
         equation_content = re.sub(r"\s*\\tag\{[^}]+\}", "", content)
         equation_content = re.sub(r"\\notag", "", equation_content)
 
-        p = doc.add_paragraph()
-        p.style = "No Spacing"
-        p.paragraph_format.space_before = Pt(6)
-        p.paragraph_format.space_after = Pt(6)
-        p.alignment = WD_PARAGRAPH_ALIGNMENT.CENTER
-        p._p.append(self._formula(equation_content))  # noqa: SLF001
-        if tag:
-            p.add_run(f" ({tag})")
+        # Split equation content on line breaks (\\)
+        lines = equation_content.replace("\\begin{multline}", "").replace("\\end{multline}", "").split(r"\\")
+        for idx, line in enumerate(lines):
+            p = doc.add_paragraph()
+            p.style = "No Spacing"
+            p.paragraph_format.space_before = Pt(6)
+            p.paragraph_format.space_after = Pt(6)
+            p.alignment = WD_PARAGRAPH_ALIGNMENT.CENTER
+            p._p.append(self._formula(line))  # noqa: SLF001
+            # Only add tag to the last line
+            if tag and idx == len(lines) - 1:
+                p.add_run(f" ({tag})")
 
     def _add_table_to_doc(self, doc: DocumentObject, table_latex: str) -> None:
         """Parse LaTeX table and add it to the Word document.
diff --git a/blueprints/utils/report.py b/blueprints/utils/report.py
index 48630081d..2a082681d 100644
--- a/blueprints/utils/report.py
+++ b/blueprints/utils/report.py
@@ -119,7 +119,7 @@ def add_equation(
         equation: str,
         tag: str | None = None,
         inline: bool = False,
-        split_on: list[tuple[int, str]] | None = None,
+        split_after: list[tuple[int, str]] | None = None,
     ) -> Self:
         r"""Add an equation to the report. For adding Blueprints formulas, use add_formula instead.
 
@@ -131,9 +131,9 @@ def add_equation(
             Tag to label the equation (e.g., "6.83", "EN 1992-1-1:2004 6.6n", etc.).
         inline : bool, optional
             Whether to add the equation inline (meaning within text) or as a separate equation block. Default is False.
-        split_on: list[tuple[int, str]], optional
+        split_after: list[tuple[int, str]], optional
             List of characters to split the equation line on for better readability.
-            e.g. a = b + c = 2 + 3 = 5 with split_on=[(2, "="), (2, "+")] will split after second "=" and second "+"
+            e.g. a = b + c = 2 + 3 = 5 with split_after=[(2, "="), (2, "+")] will split after second "=" and second "+"
             to give: a = b + c = \\ 2 + \\ 3 = 5. Default is None.
 
         Returns
@@ -151,12 +151,12 @@ def add_equation(
 
         """
 
-        def _split_equation(eq: str, split_on: list[tuple[int, str]] | None) -> str:
-            if not split_on:
+        def _split_equation(eq: str, split_after: list[tuple[int, str]] | None) -> str:
+            if not split_after:
                 return eq
             eq_mod = eq
             # Sort by decreasing index so insertion doesn't affect later positions
-            for n, char in sorted(split_on, reverse=True):
+            for n, char in sorted(split_after, reverse=True):
                 # Find nth occurrence of char
                 idx = -1
                 count = 0
@@ -170,7 +170,7 @@ def _split_equation(eq: str, split_on: list[tuple[int, str]] | None) -> str:
                     eq_mod = eq_mod[: idx + 1] + r" \\" + eq_mod[idx + 1 :]
             return eq_mod
 
-        eq_to_use = _split_equation(equation, split_on)
+        eq_to_use = _split_equation(equation, split_after)
 
         if inline:
             self.content += r"\txt{ " + rf"${eq_to_use}$" + f"{f' ({tag})' if tag else ''}" + r" }"
@@ -192,7 +192,7 @@ def add_formula(
         include_source: bool = True,
         include_formula_number: bool = True,
         inline: bool = False,
-        split_on: list[tuple[int, str]] | None = None,
+        split_after: list[tuple[int, str]] | None = None,
     ) -> Self:
         r"""Add a Blueprints formula to the report, for generic equations, use add_equation.
 
@@ -215,6 +215,10 @@ def add_formula(
             For example: "6.5" or "6.6n".
         inline : bool, optional
             Whether to add the formula inline (meaning within text) or as a separate equation block (default).
+        split_after: list[tuple[int, str]], optional
+            List of characters to split the equation line on for better readability.
+            e.g. a = b + c = 2 + 3 = 5 with split_after=[(2, "="), (2, "+")] will split after second "=" and second "+"
+            to give: a = b + c = \\ 2 + \\ 3 = 5. Default is None.
 
         Returns
         -------
@@ -255,7 +259,7 @@ def add_formula(
                 tag_parts.append(formula.label)
         tag_str = " ".join(tag_parts).strip()
 
-        return self.add_equation(equation=equation_str, inline=inline, tag=tag_str or None, split_on=split_on)
+        return self.add_equation(equation=equation_str, inline=inline, tag=tag_str or None, split_after=split_after)
 
     def add_heading(self, text: str, level: int = 1) -> Self:
         """Add a heading to the report.

From 84bd641d68f18ba33879a22c17492f814afb06e9 Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Sat, 31 Jan 2026 11:16:00 +0100
Subject: [PATCH 03/46] feat: update Report class to support multline equations
 and enhance tests for equation handling

---
 blueprints/utils/report.py         |  4 ++--
 tests/utils/test_report.py         | 27 ++++++++++++++++++++-------
 tests/utils/test_report_to_word.py |  6 ++++++
 3 files changed, 28 insertions(+), 9 deletions(-)

diff --git a/blueprints/utils/report.py b/blueprints/utils/report.py
index 2a082681d..aa1405814 100644
--- a/blueprints/utils/report.py
+++ b/blueprints/utils/report.py
@@ -538,7 +538,7 @@ def __repr__(self) -> str:
         """Return a concise representation showing report structure and content summary."""
         sections = self.content.count(r"\section{")
         subsections = self.content.count(r"\subsection{")
-        equations = self.content.count(r"\begin{equation}")
+        equations = self.content.count(r"\begin{multline}")
         tables = self.content.count(r"\begin{table}")
         figures = self.content.count(r"\begin{figure}")
         lists = self.content.count(r"\begin{itemize}") + self.content.count(r"\begin{enumerate}")
@@ -556,7 +556,7 @@ def __str__(self) -> str:
         """Return a human-readable representation of the report structure and content."""
         sections = self.content.count(r"\section{")
         subsections = self.content.count(r"\subsection{")
-        equations = self.content.count(r"\begin{equation}")
+        equations = self.content.count(r"\begin{multline}")
         tables = self.content.count(r"\begin{table}")
         figures = self.content.count(r"\begin{figure}")
         lists = self.content.count(r"\begin{itemize}") + self.content.count(r"\begin{enumerate}")
diff --git a/tests/utils/test_report.py b/tests/utils/test_report.py
index 398b2bebc..199f7f642 100644
--- a/tests/utils/test_report.py
+++ b/tests/utils/test_report.py
@@ -103,7 +103,7 @@ def test_add_text_bold_and_italic(self, fixture_report: Report) -> None:
         expected = r"\textbf{\textit{This is bold and italic}}" + "\n"
         assert fixture_report.content == expected
 
-    def test_multiline_add_text_calls(self, fixture_report: Report) -> None:
+    def test_multline_add_text_calls(self, fixture_report: Report) -> None:
         """Test multline add_text calls."""
         fixture_report.add_paragraph("First line.Second line.")
         expected = r"\txt{First line.Second line.}" + "\n"
@@ -119,15 +119,28 @@ def test_add_text_method_chaining(self, fixture_report: Report) -> None:
     def test_add_equation_without_tag(self, fixture_report: Report) -> None:
         """Test adding equation without tag."""
         fixture_report.add_equation("a^2+b^2=c^2")
-        expected = r"\begin{equation} a^2+b^2=c^2 \notag \end{equation}" + "\n"
+        expected = r"\begin{multline} a^2+b^2=c^2 \notag \end{multline}" + "\n"
         assert fixture_report.content == expected
 
     def test_add_equation_with_tag(self, fixture_report: Report) -> None:
         """Test adding equation with tag."""
         fixture_report.add_equation("a^2+b^2=c^2", tag="6.83")
-        expected = r"\begin{equation} a^2+b^2=c^2 \tag{6.83} \end{equation}" + "\n"
+        expected = r"\begin{multline} a^2+b^2=c^2 \tag{6.83} \end{multline}" + "\n"
         assert fixture_report.content == expected
 
+    def test_very_long_equation_splitting(self, fixture_report: Report) -> None:
+        """Test adding a very long equation that requires splitting."""
+        long_equation = "a = b + c + d + e + f + g + h + i + j + k + l + m + n + o + p + q + r + s + t + u + v + w + x + y + z"
+        fixture_report.add_equation(long_equation, split_after=[(3, "+"), (6, "+"), (9, "+")])
+        expected_parts = [
+            r"\begin{multline} a = b + c + d + \\",
+            r"e + f + g + \\",
+            r"h + i + j + \\",
+            r"k + l + m + n + o + p + q + r + s + t + u + v + w + x + y + z \notag \end{multline}",
+        ]
+        for part in expected_parts:
+            assert part in fixture_report.content
+
     def test_add_equation_method_chaining(self, fixture_report: Report) -> None:
         """Test that add_equation returns self for method chaining."""
         result = fixture_report.add_equation("E=mc^2")
@@ -147,7 +160,7 @@ def test_add_equation_inline_method_chaining(self, fixture_report: Report) -> No
     def test_add_formula(self, fixture_report: Report) -> None:
         """Test adding formula."""
         fixture_report.add_formula(formula_6_5.Form6Dot5UnityCheckTensileStrength(n_ed=150000, n_t_rd=200000), options="complete")
-        expected = r"\begin{equation} CHECK"
+        expected = r"\begin{multline} CHECK"
         assert expected in fixture_report.content
 
     def test_add_formula_inline(self, fixture_report: Report) -> None:
@@ -159,7 +172,7 @@ def test_add_formula_inline(self, fixture_report: Report) -> None:
     def test_add_formula_complete_with_units(self, fixture_report: Report) -> None:
         """Test adding formula with complete_with_units option."""
         fixture_report.add_formula(formula_6_5.Form6Dot5UnityCheckTensileStrength(n_ed=150000, n_t_rd=200000), options="complete_with_units")
-        expected = r"\begin{equation} CHECK"
+        expected = r"\begin{multline} CHECK"
         assert expected in fixture_report.content
 
     def test_add_section(self, fixture_report: Report) -> None:
@@ -386,8 +399,8 @@ def test_comprehensive_example_from_docstring(self) -> None:
         assert r"\textbf{This is bold text with newline after.}" in latex_document
         assert r"\textit{This is italic text with 4 newlines after.}" in latex_document
         assert r"\textbf{\textit{This is bold and italic text.}}" in latex_document
-        assert r"\begin{equation} E=mc^2 \tag{3.14} \end{equation}" in latex_document
-        assert r"\begin{equation} CHECK" in latex_document
+        assert r"\begin{multline} E=mc^2 \tag{3.14} \end{multline}" in latex_document
+        assert r"\begin{multline} CHECK" in latex_document
         assert r"$\frac{a}{b}$" in latex_document
         assert r"Parameter & Value & Unit" in latex_document
         assert r"\text{Length} & 10 & \text{m}" in latex_document
diff --git a/tests/utils/test_report_to_word.py b/tests/utils/test_report_to_word.py
index d3b4c59ed..28b1a7ab6 100644
--- a/tests/utils/test_report_to_word.py
+++ b/tests/utils/test_report_to_word.py
@@ -30,6 +30,12 @@ def test_complex_document_conversion(self) -> None:
         report.add_paragraph("test").add_equation("E=mc^2", inline=True).add_paragraph("more text.").add_newline()
         report.add_equation("E=mc^2", tag="4")
         report.add_equation(r"\int_a^b f(x)dx = F(b) - F(a)")
+        report.add_equation(
+            "A_v = max(A - 2 \\cdot b \\cdot t_f + (t_w + 2 \\cdot r) \\cdot t_f;"
+            " \\eta \\cdot h_w \\cdot t_w) = max("
+            "12324.48 - 2 \\cdot 297.00 \\cdot 16.00 + (8.00 + 2 \\cdot 28.50) \\cdot 16.00;"
+            " 1.00 \\cdot 265.00 \\cdot 8.00) = 3860.48 \\ mm^2 "
+        )
         report.add_list(["One", ["A", "B", "C"], "Two", ["A", ["I", "II", ["A", "B"], "III"]]], style="numbered")
         report.add_list(["First", "Second", ["Subfirst", "Subsecond"], "Third"], style="bulleted")
         report.add_paragraph("Here is a table:")

From a7a61a55484b6ebfd1738fa2fa808c429430fbef Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Sat, 31 Jan 2026 11:18:50 +0100
Subject: [PATCH 04/46] feat: update report title for plastic shear strength
 check and modify output format to PDF

---
 .../checks/eurocode/steel/shear_strength.py   | 19 +------------------
 1 file changed, 1 insertion(+), 18 deletions(-)

diff --git a/blueprints/checks/eurocode/steel/shear_strength.py b/blueprints/checks/eurocode/steel/shear_strength.py
index 1d7ec257c..31df7af94 100644
--- a/blueprints/checks/eurocode/steel/shear_strength.py
+++ b/blueprints/checks/eurocode/steel/shear_strength.py
@@ -150,7 +150,7 @@ def report(self, n: int = 2) -> Report:
         Report
             Report of the plastic shear force check.
         """
-        report = Report("Check: plastic shear force steel I-profile")
+        report = Report("Check: shear force steel I-beam")
         if self.v == 0:
             report.add_paragraph("No shear force was applied; therefore, no shear force check is necessary.")
             return report
@@ -171,20 +171,3 @@ def report(self, n: int = 2) -> Report:
         else:
             report.add_paragraph("The check for plastic shear force does NOT satisfy the requirements.")
         return report
-
-
-if __name__ == "__main__":
-    from blueprints.checks.eurocode.steel.shear_strength import PlasticShearStrengthIProfileCheck
-    from blueprints.materials.steel import SteelMaterial, SteelStrengthClass
-    from blueprints.structural_sections.steel.standard_profiles.heb import HEB
-
-    steel_material = SteelMaterial(steel_class=SteelStrengthClass.S355)
-    heb_300_profile = HEB.HEB300.with_corrosion(1.5)
-    v = 100  # Applied shear force in kN
-
-    heb_300_s355 = SteelCrossSection(profile=heb_300_profile, material=steel_material)
-    calc = PlasticShearStrengthIProfileCheck(heb_300_s355, v, axis="Vz", gamma_m0=1.0)
-    calc.report().to_word("shear_strength.docx", language="en")
-    import os
-
-    os.startfile("shear_strength.docx")

From e9d6768088c59ca386e37a2029f6bb56619480f2 Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Sun, 1 Feb 2026 16:57:37 +0100
Subject: [PATCH 05/46] feat: modify Form6Dot18SubARolledIandHSection to split
 flange effects and update tests accordingly

---
 .../formula_6_18_sub_av.py                    | 68 +++++++++++++------
 .../test_formula_6_18_sub_av.py               | 54 +++++++++------
 2 files changed, 79 insertions(+), 43 deletions(-)

diff --git a/blueprints/codes/eurocode/en_1993_1_1_2005/chapter_6_ultimate_limit_state/formula_6_18_sub_av.py b/blueprints/codes/eurocode/en_1993_1_1_2005/chapter_6_ultimate_limit_state/formula_6_18_sub_av.py
index 06ca59514..15359693c 100644
--- a/blueprints/codes/eurocode/en_1993_1_1_2005/chapter_6_ultimate_limit_state/formula_6_18_sub_av.py
+++ b/blueprints/codes/eurocode/en_1993_1_1_2005/chapter_6_ultimate_limit_state/formula_6_18_sub_av.py
@@ -10,7 +10,10 @@
 
 
 class Form6Dot18SubARolledIandHSection(Formula):
-    r"""Class representing formula 6.18suba for the calculation of shear area for a rolled I and H section."""
+    r"""Class representing formula 6.18suba for the calculation of shear area for a rolled I and H section.
+
+    The equations has been slightly modified to split effects of top and bottom flange.
+    """
 
     label = "6.18suba"
     source_document = EN_1993_1_1_2005
@@ -18,10 +21,13 @@ class Form6Dot18SubARolledIandHSection(Formula):
     def __init__(
         self,
         a: MM2,
-        b: MM,
+        b1: MM,
+        b2: MM,
         hw: MM,
-        r: MM,
-        tf: MM,
+        r1: MM,
+        r2: MM,
+        tf1: MM,
+        tf2: MM,
         tw: MM,
         eta: DIMENSIONLESS,
     ) -> None:
@@ -33,14 +39,20 @@ def __init__(
         ----------
         a : MM2
             [$A$] Cross-sectional area [$mm^2$].
-        b : MM
-            [$b$] Overall breadth [$mm$].
+        b1 : MM
+            [$b$] Overall breadth of flange 1 [$mm$].
+        b2 : MM
+            [$b$] Overall breadth of flange 2 [$mm$].
         hw : MM
             [$h_w$] Depth of the web [$mm$].
-        r : MM
-            [$r$] Root radius [$mm$].
-        tf : MM
-            [$t_f$] Flange thickness [$mm$].
+        r1 : MM
+            [$r$] Root radius at flange 1 [$mm$].
+        r2 : MM
+            [$r$] Root radius at flange 2 [$mm$].
+        tf1 : MM
+            [$t_f$] Flange thickness 1 [$mm$].
+        tf2 : MM
+            [$t_f$] Flange thickness 2 [$mm$].
         tw : MM
             [$t_w$] Web thickness [$mm$]. If the web thickness is not constant, tw should be taken as the minimum thickness.
         eta : DIMENSIONLESS, optional
@@ -48,42 +60,54 @@ def __init__(
         """
         super().__init__()
         self.a = a
-        self.b = b
+        self.b1 = b1
+        self.b2 = b2
         self.hw = hw
-        self.r = r
-        self.tf = tf
+        self.r1 = r1
+        self.r2 = r2
+        self.tf1 = tf1
+        self.tf2 = tf2
         self.tw = tw
         self.eta = eta
 
     @staticmethod
     def _evaluate(
         a: MM2,
-        b: MM,
+        b1: MM,
+        b2: MM,
         hw: MM,
-        r: MM,
-        tf: MM,
+        r1: MM,
+        r2: MM,
+        tf1: MM,
+        tf2: MM,
         tw: MM,
         eta: DIMENSIONLESS,
     ) -> MM2:
         """Evaluates the formula, for more information see the __init__ method."""
-        raise_if_negative(a=a, b=b, hw=hw, r=r, tf=tf, tw=tw, eta=eta)
+        raise_if_negative(a=a, b1=b1, b2=b2, hw=hw, r1=r1, r2=r2, tf1=tf1, tf2=tf2, tw=tw, eta=eta)
 
-        av = a - 2 * b * tf + (tw + 2 * r) * tf
+        av = a - b1 * tf1 - b2 * tf2 + (tw + 2 * r1) * tf1 / 2 + (tw + 2 * r2) * tf2 / 2
         av_min = eta * hw * tw
 
         return max(0, av, av_min)
 
     def latex(self, n: int = 3) -> LatexFormula:
         """Returns LatexFormula object for formula 6.18suba."""
-        _equation: str = r"max(A - 2 \cdot b \cdot t_f + (t_w + 2 \cdot r) \cdot t_f; \eta \cdot h_w \cdot t_w)"
+        _equation: str = (
+            r"max(A - b_1 \cdot t_{f1} - b_2 \cdot t_{f2} + (t_w + 2 \cdot r_1) \cdot \frac{t_{f1}}{2} + "
+            r"(t_w + 2 \cdot r_2) \cdot \frac{t_{f2}}{2}; \eta \cdot h_w \cdot t_w)"
+        )
         _numeric_equation: str = latex_replace_symbols(
             _equation,
             {
                 r"A": f"{self.a:.{n}f}",
-                r"b": f"{self.b:.{n}f}",
+                r"b_1": f"{self.b_1:.{n}f}",
+                r"b_2": f"{self.b_2:.{n}f}",
                 r"h_w": f"{self.hw:.{n}f}",
-                r"r": f"{self.r:.{n}f}",
-                r"t_f": f"{self.tf:.{n}f}",
+                r"r_1": f"{self.r_1:.{n}f}",
+                r"r_2": f"{self.r_2:.{n}f}",
+                r"t_{f1}": f"{self.tf_1:.{n}f}",
+                r"t_{f2}": f"{self.tf_2:.{n}f}",
                 r"t_w": f"{self.tw:.{n}f}",
                 r"\eta": f"{self.eta:.{n}f}",
             },
diff --git a/tests/codes/eurocode/en_1993_1_1_2005/chapter_6_ultimate_limit_state/test_formula_6_18_sub_av.py b/tests/codes/eurocode/en_1993_1_1_2005/chapter_6_ultimate_limit_state/test_formula_6_18_sub_av.py
index 0cb31bb07..6257aed3d 100644
--- a/tests/codes/eurocode/en_1993_1_1_2005/chapter_6_ultimate_limit_state/test_formula_6_18_sub_av.py
+++ b/tests/codes/eurocode/en_1993_1_1_2005/chapter_6_ultimate_limit_state/test_formula_6_18_sub_av.py
@@ -22,43 +22,52 @@ class TestForm6Dot18SubARolledIandHSection:
     def test_evaluation(self) -> None:
         """Tests the evaluation of the result."""
         a = 10000.0
-        b = 200.0
+        b1 = 200.0
+        b2 = 200.0
         hw = 250.0
-        r = 10.0
-        tf = 15.0
+        r1 = 10.0
+        r2 = 10.0
+        tf1 = 15.0
+        tf2 = 15.0
         tw = 8.0
         eta = 1.0
 
-        formula = Form6Dot18SubARolledIandHSection(a=a, b=b, hw=hw, r=r, tf=tf, tw=tw, eta=eta)
+        formula = Form6Dot18SubARolledIandHSection(a=a, b1=b1, b2=b2, hw=hw, r1=r1, r2=r2, tf1=tf1, tf2=tf2, tw=tw, eta=eta)
         manually_calculated_result = 4420.0  # mm^2
 
         assert formula == pytest.approx(expected=manually_calculated_result, rel=1e-4)
 
     @pytest.mark.parametrize(
-        ("a", "b", "hw", "r", "tf", "tw", "eta"),
+        ("a", "b1", "b2", "hw", "r1", "r2", "tf1", "tf2", "tw", "eta"),
         [
-            (-10000.0, 200.0, 250.0, 10.0, 15.0, 8.0, 1.0),  # a is negative
-            (10000.0, -200.0, 250.0, 10.0, 15.0, 8.0, 1.0),  # b is negative
-            (10000.0, 200.0, -250.0, 10.0, 15.0, 8.0, 1.0),  # hw is negative
-            (10000.0, 200.0, 250.0, -10.0, 15.0, 8.0, 1.0),  # r is negative
-            (10000.0, 200.0, 250.0, 10.0, -15.0, 8.0, 1.0),  # tf is negative
-            (10000.0, 200.0, 250.0, 10.0, 15.0, -8.0, 1.0),  # tw is negative
-            (10000.0, 200.0, 250.0, 10.0, 15.0, 8.0, -1.0),  # eta is negative
+            (-10000.0, 200.0, 200.0, 250.0, 10.0, 10.0, 15.0, 15.0, 8.0, 1.0),  # a is negative
+            (10000.0, -200.0, 200.0, 250.0, 10.0, 10.0, 15.0, 15.0, 8.0, 1.0),  # b1 is negative
+            (10000.0, 200.0, -200.0, 250.0, 10.0, 10.0, 15.0, 15.0, 8.0, 1.0),  # b2 is negative
+            (10000.0, 200.0, 200.0, -250.0, 10.0, 10.0, 15.0, 15.0, 8.0, 1.0),  # hw is negative
+            (10000.0, 200.0, 200.0, 250.0, -10.0, 10.0, 15.0, 15.0, 8.0, 1.0),  # r1 is negative
+            (10000.0, 200.0, 200.0, 250.0, 10.0, -10.0, 15.0, 15.0, 8.0, 1.0),  # r2 is negative
+            (10000.0, 200.0, 200.0, 250.0, 10.0, 10.0, -15.0, 15.0, 8.0, 1.0),  # tf1 is negative
+            (10000.0, 200.0, 200.0, 250.0, 10.0, 10.0, 15.0, -15.0, 8.0, 1.0),  # tf2 is negative
+            (10000.0, 200.0, 200.0, 250.0, 10.0, 10.0, 15.0, 15.0, -8.0, 1.0),  # tw is negative
+            (10000.0, 200.0, 200.0, 250.0, 10.0, 10.0, 15.0, 15.0, 8.0, -1.0),  # eta is negative
         ],
     )
-    def test_raise_error_when_invalid_values_are_given(self, a: float, b: float, hw: float, r: float, tf: float, tw: float, eta: float) -> None:
+    def test_raise_error_when_invalid_values_are_given(
+        self, a: float, b1: float, b2: float, hw: float, r1: float, r2: float, tf1: float, tf2: float, tw: float, eta: float
+    ) -> None:
         """Test invalid values."""
         with pytest.raises(NegativeValueError):
-            Form6Dot18SubARolledIandHSection(a=a, b=b, hw=hw, r=r, tf=tf, tw=tw, eta=eta)
+            Form6Dot18SubARolledIandHSection(a=a, b1=b1, b2=b2, hw=hw, r1=r1, r2=r2, tf1=tf1, tf2=tf2, tw=tw, eta=eta)
 
     @pytest.mark.parametrize(
         ("representation", "expected"),
         [
             (
                 "complete",
-                r"A_v = max(A - 2 \cdot b \cdot t_f + (t_w + 2 \cdot r) \cdot t_f; \eta \cdot h_w \cdot t_w) = "
-                r"max(10000.000 - 2 \cdot 200.000 \cdot 15.000 + (8.000 + 2 \cdot 10.000) \cdot 15.000; 1.000 \cdot 250.000 \cdot 8.000) = "
-                r"4420.000 \ mm^2",
+                r"A_v = \max(A - b_1 \cdot t_{f1} - b_2 \cdot t_{f2} + (t_w + 2 \cdot r_1) \cdot \frac{t_{f1}}{2} + "
+                r"(t_w + 2 \cdot r_2) \cdot \frac{t_{f2}}{2}; \eta \cdot h_w \cdot t_w) = "
+                r"\max(10000.000 - 200.000 \cdot 15.000 - 200.000 \cdot 15.000 + (8.000 + 2 \cdot 10.000) "
+                r"\cdot \frac{15.000}{2} + (8.000 + 2 \cdot 10.000) \cdot \frac{15.000}{2}; 1.000 \cdot 250.000 \cdot 8.000) = 4420.000 \ mm^2",
             ),
             ("short", r"A_v = 4420.000 \ mm^2"),
         ],
@@ -66,14 +75,17 @@ def test_raise_error_when_invalid_values_are_given(self, a: float, b: float, hw:
     def test_latex(self, representation: str, expected: str) -> None:
         """Test the latex representation of the formula."""
         a = 10000.0
-        b = 200.0
+        b_1 = 200.0
+        b_2 = 200.0
         hw = 250.0
-        r = 10.0
-        tf = 15.0
+        r_1 = 10.0
+        r_2 = 10.0
+        tf_1 = 15.0
+        tf_2 = 15.0
         tw = 8.0
         eta = 1.0
 
-        latex = Form6Dot18SubARolledIandHSection(a=a, b=b, hw=hw, r=r, tf=tf, tw=tw, eta=eta).latex()
+        latex = Form6Dot18SubARolledIandHSection(a=a, b_1=b_1, b_2=b_2, hw=hw, r_1=r_1, r_2=r_2, tf_1=tf_1, tf_2=tf_2, tw=tw, eta=eta).latex()
 
         actual = {
             "complete": latex.complete,

From b6485e5d9af11d94050641fba28a7e830c242bd8 Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Sun, 1 Feb 2026 17:02:58 +0100
Subject: [PATCH 06/46] fix: correct attribute names in latex output for
 Form6Dot18SubARolledIandHSection

---
 .../formula_6_18_sub_av.py                           | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/blueprints/codes/eurocode/en_1993_1_1_2005/chapter_6_ultimate_limit_state/formula_6_18_sub_av.py b/blueprints/codes/eurocode/en_1993_1_1_2005/chapter_6_ultimate_limit_state/formula_6_18_sub_av.py
index 15359693c..2a9f405b1 100644
--- a/blueprints/codes/eurocode/en_1993_1_1_2005/chapter_6_ultimate_limit_state/formula_6_18_sub_av.py
+++ b/blueprints/codes/eurocode/en_1993_1_1_2005/chapter_6_ultimate_limit_state/formula_6_18_sub_av.py
@@ -101,13 +101,13 @@ def latex(self, n: int = 3) -> LatexFormula:
             _equation,
             {
                 r"A": f"{self.a:.{n}f}",
-                r"b_1": f"{self.b_1:.{n}f}",
-                r"b_2": f"{self.b_2:.{n}f}",
+                r"b_1": f"{self.b1:.{n}f}",
+                r"b_2": f"{self.b2:.{n}f}",
                 r"h_w": f"{self.hw:.{n}f}",
-                r"r_1": f"{self.r_1:.{n}f}",
-                r"r_2": f"{self.r_2:.{n}f}",
-                r"t_{f1}": f"{self.tf_1:.{n}f}",
-                r"t_{f2}": f"{self.tf_2:.{n}f}",
+                r"r_1": f"{self.r1:.{n}f}",
+                r"r_2": f"{self.r2:.{n}f}",
+                r"t_{f1}": f"{self.tf1:.{n}f}",
+                r"t_{f2}": f"{self.tf2:.{n}f}",
                 r"t_w": f"{self.tw:.{n}f}",
                 r"\eta": f"{self.eta:.{n}f}",
             },

From 914fc0e05126db77a7c6b6628a145b899e8893dc Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Sun, 1 Feb 2026 17:05:00 +0100
Subject: [PATCH 07/46] refactor: rename variables in test_latex method for
 consistency

---
 .../test_formula_6_18_sub_av.py                    | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/tests/codes/eurocode/en_1993_1_1_2005/chapter_6_ultimate_limit_state/test_formula_6_18_sub_av.py b/tests/codes/eurocode/en_1993_1_1_2005/chapter_6_ultimate_limit_state/test_formula_6_18_sub_av.py
index 6257aed3d..c62c2ccaf 100644
--- a/tests/codes/eurocode/en_1993_1_1_2005/chapter_6_ultimate_limit_state/test_formula_6_18_sub_av.py
+++ b/tests/codes/eurocode/en_1993_1_1_2005/chapter_6_ultimate_limit_state/test_formula_6_18_sub_av.py
@@ -75,17 +75,17 @@ def test_raise_error_when_invalid_values_are_given(
     def test_latex(self, representation: str, expected: str) -> None:
         """Test the latex representation of the formula."""
         a = 10000.0
-        b_1 = 200.0
-        b_2 = 200.0
+        b1 = 200.0
+        b2 = 200.0
         hw = 250.0
-        r_1 = 10.0
-        r_2 = 10.0
-        tf_1 = 15.0
-        tf_2 = 15.0
+        r1 = 10.0
+        r2 = 10.0
+        tf1 = 15.0
+        tf2 = 15.0
         tw = 8.0
         eta = 1.0
 
-        latex = Form6Dot18SubARolledIandHSection(a=a, b_1=b_1, b_2=b_2, hw=hw, r_1=r_1, r_2=r_2, tf_1=tf_1, tf_2=tf_2, tw=tw, eta=eta).latex()
+        latex = Form6Dot18SubARolledIandHSection(a=a, b1=b1, b2=b2, hw=hw, r1=r1, r2=r2, tf1=tf1, tf2=tf2, tw=tw, eta=eta).latex()
 
         actual = {
             "complete": latex.complete,

From 5ef3281dd163d4ef01c503aa732c4be7eeb94713 Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Sun, 1 Feb 2026 17:08:11 +0100
Subject: [PATCH 08/46] fix: correct latex equation formatting in
 Form6Dot18SubARolledIandHSection

---
 .../chapter_6_ultimate_limit_state/formula_6_18_sub_av.py       | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/blueprints/codes/eurocode/en_1993_1_1_2005/chapter_6_ultimate_limit_state/formula_6_18_sub_av.py b/blueprints/codes/eurocode/en_1993_1_1_2005/chapter_6_ultimate_limit_state/formula_6_18_sub_av.py
index 2a9f405b1..ba919f57e 100644
--- a/blueprints/codes/eurocode/en_1993_1_1_2005/chapter_6_ultimate_limit_state/formula_6_18_sub_av.py
+++ b/blueprints/codes/eurocode/en_1993_1_1_2005/chapter_6_ultimate_limit_state/formula_6_18_sub_av.py
@@ -94,7 +94,7 @@ def _evaluate(
     def latex(self, n: int = 3) -> LatexFormula:
         """Returns LatexFormula object for formula 6.18suba."""
         _equation: str = (
-            r"max(A - b_1 \cdot t_{f1} - b_2 \cdot t_{f2} + (t_w + 2 \cdot r_1) \cdot \frac{t_{f1}}{2} + "
+            r"\max(A - b_1 \cdot t_{f1} - b_2 \cdot t_{f2} + (t_w + 2 \cdot r_1) \cdot \frac{t_{f1}}{2} + "
             r"(t_w + 2 \cdot r_2) \cdot \frac{t_{f2}}{2}; \eta \cdot h_w \cdot t_w)"
         )
         _numeric_equation: str = latex_replace_symbols(

From baea411908798f9e69b9af5e8b94a9ff531e5d84 Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Sun, 1 Feb 2026 17:10:10 +0100
Subject: [PATCH 09/46] feat: update PlasticShearStrengthIProfileCheck to use
 individual flange properties for calculations

---
 blueprints/checks/eurocode/steel/shear_strength.py  | 13 +++++++++----
 .../steel/steel_cross_section.py                    |  1 -
 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/blueprints/checks/eurocode/steel/shear_strength.py b/blueprints/checks/eurocode/steel/shear_strength.py
index 31df7af94..d024a69a4 100644
--- a/blueprints/checks/eurocode/steel/shear_strength.py
+++ b/blueprints/checks/eurocode/steel/shear_strength.py
@@ -97,16 +97,21 @@ def calculation_formula(self) -> dict[str, Formula]:
 
         # Get parameters from profile, average top and bottom flange properties
         a = self.section_properties.area
-        b = (self.steel_cross_section.profile.top_flange_width + self.steel_cross_section.profile.bottom_flange_width) / 2
-        tf = (self.steel_cross_section.profile.top_flange_thickness + self.steel_cross_section.profile.bottom_flange_thickness) / 2
+        b_1 = self.steel_cross_section.profile.top_flange_width
+        b_2 = self.steel_cross_section.profile.bottom_flange_width
+        tf_1 = self.steel_cross_section.profile.top_flange_thickness
+        tf_2 = self.steel_cross_section.profile.bottom_flange_thickness
         tw = self.steel_cross_section.profile.web_thickness
         hw = self.steel_cross_section.profile.total_height - (
             self.steel_cross_section.profile.top_flange_thickness + self.steel_cross_section.profile.bottom_flange_thickness
         )
-        r = (self.steel_cross_section.profile.top_radius + self.steel_cross_section.profile.bottom_radius) / 2
+        r_1 = self.steel_cross_section.profile.top_radius
+        r_2 = self.steel_cross_section.profile.bottom_radius
 
         if self.axis == "Vz" and self.steel_cross_section.fabrication_method == "rolled":
-            av = formula_6_18_sub_av.Form6Dot18SubARolledIandHSection(a=a, b=b, hw=hw, r=r, tf=tf, tw=tw, eta=1.0)
+            av = formula_6_18_sub_av.Form6Dot18SubARolledIandHSection(
+                a=a, b_1=b_1, b_2=b_2, hw=hw, r_1=r_1, r_2=r_2, tf_1=tf_1, tf_2=tf_2, tw=tw, eta=1.0
+            )
         elif self.axis == "Vz" and self.steel_cross_section.fabrication_method == "welded":
             av = formula_6_18_sub_av.Form6Dot18SubDWeldedIHandBoxSection(hw_list=[hw], tw_list=[tw], eta=1.0)
         else:  # axis == "Vy"
diff --git a/blueprints/structural_sections/steel/steel_cross_section.py b/blueprints/structural_sections/steel/steel_cross_section.py
index a3fbcddd7..89701c1de 100644
--- a/blueprints/structural_sections/steel/steel_cross_section.py
+++ b/blueprints/structural_sections/steel/steel_cross_section.py
@@ -32,7 +32,6 @@ class SteelCrossSection:
     """The material type of the steel."""
     fabrication_method: Literal["rolled", "welded"] = "rolled"
 
-
     @property
     def yield_strength(self) -> MPA:
         """

From 79e6cc52d4bd4b1b5ec8ca000e5b3f31f7d7fa7e Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Sun, 1 Feb 2026 17:39:48 +0100
Subject: [PATCH 10/46] feat: update PlasticShearStrengthIProfileCheck to use
 consistent variable naming for flange properties

---
 .../checks/eurocode/steel/shear_strength.py   | 26 +++++++++----------
 1 file changed, 12 insertions(+), 14 deletions(-)

diff --git a/blueprints/checks/eurocode/steel/shear_strength.py b/blueprints/checks/eurocode/steel/shear_strength.py
index d024a69a4..ecebf7b38 100644
--- a/blueprints/checks/eurocode/steel/shear_strength.py
+++ b/blueprints/checks/eurocode/steel/shear_strength.py
@@ -96,22 +96,20 @@ def calculation_formula(self) -> dict[str, Formula]:
             return {}
 
         # Get parameters from profile, average top and bottom flange properties
-        a = self.section_properties.area
-        b_1 = self.steel_cross_section.profile.top_flange_width
-        b_2 = self.steel_cross_section.profile.bottom_flange_width
-        tf_1 = self.steel_cross_section.profile.top_flange_thickness
-        tf_2 = self.steel_cross_section.profile.bottom_flange_thickness
-        tw = self.steel_cross_section.profile.web_thickness
-        hw = self.steel_cross_section.profile.total_height - (
-            self.steel_cross_section.profile.top_flange_thickness + self.steel_cross_section.profile.bottom_flange_thickness
+        a = float(self.section_properties.area)  # type: ignore[attr-defined]
+        b1 = self.steel_cross_section.profile.top_flange_width  # type: ignore[attr-defined]
+        b2 = self.steel_cross_section.profile.bottom_flange_width  # type: ignore[attr-defined]
+        tf1 = self.steel_cross_section.profile.top_flange_thickness  # type: ignore[attr-defined]
+        tf2 = self.steel_cross_section.profile.bottom_flange_thickness  # type: ignore[attr-defined]
+        tw = self.steel_cross_section.profile.web_thickness  # type: ignore[attr-defined]
+        hw = self.steel_cross_section.profile.total_height - (  # type: ignore[attr-defined]
+            self.steel_cross_section.profile.top_flange_thickness + self.steel_cross_section.profile.bottom_flange_thickness  # type: ignore[attr-defined]
         )
-        r_1 = self.steel_cross_section.profile.top_radius
-        r_2 = self.steel_cross_section.profile.bottom_radius
+        r1 = self.steel_cross_section.profile.top_radius  # type: ignore[attr-defined]
+        r2 = self.steel_cross_section.profile.bottom_radius  # type: ignore[attr-defined]
 
         if self.axis == "Vz" and self.steel_cross_section.fabrication_method == "rolled":
-            av = formula_6_18_sub_av.Form6Dot18SubARolledIandHSection(
-                a=a, b_1=b_1, b_2=b_2, hw=hw, r_1=r_1, r_2=r_2, tf_1=tf_1, tf_2=tf_2, tw=tw, eta=1.0
-            )
+            av = formula_6_18_sub_av.Form6Dot18SubARolledIandHSection(a=a, b1=b1, b2=b2, hw=hw, r1=r1, r2=r2, tf1=tf1, tf2=tf2, tw=tw, eta=1.0)
         elif self.axis == "Vz" and self.steel_cross_section.fabrication_method == "welded":
             av = formula_6_18_sub_av.Form6Dot18SubDWeldedIHandBoxSection(hw_list=[hw], tw_list=[tw], eta=1.0)
         else:  # axis == "Vy"
@@ -166,7 +164,7 @@ def report(self, n: int = 2) -> Report:
             rf"The shear area $A_v$ is calculated as follows:"
         )
         formulas = self.calculation_formula()
-        report.add_formula(formulas["shear_area"], n=n, split_after=[[2, "="], [3, "="]])
+        report.add_formula(formulas["shear_area"], n=n, split_after=[(2, "="), (3, "=")])
         report.add_paragraph("The shear resistance is calculated as follows:")
         report.add_formula(formulas["shear_resistance"], n=n)
         report.add_paragraph("The unity check is calculated as follows:")

From f9b2d6ebe49eb3240893790cf79dff93467f25c7 Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Sun, 1 Feb 2026 18:38:52 +0100
Subject: [PATCH 11/46] feat: add evaluation test for non-symmetric profile in
 Form6Dot18SubARolledIandHSection

---
 .../formula_6_18_sub_av.py                     | 14 ++++++++++++++
 .../test_formula_6_18_sub_av.py                | 18 ++++++++++++++++++
 2 files changed, 32 insertions(+)

diff --git a/blueprints/codes/eurocode/en_1993_1_1_2005/chapter_6_ultimate_limit_state/formula_6_18_sub_av.py b/blueprints/codes/eurocode/en_1993_1_1_2005/chapter_6_ultimate_limit_state/formula_6_18_sub_av.py
index ba919f57e..e480dd056 100644
--- a/blueprints/codes/eurocode/en_1993_1_1_2005/chapter_6_ultimate_limit_state/formula_6_18_sub_av.py
+++ b/blueprints/codes/eurocode/en_1993_1_1_2005/chapter_6_ultimate_limit_state/formula_6_18_sub_av.py
@@ -641,3 +641,17 @@ def latex(self, n: int = 3) -> LatexFormula:
             comparison_operator_label="=",
             unit="mm^2",
         )
+
+a = 10000.0
+b1 = 180.0
+b2 = 200.0
+hw = 250.0
+r1 = 10.0
+r2 = 10.0
+tf1 = 15.0
+tf2 = 15.0
+tw = 8.0
+eta = 1.0
+
+formula = Form6Dot18SubARolledIandHSection(a=a, b1=b1, b2=b2, hw=hw, r1=r1, r2=r2, tf1=tf1, tf2=tf2, tw=tw, eta=eta)
+print(formula)
\ No newline at end of file
diff --git a/tests/codes/eurocode/en_1993_1_1_2005/chapter_6_ultimate_limit_state/test_formula_6_18_sub_av.py b/tests/codes/eurocode/en_1993_1_1_2005/chapter_6_ultimate_limit_state/test_formula_6_18_sub_av.py
index c62c2ccaf..91672a6df 100644
--- a/tests/codes/eurocode/en_1993_1_1_2005/chapter_6_ultimate_limit_state/test_formula_6_18_sub_av.py
+++ b/tests/codes/eurocode/en_1993_1_1_2005/chapter_6_ultimate_limit_state/test_formula_6_18_sub_av.py
@@ -37,6 +37,24 @@ def test_evaluation(self) -> None:
 
         assert formula == pytest.approx(expected=manually_calculated_result, rel=1e-4)
 
+    def test_evaluation_non_symmetric(self) -> None:
+        """Tests the evaluation of the result for a non-symmetric profile."""
+        a = 10000.0
+        b1 = 180.0
+        b2 = 200.0
+        hw = 250.0
+        r1 = 10.0
+        r2 = 10.0
+        tf1 = 15.0
+        tf2 = 15.0
+        tw = 8.0
+        eta = 1.0
+
+        formula = Form6Dot18SubARolledIandHSection(a=a, b1=b1, b2=b2, hw=hw, r1=r1, r2=r2, tf1=tf1, tf2=tf2, tw=tw, eta=eta)
+        manually_calculated_result = 4720.0  # mm^2
+
+        assert formula == pytest.approx(expected=manually_calculated_result, rel=1e-4)
+
     @pytest.mark.parametrize(
         ("a", "b1", "b2", "hw", "r1", "r2", "tf1", "tf2", "tw", "eta"),
         [

From b3399903bb31779077fa1b4e798de6357146a88f Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Sun, 1 Feb 2026 19:07:43 +0100
Subject: [PATCH 12/46] feat: implement plastic shear strength checks for I
 profiles with comprehensive test coverage

---
 .../checks/eurocode/steel/shear_strength.py   | 12 +--
 .../test_shear_strength.py                    | 94 +++++++++++++++++++
 2 files changed, 98 insertions(+), 8 deletions(-)
 create mode 100644 tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/test_shear_strength.py

diff --git a/blueprints/checks/eurocode/steel/shear_strength.py b/blueprints/checks/eurocode/steel/shear_strength.py
index ecebf7b38..cb85816aa 100644
--- a/blueprints/checks/eurocode/steel/shear_strength.py
+++ b/blueprints/checks/eurocode/steel/shear_strength.py
@@ -92,9 +92,7 @@ def calculation_formula(self) -> dict[str, Formula]:
         dict[str, Formula]
             Calculation results keyed by formula number. Returns an empty dict if no shear force is applied.
         """
-        if self.v == 0:
-            return {}
-
+        
         # Get parameters from profile, average top and bottom flange properties
         a = float(self.section_properties.area)  # type: ignore[attr-defined]
         b1 = self.steel_cross_section.profile.top_flange_width  # type: ignore[attr-defined]
@@ -121,7 +119,7 @@ def calculation_formula(self) -> dict[str, Formula]:
         check_shear = formula_6_17.Form6Dot17CheckShearForce(v_ed=v_ed, v_c_rd=v_pl_rd)
         return {
             "shear_area": av,
-            "shear_resistance": v_pl_rd,
+            "resistance": v_pl_rd,
             "check": check_shear,
         }
 
@@ -134,10 +132,8 @@ def result(self) -> CheckResult:
             True if the shear force check passes, False otherwise.
         """
         steps = self.calculation_formula()
-        if not steps:
-            return CheckResult(is_ok=True, unity_check=0.0)
         provided = abs(self.v) * KN_TO_N
-        required = float(steps["shear_resistance"])
+        required = steps["resistance"]
         return CheckResult.from_comparison(provided=provided, required=required)
 
     def report(self, n: int = 2) -> Report:
@@ -166,7 +162,7 @@ def report(self, n: int = 2) -> Report:
         formulas = self.calculation_formula()
         report.add_formula(formulas["shear_area"], n=n, split_after=[(2, "="), (3, "=")])
         report.add_paragraph("The shear resistance is calculated as follows:")
-        report.add_formula(formulas["shear_resistance"], n=n)
+        report.add_formula(formulas["resistance"], n=n)
         report.add_paragraph("The unity check is calculated as follows:")
         report.add_formula(formulas["check"], n=n)
         if self.result().is_ok:
diff --git a/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/test_shear_strength.py b/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/test_shear_strength.py
new file mode 100644
index 000000000..d2ca67d8b
--- /dev/null
+++ b/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/test_shear_strength.py
@@ -0,0 +1,94 @@
+"""Tests for PlasticShearStrengthIProfileCheck according to Eurocode 3."""
+
+import pytest
+from sectionproperties.post.post import SectionProperties
+
+from blueprints.checks.eurocode.steel.shear_strength import PlasticShearStrengthIProfileCheck
+from blueprints.structural_sections.steel.steel_cross_section import SteelCrossSection
+
+
+class TestPlasticShearStrengthIProfileCheck:
+    """Tests for PlasticShearStrengthIProfileCheck."""
+
+    def test_result_none(self, heb_steel_cross_section: tuple[SteelCrossSection, SectionProperties]) -> None:
+        """Test result() returns True for no shear force."""
+        cross_section, section_properties = heb_steel_cross_section
+        v = 0
+        calc = PlasticShearStrengthIProfileCheck(cross_section, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
+        result = calc.result()
+        assert result.is_ok is True
+        assert result.unity_check == 0
+        assert result.factor_of_safety == float("inf")
+        assert result.provided == 0.0
+        assert calc.report()
+
+        calc_without_section_props = PlasticShearStrengthIProfileCheck(cross_section, v, axis="Vz", gamma_m0=1.0)
+        assert calc == calc_without_section_props
+
+    def test_result_shear_ok(self, heb_steel_cross_section: tuple[SteelCrossSection, SectionProperties]) -> None:
+        """Test result() for ok shear force."""
+        cross_section, section_properties = heb_steel_cross_section
+        v = 355 * 2.73 * 0.99
+        calc = PlasticShearStrengthIProfileCheck(cross_section, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
+        result = calc.result()
+        assert result.is_ok is True
+        assert pytest.approx(result.unity_check, 0.005) == 0.99
+        assert pytest.approx(result.factor_of_safety, 0.005) == 1 / 0.99
+
+        v = -v
+        calc = PlasticShearStrengthIProfileCheck(cross_section, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
+        result = calc.result()
+        assert result.is_ok is True
+        assert pytest.approx(result.unity_check, 0.005) == 0.99
+        assert pytest.approx(result.factor_of_safety, 0.005) == 1 / 0.99
+
+        v = 355 * 6.95 * 0.99
+        calc = PlasticShearStrengthIProfileCheck(cross_section, v, axis="Vy", gamma_m0=1.0, section_properties=section_properties)
+        result = calc.result()
+        assert result.is_ok is True
+        assert pytest.approx(result.unity_check, 0.005) == 0.99
+        assert pytest.approx(result.factor_of_safety, 0.005) == 1 / 0.99
+
+        v = 355 * 1.67 * 0.99
+        object.__setattr__(cross_section, "fabrication_method", "welded")
+        calc = PlasticShearStrengthIProfileCheck(cross_section, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
+        result = calc.result()
+        assert result.is_ok is True
+        assert pytest.approx(result.unity_check, 0.005) == 0.99
+        assert pytest.approx(result.factor_of_safety, 0.005) == 1 / 0.99
+        
+
+    def test_result_shear_not_ok(self, heb_steel_cross_section: tuple[SteelCrossSection, SectionProperties]) -> None:
+        """Test result() for not ok shear force."""
+        cross_section, section_properties = heb_steel_cross_section
+        object.__setattr__(cross_section, "fabrication_method", "rolled")
+        v = 355 * 2.73 * 1.01
+        calc = PlasticShearStrengthIProfileCheck(cross_section, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
+        result = calc.result()
+        assert result.is_ok is False
+        assert pytest.approx(result.unity_check, 0.005) == 1.01
+        assert pytest.approx(result.factor_of_safety, 0.005) == 1 / 1.01
+        assert calc.report()
+
+        v = 355 * 6.95 * 1.01
+        calc = PlasticShearStrengthIProfileCheck(cross_section, v, axis="Vy", gamma_m0=1.0, section_properties=section_properties)
+        result = calc.result()
+        assert result.is_ok is False
+        assert pytest.approx(result.unity_check, 0.005) == 1.01
+        assert pytest.approx(result.factor_of_safety, 0.005) == 1 / 1.01
+        assert calc.report()
+
+        v = 355 * 1.67 * 1.01
+        object.__setattr__(cross_section, "fabrication_method", "welded")
+        calc = PlasticShearStrengthIProfileCheck(cross_section, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
+        result = calc.result()
+        assert result.is_ok is False
+        assert pytest.approx(result.unity_check, 0.005) == 1.01
+        assert pytest.approx(result.factor_of_safety, 0.005) == 1 / 1.01
+
+    def test_report_shear(self, heb_steel_cross_section: tuple[SteelCrossSection, SectionProperties]) -> None:
+        """Test report output for shear force."""
+        cross_section, section_properties = heb_steel_cross_section
+        v = 1
+        calc = PlasticShearStrengthIProfileCheck(cross_section, v, gamma_m0=1.0, section_properties=section_properties)
+        assert calc.report()

From f54f0e536b8966fe40260551f5b49e3af432b6e8 Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Sun, 1 Feb 2026 19:10:52 +0100
Subject: [PATCH 13/46] feat: add test for TypeError when checking
 non-I-profile in PlasticShearStrengthIProfileCheck

---
 .../ultimate_limit_states/test_shear_strength.py           | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/test_shear_strength.py b/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/test_shear_strength.py
index d2ca67d8b..17a25c9fa 100644
--- a/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/test_shear_strength.py
+++ b/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/test_shear_strength.py
@@ -92,3 +92,10 @@ def test_report_shear(self, heb_steel_cross_section: tuple[SteelCrossSection, Se
         v = 1
         calc = PlasticShearStrengthIProfileCheck(cross_section, v, gamma_m0=1.0, section_properties=section_properties)
         assert calc.report()
+
+    def test_check_wrong_profile(self, chs_steel_cross_section: tuple[SteelCrossSection, SectionProperties]) -> None:
+        """Test check() raises TypeError for non-I-profile."""
+        cross_section, section_properties = chs_steel_cross_section
+        v = 1
+        with pytest.raises(TypeError, match="The provided profile is not an I-profile"):
+            PlasticShearStrengthIProfileCheck(cross_section, v, gamma_m0=1.0, section_properties=section_properties)
\ No newline at end of file

From c8797930aeea14df255db291498fbcf22d5a16c5 Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Sun, 1 Feb 2026 19:17:17 +0100
Subject: [PATCH 14/46] feat: update shear force calculations in
 PlasticShearStrengthIProfileCheck tests for accuracy

---
 .../ultimate_limit_states/test_shear_strength.py    | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/test_shear_strength.py b/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/test_shear_strength.py
index 17a25c9fa..17844bc83 100644
--- a/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/test_shear_strength.py
+++ b/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/test_shear_strength.py
@@ -1,6 +1,7 @@
 """Tests for PlasticShearStrengthIProfileCheck according to Eurocode 3."""
 
 import pytest
+import numpy as np
 from sectionproperties.post.post import SectionProperties
 
 from blueprints.checks.eurocode.steel.shear_strength import PlasticShearStrengthIProfileCheck
@@ -28,7 +29,7 @@ def test_result_none(self, heb_steel_cross_section: tuple[SteelCrossSection, Sec
     def test_result_shear_ok(self, heb_steel_cross_section: tuple[SteelCrossSection, SectionProperties]) -> None:
         """Test result() for ok shear force."""
         cross_section, section_properties = heb_steel_cross_section
-        v = 355 * 2.73 * 0.99
+        v = 355 * 4.74 / 1.732 * 0.99
         calc = PlasticShearStrengthIProfileCheck(cross_section, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
         result = calc.result()
         assert result.is_ok is True
@@ -42,14 +43,14 @@ def test_result_shear_ok(self, heb_steel_cross_section: tuple[SteelCrossSection,
         assert pytest.approx(result.unity_check, 0.005) == 0.99
         assert pytest.approx(result.factor_of_safety, 0.005) == 1 / 0.99
 
-        v = 355 * 6.95 * 0.99
+        v = 355 * 11.4 / 1.732 * 0.99
         calc = PlasticShearStrengthIProfileCheck(cross_section, v, axis="Vy", gamma_m0=1.0, section_properties=section_properties)
         result = calc.result()
         assert result.is_ok is True
         assert pytest.approx(result.unity_check, 0.005) == 0.99
         assert pytest.approx(result.factor_of_safety, 0.005) == 1 / 0.99
 
-        v = 355 * 1.67 * 0.99
+        v = 355 * 2.89 / 1.732 * 0.99
         object.__setattr__(cross_section, "fabrication_method", "welded")
         calc = PlasticShearStrengthIProfileCheck(cross_section, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
         result = calc.result()
@@ -62,7 +63,7 @@ def test_result_shear_not_ok(self, heb_steel_cross_section: tuple[SteelCrossSect
         """Test result() for not ok shear force."""
         cross_section, section_properties = heb_steel_cross_section
         object.__setattr__(cross_section, "fabrication_method", "rolled")
-        v = 355 * 2.73 * 1.01
+        v = 355 * 4.74 / 1.732 * 1.01
         calc = PlasticShearStrengthIProfileCheck(cross_section, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
         result = calc.result()
         assert result.is_ok is False
@@ -70,7 +71,7 @@ def test_result_shear_not_ok(self, heb_steel_cross_section: tuple[SteelCrossSect
         assert pytest.approx(result.factor_of_safety, 0.005) == 1 / 1.01
         assert calc.report()
 
-        v = 355 * 6.95 * 1.01
+        v = 355 * 11.4 / 1.732 * 1.01
         calc = PlasticShearStrengthIProfileCheck(cross_section, v, axis="Vy", gamma_m0=1.0, section_properties=section_properties)
         result = calc.result()
         assert result.is_ok is False
@@ -78,7 +79,7 @@ def test_result_shear_not_ok(self, heb_steel_cross_section: tuple[SteelCrossSect
         assert pytest.approx(result.factor_of_safety, 0.005) == 1 / 1.01
         assert calc.report()
 
-        v = 355 * 1.67 * 1.01
+        v = 355 * 1.89 / 1.732 * 1.01
         object.__setattr__(cross_section, "fabrication_method", "welded")
         calc = PlasticShearStrengthIProfileCheck(cross_section, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
         result = calc.result()

From 88334accbfdafc661b14100279ca35e44b42b0e7 Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Sun, 1 Feb 2026 19:27:45 +0100
Subject: [PATCH 15/46] feat: enhance plastic shear strength calculations and
 add main execution block for HEB profile

---
 .../checks/eurocode/steel/shear_strength.py       | 15 +++++++++++++++
 .../ultimate_limit_states/test_shear_strength.py  |  8 ++++----
 2 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/blueprints/checks/eurocode/steel/shear_strength.py b/blueprints/checks/eurocode/steel/shear_strength.py
index cb85816aa..d9df32323 100644
--- a/blueprints/checks/eurocode/steel/shear_strength.py
+++ b/blueprints/checks/eurocode/steel/shear_strength.py
@@ -170,3 +170,18 @@ def report(self, n: int = 2) -> Report:
         else:
             report.add_paragraph("The check for plastic shear force does NOT satisfy the requirements.")
         return report
+
+if __name__ == "__main__":
+    from blueprints.materials.steel import SteelMaterial, SteelStrengthClass
+    from blueprints.structural_sections.steel.standard_profiles.heb import HEB
+
+    steel_material = SteelMaterial(steel_class=SteelStrengthClass.S355)
+    heb_300_profile = HEB.HEB300
+    v = 100  # Applied shear force in kN
+
+    heb_300_s355 = SteelCrossSection(profile=heb_300_profile, material=steel_material)
+    object.__setattr__(heb_300_s355, "fabrication_method", "welded")
+    calc = PlasticShearStrengthIProfileCheck(heb_300_s355, v, axis="Vz", gamma_m0=1.0)
+    print(calc._profile.area)
+    print(calc._profile.area - 11 * 260)
+    print(calc.calculation_formula())
\ No newline at end of file
diff --git a/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/test_shear_strength.py b/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/test_shear_strength.py
index 17844bc83..4195698af 100644
--- a/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/test_shear_strength.py
+++ b/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/test_shear_strength.py
@@ -43,14 +43,14 @@ def test_result_shear_ok(self, heb_steel_cross_section: tuple[SteelCrossSection,
         assert pytest.approx(result.unity_check, 0.005) == 0.99
         assert pytest.approx(result.factor_of_safety, 0.005) == 1 / 0.99
 
-        v = 355 * 11.4 / 1.732 * 0.99
+        v = 355 * 12.03 / 1.732 * 0.99
         calc = PlasticShearStrengthIProfileCheck(cross_section, v, axis="Vy", gamma_m0=1.0, section_properties=section_properties)
         result = calc.result()
         assert result.is_ok is True
         assert pytest.approx(result.unity_check, 0.005) == 0.99
         assert pytest.approx(result.factor_of_safety, 0.005) == 1 / 0.99
 
-        v = 355 * 2.89 / 1.732 * 0.99
+        v = 355 * 2.882 / 1.732 * 0.99
         object.__setattr__(cross_section, "fabrication_method", "welded")
         calc = PlasticShearStrengthIProfileCheck(cross_section, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
         result = calc.result()
@@ -71,7 +71,7 @@ def test_result_shear_not_ok(self, heb_steel_cross_section: tuple[SteelCrossSect
         assert pytest.approx(result.factor_of_safety, 0.005) == 1 / 1.01
         assert calc.report()
 
-        v = 355 * 11.4 / 1.732 * 1.01
+        v = 355 * 12.03 / 1.732 * 1.01
         calc = PlasticShearStrengthIProfileCheck(cross_section, v, axis="Vy", gamma_m0=1.0, section_properties=section_properties)
         result = calc.result()
         assert result.is_ok is False
@@ -79,7 +79,7 @@ def test_result_shear_not_ok(self, heb_steel_cross_section: tuple[SteelCrossSect
         assert pytest.approx(result.factor_of_safety, 0.005) == 1 / 1.01
         assert calc.report()
 
-        v = 355 * 1.89 / 1.732 * 1.01
+        v = 355 * 2.882 / 1.732 * 1.01
         object.__setattr__(cross_section, "fabrication_method", "welded")
         calc = PlasticShearStrengthIProfileCheck(cross_section, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
         result = calc.result()

From ffeb259535aab5a9cbc1388a98556190f74aa8f2 Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Sun, 1 Feb 2026 19:31:39 +0100
Subject: [PATCH 16/46] feat: remove main execution block from
 PlasticShearStrengthIProfileCheck module

---
 .../checks/eurocode/steel/shear_strength.py       | 15 ---------------
 1 file changed, 15 deletions(-)

diff --git a/blueprints/checks/eurocode/steel/shear_strength.py b/blueprints/checks/eurocode/steel/shear_strength.py
index d9df32323..cb85816aa 100644
--- a/blueprints/checks/eurocode/steel/shear_strength.py
+++ b/blueprints/checks/eurocode/steel/shear_strength.py
@@ -170,18 +170,3 @@ def report(self, n: int = 2) -> Report:
         else:
             report.add_paragraph("The check for plastic shear force does NOT satisfy the requirements.")
         return report
-
-if __name__ == "__main__":
-    from blueprints.materials.steel import SteelMaterial, SteelStrengthClass
-    from blueprints.structural_sections.steel.standard_profiles.heb import HEB
-
-    steel_material = SteelMaterial(steel_class=SteelStrengthClass.S355)
-    heb_300_profile = HEB.HEB300
-    v = 100  # Applied shear force in kN
-
-    heb_300_s355 = SteelCrossSection(profile=heb_300_profile, material=steel_material)
-    object.__setattr__(heb_300_s355, "fabrication_method", "welded")
-    calc = PlasticShearStrengthIProfileCheck(heb_300_s355, v, axis="Vz", gamma_m0=1.0)
-    print(calc._profile.area)
-    print(calc._profile.area - 11 * 260)
-    print(calc.calculation_formula())
\ No newline at end of file

From 9137a1673c5f9bee7ac240f491fb80d576c07f84 Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Sun, 1 Feb 2026 19:36:49 +0100
Subject: [PATCH 17/46] feat: update shear area formula in report generation
 for PlasticShearStrengthIProfileCheck

---
 .../checks/eurocode/steel/shear_strength.py    | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/blueprints/checks/eurocode/steel/shear_strength.py b/blueprints/checks/eurocode/steel/shear_strength.py
index cb85816aa..f73e680cb 100644
--- a/blueprints/checks/eurocode/steel/shear_strength.py
+++ b/blueprints/checks/eurocode/steel/shear_strength.py
@@ -160,7 +160,7 @@ def report(self, n: int = 2) -> Report:
             rf"The shear area $A_v$ is calculated as follows:"
         )
         formulas = self.calculation_formula()
-        report.add_formula(formulas["shear_area"], n=n, split_after=[(2, "="), (3, "=")])
+        report.add_formula(formulas["shear_area"], n=n, split_after=[(2, "="), (7, "+"), (4, "=")])
         report.add_paragraph("The shear resistance is calculated as follows:")
         report.add_formula(formulas["resistance"], n=n)
         report.add_paragraph("The unity check is calculated as follows:")
@@ -170,3 +170,19 @@ def report(self, n: int = 2) -> Report:
         else:
             report.add_paragraph("The check for plastic shear force does NOT satisfy the requirements.")
         return report
+
+if __name__ == "__main__":
+    from blueprints.materials.steel import SteelMaterial, SteelStrengthClass
+    from blueprints.structural_sections.steel.standard_profiles.heb import HEB
+
+    steel_material = SteelMaterial(steel_class=SteelStrengthClass.S355)
+    heb_300_profile = HEB.HEB300
+    v = 100  # Applied shear force in kN
+
+    heb_300_s355 = SteelCrossSection(profile=heb_300_profile, material=steel_material)
+    calc = PlasticShearStrengthIProfileCheck(heb_300_s355, v, axis="Vz", gamma_m0=1.0)
+    calc.report().to_pdf("shear_strength.pdf", language="nl")
+    calc.report().to_word("shear_strength.docx", language="nl")
+    import os
+    os.startfile("shear_strength.pdf")
+    os.startfile("shear_strength.docx")
\ No newline at end of file

From 72a68f91b6b579542136c1cc2d9bcfe948001320 Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Sun, 1 Feb 2026 19:37:07 +0100
Subject: [PATCH 18/46] fix: correct split index for shear area formula in
 report generation

---
 blueprints/checks/eurocode/steel/shear_strength.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/blueprints/checks/eurocode/steel/shear_strength.py b/blueprints/checks/eurocode/steel/shear_strength.py
index f73e680cb..623b3db80 100644
--- a/blueprints/checks/eurocode/steel/shear_strength.py
+++ b/blueprints/checks/eurocode/steel/shear_strength.py
@@ -160,7 +160,7 @@ def report(self, n: int = 2) -> Report:
             rf"The shear area $A_v$ is calculated as follows:"
         )
         formulas = self.calculation_formula()
-        report.add_formula(formulas["shear_area"], n=n, split_after=[(2, "="), (7, "+"), (4, "=")])
+        report.add_formula(formulas["shear_area"], n=n, split_after=[(2, "="), (7, "+"), (3, "=")])
         report.add_paragraph("The shear resistance is calculated as follows:")
         report.add_formula(formulas["resistance"], n=n)
         report.add_paragraph("The unity check is calculated as follows:")

From fca4809637176bf0b7878d7c8188eba4cee0021e Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Sun, 1 Feb 2026 19:39:16 +0100
Subject: [PATCH 19/46] feat: remove main execution block from
 PlasticShearStrengthIProfileCheck module

---
 .../checks/eurocode/steel/shear_strength.py      | 16 ----------------
 1 file changed, 16 deletions(-)

diff --git a/blueprints/checks/eurocode/steel/shear_strength.py b/blueprints/checks/eurocode/steel/shear_strength.py
index 623b3db80..86b9a656e 100644
--- a/blueprints/checks/eurocode/steel/shear_strength.py
+++ b/blueprints/checks/eurocode/steel/shear_strength.py
@@ -170,19 +170,3 @@ def report(self, n: int = 2) -> Report:
         else:
             report.add_paragraph("The check for plastic shear force does NOT satisfy the requirements.")
         return report
-
-if __name__ == "__main__":
-    from blueprints.materials.steel import SteelMaterial, SteelStrengthClass
-    from blueprints.structural_sections.steel.standard_profiles.heb import HEB
-
-    steel_material = SteelMaterial(steel_class=SteelStrengthClass.S355)
-    heb_300_profile = HEB.HEB300
-    v = 100  # Applied shear force in kN
-
-    heb_300_s355 = SteelCrossSection(profile=heb_300_profile, material=steel_material)
-    calc = PlasticShearStrengthIProfileCheck(heb_300_s355, v, axis="Vz", gamma_m0=1.0)
-    calc.report().to_pdf("shear_strength.pdf", language="nl")
-    calc.report().to_word("shear_strength.docx", language="nl")
-    import os
-    os.startfile("shear_strength.pdf")
-    os.startfile("shear_strength.docx")
\ No newline at end of file

From d0c6439d30131820abcb833c4d0bbceaa575f069 Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Sun, 1 Feb 2026 19:44:43 +0100
Subject: [PATCH 20/46] refactor: remove unused variables and print statement
 from formula_6_18_sub_av.py

---
 blueprints/checks/eurocode/steel/shear_strength.py |  1 -
 .../formula_6_18_sub_av.py                         | 14 --------------
 .../ultimate_limit_states/test_shear_strength.py   |  5 ++---
 3 files changed, 2 insertions(+), 18 deletions(-)

diff --git a/blueprints/checks/eurocode/steel/shear_strength.py b/blueprints/checks/eurocode/steel/shear_strength.py
index 86b9a656e..a23f62402 100644
--- a/blueprints/checks/eurocode/steel/shear_strength.py
+++ b/blueprints/checks/eurocode/steel/shear_strength.py
@@ -92,7 +92,6 @@ def calculation_formula(self) -> dict[str, Formula]:
         dict[str, Formula]
             Calculation results keyed by formula number. Returns an empty dict if no shear force is applied.
         """
-        
         # Get parameters from profile, average top and bottom flange properties
         a = float(self.section_properties.area)  # type: ignore[attr-defined]
         b1 = self.steel_cross_section.profile.top_flange_width  # type: ignore[attr-defined]
diff --git a/blueprints/codes/eurocode/en_1993_1_1_2005/chapter_6_ultimate_limit_state/formula_6_18_sub_av.py b/blueprints/codes/eurocode/en_1993_1_1_2005/chapter_6_ultimate_limit_state/formula_6_18_sub_av.py
index e480dd056..ba919f57e 100644
--- a/blueprints/codes/eurocode/en_1993_1_1_2005/chapter_6_ultimate_limit_state/formula_6_18_sub_av.py
+++ b/blueprints/codes/eurocode/en_1993_1_1_2005/chapter_6_ultimate_limit_state/formula_6_18_sub_av.py
@@ -641,17 +641,3 @@ def latex(self, n: int = 3) -> LatexFormula:
             comparison_operator_label="=",
             unit="mm^2",
         )
-
-a = 10000.0
-b1 = 180.0
-b2 = 200.0
-hw = 250.0
-r1 = 10.0
-r2 = 10.0
-tf1 = 15.0
-tf2 = 15.0
-tw = 8.0
-eta = 1.0
-
-formula = Form6Dot18SubARolledIandHSection(a=a, b1=b1, b2=b2, hw=hw, r1=r1, r2=r2, tf1=tf1, tf2=tf2, tw=tw, eta=eta)
-print(formula)
\ No newline at end of file
diff --git a/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/test_shear_strength.py b/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/test_shear_strength.py
index 4195698af..6aaa92084 100644
--- a/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/test_shear_strength.py
+++ b/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/test_shear_strength.py
@@ -1,7 +1,6 @@
 """Tests for PlasticShearStrengthIProfileCheck according to Eurocode 3."""
 
 import pytest
-import numpy as np
 from sectionproperties.post.post import SectionProperties
 
 from blueprints.checks.eurocode.steel.shear_strength import PlasticShearStrengthIProfileCheck
@@ -57,7 +56,7 @@ def test_result_shear_ok(self, heb_steel_cross_section: tuple[SteelCrossSection,
         assert result.is_ok is True
         assert pytest.approx(result.unity_check, 0.005) == 0.99
         assert pytest.approx(result.factor_of_safety, 0.005) == 1 / 0.99
-        
+
 
     def test_result_shear_not_ok(self, heb_steel_cross_section: tuple[SteelCrossSection, SectionProperties]) -> None:
         """Test result() for not ok shear force."""
@@ -99,4 +98,4 @@ def test_check_wrong_profile(self, chs_steel_cross_section: tuple[SteelCrossSect
         cross_section, section_properties = chs_steel_cross_section
         v = 1
         with pytest.raises(TypeError, match="The provided profile is not an I-profile"):
-            PlasticShearStrengthIProfileCheck(cross_section, v, gamma_m0=1.0, section_properties=section_properties)
\ No newline at end of file
+            PlasticShearStrengthIProfileCheck(cross_section, v, gamma_m0=1.0, section_properties=section_properties)

From ba970a7545c61c38892b92118a59ff7896f940a0 Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Sun, 1 Feb 2026 19:46:23 +0100
Subject: [PATCH 21/46] fix: remove unnecessary blank line in
 test_shear_strength.py

---
 .../ultimate_limit_states/test_shear_strength.py                 | 1 -
 1 file changed, 1 deletion(-)

diff --git a/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/test_shear_strength.py b/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/test_shear_strength.py
index 6aaa92084..a285f9416 100644
--- a/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/test_shear_strength.py
+++ b/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/test_shear_strength.py
@@ -57,7 +57,6 @@ def test_result_shear_ok(self, heb_steel_cross_section: tuple[SteelCrossSection,
         assert pytest.approx(result.unity_check, 0.005) == 0.99
         assert pytest.approx(result.factor_of_safety, 0.005) == 1 / 0.99
 
-
     def test_result_shear_not_ok(self, heb_steel_cross_section: tuple[SteelCrossSection, SectionProperties]) -> None:
         """Test result() for not ok shear force."""
         cross_section, section_properties = heb_steel_cross_section

From e2f536ec03a84abd2692bad00fb6b1116eec0710 Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Thu, 5 Feb 2026 20:01:01 +0100
Subject: [PATCH 22/46] feat: add stress calculation method to Profile class

---
 blueprints/structural_sections/_profile.py | 29 ++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/blueprints/structural_sections/_profile.py b/blueprints/structural_sections/_profile.py
index 146ad3a19..a15d53477 100644
--- a/blueprints/structural_sections/_profile.py
+++ b/blueprints/structural_sections/_profile.py
@@ -13,6 +13,7 @@
 from shapely import Point, Polygon
 from shapely.affinity import rotate, translate
 
+from blueprints.saf.results.result_internal_force_1d import ResultInternalForce1D
 from blueprints.type_alias import DEG, M3_M, MM, MM2
 from blueprints.unit_conversion import M_TO_MM, MM3_TO_M3
 
@@ -185,6 +186,34 @@ def plotter(self) -> Callable[[Any], plt.Figure]:
         """Default plotter function for the profile."""
         raise AttributeError("No plotter is defined.")
 
+    def calculate_stress(self, result_internal_force_1d: ResultInternalForce1D) -> Callable[..., SectionProperties]:
+        """Calculate the stress distribution for the profile given internal forces.
+
+        Parameters
+        ----------
+        result_internal_force_1d : ResultInternalForce1D
+            The internal forces and moments to calculate the stress for.
+
+        Returns
+        -------
+        Callable[..., SectionProperties]
+            A function that calculates the stress distribution when called.
+        """
+        section = self._section()
+        section.calculate_geometric_properties()
+        section.calculate_warping_properties()
+        # Note: The mapping of internal forces to sectionproperties parameters
+        # Blueprints uses x for longitudinal axis, y for horizontal, z for vertical
+        # sectionproperties uses x for horizontal, y for vertical, z for longitudinal
+        return section.calculate_stress(
+            n=-float(result_internal_force_1d.n) * 1e3,
+            vx=-float(result_internal_force_1d.vy) * 1e3,
+            vy=float(result_internal_force_1d.vz) * 1e3,
+            mxx=-float(result_internal_force_1d.my) * 1e6,
+            myy=float(result_internal_force_1d.mz) * 1e6,
+            mzz=-float(result_internal_force_1d.mx) * 1e6,
+        )
+
     def plot(self, plotter: Callable[[Any], plt.Figure] | None = None, *args, **kwargs) -> plt.Figure:
         """Plot the profile. Making use of the standard plotter.
 

From 5849cecd559e0b087900dc8d54e0cdfce40bfce2 Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Thu, 5 Feb 2026 21:14:59 +0100
Subject: [PATCH 23/46] feat: add TorsionStrengthCheck module for torsional
 shear stress resistance

---
 .../checks/eurocode/steel/torsion_strength.py | 182 ++++++++++++++++++
 1 file changed, 182 insertions(+)
 create mode 100644 blueprints/checks/eurocode/steel/torsion_strength.py

diff --git a/blueprints/checks/eurocode/steel/torsion_strength.py b/blueprints/checks/eurocode/steel/torsion_strength.py
new file mode 100644
index 000000000..80fe32b52
--- /dev/null
+++ b/blueprints/checks/eurocode/steel/torsion_strength.py
@@ -0,0 +1,182 @@
+"""Module for checking torsional shear stress resistance (Eurocode 2, formula 6.23)."""
+
+from dataclasses import dataclass
+from typing import ClassVar
+
+import numpy as np
+from sectionproperties.post.post import SectionProperties
+
+from blueprints.checks.check_result import CheckResult
+from blueprints.codes.eurocode.en_1993_1_1_2005 import EN_1993_1_1_2005
+from blueprints.codes.eurocode.en_1993_1_1_2005.chapter_6_ultimate_limit_state.formula_6_23 import Form6Dot23CheckTorsionalMoment
+from blueprints.codes.formula import Formula
+from blueprints.saf.results.result_internal_force_1d import ResultFor, ResultInternalForce1D, ResultOn
+from blueprints.structural_sections.steel.steel_cross_section import SteelCrossSection
+from blueprints.type_alias import DIMENSIONLESS, KNM
+from blueprints.unit_conversion import KNM_TO_NMM, NMM_TO_KNM
+from blueprints.utils.report import Report
+
+
+@dataclass(frozen=True)
+class TorsionStrengthCheck:
+    """Class to perform torsion resistance check (Eurocode 3).
+
+    Coordinate System:
+
+        z (vertical, usually strong axis)
+            ↑
+            |     x (longitudinal beam direction, into screen)
+            |    ↗
+            |   /
+            |  /
+            | /
+            |/
+      ←-----O
+       y (horizontal/side, usually weak axis)
+
+    Parameters
+    ----------
+    steel_cross_section : SteelCrossSection
+        The steel cross-section, of type I-profile, to check.
+    mx : KNM
+        The applied shear force (positive value, in kN).
+    gamma_m0 : DIMENSIONLESS, optional
+        Partial safety factor for resistance of cross-sections, default is 1.0.
+    section_properties : SectionProperties | None, optional
+        Pre-calculated section properties. If None, they will be calculated internally.
+
+    Example
+    -------
+    from blueprints.checks.eurocode.steel.torsion_strength import TorsionStrengthCheck
+    from blueprints.materials.steel import SteelMaterial, SteelStrengthClass
+    from blueprints.structural_sections.steel.standard_profiles.heb import HEB
+
+    steel_material = SteelMaterial(steel_class=SteelStrengthClass.S355)
+    heb_300_profile = HEB.HEB300.with_corrosion(1.5)
+    mx = 10  # Applied torsional moment in kNm
+
+    heb_300_s355 = SteelCrossSection(profile=heb_300_profile, material=steel_material)
+    calc = TorsionStrengthCheck(heb_300_s355, mx, gamma_m0=1.0)
+    calc.report().to_word("torsion_strength.docx", language="nl")
+
+    """
+
+    steel_cross_section: SteelCrossSection
+    mx: KNM = 0
+    gamma_m0: DIMENSIONLESS = 1.0
+    section_properties: SectionProperties | None = None
+    name: str = "Torsion strength check for steel I-profiles"
+    source_docs: ClassVar[list] = [EN_1993_1_1_2005]
+
+    def __post_init__(self) -> None:
+        """Post-initialization to extract section properties."""
+        if self.section_properties is None:
+            section_properties = self.steel_cross_section.profile.section_properties()
+            object.__setattr__(self, "section_properties", section_properties)
+
+    def calculation_formula(self) -> dict[str, Formula]:
+        """Calculate torsion force resistance check.
+
+        Returns
+        -------
+        dict[str, Formula]
+            Calculation results keyed by formula number. Returns an empty dict if no torsion is applied.
+        """
+        rif1d = ResultInternalForce1D(
+            result_on=ResultOn.ON_BEAM,
+            member="N/A",
+            result_for=ResultFor.LOAD_CASE,
+            load_case="N/A",
+            mx=1,  # 1 kNm
+        )
+
+        stress = self.steel_cross_section.profile.calculate_stress(rif1d)
+        sig_zx_mzz = stress.get_stress()[0]["sig_zx_mzz"]
+        sig_zy_mzz = stress.get_stress()[0]["sig_zy_mzz"]
+        max_mzz_zxy = max((sig_zx_mzz**2 + sig_zy_mzz**2) ** 0.5)
+
+        t_rd = self.steel_cross_section.yield_strength / self.gamma_m0 / np.sqrt(3) / max_mzz_zxy * KNM_TO_NMM
+
+        check_torsion = Form6Dot23CheckTorsionalMoment(t_ed=self.mx, t_rd=t_rd * NMM_TO_KNM)
+
+        return {
+            "kNm_unit_stress": max_mzz_zxy,
+            "resistance": t_rd * NMM_TO_KNM,
+            "check": check_torsion,
+        }
+
+    def result(self) -> CheckResult:
+        """Calculate result of torsion force resistance.
+
+        Returns
+        -------
+        CheckResult
+            True if the torsion force check passes, False otherwise.
+        """
+        steps = self.calculation_formula()
+        provided = self.mx
+        required = steps["resistance"]
+        return CheckResult.from_comparison(provided=provided, required=float(required))
+
+    def report(self, n: int = 2) -> Report:
+        """Returns the report for the torsion force check.
+
+        Parameters
+        ----------
+        n : int, optional
+            Number of decimal places for numerical values in the report (default is 2).
+
+        Returns
+        -------
+        Report
+            Report of the torsion force check.
+        """
+        report = Report("Check: torsion force steel beam")
+        if self.mx == 0:
+            report.add_paragraph("No torsion force was applied; therefore, no torsion force check is necessary.")
+            return report
+        profile_name = self.steel_cross_section.profile.name
+        steel_quality = self.steel_cross_section.material.steel_class.name
+        mx_val = f"{self.mx:.{n}f}"
+        unit_stress_val = f"{self.calculation_formula()['kNm_unit_stress']:.{n}f}"
+        report.add_paragraph(
+            rf"Profile {profile_name} with steel quality {steel_quality} "
+            rf"is loaded with a torsion force of {mx_val} kNm. "
+            rf"First, the unit torsional stress (at 1 kNm) is defined as {unit_stress_val} MPa. "
+            rf"The torsional resistance is calculated as follows:"
+        )
+
+        fy = self.steel_cross_section.yield_strength
+        gamma_m0 = self.gamma_m0
+        unit_stress = self.calculation_formula()["kNm_unit_stress"]
+        result = self.calculation_formula()["resistance"]
+        eqn_1 = (
+            rf"T_{{Rd}} = \frac{{f_y}}{{\gamma_{{M0}} \cdot \sqrt{{3}} \cdot \text{{unit-stress}}}} = "
+            rf"\frac{{{fy:.{n}f}}}{{{gamma_m0:.{n}f} \cdot \sqrt{{3}} \cdot {unit_stress:.{n}f}}} = {result:.{n}f} \ kNm"
+        )
+        report.add_equation(eqn_1)
+        report.add_paragraph("The unity check is calculated as follows:")
+        report.add_formula(self.calculation_formula()["check"], n=n)
+        if self.result().is_ok:
+            report.add_paragraph("The check for torsion force satisfies the requirements.")
+        else:
+            report.add_paragraph("The check for torsion force does NOT satisfy the requirements.")
+        return report
+
+
+if __name__ == "__main__":
+    from blueprints.materials.steel import SteelMaterial, SteelStrengthClass
+    from blueprints.structural_sections.steel.standard_profiles.heb import HEB
+
+    steel_material = SteelMaterial(steel_class=SteelStrengthClass.S355)
+    heb_300_profile = HEB.HEB300.with_corrosion(0)
+    mx = 10  # Applied torsional moment in kNm
+
+    heb_300_s355 = SteelCrossSection(profile=heb_300_profile, material=steel_material)
+    calc = TorsionStrengthCheck(heb_300_s355, mx, gamma_m0=1.0)
+    calc.report().to_pdf("torsion_strength.pdf")
+    calc.report().to_word("torsion_strength.docx", language="nl")
+    import os
+
+    os.startfile("torsion_strength.pdf")
+    os.startfile("torsion_strength.docx")

From 4bd30b1ba3371860321d6047844e92dcc5d338a8 Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Fri, 6 Feb 2026 16:44:19 +0100
Subject: [PATCH 24/46] feat: enhance TorsionStrengthCheck with additional
 calculations and tests

---
 .../checks/eurocode/steel/torsion_strength.py | 28 ++---------
 .../ultimate_limit_states/conftest.py         |  9 ++++
 .../test_torsion_strength.py                  | 48 +++++++++++++++++++
 3 files changed, 62 insertions(+), 23 deletions(-)
 create mode 100644 tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/test_torsion_strength.py

diff --git a/blueprints/checks/eurocode/steel/torsion_strength.py b/blueprints/checks/eurocode/steel/torsion_strength.py
index 80fe32b52..310aba87c 100644
--- a/blueprints/checks/eurocode/steel/torsion_strength.py
+++ b/blueprints/checks/eurocode/steel/torsion_strength.py
@@ -13,7 +13,6 @@
 from blueprints.saf.results.result_internal_force_1d import ResultFor, ResultInternalForce1D, ResultOn
 from blueprints.structural_sections.steel.steel_cross_section import SteelCrossSection
 from blueprints.type_alias import DIMENSIONLESS, KNM
-from blueprints.unit_conversion import KNM_TO_NMM, NMM_TO_KNM
 from blueprints.utils.report import Report
 
 
@@ -95,13 +94,14 @@ def calculation_formula(self) -> dict[str, Formula]:
         sig_zy_mzz = stress.get_stress()[0]["sig_zy_mzz"]
         max_mzz_zxy = max((sig_zx_mzz**2 + sig_zy_mzz**2) ** 0.5)
 
-        t_rd = self.steel_cross_section.yield_strength / self.gamma_m0 / np.sqrt(3) / max_mzz_zxy * KNM_TO_NMM
+        t_rd = self.steel_cross_section.yield_strength / self.gamma_m0 / np.sqrt(3) / max_mzz_zxy
+        t_ed = abs(self.mx)
 
-        check_torsion = Form6Dot23CheckTorsionalMoment(t_ed=self.mx, t_rd=t_rd * NMM_TO_KNM)
+        check_torsion = Form6Dot23CheckTorsionalMoment(t_ed=t_ed, t_rd=t_rd)
 
         return {
             "kNm_unit_stress": max_mzz_zxy,
-            "resistance": t_rd * NMM_TO_KNM,
+            "resistance": t_rd,
             "check": check_torsion,
         }
 
@@ -114,7 +114,7 @@ def result(self) -> CheckResult:
             True if the torsion force check passes, False otherwise.
         """
         steps = self.calculation_formula()
-        provided = self.mx
+        provided = abs(self.mx)
         required = steps["resistance"]
         return CheckResult.from_comparison(provided=provided, required=float(required))
 
@@ -162,21 +162,3 @@ def report(self, n: int = 2) -> Report:
         else:
             report.add_paragraph("The check for torsion force does NOT satisfy the requirements.")
         return report
-
-
-if __name__ == "__main__":
-    from blueprints.materials.steel import SteelMaterial, SteelStrengthClass
-    from blueprints.structural_sections.steel.standard_profiles.heb import HEB
-
-    steel_material = SteelMaterial(steel_class=SteelStrengthClass.S355)
-    heb_300_profile = HEB.HEB300.with_corrosion(0)
-    mx = 10  # Applied torsional moment in kNm
-
-    heb_300_s355 = SteelCrossSection(profile=heb_300_profile, material=steel_material)
-    calc = TorsionStrengthCheck(heb_300_s355, mx, gamma_m0=1.0)
-    calc.report().to_pdf("torsion_strength.pdf")
-    calc.report().to_word("torsion_strength.docx", language="nl")
-    import os
-
-    os.startfile("torsion_strength.pdf")
-    os.startfile("torsion_strength.docx")
diff --git a/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/conftest.py b/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/conftest.py
index 32d218fb3..7d79e95ac 100644
--- a/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/conftest.py
+++ b/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/conftest.py
@@ -6,6 +6,7 @@
 from blueprints.materials.steel import SteelMaterial, SteelStrengthClass
 from blueprints.structural_sections.steel.standard_profiles.chs import CHS
 from blueprints.structural_sections.steel.standard_profiles.heb import HEB
+from blueprints.structural_sections.steel.standard_profiles.unp import UNP
 from blueprints.structural_sections.steel.steel_cross_section import SteelCrossSection
 
 
@@ -23,3 +24,11 @@ def chs_steel_cross_section() -> tuple[SteelCrossSection, SectionProperties]:
     steel_material = SteelMaterial(steel_class=SteelStrengthClass.S355)
     profile = CHS.CHS1016x12_5
     return SteelCrossSection(profile=profile, material=steel_material), profile.section_properties()
+
+
+@pytest.fixture(scope="class")
+def unp_steel_cross_section() -> tuple[SteelCrossSection, SectionProperties]:
+    """Create a SteelCrossSection fixture with UNP80 profile and S355 steel material."""
+    steel_material = SteelMaterial(steel_class=SteelStrengthClass.S355)
+    profile = UNP.UNP80
+    return SteelCrossSection(profile=profile, material=steel_material), profile.section_properties()
diff --git a/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/test_torsion_strength.py b/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/test_torsion_strength.py
new file mode 100644
index 000000000..9d15cacd0
--- /dev/null
+++ b/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/test_torsion_strength.py
@@ -0,0 +1,48 @@
+"""Tests for TorsionStrengthCheck according to Eurocode 3."""
+
+import pytest
+from sectionproperties.post.post import SectionProperties
+
+from blueprints.checks.eurocode.steel.torsion_strength import TorsionStrengthCheck
+from blueprints.structural_sections.steel.steel_cross_section import SteelCrossSection
+
+
+class TestTorsionStrengthCheck:
+    """Tests for TorsionStrengthCheck."""
+
+    def test_result_none(self, unp_steel_cross_section: tuple[SteelCrossSection, SectionProperties]) -> None:
+        """Test result() returns True for no torsion."""
+        mx = 0
+        cross_section, section_properties = unp_steel_cross_section
+        calc = TorsionStrengthCheck(cross_section, mx, gamma_m0=1.0, section_properties=section_properties)
+        result = calc.result()
+        assert result.is_ok is True
+        assert result.unity_check == 0.0
+        assert result.factor_of_safety == float("inf")
+        assert result.provided == 0.0
+        assert calc.report()
+
+        calc_without_section_props = TorsionStrengthCheck(cross_section, mx, gamma_m0=1.0)
+        assert calc == calc_without_section_props
+
+    def test_result_tension_ok(self, unp_steel_cross_section: tuple[SteelCrossSection, SectionProperties]) -> None:
+        """Test result() for ok tension load."""
+        mx = -0.3896 * 0.99
+        cross_section, section_properties = unp_steel_cross_section
+        calc = TorsionStrengthCheck(cross_section, mx, gamma_m0=1.0, section_properties=section_properties)
+        result = calc.result()
+        assert result.is_ok is True
+        assert pytest.approx(result.unity_check, 0.005) == 0.99
+        assert pytest.approx(result.factor_of_safety, 0.005) == 1 / 0.99
+        assert calc.report()
+
+    def test_result_tension_not_ok(self, unp_steel_cross_section: tuple[SteelCrossSection, SectionProperties]) -> None:
+        """Test result() for not ok tension load."""
+        mx = 0.3896 * 1.01
+        cross_section, section_properties = unp_steel_cross_section
+        calc = TorsionStrengthCheck(cross_section, mx, gamma_m0=1.0, section_properties=section_properties)
+        result = calc.result()
+        assert result.is_ok is False
+        assert pytest.approx(result.unity_check, 0.005) == 1.01
+        assert pytest.approx(result.factor_of_safety, 0.005) == 1 / 1.01
+        assert calc.report()

From 86cb3514320b373e4a9178b2248f2d42ca21e87d Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Fri, 6 Feb 2026 19:45:28 +0100
Subject: [PATCH 25/46] feat: optimize torsion strength calculations and
 improve report clarity

---
 .../eurocode/steel/compression_strength.py    |  8 ++-
 .../checks/eurocode/steel/tension_strength.py |  8 ++-
 .../checks/eurocode/steel/torsion_strength.py | 53 +++++++++++--------
 3 files changed, 43 insertions(+), 26 deletions(-)

diff --git a/blueprints/checks/eurocode/steel/compression_strength.py b/blueprints/checks/eurocode/steel/compression_strength.py
index 2cca3519f..d98dab82f 100644
--- a/blueprints/checks/eurocode/steel/compression_strength.py
+++ b/blueprints/checks/eurocode/steel/compression_strength.py
@@ -127,14 +127,18 @@ def report(self, n: int = 2) -> Report:
         if self.n == 0:
             report.add_paragraph("No compressive force was applied; therefore, no compression force check is necessary.")
             return report
+
+        # Cache calculation formulas to avoid redundant recalculations
+        formulas = self.calculation_formula()
+
         report.add_paragraph(
             rf"Profile {self.steel_cross_section.profile.name} with steel quality {self.steel_cross_section.material.steel_class.name} "
             rf"is loaded with a compressive force of {abs(self.n):.{n}f} kN. "
             rf"The resistance is calculated as follows:"
         )
-        report.add_formula(self.calculation_formula()["resistance"], n=n)
+        report.add_formula(formulas["resistance"], n=n)
         report.add_paragraph("The unity check is calculated as follows:")
-        report.add_formula(self.calculation_formula()["check"], n=n)
+        report.add_formula(formulas["check"], n=n)
         if self.result().is_ok:
             report.add_paragraph("The check for compression force satisfies the requirements.")
         else:
diff --git a/blueprints/checks/eurocode/steel/tension_strength.py b/blueprints/checks/eurocode/steel/tension_strength.py
index ea62623c2..e2073a377 100644
--- a/blueprints/checks/eurocode/steel/tension_strength.py
+++ b/blueprints/checks/eurocode/steel/tension_strength.py
@@ -126,14 +126,18 @@ def report(self, n: int = 2) -> Report:
         if self.n == 0:
             report.add_paragraph("No tensile force was applied; therefore, no tensile force check is necessary.")
             return report
+
+        # Cache calculation formulas to avoid redundant recalculations
+        formulas = self.calculation_formula()
+
         report.add_paragraph(
             rf"Profile {self.steel_cross_section.profile.name} with steel quality {self.steel_cross_section.material.steel_class.name} "
             rf"is loaded with a tensile force of {self.n:.{n}f} kN. "
             rf"The resistance is calculated as follows:"
         )
-        report.add_formula(self.calculation_formula()["resistance"], n=n)
+        report.add_formula(formulas["resistance"], n=n)
         report.add_paragraph("The unity check is calculated as follows:")
-        report.add_formula(self.calculation_formula()["check"], n=n)
+        report.add_formula(formulas["check"], n=n)
         if self.result().is_ok:
             report.add_paragraph("The check for tensile force satisfies the requirements.")
         else:
diff --git a/blueprints/checks/eurocode/steel/torsion_strength.py b/blueprints/checks/eurocode/steel/torsion_strength.py
index 310aba87c..16f232faf 100644
--- a/blueprints/checks/eurocode/steel/torsion_strength.py
+++ b/blueprints/checks/eurocode/steel/torsion_strength.py
@@ -13,6 +13,7 @@
 from blueprints.saf.results.result_internal_force_1d import ResultFor, ResultInternalForce1D, ResultOn
 from blueprints.structural_sections.steel.steel_cross_section import SteelCrossSection
 from blueprints.type_alias import DIMENSIONLESS, KNM
+from blueprints.unit_conversion import KNM_TO_NMM
 from blueprints.utils.report import Report
 
 
@@ -74,7 +75,7 @@ def __post_init__(self) -> None:
             object.__setattr__(self, "section_properties", section_properties)
 
     def calculation_formula(self) -> dict[str, Formula]:
-        """Calculate torsion force resistance check.
+        """Calculate torsion resistance check.
 
         Returns
         -------
@@ -89,37 +90,37 @@ def calculation_formula(self) -> dict[str, Formula]:
             mx=1,  # 1 kNm
         )
 
-        stress = self.steel_cross_section.profile.calculate_stress(rif1d)
-        sig_zx_mzz = stress.get_stress()[0]["sig_zx_mzz"]
-        sig_zy_mzz = stress.get_stress()[0]["sig_zy_mzz"]
-        max_mzz_zxy = max((sig_zx_mzz**2 + sig_zy_mzz**2) ** 0.5)
+        unit_stress = self.steel_cross_section.profile.calculate_stress(rif1d)
+        unit_sig_zx_mzz = unit_stress.get_stress()[0]["sig_zx_mzz"]
+        unit_sig_zy_mzz = unit_stress.get_stress()[0]["sig_zy_mzz"]
+        unit_max_mzz_zxy = max((unit_sig_zx_mzz**2 + unit_sig_zy_mzz**2) ** 0.5)
 
-        t_rd = self.steel_cross_section.yield_strength / self.gamma_m0 / np.sqrt(3) / max_mzz_zxy
+        t_rd = self.steel_cross_section.yield_strength / self.gamma_m0 / np.sqrt(3) / unit_max_mzz_zxy
         t_ed = abs(self.mx)
 
         check_torsion = Form6Dot23CheckTorsionalMoment(t_ed=t_ed, t_rd=t_rd)
 
         return {
-            "kNm_unit_stress": max_mzz_zxy,
+            "unit_shear_stress": unit_max_mzz_zxy,
             "resistance": t_rd,
             "check": check_torsion,
         }
 
     def result(self) -> CheckResult:
-        """Calculate result of torsion force resistance.
+        """Calculate result of torsion resistance.
 
         Returns
         -------
         CheckResult
-            True if the torsion force check passes, False otherwise.
+            True if the torsion check passes, False otherwise.
         """
         steps = self.calculation_formula()
-        provided = abs(self.mx)
-        required = steps["resistance"]
+        provided = abs(self.mx) * KNM_TO_NMM
+        required = steps["resistance"] * KNM_TO_NMM
         return CheckResult.from_comparison(provided=provided, required=float(required))
 
     def report(self, n: int = 2) -> Report:
-        """Returns the report for the torsion force check.
+        """Returns the report for the torsion check.
 
         Parameters
         ----------
@@ -129,36 +130,44 @@ def report(self, n: int = 2) -> Report:
         Returns
         -------
         Report
-            Report of the torsion force check.
+            Report of the torsion check.
         """
-        report = Report("Check: torsion force steel beam")
+        report = Report("Check: torsion steel beam")
         if self.mx == 0:
-            report.add_paragraph("No torsion force was applied; therefore, no torsion force check is necessary.")
+            report.add_paragraph("No torsion was applied; therefore, no torsion check is necessary.")
             return report
+
+        # Cache calculation formulas to avoid redundant recalculations
+        formulas = self.calculation_formula()
+
+        # Get information for the introduction of the report
         profile_name = self.steel_cross_section.profile.name
         steel_quality = self.steel_cross_section.material.steel_class.name
         mx_val = f"{self.mx:.{n}f}"
-        unit_stress_val = f"{self.calculation_formula()['kNm_unit_stress']:.{n}f}"
+        unit_stress_val = f"{formulas['unit_shear_stress']:.{n}f}"
+
         report.add_paragraph(
             rf"Profile {profile_name} with steel quality {steel_quality} "
-            rf"is loaded with a torsion force of {mx_val} kNm. "
+            rf"is loaded with a torsion of {mx_val} kNm. "
             rf"First, the unit torsional stress (at 1 kNm) is defined as {unit_stress_val} MPa. "
             rf"The torsional resistance is calculated as follows:"
         )
 
+        # Get values for the formula of torsion resistance
         fy = self.steel_cross_section.yield_strength
         gamma_m0 = self.gamma_m0
-        unit_stress = self.calculation_formula()["kNm_unit_stress"]
-        result = self.calculation_formula()["resistance"]
+        unit_stress = formulas["unit_shear_stress"]
+        result = formulas["resistance"]
+
         eqn_1 = (
             rf"T_{{Rd}} = \frac{{f_y}}{{\gamma_{{M0}} \cdot \sqrt{{3}} \cdot \text{{unit-stress}}}} = "
             rf"\frac{{{fy:.{n}f}}}{{{gamma_m0:.{n}f} \cdot \sqrt{{3}} \cdot {unit_stress:.{n}f}}} = {result:.{n}f} \ kNm"
         )
         report.add_equation(eqn_1)
         report.add_paragraph("The unity check is calculated as follows:")
-        report.add_formula(self.calculation_formula()["check"], n=n)
+        report.add_formula(formulas["check"], n=n)
         if self.result().is_ok:
-            report.add_paragraph("The check for torsion force satisfies the requirements.")
+            report.add_paragraph("The check for torsion satisfies the requirements.")
         else:
-            report.add_paragraph("The check for torsion force does NOT satisfy the requirements.")
+            report.add_paragraph("The check for torsion does NOT satisfy the requirements.")
         return report

From 665e2becdf5279c4e5aa615e8965ada163a4c4d8 Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Fri, 6 Feb 2026 20:08:36 +0100
Subject: [PATCH 26/46] feat: add TorsionWithShearStrengthIProfileCheck module
 and corresponding tests

---
 .../steel/torsion_with_shear_strength.py      | 204 ++++++++++++++++++
 .../test_torsion_with_shear_strength.py       | 108 ++++++++++
 2 files changed, 312 insertions(+)
 create mode 100644 blueprints/checks/eurocode/steel/torsion_with_shear_strength.py
 create mode 100644 tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/test_torsion_with_shear_strength.py

diff --git a/blueprints/checks/eurocode/steel/torsion_with_shear_strength.py b/blueprints/checks/eurocode/steel/torsion_with_shear_strength.py
new file mode 100644
index 000000000..318743c4c
--- /dev/null
+++ b/blueprints/checks/eurocode/steel/torsion_with_shear_strength.py
@@ -0,0 +1,204 @@
+"""Module for checking torsional shear stress resistance with shear force present (Eurocode 2, formula 6.23)."""
+
+from dataclasses import dataclass, field
+from typing import ClassVar, Literal
+
+from sectionproperties.post.post import SectionProperties
+
+from blueprints.checks.check_result import CheckResult
+from blueprints.checks.eurocode.steel.shear_strength import PlasticShearStrengthIProfileCheck
+from blueprints.codes.eurocode.en_1993_1_1_2005 import EN_1993_1_1_2005
+from blueprints.codes.eurocode.en_1993_1_1_2005.chapter_6_ultimate_limit_state.formula_6_25 import Form6Dot25CheckCombinedShearForceAndTorsionalMoment
+from blueprints.codes.eurocode.en_1993_1_1_2005.chapter_6_ultimate_limit_state.formula_6_26 import Form6Dot26VplTRdIOrHSection
+from blueprints.codes.formula import Formula
+from blueprints.saf.results.result_internal_force_1d import ResultFor, ResultInternalForce1D, ResultOn
+from blueprints.structural_sections.steel.profile_definitions.i_profile import IProfile
+from blueprints.structural_sections.steel.steel_cross_section import SteelCrossSection
+from blueprints.type_alias import DIMENSIONLESS, KN, KNM
+from blueprints.unit_conversion import KN_TO_N
+from blueprints.utils.report import Report
+
+
+@dataclass(frozen=True)
+class TorsionWithShearStrengthIProfileCheck:
+    """Class to perform torsion resistance check with extra shear force for I profiles (Eurocode 3).
+
+    Coordinate System:
+
+        z (vertical, usually strong axis)
+            ↑
+            |     x (longitudinal beam direction, into screen)
+            |    ↗
+            |   /
+            |  /
+            | /
+            |/
+      ←-----O
+       y (horizontal/side, usually weak axis)
+
+    Parameters
+    ----------
+    steel_cross_section : SteelCrossSection
+        The steel cross-section, of type I-profile, to check.
+    mx : KNM
+        The applied shear force (positive value, in kN).
+    v : KN
+        The applied shear force (positive value, in kN).
+    axis : Literal["Vz", "Vy"]
+        Axis along which the shear force is applied. "Vz" (default) for z (vertical), "Vy" for y (horizontal).
+    gamma_m0 : DIMENSIONLESS, optional
+        Partial safety factor for resistance of cross-sections, default is 1.0.
+    section_properties : SectionProperties | None, optional
+        Pre-calculated section properties. If None, they will be calculated internally.
+
+    Example
+    -------
+    from blueprints.checks.eurocode.steel.torsion_with_shear_strength import TorsionWithShearStrengthIProfileCheck
+    from blueprints.materials.steel import SteelMaterial, SteelStrengthClass
+    from blueprints.structural_sections.steel.standard_profiles.heb import HEB
+
+    steel_material = SteelMaterial(steel_class=SteelStrengthClass.S355)
+    heb_300_profile = HEB.HEB300.with_corrosion(1.5)
+    mx = 10  # Applied torsional moment in kNm
+    v = 100  # Applied shear force in kN
+    axis = "Vz"  # Shear force applied in z-direction
+
+    heb_300_s355 = SteelCrossSection(profile=heb_300_profile, material=steel_material)
+    calc = TorsionWithShearStrengthIProfileCheck(heb_300_s355, mx, v=v, axis=axis, gamma_m0=1.0)
+    calc.report().to_word("torsion_and_shear_strength.docx", language="nl")
+
+    """
+
+    steel_cross_section: SteelCrossSection
+    mx: KNM = 0
+    v: KN = 0
+    axis: Literal["Vz", "Vy"] = "Vz"
+    gamma_m0: DIMENSIONLESS = 1.0
+    section_properties: SectionProperties | None = None
+    name: str = "Torsion strength check for steel I-profiles"
+    source_docs: ClassVar[list] = [EN_1993_1_1_2005]
+    _profile: IProfile = field(init=False, repr=False)
+
+    def __post_init__(self) -> None:
+        """Post-initialization to extract section properties and check profile type."""
+        if not isinstance(self.steel_cross_section.profile, IProfile):
+            raise TypeError("The provided profile is not an I-profile.")
+        object.__setattr__(self, "_profile", self.steel_cross_section.profile)
+        if self.section_properties is None:
+            section_properties = self.steel_cross_section.profile.section_properties()
+            object.__setattr__(self, "section_properties", section_properties)
+
+    def calculation_formula(self) -> dict[str, Formula]:
+        """Calculate torsion resistance check.
+
+        Returns
+        -------
+        dict[str, Formula]
+            Calculation results keyed by formula number. Returns an empty dict if no torsion is applied.
+        """
+        shear_calculation = PlasticShearStrengthIProfileCheck(
+            steel_cross_section=self.steel_cross_section,
+            v=self.v,
+            axis=self.axis,
+            gamma_m0=self.gamma_m0,
+            section_properties=self.section_properties,
+        )
+
+        shear_formulas = shear_calculation.calculation_formula()
+        a_v = shear_formulas["shear_area"]
+        v_pl_rd = shear_formulas["resistance"]
+
+        rif1d = ResultInternalForce1D(
+            result_on=ResultOn.ON_BEAM,
+            member="N/A",
+            result_for=ResultFor.LOAD_CASE,
+            load_case="N/A",
+            mx=1,  # 1 kNm
+        )
+
+        unit_stress = self.steel_cross_section.profile.calculate_stress(rif1d)
+        unit_sig_zx_mzz = unit_stress.get_stress()[0]["sig_zx_mzz"]
+        unit_sig_zy_mzz = unit_stress.get_stress()[0]["sig_zy_mzz"]
+        unit_max_mzz_zxy = max((unit_sig_zx_mzz**2 + unit_sig_zy_mzz**2) ** 0.5)
+
+        tau_t_ed = abs(self.mx) * unit_max_mzz_zxy
+        v_ed = abs(self.v) * KN_TO_N
+
+        v_pl_t_rd = Form6Dot26VplTRdIOrHSection(
+            tau_t_ed=tau_t_ed, f_y=self.steel_cross_section.yield_strength, gamma_m0=self.gamma_m0, v_pl_rd=v_pl_rd
+        )
+
+        check_torsion_with_shear = Form6Dot25CheckCombinedShearForceAndTorsionalMoment(v_ed=v_ed, v_pl_t_rd=v_pl_t_rd)
+
+        return {
+            "unit_shear_stress": unit_max_mzz_zxy,
+            "shear_area": a_v,
+            "raw_shear_resistance": v_pl_rd,
+            "resistance": v_pl_t_rd,
+            "check": check_torsion_with_shear,
+        }
+
+    def result(self) -> CheckResult:
+        """Calculate result of torsion resistance.
+
+        Returns
+        -------
+        CheckResult
+            True if the torsion check passes, False otherwise.
+        """
+        steps = self.calculation_formula()
+        provided = 0 if self.mx == 0 else abs(self.v) * KN_TO_N
+        required = steps["resistance"]
+        return CheckResult.from_comparison(provided=provided, required=float(required))
+
+    def report(self, n: int = 2) -> Report:
+        """Returns the report for the torsion check.
+
+        Parameters
+        ----------
+        n : int, optional
+            Number of decimal places for numerical values in the report (default is 2).
+
+        Returns
+        -------
+        Report
+            Report of the torsion check.
+        """
+        report = Report("Check: torsion with shear force on steel beam")
+        if self.mx == 0:
+            report.add_paragraph("No torsion was applied; therefore, no combined torsion with shear force check is necessary.")
+            return report
+        if self.v == 0:
+            report.add_paragraph("No shear force was applied; therefore, no combined torsion with shear force check is necessary.")
+            return report
+
+        # Cache calculation formulas to avoid redundant recalculations
+        formulas = self.calculation_formula()
+
+        # Get information for the introduction of the report
+        profile_name = self.steel_cross_section.profile.name
+        steel_quality = self.steel_cross_section.material.steel_class.name
+        mx_val = f"{self.mx:.{n}f}"
+        unit_stress_val = f"{formulas['unit_shear_stress']:.{n}f}"
+        axis_label = "(vertical) z" if self.axis == "Vz" else "(horizontal) y"
+        total_stress_val = f"{formulas['unit_shear_stress'] * self.mx:.{n}f}"
+
+        report.add_paragraph(
+            rf"Profile {profile_name} with steel quality {steel_quality} "
+            rf"is loaded with a torsion of {mx_val} kNm a shear force of {abs(self.v):.{n}f} kN in the {axis_label}-direction. "
+            rf"First, the unit torsional stress (at 1 kNm) is defined as {unit_stress_val} MPa. "
+            rf"With the applied torsion, this results in a torsional stress of {total_stress_val} MPa. "
+            rf"The shear area and resistance (without torsion) are calculated as follows:"
+        )
+
+        report.add_formula(formulas["shear_area"], n=n, split_after=[(2, "="), (7, "+"), (3, "=")])
+        report.add_formula(formulas["raw_shear_resistance"], n=n)
+        report.add_paragraph("Next, the combined torsion and shear resistance is calculated as follows:")
+        report.add_formula(formulas["resistance"], n=n)
+        report.add_paragraph("The unity check is calculated as follows:")
+        report.add_formula(formulas["check"], n=n)
+        if self.result().is_ok:
+            report.add_paragraph("The check for torsion satisfies the requirements.")
+        else:
+            report.add_paragraph("The check for torsion does NOT satisfy the requirements.")
+        return report
diff --git a/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/test_torsion_with_shear_strength.py b/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/test_torsion_with_shear_strength.py
new file mode 100644
index 000000000..0d3c15086
--- /dev/null
+++ b/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/test_torsion_with_shear_strength.py
@@ -0,0 +1,108 @@
+"""Tests for torsion with shear strength according to Eurocode 3."""
+
+import pytest
+from sectionproperties.post.post import SectionProperties
+
+from blueprints.checks.eurocode.steel.torsion_with_shear_strength import TorsionWithShearStrengthIProfileCheck
+from blueprints.structural_sections.steel.steel_cross_section import SteelCrossSection
+
+
+class TestTorsionWithShearStrengthIProfileCheck:
+    """Tests for TorsionWithShearStrengthIProfileCheck."""
+
+    def test_result_none_v(self, heb_steel_cross_section: tuple[SteelCrossSection, SectionProperties]) -> None:
+        """Test result() returns True for no shear force."""
+        cross_section, section_properties = heb_steel_cross_section
+        v = 0
+        mx = 1
+        calc = TorsionWithShearStrengthIProfileCheck(cross_section, mx, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
+        result = calc.result()
+        assert result.is_ok is True
+        assert result.unity_check == 0
+        assert result.factor_of_safety == float("inf")
+        assert result.provided == 0.0
+        assert calc.report()
+
+        calc_without_section_props = TorsionWithShearStrengthIProfileCheck(cross_section, mx, v, axis="Vz", gamma_m0=1.0)
+        assert calc == calc_without_section_props
+
+    def test_result_none_mx(self, heb_steel_cross_section: tuple[SteelCrossSection, SectionProperties]) -> None:
+        """Test result() returns True for no shear force."""
+        cross_section, section_properties = heb_steel_cross_section
+        mx = 0
+        v = 1
+        calc = TorsionWithShearStrengthIProfileCheck(cross_section, mx, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
+        result = calc.result()
+        assert result.is_ok is True
+        assert result.unity_check == 0
+        assert result.factor_of_safety == float("inf")
+        assert result.provided == 0.0
+        assert calc.report()
+
+    def test_result_shear_ok(self, heb_steel_cross_section: tuple[SteelCrossSection, SectionProperties]) -> None:
+        """Test result() for ok shear force."""
+        cross_section, section_properties = heb_steel_cross_section
+        v = 585.023 * 0.99
+        mx = 10
+        calc = TorsionWithShearStrengthIProfileCheck(cross_section, mx, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
+        result = calc.result()
+        assert result.is_ok is True
+        assert pytest.approx(result.unity_check, 0.005) == 0.99
+        assert pytest.approx(result.factor_of_safety, 0.005) == 1 / 0.99
+
+        v = -v
+        calc = TorsionWithShearStrengthIProfileCheck(cross_section, mx, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
+        result = calc.result()
+        assert result.is_ok is True
+        assert pytest.approx(result.unity_check, 0.005) == 0.99
+        assert pytest.approx(result.factor_of_safety, 0.005) == 1 / 0.99
+
+        v = 1482.833 * 0.99
+        calc = TorsionWithShearStrengthIProfileCheck(cross_section, mx, v, axis="Vy", gamma_m0=1.0, section_properties=section_properties)
+        result = calc.result()
+        assert result.is_ok is True
+        assert pytest.approx(result.unity_check, 0.005) == 0.99
+        assert pytest.approx(result.factor_of_safety, 0.005) == 1 / 0.99
+
+        v = 355.277 * 0.99
+        object.__setattr__(cross_section, "fabrication_method", "welded")
+        calc = TorsionWithShearStrengthIProfileCheck(cross_section, mx, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
+        result = calc.result()
+        assert result.is_ok is True
+        assert pytest.approx(result.unity_check, 0.005) == 0.99
+        assert pytest.approx(result.factor_of_safety, 0.005) == 1 / 0.99
+
+    def test_result_shear_not_ok(self, heb_steel_cross_section: tuple[SteelCrossSection, SectionProperties]) -> None:
+        """Test result() for not ok shear force."""
+        cross_section, section_properties = heb_steel_cross_section
+        object.__setattr__(cross_section, "fabrication_method", "rolled")
+        v = 585.023 * 1.01
+        mx = 10
+        calc = TorsionWithShearStrengthIProfileCheck(cross_section, mx, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
+        result = calc.result()
+        assert result.is_ok is False
+        assert pytest.approx(result.unity_check, 0.005) == 1.01
+        assert pytest.approx(result.factor_of_safety, 0.005) == 1 / 1.01
+        assert calc.report()
+
+        v = 1482.833 * 1.01
+        calc = TorsionWithShearStrengthIProfileCheck(cross_section, mx, v, axis="Vy", gamma_m0=1.0, section_properties=section_properties)
+        result = calc.result()
+        assert result.is_ok is False
+        assert pytest.approx(result.unity_check, 0.005) == 1.01
+        assert pytest.approx(result.factor_of_safety, 0.005) == 1 / 1.01
+        assert calc.report()
+
+        v = 355.277 * 1.01
+        object.__setattr__(cross_section, "fabrication_method", "welded")
+        calc = TorsionWithShearStrengthIProfileCheck(cross_section, mx, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
+        result = calc.result()
+        assert result.is_ok is False
+        assert pytest.approx(result.unity_check, 0.005) == 1.01
+        assert pytest.approx(result.factor_of_safety, 0.005) == 1 / 1.01
+
+    def test_check_wrong_profile(self, chs_steel_cross_section: tuple[SteelCrossSection, SectionProperties]) -> None:
+        """Test check() raises TypeError for non-I-profile."""
+        cross_section, section_properties = chs_steel_cross_section
+        with pytest.raises(TypeError, match="The provided profile is not an I-profile"):
+            TorsionWithShearStrengthIProfileCheck(cross_section, mx=10, v=1, gamma_m0=1.0, section_properties=section_properties)

From 4617877484942a64ec98c18aaafe79a53b37fc03 Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Fri, 6 Feb 2026 20:31:21 +0100
Subject: [PATCH 27/46] feat: rename TorsionStrengthCheck to
 StVenantTorsionStrengthCheck and update related tests

---
 .../checks/eurocode/steel/torsion_strength.py    |  2 +-
 .../steel/torsion_with_shear_strength.py         |  2 +-
 .../test_torsion_strength.py                     | 16 ++++++++--------
 .../test_torsion_with_shear_strength.py          |  2 +-
 4 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/blueprints/checks/eurocode/steel/torsion_strength.py b/blueprints/checks/eurocode/steel/torsion_strength.py
index 16f232faf..001126267 100644
--- a/blueprints/checks/eurocode/steel/torsion_strength.py
+++ b/blueprints/checks/eurocode/steel/torsion_strength.py
@@ -18,7 +18,7 @@
 
 
 @dataclass(frozen=True)
-class TorsionStrengthCheck:
+class StVenantTorsionStrengthCheck:
     """Class to perform torsion resistance check (Eurocode 3).
 
     Coordinate System:
diff --git a/blueprints/checks/eurocode/steel/torsion_with_shear_strength.py b/blueprints/checks/eurocode/steel/torsion_with_shear_strength.py
index 318743c4c..7d82fac49 100644
--- a/blueprints/checks/eurocode/steel/torsion_with_shear_strength.py
+++ b/blueprints/checks/eurocode/steel/torsion_with_shear_strength.py
@@ -21,7 +21,7 @@
 
 @dataclass(frozen=True)
 class TorsionWithShearStrengthIProfileCheck:
-    """Class to perform torsion resistance check with extra shear force for I profiles (Eurocode 3).
+    """Class to perform torsion resistance check with extra shear force for I profiles (Eurocode 3), using St. Venant torsion.
 
     Coordinate System:
 
diff --git a/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/test_torsion_strength.py b/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/test_torsion_strength.py
index 9d15cacd0..df74eee4a 100644
--- a/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/test_torsion_strength.py
+++ b/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/test_torsion_strength.py
@@ -1,20 +1,20 @@
-"""Tests for TorsionStrengthCheck according to Eurocode 3."""
+"""Tests for StVenantTorsionStrengthCheck according to Eurocode 3."""
 
 import pytest
 from sectionproperties.post.post import SectionProperties
 
-from blueprints.checks.eurocode.steel.torsion_strength import TorsionStrengthCheck
+from blueprints.checks.eurocode.steel.torsion_strength import StVenantTorsionStrengthCheck
 from blueprints.structural_sections.steel.steel_cross_section import SteelCrossSection
 
 
-class TestTorsionStrengthCheck:
-    """Tests for TorsionStrengthCheck."""
+class TestStVenantTorsionStrengthCheck:
+    """Tests for StVenantTorsionStrengthCheck."""
 
     def test_result_none(self, unp_steel_cross_section: tuple[SteelCrossSection, SectionProperties]) -> None:
         """Test result() returns True for no torsion."""
         mx = 0
         cross_section, section_properties = unp_steel_cross_section
-        calc = TorsionStrengthCheck(cross_section, mx, gamma_m0=1.0, section_properties=section_properties)
+        calc = StVenantTorsionStrengthCheck(cross_section, mx, gamma_m0=1.0, section_properties=section_properties)
         result = calc.result()
         assert result.is_ok is True
         assert result.unity_check == 0.0
@@ -22,14 +22,14 @@ def test_result_none(self, unp_steel_cross_section: tuple[SteelCrossSection, Sec
         assert result.provided == 0.0
         assert calc.report()
 
-        calc_without_section_props = TorsionStrengthCheck(cross_section, mx, gamma_m0=1.0)
+        calc_without_section_props = StVenantTorsionStrengthCheck(cross_section, mx, gamma_m0=1.0)
         assert calc == calc_without_section_props
 
     def test_result_tension_ok(self, unp_steel_cross_section: tuple[SteelCrossSection, SectionProperties]) -> None:
         """Test result() for ok tension load."""
         mx = -0.3896 * 0.99
         cross_section, section_properties = unp_steel_cross_section
-        calc = TorsionStrengthCheck(cross_section, mx, gamma_m0=1.0, section_properties=section_properties)
+        calc = StVenantTorsionStrengthCheck(cross_section, mx, gamma_m0=1.0, section_properties=section_properties)
         result = calc.result()
         assert result.is_ok is True
         assert pytest.approx(result.unity_check, 0.005) == 0.99
@@ -40,7 +40,7 @@ def test_result_tension_not_ok(self, unp_steel_cross_section: tuple[SteelCrossSe
         """Test result() for not ok tension load."""
         mx = 0.3896 * 1.01
         cross_section, section_properties = unp_steel_cross_section
-        calc = TorsionStrengthCheck(cross_section, mx, gamma_m0=1.0, section_properties=section_properties)
+        calc = StVenantTorsionStrengthCheck(cross_section, mx, gamma_m0=1.0, section_properties=section_properties)
         result = calc.result()
         assert result.is_ok is False
         assert pytest.approx(result.unity_check, 0.005) == 1.01
diff --git a/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/test_torsion_with_shear_strength.py b/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/test_torsion_with_shear_strength.py
index 0d3c15086..e40376360 100644
--- a/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/test_torsion_with_shear_strength.py
+++ b/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/test_torsion_with_shear_strength.py
@@ -8,7 +8,7 @@
 
 
 class TestTorsionWithShearStrengthIProfileCheck:
-    """Tests for TorsionWithShearStrengthIProfileCheck."""
+    """Tests for TorsionWithShearStrengthIProfileCheck, using St. Venant torsion."""
 
     def test_result_none_v(self, heb_steel_cross_section: tuple[SteelCrossSection, SectionProperties]) -> None:
         """Test result() returns True for no shear force."""

From 84fa85b882a2f40a38c7c5620e34dafcfa0fce03 Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Sat, 7 Feb 2026 08:41:07 +0100
Subject: [PATCH 28/46] test: add report assertion to shear strength test cases

---
 .../ultimate_limit_states/test_torsion_with_shear_strength.py   | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/test_torsion_with_shear_strength.py b/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/test_torsion_with_shear_strength.py
index e40376360..85469b258 100644
--- a/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/test_torsion_with_shear_strength.py
+++ b/tests/checks/eurocode/en_1993_1_1_2005/ultimate_limit_states/test_torsion_with_shear_strength.py
@@ -49,6 +49,7 @@ def test_result_shear_ok(self, heb_steel_cross_section: tuple[SteelCrossSection,
         assert result.is_ok is True
         assert pytest.approx(result.unity_check, 0.005) == 0.99
         assert pytest.approx(result.factor_of_safety, 0.005) == 1 / 0.99
+        assert calc.report()
 
         v = -v
         calc = TorsionWithShearStrengthIProfileCheck(cross_section, mx, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
@@ -91,7 +92,6 @@ def test_result_shear_not_ok(self, heb_steel_cross_section: tuple[SteelCrossSect
         assert result.is_ok is False
         assert pytest.approx(result.unity_check, 0.005) == 1.01
         assert pytest.approx(result.factor_of_safety, 0.005) == 1 / 1.01
-        assert calc.report()
 
         v = 355.277 * 1.01
         object.__setattr__(cross_section, "fabrication_method", "welded")

From ca29d2c5b318dd6e4436b2cf13f95cb1ace26e00 Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Sat, 7 Feb 2026 08:50:54 +0100
Subject: [PATCH 29/46] feat: optimize stress calculation in torsion checks and
 update return type in Profile class

---
 blueprints/checks/eurocode/steel/torsion_strength.py         | 2 +-
 .../checks/eurocode/steel/torsion_with_shear_strength.py     | 3 ++-
 blueprints/structural_sections/_profile.py                   | 5 +++--
 3 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/blueprints/checks/eurocode/steel/torsion_strength.py b/blueprints/checks/eurocode/steel/torsion_strength.py
index 001126267..63e3eab81 100644
--- a/blueprints/checks/eurocode/steel/torsion_strength.py
+++ b/blueprints/checks/eurocode/steel/torsion_strength.py
@@ -93,7 +93,7 @@ def calculation_formula(self) -> dict[str, Formula]:
         unit_stress = self.steel_cross_section.profile.calculate_stress(rif1d)
         unit_sig_zx_mzz = unit_stress.get_stress()[0]["sig_zx_mzz"]
         unit_sig_zy_mzz = unit_stress.get_stress()[0]["sig_zy_mzz"]
-        unit_max_mzz_zxy = max((unit_sig_zx_mzz**2 + unit_sig_zy_mzz**2) ** 0.5)
+        unit_max_mzz_zxy = np.max(np.sqrt(np.array(unit_sig_zx_mzz) ** 2 + np.array(unit_sig_zy_mzz) ** 2))
 
         t_rd = self.steel_cross_section.yield_strength / self.gamma_m0 / np.sqrt(3) / unit_max_mzz_zxy
         t_ed = abs(self.mx)
diff --git a/blueprints/checks/eurocode/steel/torsion_with_shear_strength.py b/blueprints/checks/eurocode/steel/torsion_with_shear_strength.py
index 7d82fac49..8c9742f80 100644
--- a/blueprints/checks/eurocode/steel/torsion_with_shear_strength.py
+++ b/blueprints/checks/eurocode/steel/torsion_with_shear_strength.py
@@ -3,6 +3,7 @@
 from dataclasses import dataclass, field
 from typing import ClassVar, Literal
 
+import numpy as np
 from sectionproperties.post.post import SectionProperties
 
 from blueprints.checks.check_result import CheckResult
@@ -119,7 +120,7 @@ def calculation_formula(self) -> dict[str, Formula]:
         unit_stress = self.steel_cross_section.profile.calculate_stress(rif1d)
         unit_sig_zx_mzz = unit_stress.get_stress()[0]["sig_zx_mzz"]
         unit_sig_zy_mzz = unit_stress.get_stress()[0]["sig_zy_mzz"]
-        unit_max_mzz_zxy = max((unit_sig_zx_mzz**2 + unit_sig_zy_mzz**2) ** 0.5)
+        unit_max_mzz_zxy = np.max(np.sqrt(np.array(unit_sig_zx_mzz) ** 2 + np.array(unit_sig_zy_mzz) ** 2))
 
         tau_t_ed = abs(self.mx) * unit_max_mzz_zxy
         v_ed = abs(self.v) * KN_TO_N
diff --git a/blueprints/structural_sections/_profile.py b/blueprints/structural_sections/_profile.py
index a15d53477..d0fc8502f 100644
--- a/blueprints/structural_sections/_profile.py
+++ b/blueprints/structural_sections/_profile.py
@@ -9,6 +9,7 @@
 import matplotlib.pyplot as plt
 from sectionproperties.analysis import Section
 from sectionproperties.post.post import SectionProperties
+from sectionproperties.post.stress_post import StressPost
 from sectionproperties.pre import Geometry
 from shapely import Point, Polygon
 from shapely.affinity import rotate, translate
@@ -186,7 +187,7 @@ def plotter(self) -> Callable[[Any], plt.Figure]:
         """Default plotter function for the profile."""
         raise AttributeError("No plotter is defined.")
 
-    def calculate_stress(self, result_internal_force_1d: ResultInternalForce1D) -> Callable[..., SectionProperties]:
+    def calculate_stress(self, result_internal_force_1d: ResultInternalForce1D) -> StressPost:
         """Calculate the stress distribution for the profile given internal forces.
 
         Parameters
@@ -196,7 +197,7 @@ def calculate_stress(self, result_internal_force_1d: ResultInternalForce1D) -> C
 
         Returns
         -------
-        Callable[..., SectionProperties]
+        Callable[..., StressPost]
             A function that calculates the stress distribution when called.
         """
         section = self._section()

From 17def6cc69c66bf3b74a20a57489c85dad7b45fb Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Sat, 7 Feb 2026 08:54:15 +0100
Subject: [PATCH 30/46] feat: simplify name of torsion strength check for
 clarity

---
 blueprints/checks/eurocode/steel/torsion_strength.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/blueprints/checks/eurocode/steel/torsion_strength.py b/blueprints/checks/eurocode/steel/torsion_strength.py
index 63e3eab81..035e7bd0a 100644
--- a/blueprints/checks/eurocode/steel/torsion_strength.py
+++ b/blueprints/checks/eurocode/steel/torsion_strength.py
@@ -65,7 +65,7 @@ class StVenantTorsionStrengthCheck:
     mx: KNM = 0
     gamma_m0: DIMENSIONLESS = 1.0
     section_properties: SectionProperties | None = None
-    name: str = "Torsion strength check for steel I-profiles"
+    name: str = "Torsion strength check"
     source_docs: ClassVar[list] = [EN_1993_1_1_2005]
 
     def __post_init__(self) -> None:

From cdc567601b55a9dd862670e3fe0f3b957bfb8b40 Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Sat, 7 Feb 2026 10:03:26 +0100
Subject: [PATCH 31/46] refactor: remove unused profile attribute in
 TorsionWithShearStrengthIProfileCheck

---
 .../checks/eurocode/steel/torsion_with_shear_strength.py      | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/blueprints/checks/eurocode/steel/torsion_with_shear_strength.py b/blueprints/checks/eurocode/steel/torsion_with_shear_strength.py
index 8c9742f80..da4d5c6bc 100644
--- a/blueprints/checks/eurocode/steel/torsion_with_shear_strength.py
+++ b/blueprints/checks/eurocode/steel/torsion_with_shear_strength.py
@@ -1,6 +1,6 @@
 """Module for checking torsional shear stress resistance with shear force present (Eurocode 2, formula 6.23)."""
 
-from dataclasses import dataclass, field
+from dataclasses import dataclass
 from typing import ClassVar, Literal
 
 import numpy as np
@@ -78,13 +78,11 @@ class TorsionWithShearStrengthIProfileCheck:
     section_properties: SectionProperties | None = None
     name: str = "Torsion strength check for steel I-profiles"
     source_docs: ClassVar[list] = [EN_1993_1_1_2005]
-    _profile: IProfile = field(init=False, repr=False)
 
     def __post_init__(self) -> None:
         """Post-initialization to extract section properties and check profile type."""
         if not isinstance(self.steel_cross_section.profile, IProfile):
             raise TypeError("The provided profile is not an I-profile.")
-        object.__setattr__(self, "_profile", self.steel_cross_section.profile)
         if self.section_properties is None:
             section_properties = self.steel_cross_section.profile.section_properties()
             object.__setattr__(self, "section_properties", section_properties)

From 3dbacdf7fdca572b3f70a533ff5f23b04ba571b9 Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Sat, 7 Feb 2026 10:04:01 +0100
Subject: [PATCH 32/46] refactor: remove unused profile attribute from
 PlasticShearStrengthIProfileCheck

---
 blueprints/checks/eurocode/steel/shear_strength.py | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/blueprints/checks/eurocode/steel/shear_strength.py b/blueprints/checks/eurocode/steel/shear_strength.py
index a23f62402..9dd71f766 100644
--- a/blueprints/checks/eurocode/steel/shear_strength.py
+++ b/blueprints/checks/eurocode/steel/shear_strength.py
@@ -1,6 +1,6 @@
 """Module for checking plastic shear force resistance of steel(Eurocode 3)."""
 
-from dataclasses import dataclass, field
+from dataclasses import dataclass
 from typing import ClassVar, Literal
 
 from sectionproperties.post.post import SectionProperties
@@ -73,13 +73,11 @@ class PlasticShearStrengthIProfileCheck:
     section_properties: SectionProperties | None = None
     name: str = "Plastic shear strength check for steel I-profiles"
     source_docs: ClassVar[list] = [EN_1993_1_1_2005]
-    _profile: IProfile = field(init=False, repr=False)
 
     def __post_init__(self) -> None:
         """Post-initialization to extract section properties and check profile type."""
         if not isinstance(self.steel_cross_section.profile, IProfile):
             raise TypeError("The provided profile is not an I-profile.")
-        object.__setattr__(self, "_profile", self.steel_cross_section.profile)
         if self.section_properties is None:
             section_properties = self.steel_cross_section.profile.section_properties()
             object.__setattr__(self, "section_properties", section_properties)

From 483441649e5853a9a01c38cd6de3279d55973f17 Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Sat, 7 Feb 2026 16:06:16 +0100
Subject: [PATCH 33/46] Update torsion_strength.py

---
 blueprints/checks/eurocode/steel/torsion_strength.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/blueprints/checks/eurocode/steel/torsion_strength.py b/blueprints/checks/eurocode/steel/torsion_strength.py
index 035e7bd0a..3b236bd17 100644
--- a/blueprints/checks/eurocode/steel/torsion_strength.py
+++ b/blueprints/checks/eurocode/steel/torsion_strength.py
@@ -39,7 +39,7 @@ class StVenantTorsionStrengthCheck:
     steel_cross_section : SteelCrossSection
         The steel cross-section, of type I-profile, to check.
     mx : KNM
-        The applied shear force (positive value, in kN).
+        The applied shear force (in kN).
     gamma_m0 : DIMENSIONLESS, optional
         Partial safety factor for resistance of cross-sections, default is 1.0.
     section_properties : SectionProperties | None, optional

From e6ecdbd83ebb9a75913bd0b8cc41aea1e9ca83aa Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Sat, 7 Feb 2026 16:06:58 +0100
Subject: [PATCH 34/46] Update shear_strength.py

---
 blueprints/checks/eurocode/steel/shear_strength.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/blueprints/checks/eurocode/steel/shear_strength.py b/blueprints/checks/eurocode/steel/shear_strength.py
index 9dd71f766..0d72a56fc 100644
--- a/blueprints/checks/eurocode/steel/shear_strength.py
+++ b/blueprints/checks/eurocode/steel/shear_strength.py
@@ -42,7 +42,7 @@ class PlasticShearStrengthIProfileCheck:
     steel_cross_section : SteelCrossSection
         The steel cross-section, of type I-profile, to check.
     v : KN
-        The applied shear force (positive value, in kN).
+        The applied shear force (in kN).
     axis : Literal["Vz", "Vy"]
         Axis along which the shear force is applied. "Vz" (default) for z (vertical), "Vy" for y (horizontal).
     gamma_m0 : DIMENSIONLESS, optional

From 19dbdaf9c2569fd0dbf6c865f95d896de133293f Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Sat, 7 Feb 2026 18:04:42 +0100
Subject: [PATCH 35/46] fix: use variable for equation type in LaTeX output

---
 blueprints/utils/report.py | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/blueprints/utils/report.py b/blueprints/utils/report.py
index aa1405814..5b28af5ad 100644
--- a/blueprints/utils/report.py
+++ b/blueprints/utils/report.py
@@ -171,13 +171,14 @@ def _split_equation(eq: str, split_after: list[tuple[int, str]] | None) -> str:
             return eq_mod
 
         eq_to_use = _split_equation(equation, split_after)
+        multline_vs_equation = "multline" if split_after else "equation"
 
         if inline:
             self.content += r"\txt{ " + rf"${eq_to_use}$" + f"{f' ({tag})' if tag else ''}" + r" }"
         elif tag:
-            self.content += rf"\begin{{multline}} {eq_to_use} \tag{{{tag}}} \end{{multline}}"
+            self.content += rf"\begin{{{multline_vs_equation}}} {eq_to_use} \tag{{{tag}}} \end{{{multline_vs_equation}}}"
         else:
-            self.content += rf"\begin{{multline}} {eq_to_use} \notag \end{{multline}}"
+            self.content += rf"\begin{{{multline_vs_equation}}} {eq_to_use} \notag \end{{{multline_vs_equation}}}"
 
         # Add a newline for visual separation
         self.content += "\n"

From 14a9b4d173c7e66892fe090bd699546faaf9147c Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Sat, 7 Feb 2026 18:07:09 +0100
Subject: [PATCH 36/46] fix: update equation formatting in test_report.py to
 use equation environment

---
 tests/utils/test_report.py | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/tests/utils/test_report.py b/tests/utils/test_report.py
index 199f7f642..2f2f10d83 100644
--- a/tests/utils/test_report.py
+++ b/tests/utils/test_report.py
@@ -119,13 +119,13 @@ def test_add_text_method_chaining(self, fixture_report: Report) -> None:
     def test_add_equation_without_tag(self, fixture_report: Report) -> None:
         """Test adding equation without tag."""
         fixture_report.add_equation("a^2+b^2=c^2")
-        expected = r"\begin{multline} a^2+b^2=c^2 \notag \end{multline}" + "\n"
+        expected = r"\begin{equation} a^2+b^2=c^2 \notag \end{equation}" + "\n"
         assert fixture_report.content == expected
 
     def test_add_equation_with_tag(self, fixture_report: Report) -> None:
         """Test adding equation with tag."""
         fixture_report.add_equation("a^2+b^2=c^2", tag="6.83")
-        expected = r"\begin{multline} a^2+b^2=c^2 \tag{6.83} \end{multline}" + "\n"
+        expected = r"\begin{equation} a^2+b^2=c^2 \tag{6.83} \end{equation}" + "\n"
         assert fixture_report.content == expected
 
     def test_very_long_equation_splitting(self, fixture_report: Report) -> None:
@@ -160,7 +160,7 @@ def test_add_equation_inline_method_chaining(self, fixture_report: Report) -> No
     def test_add_formula(self, fixture_report: Report) -> None:
         """Test adding formula."""
         fixture_report.add_formula(formula_6_5.Form6Dot5UnityCheckTensileStrength(n_ed=150000, n_t_rd=200000), options="complete")
-        expected = r"\begin{multline} CHECK"
+        expected = r"\begin{equation} CHECK"
         assert expected in fixture_report.content
 
     def test_add_formula_inline(self, fixture_report: Report) -> None:
@@ -172,7 +172,7 @@ def test_add_formula_inline(self, fixture_report: Report) -> None:
     def test_add_formula_complete_with_units(self, fixture_report: Report) -> None:
         """Test adding formula with complete_with_units option."""
         fixture_report.add_formula(formula_6_5.Form6Dot5UnityCheckTensileStrength(n_ed=150000, n_t_rd=200000), options="complete_with_units")
-        expected = r"\begin{multline} CHECK"
+        expected = r"\begin{equation} CHECK"
         assert expected in fixture_report.content
 
     def test_add_section(self, fixture_report: Report) -> None:
@@ -399,8 +399,8 @@ def test_comprehensive_example_from_docstring(self) -> None:
         assert r"\textbf{This is bold text with newline after.}" in latex_document
         assert r"\textit{This is italic text with 4 newlines after.}" in latex_document
         assert r"\textbf{\textit{This is bold and italic text.}}" in latex_document
-        assert r"\begin{multline} E=mc^2 \tag{3.14} \end{multline}" in latex_document
-        assert r"\begin{multline} CHECK" in latex_document
+        assert r"\begin{equation} E=mc^2 \tag{3.14} \end{equation}" in latex_document
+        assert r"\begin{equation} CHECK" in latex_document
         assert r"$\frac{a}{b}$" in latex_document
         assert r"Parameter & Value & Unit" in latex_document
         assert r"\text{Length} & 10 & \text{m}" in latex_document

From 9047dd4b4a388609440192bbf6970bd7000ba22a Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Sat, 7 Feb 2026 18:10:15 +0100
Subject: [PATCH 37/46] fix: include additional equation count in report
 summary

---
 blueprints/utils/report.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/blueprints/utils/report.py b/blueprints/utils/report.py
index 5b28af5ad..c989502e6 100644
--- a/blueprints/utils/report.py
+++ b/blueprints/utils/report.py
@@ -539,7 +539,7 @@ def __repr__(self) -> str:
         """Return a concise representation showing report structure and content summary."""
         sections = self.content.count(r"\section{")
         subsections = self.content.count(r"\subsection{")
-        equations = self.content.count(r"\begin{multline}")
+        equations = self.content.count(r"\begin{multline}") + self.content.count(r"\begin{equation}")
         tables = self.content.count(r"\begin{table}")
         figures = self.content.count(r"\begin{figure}")
         lists = self.content.count(r"\begin{itemize}") + self.content.count(r"\begin{enumerate}")
@@ -557,7 +557,7 @@ def __str__(self) -> str:
         """Return a human-readable representation of the report structure and content."""
         sections = self.content.count(r"\section{")
         subsections = self.content.count(r"\subsection{")
-        equations = self.content.count(r"\begin{multline}")
+        equations = self.content.count(r"\begin{multline}") + self.content.count(r"\begin{equation}")
         tables = self.content.count(r"\begin{table}")
         figures = self.content.count(r"\begin{figure}")
         lists = self.content.count(r"\begin{itemize}") + self.content.count(r"\begin{enumerate}")

From d99985fbed32e892344a7397ea788dea602c49b0 Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Sat, 7 Feb 2026 18:12:53 +0100
Subject: [PATCH 38/46] fix: update equation handling to support both multline
 and equation environments

---
 blueprints/utils/_report_to_word.py | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/blueprints/utils/_report_to_word.py b/blueprints/utils/_report_to_word.py
index e7fd14df0..cf5a2ad21 100644
--- a/blueprints/utils/_report_to_word.py
+++ b/blueprints/utils/_report_to_word.py
@@ -26,7 +26,7 @@ class _ReportToWordConverter:
 
     Limitations and Usage Notes:
     - Text blocks using \text{...} (can also be \textbf{...} and/or \textit{...} for bold/italic).
-    - Equations in \begin{multline}...\end{multline} environments (with optional \tag{...}).
+    - Equations in \begin{multline}...\end{multline} or \begin{equation}...\end{equation} environments (with optional \tag{...}).
     - Titles, sections, subsections, and subsubsections using \title{...}, \section{...}, \subsection{...}, \subsubsection{...}.
     - Tables in \begin{table}...\end{table} environments with tabular content
     - Figures in \begin{figure}...\end{figure} environments with \includegraphics.
@@ -175,7 +175,7 @@ def _extract_structural_elements(content: str) -> list[dict[str, str | int]]:
             "figure": r"\\begin\{figure\}",
             "itemize": r"\\begin\{itemize\}",
             "enumerate": r"\\begin\{enumerate\}",
-            "equation": r"\\begin\{multline\}",
+            "equation": r"\\begin\{(multline|equation)\}",
             "newline": r"\\newline",
         }
 
@@ -438,7 +438,13 @@ def _add_equation(self, doc: DocumentObject, content: str) -> None:
         equation_content = re.sub(r"\\notag", "", equation_content)
 
         # Split equation content on line breaks (\\)
-        lines = equation_content.replace("\\begin{multline}", "").replace("\\end{multline}", "").split(r"\\")
+        lines = (
+            equation_content.replace("\\begin{multline}", "")
+            .replace("\\end{multline}", "")
+            .replace("\\begin{equation}", "")
+            .replace("\\end{equation}", "")
+            .split(r"\\")
+        )
         for idx, line in enumerate(lines):
             p = doc.add_paragraph()
             p.style = "No Spacing"

From 40c581d43d730589d0f1032822a11844d883c7ec Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Sat, 7 Feb 2026 20:45:08 +0100
Subject: [PATCH 39/46] feat: update stress calculation to use correct unit
 conversions for forces and moments

---
 blueprints/structural_sections/_profile.py | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/blueprints/structural_sections/_profile.py b/blueprints/structural_sections/_profile.py
index d0fc8502f..d52a0bcfc 100644
--- a/blueprints/structural_sections/_profile.py
+++ b/blueprints/structural_sections/_profile.py
@@ -16,7 +16,7 @@
 
 from blueprints.saf.results.result_internal_force_1d import ResultInternalForce1D
 from blueprints.type_alias import DEG, M3_M, MM, MM2
-from blueprints.unit_conversion import M_TO_MM, MM3_TO_M3
+from blueprints.unit_conversion import KN_TO_N, KNM_TO_NMM, M_TO_MM, MM3_TO_M3
 
 
 @dataclass(frozen=True)
@@ -207,12 +207,12 @@ def calculate_stress(self, result_internal_force_1d: ResultInternalForce1D) -> S
         # Blueprints uses x for longitudinal axis, y for horizontal, z for vertical
         # sectionproperties uses x for horizontal, y for vertical, z for longitudinal
         return section.calculate_stress(
-            n=-float(result_internal_force_1d.n) * 1e3,
-            vx=-float(result_internal_force_1d.vy) * 1e3,
-            vy=float(result_internal_force_1d.vz) * 1e3,
-            mxx=-float(result_internal_force_1d.my) * 1e6,
-            myy=float(result_internal_force_1d.mz) * 1e6,
-            mzz=-float(result_internal_force_1d.mx) * 1e6,
+            n=float(result_internal_force_1d.n) * KN_TO_N,
+            vx=-float(result_internal_force_1d.vy) * KN_TO_N,
+            vy=float(result_internal_force_1d.vz) * KN_TO_N,
+            mxx=-float(result_internal_force_1d.my) * KNM_TO_NMM,
+            myy=float(result_internal_force_1d.mz) * KNM_TO_NMM,
+            mzz=float(result_internal_force_1d.mx) * KNM_TO_NMM,
         )
 
     def plot(self, plotter: Callable[[Any], plt.Figure] | None = None, *args, **kwargs) -> plt.Figure:

From 350d3959f8660f408f49dff744b1d86bded69c2b Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Sun, 8 Feb 2026 12:03:59 +0100
Subject: [PATCH 40/46] Add stress calculation method to Profile class for
 internal force analysis

---
 blueprints/structural_sections/_profile.py | 45 +++++++++++++++++++++-
 1 file changed, 44 insertions(+), 1 deletion(-)

diff --git a/blueprints/structural_sections/_profile.py b/blueprints/structural_sections/_profile.py
index 146ad3a19..5ca030a52 100644
--- a/blueprints/structural_sections/_profile.py
+++ b/blueprints/structural_sections/_profile.py
@@ -9,12 +9,14 @@
 import matplotlib.pyplot as plt
 from sectionproperties.analysis import Section
 from sectionproperties.post.post import SectionProperties
+from sectionproperties.post.stress_post import StressPost
 from sectionproperties.pre import Geometry
 from shapely import Point, Polygon
 from shapely.affinity import rotate, translate
 
+from blueprints.saf.results.result_internal_force_1d import ResultInternalForce1D
 from blueprints.type_alias import DEG, M3_M, MM, MM2
-from blueprints.unit_conversion import M_TO_MM, MM3_TO_M3
+from blueprints.unit_conversion import KN_TO_N, KNM_TO_NMM, M_TO_MM, MM3_TO_M3
 
 
 @dataclass(frozen=True)
@@ -185,6 +187,47 @@ def plotter(self) -> Callable[[Any], plt.Figure]:
         """Default plotter function for the profile."""
         raise AttributeError("No plotter is defined.")
 
+    def calculate_stress(self, result_internal_force_1d: ResultInternalForce1D) -> StressPost:
+        """Calculate the stress distribution for the profile given internal forces.
+
+        Parameters
+        ----------
+        result_internal_force_1d : ResultInternalForce1D
+            The internal forces and moments to calculate the stress for.
+
+        Returns
+        -------
+        Callable[..., StressPost]
+            A function that calculates the stress distribution when called.
+        """
+        section = self._section()
+        section.calculate_geometric_properties()
+        section.calculate_warping_properties()
+        # Note: The mapping of internal forces to sectionproperties parameters
+        # Blueprints uses x for longitudinal axis, y for horizontal, z for vertical
+        # sectionproperties uses x for horizontal, y for vertical, z for longitudinal
+
+        # Coordinate System Blueprints:                              Coordinate System SectionProperties:
+        #     z (vertical, usually strong axis)                          y (vertical, usually strong axis)
+        #         ↑                                                        ↑
+        #         |     x (longitudinal beam direction, into screen)       |      z (longitudinal beam direction, into screen)
+        #         |    ↗                                                   |    ↗
+        #         |   /                                                    |   /
+        #         |  /                                                     |  /
+        #         | /                                                      | /
+        #         |/                                                       |/
+        #   ←-----O                                                        O------>
+        #    y (horizontal/side, usually weak axis)                      x (horizontal/side, usually weak axis)
+
+        return section.calculate_stress(
+            n=float(result_internal_force_1d.n) * KN_TO_N,
+            vx=-float(result_internal_force_1d.vy) * KN_TO_N,
+            vy=float(result_internal_force_1d.vz) * KN_TO_N,
+            mxx=-float(result_internal_force_1d.my) * KNM_TO_NMM,
+            myy=float(result_internal_force_1d.mz) * KNM_TO_NMM,
+            mzz=float(result_internal_force_1d.mx) * KNM_TO_NMM,
+        )
+
     def plot(self, plotter: Callable[[Any], plt.Figure] | None = None, *args, **kwargs) -> plt.Figure:
         """Plot the profile. Making use of the standard plotter.
 

From d147fc5b8c923c2373079622f9e0b039f48306a0 Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Sun, 8 Feb 2026 13:02:43 +0100
Subject: [PATCH 41/46] Add plastic shear strength check for steel
 cross-section class 3 and 4

---
 .../checks/eurocode/steel/strength_shear.py   | 154 +++++++++++++++++-
 .../eurocode/steel/test_strength_shear.py     |  59 ++++++-
 2 files changed, 205 insertions(+), 8 deletions(-)

diff --git a/blueprints/checks/eurocode/steel/strength_shear.py b/blueprints/checks/eurocode/steel/strength_shear.py
index c6307b89b..9c77d082b 100644
--- a/blueprints/checks/eurocode/steel/strength_shear.py
+++ b/blueprints/checks/eurocode/steel/strength_shear.py
@@ -3,16 +3,14 @@
 from dataclasses import dataclass
 from typing import ClassVar, Literal
 
+import numpy as np
 from sectionproperties.post.post import SectionProperties
 
 from blueprints.checks.check_result import CheckResult
 from blueprints.codes.eurocode.en_1993_1_1_2005 import EN_1993_1_1_2005
-from blueprints.codes.eurocode.en_1993_1_1_2005.chapter_6_ultimate_limit_state import (
-    formula_6_17,
-    formula_6_18,
-    formula_6_18_sub_av,
-)
+from blueprints.codes.eurocode.en_1993_1_1_2005.chapter_6_ultimate_limit_state import formula_6_17, formula_6_18, formula_6_18_sub_av, formula_6_19
 from blueprints.codes.formula import Formula
+from blueprints.saf.results.result_internal_force_1d import ResultFor, ResultInternalForce1D, ResultOn
 from blueprints.structural_sections.steel.profile_definitions.i_profile import IProfile
 from blueprints.structural_sections.steel.steel_cross_section import SteelCrossSection
 from blueprints.type_alias import DIMENSIONLESS, KN
@@ -22,7 +20,7 @@
 
 @dataclass(frozen=True)
 class CheckStrengthShearClass12IProfile:
-    """Class to perform plastic shear force resistance check for steel I-profiles (Eurocode 3).
+    """Class to perform plastic shear force resistance check for steel I-profiles of cross-section class 1 and 2 (Eurocode 3).
 
     Coordinate System:
 
@@ -167,3 +165,147 @@ def report(self, n: int = 2) -> Report:
         else:
             report.add_paragraph("The check for plastic shear force does NOT satisfy the requirements.")
         return report
+
+
+@dataclass(frozen=True)
+class CheckStrengthShearClass34:
+    """Class to perform plastic shear force resistance check for steel cross-section class 3 and 4 (Eurocode 3).
+
+    Coordinate System:
+
+        z (vertical, usually strong axis)
+            ↑
+            |     x (longitudinal beam direction, into screen)
+            |    ↗
+            |   /
+            |  /
+            | /
+            |/
+      ←-----O
+       y (horizontal/side, usually weak axis)
+
+    Parameters
+    ----------
+    steel_cross_section : SteelCrossSection
+        The steel cross-section, of type I-profile, to check.
+    v : KN
+        The applied shear force (in kN).
+    axis : Literal["Vz", "Vy"]
+        Axis along which the shear force is applied. "Vz" (default) for z (vertical), "Vy" for y (horizontal).
+    gamma_m0 : DIMENSIONLESS, optional
+        Partial safety factor for resistance of cross-sections, default is 1.0.
+    section_properties : SectionProperties | None, optional
+        Pre-calculated section properties. If None, they will be calculated internally.
+
+    Example
+    -------
+    from blueprints.checks.eurocode.steel.strength_shear import CheckStrengthShearClass34IProfile
+    from blueprints.materials.steel import SteelMaterial, SteelStrengthClass
+    from blueprints.structural_sections.steel.standard_profiles.heb import HEB
+
+    steel_material = SteelMaterial(steel_class=SteelStrengthClass.S355)
+    heb_300_profile = HEB.HEB300.with_corrosion(1.5)
+    v = 100  # Applied shear force in kN
+
+    heb_300_s355 = SteelCrossSection(profile=heb_300_profile, material=steel_material)
+    calc = CheckStrengthShearClass34IProfile(heb_300_s355, v, axis="Vz", gamma_m0=1.0)
+    calc.report().to_word("shear_strength.docx", language="nl")
+
+    """
+
+    steel_cross_section: SteelCrossSection
+    v: KN = 0
+    axis: Literal["Vz", "Vy"] = "Vz"
+    gamma_m0: DIMENSIONLESS = 1.0
+    section_properties: SectionProperties | None = None
+    name: str = "Elastic shear strength check"
+    source_docs: ClassVar[list] = [EN_1993_1_1_2005]
+
+    def __post_init__(self) -> None:
+        """Post-initialization to extract section properties and check profile type."""
+        if self.section_properties is None:
+            section_properties = self.steel_cross_section.profile.section_properties()
+            object.__setattr__(self, "section_properties", section_properties)
+
+    def calculation_formula(self) -> dict[str, Formula]:
+        """Calculate plastic shear force resistance check.
+
+        Returns
+        -------
+        dict[str, Formula]
+            Calculation results keyed by formula number. Returns an empty dict if no shear force is applied.
+        """
+        rif1d = ResultInternalForce1D(
+            result_on=ResultOn.ON_BEAM,
+            member="N/A",
+            result_for=ResultFor.LOAD_CASE,
+            load_case="N/A",
+            vy=self.v if self.axis == "Vy" else 0,
+            vz=self.v if self.axis == "Vz" else 0,
+        )
+
+        stress = self.steel_cross_section.profile.calculate_stress(rif1d)
+        sig_zxy = float(max(abs(stress.get_stress()[0]["sig_zxy"])))
+
+        resistance = float(self.steel_cross_section.yield_strength / np.sqrt(3) / self.gamma_m0 / sig_zxy * self.v * KN_TO_N)
+
+        check_shear = formula_6_19.Form6Dot19CheckDesignElasticShearResistance(
+            tau_ed=sig_zxy, f_y=self.steel_cross_section.yield_strength, gamma_m0=self.gamma_m0
+        )
+
+        return {
+            "shear_stress": sig_zxy,
+            "resistance": resistance,
+            "check": check_shear,
+        }
+
+    def result(self) -> CheckResult:
+        """Calculate result of plastic shear force resistance.
+
+        Returns
+        -------
+        CheckResult
+            True if the shear force check passes, False otherwise.
+        """
+        steps = self.calculation_formula()
+        provided = abs(self.v) * KN_TO_N
+        required = steps["resistance"]
+        return CheckResult.from_comparison(provided=provided, required=required)
+
+    def report(self, n: int = 2) -> Report:
+        """Returns the report for the elastic shear force check.
+
+        Parameters
+        ----------
+        n : int, optional
+            Number of decimal places for numerical values in the report (default is 2).
+
+        Returns
+        -------
+        Report
+            Report of the elastic shear force check.
+        """
+        report = Report("Check: shear force steel I-beam (Class 3/4)")
+        if self.v == 0:
+            report.add_paragraph("No shear force was applied; therefore, no shear force check is necessary.")
+            return report
+        axis_label = "(vertical) z" if self.axis == "Vz" else "(horizontal) y"
+        report.add_paragraph(
+            rf"Profile {self.steel_cross_section.profile.name} with steel quality {self.steel_cross_section.material.steel_class.name} "
+            rf"is loaded with a shear force of {abs(self.v):.{n}f} kN in the {axis_label}-direction. "
+            rf"The shear stress $\tau_{{ed}}$ is calculated using elastic theory. "
+        )
+        formulas = self.calculation_formula()
+        report.add_paragraph(f"The maximum shear stress is: {formulas['shear_stress']:.{n}f} N/mm². ")
+
+        tau_max = self.steel_cross_section.yield_strength / (np.sqrt(3) * self.gamma_m0)
+        report.add_paragraph("The maximum allowed shear stress is calculated as follows:")
+        report.add_paragraph(rf"$f_y / (\sqrt{{3}} \cdot \gamma_{{M0}})$ = {tau_max} N/mm². ")
+
+        report.add_paragraph("The unity check is calculated as follows:")
+        report.add_formula(formulas["check"], n=n)
+        if self.result().is_ok:
+            report.add_paragraph("The check for elastic shear force satisfies the requirements.")
+        else:
+            report.add_paragraph("The check for elastic shear force does NOT satisfy the requirements.")
+        return report
diff --git a/tests/checks/eurocode/steel/test_strength_shear.py b/tests/checks/eurocode/steel/test_strength_shear.py
index 9241c781c..6c8002924 100644
--- a/tests/checks/eurocode/steel/test_strength_shear.py
+++ b/tests/checks/eurocode/steel/test_strength_shear.py
@@ -1,9 +1,9 @@
-"""Tests for CheckStrengthShearClass12IProfile according to Eurocode 3."""
+"""Tests for shear strength checks according to Eurocode 3."""
 
 import pytest
 from sectionproperties.post.post import SectionProperties
 
-from blueprints.checks.eurocode.steel.strength_shear import CheckStrengthShearClass12IProfile
+from blueprints.checks.eurocode.steel.strength_shear import CheckStrengthShearClass12IProfile, CheckStrengthShearClass34
 from blueprints.structural_sections.steel.steel_cross_section import SteelCrossSection
 
 
@@ -98,3 +98,58 @@ def test_check_wrong_profile(self, chs_steel_cross_section: tuple[SteelCrossSect
         v = 1
         with pytest.raises(TypeError, match="The provided profile is not an I-profile"):
             CheckStrengthShearClass12IProfile(cross_section, v, gamma_m0=1.0, section_properties=section_properties)
+
+
+class TestCheckStrengthShearClass34:
+    """Tests for CheckStrengthShearClass34."""
+
+    def test_result_none(self, heb_steel_cross_section: tuple[SteelCrossSection, SectionProperties]) -> None:
+        """Test report output for shear force."""
+        cross_section, section_properties = heb_steel_cross_section
+        v = 0
+        calc = CheckStrengthShearClass34(cross_section, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
+        result = calc.result()
+        assert result.is_ok is True
+        assert result.unity_check == 0
+        assert result.factor_of_safety == float("inf")
+        assert result.provided == 0.0
+        assert calc.report()
+
+        calc_without_section_props = CheckStrengthShearClass34(cross_section, v, axis="Vz", gamma_m0=1.0)
+        assert calc == calc_without_section_props
+
+    def test_result_ok(self, heb_steel_cross_section: tuple[SteelCrossSection, SectionProperties]) -> None:
+        """Test result() for ok shear force in Vz direction."""
+        cross_section, section_properties = heb_steel_cross_section
+        v = 1379 * 0.99
+        calc = CheckStrengthShearClass34(cross_section, v, axis="Vy", gamma_m0=1.0, section_properties=section_properties)
+        result = calc.result()
+        assert result.is_ok is True
+        assert pytest.approx(result.unity_check, 0.005) == 0.99
+        assert pytest.approx(result.factor_of_safety, 0.005) == 1 / 0.99
+        assert calc.report()
+
+        v = 607 * 0.99
+        calc = CheckStrengthShearClass34(cross_section, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
+        result = calc.result()
+        assert result.is_ok is True
+        assert pytest.approx(result.unity_check, 0.005) == 0.99
+        assert pytest.approx(result.factor_of_safety, 0.005) == 1 / 0.99
+
+    def test_result_not_ok(self, heb_steel_cross_section: tuple[SteelCrossSection, SectionProperties]) -> None:
+        """Test result() for not ok shear force."""
+        cross_section, section_properties = heb_steel_cross_section
+        v = 1379 * 1.01
+        calc = CheckStrengthShearClass34(cross_section, v, axis="Vy", gamma_m0=1.0, section_properties=section_properties)
+        result = calc.result()
+        assert result.is_ok is False
+        assert pytest.approx(result.unity_check, 0.005) == 1.01
+        assert pytest.approx(result.factor_of_safety, 0.005) == 1 / 1.01
+        assert calc.report()
+
+        v = 607 * 1.01
+        calc = CheckStrengthShearClass34(cross_section, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
+        result = calc.result()
+        assert result.is_ok is False
+        assert pytest.approx(result.unity_check, 0.005) == 1.01
+        assert pytest.approx(result.factor_of_safety, 0.005) == 1 / 1.01

From 50a15108bdebcd6b33c8fad7dcb4a6fc9b089ee8 Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Sun, 8 Feb 2026 13:04:45 +0100
Subject: [PATCH 42/46] Round maximum allowed shear stress calculation to
 specified decimal places

---
 blueprints/checks/eurocode/steel/strength_shear.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/blueprints/checks/eurocode/steel/strength_shear.py b/blueprints/checks/eurocode/steel/strength_shear.py
index 9c77d082b..7002b0a9e 100644
--- a/blueprints/checks/eurocode/steel/strength_shear.py
+++ b/blueprints/checks/eurocode/steel/strength_shear.py
@@ -298,7 +298,7 @@ def report(self, n: int = 2) -> Report:
         formulas = self.calculation_formula()
         report.add_paragraph(f"The maximum shear stress is: {formulas['shear_stress']:.{n}f} N/mm². ")
 
-        tau_max = self.steel_cross_section.yield_strength / (np.sqrt(3) * self.gamma_m0)
+        tau_max = round(self.steel_cross_section.yield_strength / (np.sqrt(3) * self.gamma_m0), n)
         report.add_paragraph("The maximum allowed shear stress is calculated as follows:")
         report.add_paragraph(rf"$f_y / (\sqrt{{3}} \cdot \gamma_{{M0}})$ = {tau_max} N/mm². ")
 

From 1b1f75b546afed37c902580a297f8cf93c0b66f1 Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Sun, 8 Feb 2026 13:11:52 +0100
Subject: [PATCH 43/46] Enhance calculation_formula method to support multiple
 return types and improve stress calculation in CheckStrengthShearClass34

---
 blueprints/checks/eurocode/steel/strength_shear.py | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/blueprints/checks/eurocode/steel/strength_shear.py b/blueprints/checks/eurocode/steel/strength_shear.py
index 7002b0a9e..1fe7fe5e0 100644
--- a/blueprints/checks/eurocode/steel/strength_shear.py
+++ b/blueprints/checks/eurocode/steel/strength_shear.py
@@ -227,7 +227,7 @@ def __post_init__(self) -> None:
             section_properties = self.steel_cross_section.profile.section_properties()
             object.__setattr__(self, "section_properties", section_properties)
 
-    def calculation_formula(self) -> dict[str, Formula]:
+    def calculation_formula(self) -> dict[str, Formula | float | int]:
         """Calculate plastic shear force resistance check.
 
         Returns
@@ -245,7 +245,8 @@ def calculation_formula(self) -> dict[str, Formula]:
         )
 
         stress = self.steel_cross_section.profile.calculate_stress(rif1d)
-        sig_zxy = float(max(abs(stress.get_stress()[0]["sig_zxy"])))
+        sig_zxy_data = stress.get_stress()[0]["sig_zxy"]
+        sig_zxy = float(np.max(np.abs(sig_zxy_data)))
 
         resistance = float(self.steel_cross_section.yield_strength / np.sqrt(3) / self.gamma_m0 / sig_zxy * self.v * KN_TO_N)
 
@@ -303,7 +304,9 @@ def report(self, n: int = 2) -> Report:
         report.add_paragraph(rf"$f_y / (\sqrt{{3}} \cdot \gamma_{{M0}})$ = {tau_max} N/mm². ")
 
         report.add_paragraph("The unity check is calculated as follows:")
-        report.add_formula(formulas["check"], n=n)
+        check_formula = formulas["check"]
+        assert isinstance(check_formula, Formula), "Expected Formula for check"
+        report.add_formula(check_formula, n=n)
         if self.result().is_ok:
             report.add_paragraph("The check for elastic shear force satisfies the requirements.")
         else:

From 242c5d05acff53a69eb68545cec806aedfeb57ad Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Sun, 8 Feb 2026 13:37:50 +0100
Subject: [PATCH 44/46] Refactor CheckStrengthTorsionShearClass to simplify
 class name and update references in tests

---
 .../checks/eurocode/steel/strength_shear.py   | 11 ++++---
 .../eurocode/steel/strength_torsion_shear.py  |  6 ++--
 .../steel/test_strength_torsion_shear.py      | 30 +++++++++----------
 3 files changed, 23 insertions(+), 24 deletions(-)

diff --git a/blueprints/checks/eurocode/steel/strength_shear.py b/blueprints/checks/eurocode/steel/strength_shear.py
index 1fe7fe5e0..7708d206f 100644
--- a/blueprints/checks/eurocode/steel/strength_shear.py
+++ b/blueprints/checks/eurocode/steel/strength_shear.py
@@ -240,14 +240,13 @@ def calculation_formula(self) -> dict[str, Formula | float | int]:
             member="N/A",
             result_for=ResultFor.LOAD_CASE,
             load_case="N/A",
-            vy=self.v if self.axis == "Vy" else 0,
-            vz=self.v if self.axis == "Vz" else 0,
+            vy=1 if self.axis == "Vy" else 0,
+            vz=1 if self.axis == "Vz" else 0,
         )
 
-        stress = self.steel_cross_section.profile.calculate_stress(rif1d)
-        sig_zxy_data = stress.get_stress()[0]["sig_zxy"]
-        sig_zxy = float(np.max(np.abs(sig_zxy_data)))
-
+        unit_stress = self.steel_cross_section.profile.calculate_stress(rif1d)
+        sig_zxy_data = unit_stress.get_stress()[0]["sig_zxy"]
+        sig_zxy = float(np.max(np.abs(sig_zxy_data))) * abs(self.v)
         resistance = float(self.steel_cross_section.yield_strength / np.sqrt(3) / self.gamma_m0 / sig_zxy * self.v * KN_TO_N)
 
         check_shear = formula_6_19.Form6Dot19CheckDesignElasticShearResistance(
diff --git a/blueprints/checks/eurocode/steel/strength_torsion_shear.py b/blueprints/checks/eurocode/steel/strength_torsion_shear.py
index 981dd0f8b..16c287930 100644
--- a/blueprints/checks/eurocode/steel/strength_torsion_shear.py
+++ b/blueprints/checks/eurocode/steel/strength_torsion_shear.py
@@ -21,7 +21,7 @@
 
 
 @dataclass(frozen=True)
-class CheckStrengthTorsionShearClass1234IProfile:
+class CheckStrengthTorsionShearClass12IProfile:
     """Class to perform torsion resistance check with extra shear force for I profiles (Eurocode 3), using St. Venant torsion.
 
     Coordinate System:
@@ -54,7 +54,7 @@ class CheckStrengthTorsionShearClass1234IProfile:
 
     Example
     -------
-    from blueprints.checks.eurocode.steel.strength_torsion_shear import CheckStrengthTorsionShearClass1234IProfile
+    from blueprints.checks.eurocode.steel.strength_torsion_shear import CheckStrengthTorsionShearClass12IProfile
     from blueprints.materials.steel import SteelMaterial, SteelStrengthClass
     from blueprints.structural_sections.steel.standard_profiles.heb import HEB
 
@@ -65,7 +65,7 @@ class CheckStrengthTorsionShearClass1234IProfile:
     axis = "Vz"  # Shear force applied in z-direction
 
     heb_300_s355 = SteelCrossSection(profile=heb_300_profile, material=steel_material)
-    calc = CheckStrengthTorsionShearClass1234IProfile(heb_300_s355, mx, v=v, axis=axis, gamma_m0=1.0)
+    calc = CheckStrengthTorsionShearClass12IProfile(heb_300_s355, mx, v=v, axis=axis, gamma_m0=1.0)
     calc.report().to_word("torsion_and_shear_strength.docx", language="nl")
 
     """
diff --git a/tests/checks/eurocode/steel/test_strength_torsion_shear.py b/tests/checks/eurocode/steel/test_strength_torsion_shear.py
index 9e9ca9cb0..6965eb633 100644
--- a/tests/checks/eurocode/steel/test_strength_torsion_shear.py
+++ b/tests/checks/eurocode/steel/test_strength_torsion_shear.py
@@ -3,19 +3,19 @@
 import pytest
 from sectionproperties.post.post import SectionProperties
 
-from blueprints.checks.eurocode.steel.strength_torsion_shear import CheckStrengthTorsionShearClass1234IProfile
+from blueprints.checks.eurocode.steel.strength_torsion_shear import CheckStrengthTorsionShearClass12IProfile
 from blueprints.structural_sections.steel.steel_cross_section import SteelCrossSection
 
 
-class TestCheckStrengthTorsionShearClass1234IProfile:
-    """Tests for CheckStrengthTorsionShearClass1234IProfile, using St. Venant torsion."""
+class TestCheckStrengthTorsionShearClass12IProfile:
+    """Tests for CheckStrengthTorsionShearClass12IProfile, using St. Venant torsion, for class 1 and 2 I-profiles."""
 
     def test_result_none_v(self, heb_steel_cross_section: tuple[SteelCrossSection, SectionProperties]) -> None:
         """Test result() returns True for no shear force."""
         cross_section, section_properties = heb_steel_cross_section
         v = 0
         mx = 1
-        calc = CheckStrengthTorsionShearClass1234IProfile(cross_section, mx, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
+        calc = CheckStrengthTorsionShearClass12IProfile(cross_section, mx, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
         result = calc.result()
         assert result.is_ok is True
         assert result.unity_check == 0
@@ -23,15 +23,15 @@ def test_result_none_v(self, heb_steel_cross_section: tuple[SteelCrossSection, S
         assert result.provided == 0.0
         assert calc.report()
 
-        calc_without_section_props = CheckStrengthTorsionShearClass1234IProfile(cross_section, mx, v, axis="Vz", gamma_m0=1.0)
+        calc_without_section_props = CheckStrengthTorsionShearClass12IProfile(cross_section, mx, v, axis="Vz", gamma_m0=1.0)
         assert calc == calc_without_section_props
 
     def test_result_none_mx(self, heb_steel_cross_section: tuple[SteelCrossSection, SectionProperties]) -> None:
-        """Test result() returns True for no shear force."""
+        """Test result() returns True for no torsional moment."""
         cross_section, section_properties = heb_steel_cross_section
         mx = 0
         v = 1
-        calc = CheckStrengthTorsionShearClass1234IProfile(cross_section, mx, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
+        calc = CheckStrengthTorsionShearClass12IProfile(cross_section, mx, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
         result = calc.result()
         assert result.is_ok is True
         assert result.unity_check == 0
@@ -44,7 +44,7 @@ def test_result_shear_ok(self, heb_steel_cross_section: tuple[SteelCrossSection,
         cross_section, section_properties = heb_steel_cross_section
         v = 585.023 * 0.99
         mx = 10
-        calc = CheckStrengthTorsionShearClass1234IProfile(cross_section, mx, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
+        calc = CheckStrengthTorsionShearClass12IProfile(cross_section, mx, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
         result = calc.result()
         assert result.is_ok is True
         assert pytest.approx(result.unity_check, 0.005) == 0.99
@@ -52,14 +52,14 @@ def test_result_shear_ok(self, heb_steel_cross_section: tuple[SteelCrossSection,
         assert calc.report()
 
         v = -v
-        calc = CheckStrengthTorsionShearClass1234IProfile(cross_section, mx, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
+        calc = CheckStrengthTorsionShearClass12IProfile(cross_section, mx, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
         result = calc.result()
         assert result.is_ok is True
         assert pytest.approx(result.unity_check, 0.005) == 0.99
         assert pytest.approx(result.factor_of_safety, 0.005) == 1 / 0.99
 
         v = 1482.833 * 0.99
-        calc = CheckStrengthTorsionShearClass1234IProfile(cross_section, mx, v, axis="Vy", gamma_m0=1.0, section_properties=section_properties)
+        calc = CheckStrengthTorsionShearClass12IProfile(cross_section, mx, v, axis="Vy", gamma_m0=1.0, section_properties=section_properties)
         result = calc.result()
         assert result.is_ok is True
         assert pytest.approx(result.unity_check, 0.005) == 0.99
@@ -67,7 +67,7 @@ def test_result_shear_ok(self, heb_steel_cross_section: tuple[SteelCrossSection,
 
         v = 355.277 * 0.99
         object.__setattr__(cross_section, "fabrication_method", "welded")
-        calc = CheckStrengthTorsionShearClass1234IProfile(cross_section, mx, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
+        calc = CheckStrengthTorsionShearClass12IProfile(cross_section, mx, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
         result = calc.result()
         assert result.is_ok is True
         assert pytest.approx(result.unity_check, 0.005) == 0.99
@@ -79,7 +79,7 @@ def test_result_shear_not_ok(self, heb_steel_cross_section: tuple[SteelCrossSect
         object.__setattr__(cross_section, "fabrication_method", "rolled")
         v = 585.023 * 1.01
         mx = 10
-        calc = CheckStrengthTorsionShearClass1234IProfile(cross_section, mx, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
+        calc = CheckStrengthTorsionShearClass12IProfile(cross_section, mx, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
         result = calc.result()
         assert result.is_ok is False
         assert pytest.approx(result.unity_check, 0.005) == 1.01
@@ -87,7 +87,7 @@ def test_result_shear_not_ok(self, heb_steel_cross_section: tuple[SteelCrossSect
         assert calc.report()
 
         v = 1482.833 * 1.01
-        calc = CheckStrengthTorsionShearClass1234IProfile(cross_section, mx, v, axis="Vy", gamma_m0=1.0, section_properties=section_properties)
+        calc = CheckStrengthTorsionShearClass12IProfile(cross_section, mx, v, axis="Vy", gamma_m0=1.0, section_properties=section_properties)
         result = calc.result()
         assert result.is_ok is False
         assert pytest.approx(result.unity_check, 0.005) == 1.01
@@ -95,7 +95,7 @@ def test_result_shear_not_ok(self, heb_steel_cross_section: tuple[SteelCrossSect
 
         v = 355.277 * 1.01
         object.__setattr__(cross_section, "fabrication_method", "welded")
-        calc = CheckStrengthTorsionShearClass1234IProfile(cross_section, mx, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
+        calc = CheckStrengthTorsionShearClass12IProfile(cross_section, mx, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
         result = calc.result()
         assert result.is_ok is False
         assert pytest.approx(result.unity_check, 0.005) == 1.01
@@ -105,4 +105,4 @@ def test_check_wrong_profile(self, chs_steel_cross_section: tuple[SteelCrossSect
         """Test check() raises TypeError for non-I-profile."""
         cross_section, section_properties = chs_steel_cross_section
         with pytest.raises(TypeError, match="The provided profile is not an I-profile"):
-            CheckStrengthTorsionShearClass1234IProfile(cross_section, mx=10, v=1, gamma_m0=1.0, section_properties=section_properties)
+            CheckStrengthTorsionShearClass12IProfile(cross_section, mx=10, v=1, gamma_m0=1.0, section_properties=section_properties)

From 9ab3649d7ba14a62cbc9bc1a48c3e875a34aab74 Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Sun, 8 Feb 2026 15:19:55 +0100
Subject: [PATCH 45/46] Refactor torsional moment variable names to improve
 clarity and add CheckStrengthTorsionShearClass34 for class 3 and 4 sections

---
 .../checks/eurocode/steel/strength_torsion.py |  35 +--
 .../eurocode/steel/strength_torsion_shear.py  | 215 ++++++++++++++++--
 .../eurocode/steel/test_strength_torsion.py   |  14 +-
 .../steel/test_strength_torsion_shear.py      |  93 ++++++--
 4 files changed, 295 insertions(+), 62 deletions(-)

diff --git a/blueprints/checks/eurocode/steel/strength_torsion.py b/blueprints/checks/eurocode/steel/strength_torsion.py
index 8a2bf0476..f02cb6cb7 100644
--- a/blueprints/checks/eurocode/steel/strength_torsion.py
+++ b/blueprints/checks/eurocode/steel/strength_torsion.py
@@ -38,7 +38,7 @@ class CheckStrengthStVenantTorsionClass1234:
     ----------
     steel_cross_section : SteelCrossSection
         The steel cross-section, of type I-profile, to check.
-    mx : KNM
+    m_x : KNM
         The applied torsional moment (in kNm).
     gamma_m0 : DIMENSIONLESS, optional
         Partial safety factor for resistance of cross-sections, default is 1.0.
@@ -53,16 +53,16 @@ class CheckStrengthStVenantTorsionClass1234:
 
     steel_material = SteelMaterial(steel_class=SteelStrengthClass.S355)
     heb_300_profile = HEB.HEB300.with_corrosion(1.5)
-    mx = 10  # Applied torsional moment in kNm
+    m_x = 10  # Applied torsional moment in kNm
 
     heb_300_s355 = SteelCrossSection(profile=heb_300_profile, material=steel_material)
-    calc = TorsionStrengthCheck(heb_300_s355, mx, gamma_m0=1.0)
+    calc = TorsionStrengthCheck(heb_300_s355, m_x, gamma_m0=1.0)
     calc.report().to_word("torsion_strength.docx", language="nl")
 
     """
 
     steel_cross_section: SteelCrossSection
-    mx: KNM = 0
+    m_x: KNM = 0
     gamma_m0: DIMENSIONLESS = 1.0
     section_properties: SectionProperties | None = None
     name: str = "Torsion strength check"
@@ -74,12 +74,12 @@ def __post_init__(self) -> None:
             section_properties = self.steel_cross_section.profile.section_properties()
             object.__setattr__(self, "section_properties", section_properties)
 
-    def calculation_formula(self) -> dict[str, Formula]:
+    def calculation_formula(self) -> dict[str, Formula | float]:
         """Calculate torsion resistance check.
 
         Returns
         -------
-        dict[str, Formula]
+        dict[str, Formula | float]
             Calculation results keyed by formula number. Returns an empty dict if no torsion is applied.
         """
         rif1d = ResultInternalForce1D(
@@ -91,17 +91,16 @@ def calculation_formula(self) -> dict[str, Formula]:
         )
 
         unit_stress = self.steel_cross_section.profile.calculate_stress(rif1d)
-        unit_sig_zx_mzz = unit_stress.get_stress()[0]["sig_zx_mzz"]
-        unit_sig_zy_mzz = unit_stress.get_stress()[0]["sig_zy_mzz"]
-        unit_max_mzz_zxy = np.max(np.sqrt(np.array(unit_sig_zx_mzz) ** 2 + np.array(unit_sig_zy_mzz) ** 2))
+        unit_sig_zxy = unit_stress.get_stress()[0]["sig_zxy"]
+        unit_max_sig_zxy = float(np.max(np.abs(unit_sig_zxy)))
 
-        t_rd = self.steel_cross_section.yield_strength / self.gamma_m0 / np.sqrt(3) / unit_max_mzz_zxy
-        t_ed = abs(self.mx)
+        t_rd = self.steel_cross_section.yield_strength / self.gamma_m0 / np.sqrt(3) / unit_max_sig_zxy
+        t_ed = abs(self.m_x)
 
         check_torsion = Form6Dot23CheckTorsionalMoment(t_ed=t_ed, t_rd=t_rd)
 
         return {
-            "unit_shear_stress": unit_max_mzz_zxy,
+            "unit_shear_stress": unit_max_sig_zxy,
             "resistance": t_rd,
             "check": check_torsion,
         }
@@ -115,7 +114,7 @@ def result(self) -> CheckResult:
             True if the torsion check passes, False otherwise.
         """
         steps = self.calculation_formula()
-        provided = abs(self.mx) * KNM_TO_NMM
+        provided = abs(self.m_x) * KNM_TO_NMM
         required = steps["resistance"] * KNM_TO_NMM
         return CheckResult.from_comparison(provided=provided, required=float(required))
 
@@ -133,7 +132,7 @@ def report(self, n: int = 2) -> Report:
             Report of the torsion check.
         """
         report = Report("Check: torsion steel beam")
-        if self.mx == 0:
+        if self.m_x == 0:
             report.add_paragraph("No torsion was applied; therefore, no torsion check is necessary.")
             return report
 
@@ -143,12 +142,12 @@ def report(self, n: int = 2) -> Report:
         # Get information for the introduction of the report
         profile_name = self.steel_cross_section.profile.name
         steel_quality = self.steel_cross_section.material.steel_class.name
-        mx_val = f"{self.mx:.{n}f}"
+        m_x_val = f"{self.m_x:.{n}f}"
         unit_stress_val = f"{formulas['unit_shear_stress']:.{n}f}"
 
         report.add_paragraph(
             rf"Profile {profile_name} with steel quality {steel_quality} "
-            rf"is loaded with a torsion of {mx_val} kNm. "
+            rf"is loaded with a torsion of {m_x_val} kNm. "
             rf"First, the unit torsional stress (at 1 kNm) is defined as {unit_stress_val} MPa. "
             rf"The torsional resistance is calculated as follows:"
         )
@@ -165,7 +164,9 @@ def report(self, n: int = 2) -> Report:
         )
         report.add_equation(eqn_1)
         report.add_paragraph("The unity check is calculated as follows:")
-        report.add_formula(formulas["check"], n=n)
+        check_formula = formulas["check"]
+        assert isinstance(check_formula, Formula), "Expected Formula for check"
+        report.add_formula(check_formula, n=n)
         if self.result().is_ok:
             report.add_paragraph("The check for torsion satisfies the requirements.")
         else:
diff --git a/blueprints/checks/eurocode/steel/strength_torsion_shear.py b/blueprints/checks/eurocode/steel/strength_torsion_shear.py
index 16c287930..2bdeeab22 100644
--- a/blueprints/checks/eurocode/steel/strength_torsion_shear.py
+++ b/blueprints/checks/eurocode/steel/strength_torsion_shear.py
@@ -9,6 +9,7 @@
 from blueprints.checks.check_result import CheckResult
 from blueprints.checks.eurocode.steel.strength_shear import CheckStrengthShearClass12IProfile
 from blueprints.codes.eurocode.en_1993_1_1_2005 import EN_1993_1_1_2005
+from blueprints.codes.eurocode.en_1993_1_1_2005.chapter_6_ultimate_limit_state.formula_6_19 import Form6Dot19CheckDesignElasticShearResistance
 from blueprints.codes.eurocode.en_1993_1_1_2005.chapter_6_ultimate_limit_state.formula_6_25 import Form6Dot25CheckCombinedShearForceAndTorsionalMoment
 from blueprints.codes.eurocode.en_1993_1_1_2005.chapter_6_ultimate_limit_state.formula_6_26 import Form6Dot26VplTRdIOrHSection
 from blueprints.codes.formula import Formula
@@ -22,7 +23,7 @@
 
 @dataclass(frozen=True)
 class CheckStrengthTorsionShearClass12IProfile:
-    """Class to perform torsion resistance check with extra shear force for I profiles (Eurocode 3), using St. Venant torsion.
+    """Class to perform torsion resistance check with extra shear force for I profiles cross section 1 and 2 (Eurocode 3), using St. Venant torsion.
 
     Coordinate System:
 
@@ -60,7 +61,7 @@ class CheckStrengthTorsionShearClass12IProfile:
 
     steel_material = SteelMaterial(steel_class=SteelStrengthClass.S355)
     heb_300_profile = HEB.HEB300.with_corrosion(1.5)
-    mx = 10  # Applied torsional moment in kNm
+    m_x = 10  # Applied torsional moment in kNm
     v = 100  # Applied shear force in kN
     axis = "Vz"  # Shear force applied in z-direction
 
@@ -71,12 +72,12 @@ class CheckStrengthTorsionShearClass12IProfile:
     """
 
     steel_cross_section: SteelCrossSection
-    mx: KNM = 0
+    m_x: KNM = 0
     v: KN = 0
     axis: Literal["Vz", "Vy"] = "Vz"
     gamma_m0: DIMENSIONLESS = 1.0
     section_properties: SectionProperties | None = None
-    name: str = "Torsion strength check for steel I-profiles"
+    name: str = "Torsion strength check for steel I-profiles class 1 and 2"
     source_docs: ClassVar[list] = [EN_1993_1_1_2005]
 
     def __post_init__(self) -> None:
@@ -87,12 +88,12 @@ def __post_init__(self) -> None:
             section_properties = self.steel_cross_section.profile.section_properties()
             object.__setattr__(self, "section_properties", section_properties)
 
-    def calculation_formula(self) -> dict[str, Formula]:
+    def calculation_formula(self) -> dict[str, Formula | float]:
         """Calculate torsion resistance check.
 
         Returns
         -------
-        dict[str, Formula]
+        dict[str, Formula | float]
             Calculation results keyed by formula number. Returns an empty dict if no torsion is applied.
         """
         shear_calculation = CheckStrengthShearClass12IProfile(
@@ -116,11 +117,10 @@ def calculation_formula(self) -> dict[str, Formula]:
         )
 
         unit_stress = self.steel_cross_section.profile.calculate_stress(rif1d)
-        unit_sig_zx_mzz = unit_stress.get_stress()[0]["sig_zx_mzz"]
-        unit_sig_zy_mzz = unit_stress.get_stress()[0]["sig_zy_mzz"]
-        unit_max_mzz_zxy = np.max(np.sqrt(np.array(unit_sig_zx_mzz) ** 2 + np.array(unit_sig_zy_mzz) ** 2))
+        unit_sig_zxy = unit_stress.get_stress()[0]["sig_zxy"]
+        unit_max_sig_zxy = float(np.max(np.abs(unit_sig_zxy)))
 
-        tau_t_ed = abs(self.mx) * unit_max_mzz_zxy
+        tau_t_ed = abs(self.m_x) * unit_max_sig_zxy
         v_ed = abs(self.v) * KN_TO_N
 
         v_pl_t_rd = Form6Dot26VplTRdIOrHSection(
@@ -130,7 +130,7 @@ def calculation_formula(self) -> dict[str, Formula]:
         check_torsion_with_shear = Form6Dot25CheckCombinedShearForceAndTorsionalMoment(v_ed=v_ed, v_pl_t_rd=v_pl_t_rd)
 
         return {
-            "unit_shear_stress": unit_max_mzz_zxy,
+            "unit_shear_stress": unit_max_sig_zxy,
             "shear_area": a_v,
             "raw_shear_resistance": v_pl_rd,
             "resistance": v_pl_t_rd,
@@ -146,7 +146,7 @@ def result(self) -> CheckResult:
             True if the torsion check passes, False otherwise.
         """
         steps = self.calculation_formula()
-        provided = 0 if self.mx == 0 else abs(self.v) * KN_TO_N
+        provided = 0 if self.m_x == 0 else abs(self.v) * KN_TO_N
         required = steps["resistance"]
         return CheckResult.from_comparison(provided=provided, required=float(required))
 
@@ -164,7 +164,7 @@ def report(self, n: int = 2) -> Report:
             Report of the torsion check.
         """
         report = Report("Check: torsion with shear force on steel beam")
-        if self.mx == 0:
+        if self.m_x == 0:
             report.add_paragraph("No torsion was applied; therefore, no combined torsion with shear force check is necessary.")
             return report
         if self.v == 0:
@@ -177,27 +177,202 @@ def report(self, n: int = 2) -> Report:
         # Get information for the introduction of the report
         profile_name = self.steel_cross_section.profile.name
         steel_quality = self.steel_cross_section.material.steel_class.name
-        mx_val = f"{self.mx:.{n}f}"
+        m_x_val = f"{self.m_x:.{n}f}"
         unit_stress_val = f"{formulas['unit_shear_stress']:.{n}f}"
         axis_label = "(vertical) z" if self.axis == "Vz" else "(horizontal) y"
-        total_stress_val = f"{formulas['unit_shear_stress'] * self.mx:.{n}f}"
+        total_stress_val = f"{formulas['unit_shear_stress'] * self.m_x:.{n}f}"
 
         report.add_paragraph(
             rf"Profile {profile_name} with steel quality {steel_quality} "
-            rf"is loaded with a torsion of {mx_val} kNm a shear force of {abs(self.v):.{n}f} kN in the {axis_label}-direction. "
+            rf"is loaded with a torsion of {m_x_val} kNm a shear force of {abs(self.v):.{n}f} kN in the {axis_label}-direction. "
             rf"First, the unit torsional stress (at 1 kNm) is defined as {unit_stress_val} MPa. "
             rf"With the applied torsion, this results in a torsional stress of {total_stress_val} MPa. "
             rf"The shear area and resistance (without torsion) are calculated as follows:"
         )
 
-        report.add_formula(formulas["shear_area"], n=n, split_after=[(2, "="), (7, "+"), (3, "=")])
-        report.add_formula(formulas["raw_shear_resistance"], n=n)
+        shear_area_formula = formulas["shear_area"]
+        raw_shear_resistance_formula = formulas["raw_shear_resistance"]
+        resistance_formula = formulas["resistance"]
+        check_formula = formulas["check"]
+
+        assert isinstance(shear_area_formula, Formula), "Expected Formula for shear_area"
+        assert isinstance(raw_shear_resistance_formula, Formula), "Expected Formula for raw_shear_resistance"
+        assert isinstance(resistance_formula, Formula), "Expected Formula for resistance"
+        assert isinstance(check_formula, Formula), "Expected Formula for check"
+
+        report.add_formula(shear_area_formula, n=n, split_after=[(2, "="), (7, "+"), (3, "=")])
+        report.add_formula(raw_shear_resistance_formula, n=n)
         report.add_paragraph("Next, the combined torsion and shear resistance is calculated as follows:")
-        report.add_formula(formulas["resistance"], n=n)
+        report.add_formula(resistance_formula, n=n)
         report.add_paragraph("The unity check is calculated as follows:")
-        report.add_formula(formulas["check"], n=n)
+        report.add_formula(check_formula, n=n)
         if self.result().is_ok:
             report.add_paragraph("The check for torsion satisfies the requirements.")
         else:
             report.add_paragraph("The check for torsion does NOT satisfy the requirements.")
         return report
+
+
+@dataclass(frozen=True)
+class CheckStrengthTorsionShearClass34:
+    """Class to perform torsion resistance check with extra shear force for cross section class 3 and 4 (Eurocode 3), using St. Venant torsion.
+
+    Coordinate System:
+
+        z (vertical, usually strong axis)
+            ↑
+            |     x (longitudinal beam direction, into screen)
+            |    ↗
+            |   /
+            |  /
+            | /
+            |/
+      ←-----O
+       y (horizontal/side, usually weak axis)
+
+    Parameters
+    ----------
+    steel_cross_section : SteelCrossSection
+        The steel cross-section to check.
+    m_x : KNM
+        The applied torsional moment (positive value, in kNm).
+    v : KN
+        The applied shear force (positive value, in kN).
+    axis : Literal["Vz", "Vy"]
+        Axis along which the shear force is applied. "Vz" (default) for z (vertical), "Vy" for y (horizontal).
+    gamma_m0 : DIMENSIONLESS, optional
+        Partial safety factor for resistance of cross-sections, default is 1.0.
+    section_properties : SectionProperties | None, optional
+        Pre-calculated section properties. If None, they will be calculated internally.
+
+    Example
+    -------
+    from blueprints.checks.eurocode.steel.strength_torsion_shear import CheckStrengthTorsionShearClass34
+    from blueprints.materials.steel import SteelMaterial, SteelStrengthClass
+    from blueprints.structural_sections.steel.standard_profiles.heb import HEB
+
+    steel_material = SteelMaterial(steel_class=SteelStrengthClass.S355)
+    heb_300_profile = HEB.HEB300.with_corrosion(1.5)
+    m_x = 10  # Applied torsional moment in kNm
+    v = 100  # Applied shear force in kN
+    axis = "Vz"  # Shear force applied in z-direction
+
+    heb_300_s355 = SteelCrossSection(profile=heb_300_profile, material=steel_material)
+    calc = CheckStrengthTorsionShearClass34(heb_300_s355, m_x, v=v, axis=axis, gamma_m0=1.0)
+    calc.report().to_word("torsion_and_shear_strength.docx", language="nl")
+
+    """
+
+    steel_cross_section: SteelCrossSection
+    m_x: KNM = 0
+    v: KN = 0
+    axis: Literal["Vz", "Vy"] = "Vz"
+    gamma_m0: DIMENSIONLESS = 1.0
+    section_properties: SectionProperties | None = None
+    name: str = "Torsion strength check for steel class 3 and 4"
+    source_docs: ClassVar[list] = [EN_1993_1_1_2005]
+
+    def __post_init__(self) -> None:
+        """Post-initialization to extract section properties and check profile type."""
+        if self.section_properties is None:
+            section_properties = self.steel_cross_section.profile.section_properties()
+            object.__setattr__(self, "section_properties", section_properties)
+
+    def calculation_formula(self) -> dict[str, Formula | float]:
+        """Calculate torsion resistance check.
+
+        Returns
+        -------
+        dict[str, Formula | float]
+            Calculation results keyed by formula number. Returns an empty dict if no torsion is applied.
+        """
+        rif1d = ResultInternalForce1D(
+            result_on=ResultOn.ON_BEAM,
+            member="N/A",
+            result_for=ResultFor.LOAD_CASE,
+            load_case="N/A",
+            vy=self.v if self.axis == "Vy" else 0,
+            vz=self.v if self.axis == "Vz" else 0,
+            mx=self.m_x,
+        )
+
+        stress = self.steel_cross_section.profile.calculate_stress(rif1d)
+        sig_zxy = stress.get_stress()[0]["sig_zxy"]
+        max_sig_zxy = float(np.max(np.abs(sig_zxy)))
+
+        shear_resistance = self.steel_cross_section.yield_strength / np.sqrt(3) / self.gamma_m0
+
+        check_torsion_with_shear = Form6Dot19CheckDesignElasticShearResistance(
+            tau_ed=max_sig_zxy, f_y=self.steel_cross_section.yield_strength, gamma_m0=self.gamma_m0
+        )
+
+        return {
+            "shear_stress": max_sig_zxy,
+            "resistance": shear_resistance,
+            "check": check_torsion_with_shear,
+        }
+
+    def result(self) -> CheckResult:
+        """Calculate result of torsion resistance.
+
+        Returns
+        -------
+        CheckResult
+            True if the torsion check passes, False otherwise.
+        """
+        steps = self.calculation_formula()
+        provided = steps["shear_stress"]
+        required = steps["resistance"]
+        return CheckResult.from_comparison(provided=provided, required=float(required))
+
+    def report(self, n: int = 2) -> Report:
+        """Returns the report for the elastic torsion check (Class 3/4).
+
+        Parameters
+        ----------
+        n : int, optional
+            Number of decimal places for numerical values in the report (default is 2).
+
+        Returns
+        -------
+        Report
+            Report of the elastic torsion check.
+        """
+        report = Report("Check: elastic torsion with shear force on steel beam (Class 3/4)")
+        if self.m_x == 0:
+            report.add_paragraph("No torsion was applied; therefore, no combined torsion with shear force check is necessary.")
+            return report
+        if self.v == 0:
+            report.add_paragraph("No shear force was applied; therefore, no combined torsion with shear force check is necessary.")
+            return report
+
+        # Cache calculation formulas to avoid redundant recalculations
+        formulas = self.calculation_formula()
+
+        # Get information for the introduction of the report
+        profile_name = self.steel_cross_section.profile.name
+        steel_quality = self.steel_cross_section.material.steel_class.name
+        m_x_val = f"{self.m_x:.{n}f}"
+        axis_label = "(vertical) z" if self.axis == "Vz" else "(horizontal) y"
+        shear_stress_val = f"{formulas['shear_stress']:.{n}f}"
+
+        report.add_paragraph(
+            rf"Profile {profile_name} with steel quality {steel_quality} "
+            rf"is loaded with a torsion of {m_x_val} kNm and a shear force of {abs(self.v):.{n}f} kN in the {axis_label}-direction. "
+            rf"For class 3/4 sections, the combined shear stress from torsion and shear is calculated using elastic theory. "
+            rf"The maximum combined shear stress is: {shear_stress_val} N/mm²."
+        )
+
+        tau_max = round(self.steel_cross_section.yield_strength / (np.sqrt(3) * self.gamma_m0), n)
+        report.add_paragraph("The maximum allowed elastic shear stress is calculated as follows:")
+        report.add_paragraph(rf"$f_y / (\sqrt{{3}} \cdot \gamma_{{M0}})$ = {tau_max} N/mm².")
+
+        report.add_paragraph("The unity check is calculated as follows:")
+        check_formula = formulas["check"]
+        assert isinstance(check_formula, Formula), "Expected Formula for check"
+        report.add_formula(check_formula, n=n)
+        if self.result().is_ok:
+            report.add_paragraph("The check for elastic torsion with shear satisfies the requirements.")
+        else:
+            report.add_paragraph("The check for elastic torsion with shear does NOT satisfy the requirements.")
+        return report
diff --git a/tests/checks/eurocode/steel/test_strength_torsion.py b/tests/checks/eurocode/steel/test_strength_torsion.py
index 64ea06c72..64ea95e45 100644
--- a/tests/checks/eurocode/steel/test_strength_torsion.py
+++ b/tests/checks/eurocode/steel/test_strength_torsion.py
@@ -12,9 +12,9 @@ class TestCheckStrengthStVenantTorsionClass1234:
 
     def test_result_none(self, unp_steel_cross_section: tuple[SteelCrossSection, SectionProperties]) -> None:
         """Test result() returns True for no torsion."""
-        mx = 0
+        m_x = 0
         cross_section, section_properties = unp_steel_cross_section
-        calc = CheckStrengthStVenantTorsionClass1234(cross_section, mx, gamma_m0=1.0, section_properties=section_properties)
+        calc = CheckStrengthStVenantTorsionClass1234(cross_section, m_x, gamma_m0=1.0, section_properties=section_properties)
         result = calc.result()
         assert result.is_ok is True
         assert result.unity_check == 0.0
@@ -22,14 +22,14 @@ def test_result_none(self, unp_steel_cross_section: tuple[SteelCrossSection, Sec
         assert result.provided == 0.0
         assert calc.report()
 
-        calc_without_section_props = CheckStrengthStVenantTorsionClass1234(cross_section, mx, gamma_m0=1.0)
+        calc_without_section_props = CheckStrengthStVenantTorsionClass1234(cross_section, m_x, gamma_m0=1.0)
         assert calc == calc_without_section_props
 
     def test_result_tension_ok(self, unp_steel_cross_section: tuple[SteelCrossSection, SectionProperties]) -> None:
         """Test result() for ok tension load."""
-        mx = -0.3896 * 0.99
+        m_x = -0.3896 * 0.99
         cross_section, section_properties = unp_steel_cross_section
-        calc = CheckStrengthStVenantTorsionClass1234(cross_section, mx, gamma_m0=1.0, section_properties=section_properties)
+        calc = CheckStrengthStVenantTorsionClass1234(cross_section, m_x, gamma_m0=1.0, section_properties=section_properties)
         result = calc.result()
         assert result.is_ok is True
         assert pytest.approx(result.unity_check, 0.005) == 0.99
@@ -38,9 +38,9 @@ def test_result_tension_ok(self, unp_steel_cross_section: tuple[SteelCrossSectio
 
     def test_result_tension_not_ok(self, unp_steel_cross_section: tuple[SteelCrossSection, SectionProperties]) -> None:
         """Test result() for not ok tension load."""
-        mx = 0.3896 * 1.01
+        m_x = 0.3896 * 1.01
         cross_section, section_properties = unp_steel_cross_section
-        calc = CheckStrengthStVenantTorsionClass1234(cross_section, mx, gamma_m0=1.0, section_properties=section_properties)
+        calc = CheckStrengthStVenantTorsionClass1234(cross_section, m_x, gamma_m0=1.0, section_properties=section_properties)
         result = calc.result()
         assert result.is_ok is False
         assert pytest.approx(result.unity_check, 0.005) == 1.01
diff --git a/tests/checks/eurocode/steel/test_strength_torsion_shear.py b/tests/checks/eurocode/steel/test_strength_torsion_shear.py
index 6965eb633..91a2f480a 100644
--- a/tests/checks/eurocode/steel/test_strength_torsion_shear.py
+++ b/tests/checks/eurocode/steel/test_strength_torsion_shear.py
@@ -3,7 +3,7 @@
 import pytest
 from sectionproperties.post.post import SectionProperties
 
-from blueprints.checks.eurocode.steel.strength_torsion_shear import CheckStrengthTorsionShearClass12IProfile
+from blueprints.checks.eurocode.steel.strength_torsion_shear import CheckStrengthTorsionShearClass12IProfile, CheckStrengthTorsionShearClass34
 from blueprints.structural_sections.steel.steel_cross_section import SteelCrossSection
 
 
@@ -14,8 +14,8 @@ def test_result_none_v(self, heb_steel_cross_section: tuple[SteelCrossSection, S
         """Test result() returns True for no shear force."""
         cross_section, section_properties = heb_steel_cross_section
         v = 0
-        mx = 1
-        calc = CheckStrengthTorsionShearClass12IProfile(cross_section, mx, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
+        m_x = 1
+        calc = CheckStrengthTorsionShearClass12IProfile(cross_section, m_x, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
         result = calc.result()
         assert result.is_ok is True
         assert result.unity_check == 0
@@ -23,15 +23,15 @@ def test_result_none_v(self, heb_steel_cross_section: tuple[SteelCrossSection, S
         assert result.provided == 0.0
         assert calc.report()
 
-        calc_without_section_props = CheckStrengthTorsionShearClass12IProfile(cross_section, mx, v, axis="Vz", gamma_m0=1.0)
+        calc_without_section_props = CheckStrengthTorsionShearClass12IProfile(cross_section, m_x, v, axis="Vz", gamma_m0=1.0)
         assert calc == calc_without_section_props
 
-    def test_result_none_mx(self, heb_steel_cross_section: tuple[SteelCrossSection, SectionProperties]) -> None:
+    def test_result_none_m_x(self, heb_steel_cross_section: tuple[SteelCrossSection, SectionProperties]) -> None:
         """Test result() returns True for no torsional moment."""
         cross_section, section_properties = heb_steel_cross_section
-        mx = 0
+        m_x = 0
         v = 1
-        calc = CheckStrengthTorsionShearClass12IProfile(cross_section, mx, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
+        calc = CheckStrengthTorsionShearClass12IProfile(cross_section, m_x, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
         result = calc.result()
         assert result.is_ok is True
         assert result.unity_check == 0
@@ -43,8 +43,8 @@ def test_result_shear_ok(self, heb_steel_cross_section: tuple[SteelCrossSection,
         """Test result() for ok shear force."""
         cross_section, section_properties = heb_steel_cross_section
         v = 585.023 * 0.99
-        mx = 10
-        calc = CheckStrengthTorsionShearClass12IProfile(cross_section, mx, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
+        m_x = 10
+        calc = CheckStrengthTorsionShearClass12IProfile(cross_section, m_x, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
         result = calc.result()
         assert result.is_ok is True
         assert pytest.approx(result.unity_check, 0.005) == 0.99
@@ -52,14 +52,14 @@ def test_result_shear_ok(self, heb_steel_cross_section: tuple[SteelCrossSection,
         assert calc.report()
 
         v = -v
-        calc = CheckStrengthTorsionShearClass12IProfile(cross_section, mx, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
+        calc = CheckStrengthTorsionShearClass12IProfile(cross_section, m_x, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
         result = calc.result()
         assert result.is_ok is True
         assert pytest.approx(result.unity_check, 0.005) == 0.99
         assert pytest.approx(result.factor_of_safety, 0.005) == 1 / 0.99
 
         v = 1482.833 * 0.99
-        calc = CheckStrengthTorsionShearClass12IProfile(cross_section, mx, v, axis="Vy", gamma_m0=1.0, section_properties=section_properties)
+        calc = CheckStrengthTorsionShearClass12IProfile(cross_section, m_x, v, axis="Vy", gamma_m0=1.0, section_properties=section_properties)
         result = calc.result()
         assert result.is_ok is True
         assert pytest.approx(result.unity_check, 0.005) == 0.99
@@ -67,7 +67,7 @@ def test_result_shear_ok(self, heb_steel_cross_section: tuple[SteelCrossSection,
 
         v = 355.277 * 0.99
         object.__setattr__(cross_section, "fabrication_method", "welded")
-        calc = CheckStrengthTorsionShearClass12IProfile(cross_section, mx, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
+        calc = CheckStrengthTorsionShearClass12IProfile(cross_section, m_x, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
         result = calc.result()
         assert result.is_ok is True
         assert pytest.approx(result.unity_check, 0.005) == 0.99
@@ -76,10 +76,10 @@ def test_result_shear_ok(self, heb_steel_cross_section: tuple[SteelCrossSection,
     def test_result_shear_not_ok(self, heb_steel_cross_section: tuple[SteelCrossSection, SectionProperties]) -> None:
         """Test result() for not ok shear force."""
         cross_section, section_properties = heb_steel_cross_section
-        object.__setattr__(cross_section, "fabrication_method", "rolled")
+        object.__setattr__(cross_section, "fabrication_method", "hot-rolled")
         v = 585.023 * 1.01
-        mx = 10
-        calc = CheckStrengthTorsionShearClass12IProfile(cross_section, mx, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
+        m_x = 10
+        calc = CheckStrengthTorsionShearClass12IProfile(cross_section, m_x, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
         result = calc.result()
         assert result.is_ok is False
         assert pytest.approx(result.unity_check, 0.005) == 1.01
@@ -87,7 +87,7 @@ def test_result_shear_not_ok(self, heb_steel_cross_section: tuple[SteelCrossSect
         assert calc.report()
 
         v = 1482.833 * 1.01
-        calc = CheckStrengthTorsionShearClass12IProfile(cross_section, mx, v, axis="Vy", gamma_m0=1.0, section_properties=section_properties)
+        calc = CheckStrengthTorsionShearClass12IProfile(cross_section, m_x, v, axis="Vy", gamma_m0=1.0, section_properties=section_properties)
         result = calc.result()
         assert result.is_ok is False
         assert pytest.approx(result.unity_check, 0.005) == 1.01
@@ -95,7 +95,7 @@ def test_result_shear_not_ok(self, heb_steel_cross_section: tuple[SteelCrossSect
 
         v = 355.277 * 1.01
         object.__setattr__(cross_section, "fabrication_method", "welded")
-        calc = CheckStrengthTorsionShearClass12IProfile(cross_section, mx, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
+        calc = CheckStrengthTorsionShearClass12IProfile(cross_section, m_x, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
         result = calc.result()
         assert result.is_ok is False
         assert pytest.approx(result.unity_check, 0.005) == 1.01
@@ -105,4 +105,61 @@ def test_check_wrong_profile(self, chs_steel_cross_section: tuple[SteelCrossSect
         """Test check() raises TypeError for non-I-profile."""
         cross_section, section_properties = chs_steel_cross_section
         with pytest.raises(TypeError, match="The provided profile is not an I-profile"):
-            CheckStrengthTorsionShearClass12IProfile(cross_section, mx=10, v=1, gamma_m0=1.0, section_properties=section_properties)
+            CheckStrengthTorsionShearClass12IProfile(cross_section, m_x=10, v=1, gamma_m0=1.0, section_properties=section_properties)
+
+
+class TestCheckStrengthTorsionShearClass34:
+    """Tests for TestCheckStrengthTorsionShearClass34, using St. Venant torsion, for class 3 and 4."""
+
+    def test_result_none_v(self, heb_steel_cross_section: tuple[SteelCrossSection, SectionProperties]) -> None:
+        """Test result() returns True for no shear force."""
+        cross_section, section_properties = heb_steel_cross_section
+        v = 0
+        m_x = 1
+        calc = CheckStrengthTorsionShearClass34(cross_section, m_x, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
+        result = calc.result()
+        assert result.is_ok is True
+        assert result.unity_check == 0
+        assert result.factor_of_safety == float("inf")
+        assert result.provided == 0.0
+        assert calc.report()
+
+        calc_without_section_props = CheckStrengthTorsionShearClass34(cross_section, m_x, v, axis="Vz", gamma_m0=1.0)
+        assert calc == calc_without_section_props
+
+    def test_result_none_m_x(self, heb_steel_cross_section: tuple[SteelCrossSection, SectionProperties]) -> None:
+        """Test result() returns True for no torsional moment."""
+        cross_section, section_properties = heb_steel_cross_section
+        m_x = 0
+        v = 1
+        calc = CheckStrengthTorsionShearClass34(cross_section, m_x, v, axis="Vz", gamma_m0=1.0, section_properties=section_properties)
+        result = calc.result()
+        assert result.is_ok is True
+        assert result.unity_check == 0
+        assert result.factor_of_safety == float("inf")
+        assert result.provided == 0.0
+        assert calc.report()
+
+    def test_result_ok(self, heb_steel_cross_section: tuple[SteelCrossSection, SectionProperties]) -> None:
+        """Test result() for ok shear force in Vz direction."""
+        cross_section, section_properties = heb_steel_cross_section
+        v = 690 * 0.99
+        m_x = 7.81 * 0.99
+        calc = CheckStrengthTorsionShearClass34(cross_section, m_x, v, axis="Vy", gamma_m0=1.0, section_properties=section_properties)
+        result = calc.result()
+        assert result.is_ok is True
+        assert pytest.approx(result.unity_check, 0.005) == 0.99
+        assert pytest.approx(result.factor_of_safety, 0.005) == 1 / 0.99
+        assert calc.report()
+
+    def test_result_not_ok(self, heb_steel_cross_section: tuple[SteelCrossSection, SectionProperties]) -> None:
+        """Test result() for not ok shear force."""
+        cross_section, section_properties = heb_steel_cross_section
+        v = 690 * 1.01
+        m_x = 7.81 * 1.01
+        calc = CheckStrengthTorsionShearClass34(cross_section, m_x, v, axis="Vy", gamma_m0=1.0, section_properties=section_properties)
+        result = calc.result()
+        assert result.is_ok is False
+        assert pytest.approx(result.unity_check, 0.005) == 1.01
+        assert pytest.approx(result.factor_of_safety, 0.005) == 1 / 1.01
+        assert calc.report()

From aad589c9f6930571b81735a2f60c99aafcbfa1bd Mon Sep 17 00:00:00 2001
From: GerjanDorgelo <gerjan.dorgelo@anteagroup.nl>
Date: Sun, 8 Feb 2026 16:52:55 +0100
Subject: [PATCH 46/46] Update test_strength_torsion_shear.py

---
 tests/checks/eurocode/steel/test_strength_torsion_shear.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tests/checks/eurocode/steel/test_strength_torsion_shear.py b/tests/checks/eurocode/steel/test_strength_torsion_shear.py
index 91a2f480a..3ba32c961 100644
--- a/tests/checks/eurocode/steel/test_strength_torsion_shear.py
+++ b/tests/checks/eurocode/steel/test_strength_torsion_shear.py
@@ -144,7 +144,7 @@ def test_result_ok(self, heb_steel_cross_section: tuple[SteelCrossSection, Secti
         """Test result() for ok shear force in Vz direction."""
         cross_section, section_properties = heb_steel_cross_section
         v = 690 * 0.99
-        m_x = 7.81 * 0.99
+        m_x = 7.66 * 0.99
         calc = CheckStrengthTorsionShearClass34(cross_section, m_x, v, axis="Vy", gamma_m0=1.0, section_properties=section_properties)
         result = calc.result()
         assert result.is_ok is True
@@ -156,7 +156,7 @@ def test_result_not_ok(self, heb_steel_cross_section: tuple[SteelCrossSection, S
         """Test result() for not ok shear force."""
         cross_section, section_properties = heb_steel_cross_section
         v = 690 * 1.01
-        m_x = 7.81 * 1.01
+        m_x = 7.66 * 1.01
         calc = CheckStrengthTorsionShearClass34(cross_section, m_x, v, axis="Vy", gamma_m0=1.0, section_properties=section_properties)
         result = calc.result()
         assert result.is_ok is False