diff --git a/blueprints/codes/eurocode/nen_en_1993_1_1_c2_a1_2016/chapter_6_ultimate_limit_state/formula_6_39.py b/blueprints/codes/eurocode/nen_en_1993_1_1_c2_a1_2016/chapter_6_ultimate_limit_state/formula_6_39.py
new file mode 100644
index 000000000..6833e3509
--- /dev/null
+++ b/blueprints/codes/eurocode/nen_en_1993_1_1_c2_a1_2016/chapter_6_ultimate_limit_state/formula_6_39.py
@@ -0,0 +1,81 @@
+"""Formula 6.39 from NEN-EN 1993-1-1+C2+A1:2016: Chapter 6 - Ultimate Limit State."""
+
+from blueprints.codes.eurocode.nen_en_1993_1_1_c2_a1_2016 import NEN_EN_1993_1_1_C2_A1_2016
+from blueprints.codes.formula import Formula
+from blueprints.codes.latex_formula import LatexFormula, latex_replace_symbols
+from blueprints.type_alias import DIMENSIONLESS, NMM
+from blueprints.validations import raise_if_less_or_equal_to_zero, raise_if_negative
+
+
+class Form6Dot39ReducedBendingMomentResistance(Formula):
+    r"""Class representing formula 6.39 for the calculation of [$M_{N,y,Rd}$]."""
+
+    label = "6.39"
+    source_document = NEN_EN_1993_1_1_C2_A1_2016
+
+    def __init__(
+        self,
+        mpl_y_rd: NMM,
+        n: DIMENSIONLESS,
+        a_w: DIMENSIONLESS,
+    ) -> None:
+        r"""[$M_{N,y,Rd}$] Calculation of the reduced bending moment [$Nmm$].
+
+        NEN-EN 1993-1-1+C2+A1:2016 art.6.2.9.1(5) - Formula (6.39)
+
+        Parameters
+        ----------
+        mpl_y_rd : NMM
+            [$M_{pl,y,Rd}$] Plastic bending moment resistance about the y-axis [$Nmm$].
+        n : DIMENSIONLESS
+            [$n$] Axial force ratio, see equation 6.38n (dimensionless).
+        a_w : DIMENSIONLESS
+            [$a_w$] Reduction factor for the web (dimensionless), see equation 6.39aw.
+        """
+        super().__init__()
+        self.mpl_y_rd = mpl_y_rd
+        self.n = n
+        self.a_w = a_w
+
+    @staticmethod
+    def _evaluate(
+        mpl_y_rd: NMM,
+        n: DIMENSIONLESS,
+        a_w: DIMENSIONLESS,
+    ) -> NMM:
+        """Evaluates the formula, for more information see the __init__ method."""
+        raise_if_negative(mpl_y_rd=mpl_y_rd, n=n, a_w=a_w)
+        raise_if_less_or_equal_to_zero(denominator=(1 - 0.5 * a_w))
+
+        return min(mpl_y_rd * (1 - n) / (1 - 0.5 * a_w), mpl_y_rd)
+
+    def latex(self) -> LatexFormula:
+        """Returns LatexFormula object for formula 6.39."""
+        _equation: str = r"\min \left( M_{pl,y,Rd} \cdot \frac{1 - n}{1 - 0.5 \cdot a_w}, M_{pl,y,Rd} \right)"
+        _numeric_equation: str = latex_replace_symbols(
+            _equation,
+            {
+                r"M_{pl,y,Rd}": f"{self.mpl_y_rd:.3f}",
+                r" n": f" {self.n:.3f}",
+                r"a_w": f"{self.a_w:.3f}",
+            },
+            False,
+        )
+        _numeric_equation_with_units: str = latex_replace_symbols(
+            _equation,
+            {
+                r"M_{pl,y,Rd}": rf"{self.mpl_y_rd:.3f} \ Nmm",
+                r" n": rf" {self.n:.3f}",
+                r"a_w": rf"{self.a_w:.3f}",
+            },
+            False,
+        )
+        return LatexFormula(
+            return_symbol=r"M_{N,y,Rd}",
+            result=f"{self:.3f}",
+            equation=_equation,
+            numeric_equation=_numeric_equation,
+            numeric_equation_with_units=_numeric_equation_with_units,
+            comparison_operator_label=r"=",
+            unit="Nmm",
+        )
diff --git a/blueprints/codes/eurocode/nen_en_1993_1_1_c2_a1_2016/chapter_6_ultimate_limit_state/formula_6_39aw.py b/blueprints/codes/eurocode/nen_en_1993_1_1_c2_a1_2016/chapter_6_ultimate_limit_state/formula_6_39aw.py
new file mode 100644
index 000000000..016f344d6
--- /dev/null
+++ b/blueprints/codes/eurocode/nen_en_1993_1_1_c2_a1_2016/chapter_6_ultimate_limit_state/formula_6_39aw.py
@@ -0,0 +1,155 @@
+"""Formula 6.39aw from NEN-EN 1993-1-1+C2+A1:2016: Chapter 6 - Ultimate Limit State."""
+
+from blueprints.codes.eurocode.nen_en_1993_1_1_c2_a1_2016 import NEN_EN_1993_1_1_C2_A1_2016
+from blueprints.codes.formula import Formula
+from blueprints.codes.latex_formula import LatexFormula, latex_replace_symbols
+from blueprints.type_alias import DIMENSIONLESS, MM, MM2
+from blueprints.validations import raise_if_less_or_equal_to_zero, raise_if_negative
+
+
+class Form6Dot39awHollowSections(Formula):
+    r"""Class representing formula 6.39aw for [$a_w$] in hollow sections."""
+
+    label = "6.39aw_hollow"
+    source_document = NEN_EN_1993_1_1_C2_A1_2016
+
+    def __init__(
+        self,
+        a: MM2,
+        b: MM,
+        t: MM,
+    ) -> None:
+        r"""[$a_w$] Calculation of the reduction factor for hollow sections (dimensionless).
+
+        NEN-EN 1993-1-1+C2+A1:2016 art.6.2.9.1(5) - Formula (6.39aw)
+
+        Parameters
+        ----------
+        a : MM2
+            [$A$] Total cross-sectional area [$mm^2$].
+        b : MM
+            [$b$] Width of the section [$mm$].
+        t : MM
+            [$t$] Thickness of the section [$mm$].
+        """
+        super().__init__()
+        self.a = a
+        self.b = b
+        self.t = t
+
+    @staticmethod
+    def _evaluate(
+        a: MM2,
+        b: MM,
+        t: MM,
+    ) -> DIMENSIONLESS:
+        """Evaluates the formula, for more information see the __init__ method."""
+        raise_if_negative(a=a, b=b, t=t)
+        raise_if_less_or_equal_to_zero(denominator=a)
+
+        return min((a - 2 * b * t) / a, 0.5)
+
+    def latex(self) -> LatexFormula:
+        """Returns LatexFormula object for formula 6.39aw."""
+        _equation: str = r"\min \left( \frac{A - 2 \cdot b \cdot t}{A}, 0.5 \right)"
+        _numeric_equation: str = latex_replace_symbols(
+            _equation,
+            {
+                r"A": f"{self.a:.3f}",
+                r"b": f"{self.b:.3f}",
+                r" t": f" {self.t:.3f}",
+            },
+            False,
+        )
+        _numeric_equation_with_units: str = latex_replace_symbols(
+            _equation,
+            {
+                r"A": rf"{self.a:.3f} \ mm^2",
+                r"b": rf"{self.b:.3f} \ mm",
+                r" t": rf" {self.t:.3f} \ mm",
+            },
+            False,
+        )
+        return LatexFormula(
+            return_symbol=r"a_w",
+            result=f"{self:.3f}",
+            equation=_equation,
+            numeric_equation=_numeric_equation,
+            numeric_equation_with_units=_numeric_equation_with_units,
+            comparison_operator_label=r"=",
+            unit="-",
+        )
+
+
+class Form6Dot39awWeldedBoxSections(Formula):
+    r"""Class representing formula 6.39aw for [$a_w$] in welded box sections."""
+
+    label = "6.39aw_welded_box"
+    source_document = NEN_EN_1993_1_1_C2_A1_2016
+
+    def __init__(
+        self,
+        a: MM2,
+        b: MM,
+        t_f: MM,
+    ) -> None:
+        r"""[$a_w$] Calculation of the reduction factor for welded box sections (dimensionless).
+
+        NEN-EN 1993-1-1+C2+A1:2016 art.6.2.9.1(5) - Formula (6.39aw)
+
+        Parameters
+        ----------
+        a : MM2
+            [$A$] Total cross-sectional area [$mm^2$].
+        b : MM
+            [$b$] Width of the section [$mm$].
+        t_f : MM
+            [$t_f$] Flange thickness [$mm$].
+        """
+        super().__init__()
+        self.a = a
+        self.b = b
+        self.t_f = t_f
+
+    @staticmethod
+    def _evaluate(
+        a: MM2,
+        b: MM,
+        t_f: MM,
+    ) -> DIMENSIONLESS:
+        """Evaluates the formula, for more information see the __init__ method."""
+        raise_if_negative(a=a, b=b, t_f=t_f)
+        raise_if_less_or_equal_to_zero(denominator=a)
+
+        return min((a - 2 * b * t_f) / a, 0.5)
+
+    def latex(self) -> LatexFormula:
+        """Returns LatexFormula object for formula 6.39aw."""
+        _equation: str = r"\min \left( \frac{A - 2 \cdot b \cdot t_f}{A}, 0.5 \right)"
+        _numeric_equation: str = latex_replace_symbols(
+            _equation,
+            {
+                r"A": f"{self.a:.3f}",
+                r"b": f"{self.b:.3f}",
+                r"t_f": f"{self.t_f:.3f}",
+            },
+            False,
+        )
+        _numeric_equation_with_units: str = latex_replace_symbols(
+            _equation,
+            {
+                r"A": rf"{self.a:.3f} \ mm^2",
+                r"b": rf"{self.b:.3f} \ mm",
+                r"t_f": rf"{self.t_f:.3f} \ mm",
+            },
+            False,
+        )
+        return LatexFormula(
+            return_symbol=r"a_w",
+            result=f"{self:.3f}",
+            equation=_equation,
+            numeric_equation=_numeric_equation,
+            numeric_equation_with_units=_numeric_equation_with_units,
+            comparison_operator_label=r"=",
+            unit="-",
+        )
diff --git a/blueprints/codes/eurocode/nen_en_1993_1_1_c2_a1_2016/chapter_6_ultimate_limit_state/formula_6_40.py b/blueprints/codes/eurocode/nen_en_1993_1_1_c2_a1_2016/chapter_6_ultimate_limit_state/formula_6_40.py
new file mode 100644
index 000000000..7242200f8
--- /dev/null
+++ b/blueprints/codes/eurocode/nen_en_1993_1_1_c2_a1_2016/chapter_6_ultimate_limit_state/formula_6_40.py
@@ -0,0 +1,81 @@
+"""Formula 6.40 from NEN-EN 1993-1-1+C2+A1:2016: Chapter 6 - Ultimate Limit State."""
+
+from blueprints.codes.eurocode.nen_en_1993_1_1_c2_a1_2016 import NEN_EN_1993_1_1_C2_A1_2016
+from blueprints.codes.formula import Formula
+from blueprints.codes.latex_formula import LatexFormula, latex_replace_symbols
+from blueprints.type_alias import DIMENSIONLESS, NMM
+from blueprints.validations import raise_if_less_or_equal_to_zero, raise_if_negative
+
+
+class Form6Dot40ReducedBendingMomentResistance(Formula):
+    r"""Class representing formula 6.40 for the calculation of [$M_{N,z,Rd}$]."""
+
+    label = "6.40"
+    source_document = NEN_EN_1993_1_1_C2_A1_2016
+
+    def __init__(
+        self,
+        mpl_z_rd: NMM,
+        n: DIMENSIONLESS,
+        a_f: DIMENSIONLESS,
+    ) -> None:
+        r"""[$M_{N,z,Rd}$] Calculation of the reduced bending moment [$Nmm$].
+
+        NEN-EN 1993-1-1+C2+A1:2016 art.6.2.9.1(5) - Formula (6.40)
+
+        Parameters
+        ----------
+        mpl_z_rd : NMM
+            [$M_{pl,z,Rd}$] Plastic bending moment resistance about the z-axis [$Nmm$].
+        n : DIMENSIONLESS
+            [$n$] Axial force ratio, see equation 6.38n (dimensionless).
+        a_f : DIMENSIONLESS
+            [$a_f$] Reduction factor for the flange (dimensionless).
+        """
+        super().__init__()
+        self.mpl_z_rd = mpl_z_rd
+        self.n = n
+        self.a_f = a_f
+
+    @staticmethod
+    def _evaluate(
+        mpl_z_rd: NMM,
+        n: DIMENSIONLESS,
+        a_f: DIMENSIONLESS,
+    ) -> NMM:
+        """Evaluates the formula, for more information see the __init__ method."""
+        raise_if_negative(mpl_z_rd=mpl_z_rd, n=n, a_f=a_f)
+        raise_if_less_or_equal_to_zero(denominator=(1 - 0.5 * a_f))
+
+        return min(mpl_z_rd * (1 - n) / (1 - 0.5 * a_f), mpl_z_rd)
+
+    def latex(self) -> LatexFormula:
+        """Returns LatexFormula object for formula 6.40."""
+        _equation: str = r"\min \left( M_{pl,z,Rd} \cdot \frac{1 - n}{1 - 0.5 \cdot a_f}, M_{pl,z,Rd} \right)"
+        _numeric_equation: str = latex_replace_symbols(
+            _equation,
+            {
+                r"M_{pl,z,Rd}": f"{self.mpl_z_rd:.3f}",
+                r" n": f" {self.n:.3f}",
+                r"a_f": f"{self.a_f:.3f}",
+            },
+            False,
+        )
+        _numeric_equation_with_units: str = latex_replace_symbols(
+            _equation,
+            {
+                r"M_{pl,z,Rd}": rf"{self.mpl_z_rd:.3f} \ Nmm",
+                r" n": rf" {self.n:.3f}",
+                r"a_f": rf"{self.a_f:.3f}",
+            },
+            False,
+        )
+        return LatexFormula(
+            return_symbol=r"M_{N,z,Rd}",
+            result=f"{self:.3f}",
+            equation=_equation,
+            numeric_equation=_numeric_equation,
+            numeric_equation_with_units=_numeric_equation_with_units,
+            comparison_operator_label=r"=",
+            unit="Nmm",
+        )
diff --git a/blueprints/codes/eurocode/nen_en_1993_1_1_c2_a1_2016/chapter_6_ultimate_limit_state/formula_6_40af.py b/blueprints/codes/eurocode/nen_en_1993_1_1_c2_a1_2016/chapter_6_ultimate_limit_state/formula_6_40af.py
new file mode 100644
index 000000000..37d2d0316
--- /dev/null
+++ b/blueprints/codes/eurocode/nen_en_1993_1_1_c2_a1_2016/chapter_6_ultimate_limit_state/formula_6_40af.py
@@ -0,0 +1,155 @@
+"""Formula 6.40af from NEN-EN 1993-1-1+C2+A1:2016: Chapter 6 - Ultimate Limit State."""
+
+from blueprints.codes.eurocode.nen_en_1993_1_1_c2_a1_2016 import NEN_EN_1993_1_1_C2_A1_2016
+from blueprints.codes.formula import Formula
+from blueprints.codes.latex_formula import LatexFormula, latex_replace_symbols
+from blueprints.type_alias import DIMENSIONLESS, MM, MM2
+from blueprints.validations import raise_if_less_or_equal_to_zero, raise_if_negative
+
+
+class Form6Dot40afHollowSections(Formula):
+    r"""Class representing formula 6.40af for [$a_f$] in hollow sections."""
+
+    label = "6.40af_hollow"
+    source_document = NEN_EN_1993_1_1_C2_A1_2016
+
+    def __init__(
+        self,
+        a: MM2,
+        h: MM,
+        t: MM,
+    ) -> None:
+        r"""[$a_f$] Calculation of the reduction factor for hollow sections (dimensionless).
+
+        NEN-EN 1993-1-1+C2+A1:2016 art.6.2.9.1(5) - Formula (6.40af)
+
+        Parameters
+        ----------
+        a : MM2
+            [$A$] Total cross-sectional area [$mm^2$].
+        h : MM
+            [$h$] Height of the section [$mm$].
+        t : MM
+            [$t$] Thickness of the section [$mm$].
+        """
+        super().__init__()
+        self.a = a
+        self.h = h
+        self.t = t
+
+    @staticmethod
+    def _evaluate(
+        a: MM2,
+        h: MM,
+        t: MM,
+    ) -> DIMENSIONLESS:
+        """Evaluates the formula, for more information see the __init__ method."""
+        raise_if_negative(a=a, h=h, t=t)
+        raise_if_less_or_equal_to_zero(denominator=a)
+
+        return min((a - 2 * h * t) / a, 0.5)
+
+    def latex(self) -> LatexFormula:
+        """Returns LatexFormula object for formula 6.40af."""
+        _equation: str = r"\min \left( \frac{A - 2 \cdot h \cdot t}{A}, 0.5 \right)"
+        _numeric_equation: str = latex_replace_symbols(
+            _equation,
+            {
+                r"A": f"{self.a:.3f}",
+                r" h": f" {self.h:.3f}",
+                r" t": f" {self.t:.3f}",
+            },
+            False,
+        )
+        _numeric_equation_with_units: str = latex_replace_symbols(
+            _equation,
+            {
+                r"A": rf"{self.a:.3f} \ mm^2",
+                r" h": rf" {self.h:.3f} \ mm",
+                r" t": rf" {self.t:.3f} \ mm",
+            },
+            False,
+        )
+        return LatexFormula(
+            return_symbol=r"a_f",
+            result=f"{self:.3f}",
+            equation=_equation,
+            numeric_equation=_numeric_equation,
+            numeric_equation_with_units=_numeric_equation_with_units,
+            comparison_operator_label=r"=",
+            unit="-",
+        )
+
+
+class Form6Dot40afWeldedBoxSections(Formula):
+    r"""Class representing formula 6.40af for [$a_f$] in welded box sections."""
+
+    label = "6.40af_welded_box"
+    source_document = NEN_EN_1993_1_1_C2_A1_2016
+
+    def __init__(
+        self,
+        a: MM2,
+        h: MM,
+        t_w: MM,
+    ) -> None:
+        r"""[$a_f$] Calculation of the reduction factor for welded box sections (dimensionless).
+
+        NEN-EN 1993-1-1+C2+A1:2016 art.6.2.9.1(5) - Formula (6.40af)
+
+        Parameters
+        ----------
+        a : MM2
+            [$A$] Total cross-sectional area [$mm^2$].
+        h : MM
+            [$h$] Height of the section [$mm$].
+        t_w : MM
+            [$t_w$] Web thickness [$mm$].
+        """
+        super().__init__()
+        self.a = a
+        self.h = h
+        self.t_w = t_w
+
+    @staticmethod
+    def _evaluate(
+        a: MM2,
+        h: MM,
+        t_w: MM,
+    ) -> DIMENSIONLESS:
+        """Evaluates the formula, for more information see the __init__ method."""
+        raise_if_negative(a=a, h=h, t_w=t_w)
+        raise_if_less_or_equal_to_zero(denominator=a)
+
+        return min((a - 2 * h * t_w) / a, 0.5)
+
+    def latex(self) -> LatexFormula:
+        """Returns LatexFormula object for formula 6.40af."""
+        _equation: str = r"\min \left( \frac{A - 2 \cdot h \cdot t_w}{A}, 0.5 \right)"
+        _numeric_equation: str = latex_replace_symbols(
+            _equation,
+            {
+                r"A": f"{self.a:.3f}",
+                r" h": f" {self.h:.3f}",
+                r"t_w": f"{self.t_w:.3f}",
+            },
+            False,
+        )
+        _numeric_equation_with_units: str = latex_replace_symbols(
+            _equation,
+            {
+                r"A": rf"{self.a:.3f} \ mm^2",
+                r" h": rf" {self.h:.3f} \ mm",
+                r"t_w": rf"{self.t_w:.3f} \ mm",
+            },
+            False,
+        )
+        return LatexFormula(
+            return_symbol=r"a_f",
+            result=f"{self:.3f}",
+            equation=_equation,
+            numeric_equation=_numeric_equation,
+            numeric_equation_with_units=_numeric_equation_with_units,
+            comparison_operator_label=r"=",
+            unit="-",
+        )
diff --git a/docs/objects_overview/eurocode/ec3_1993_1_1_2016/formulas.md b/docs/objects_overview/eurocode/ec3_1993_1_1_2016/formulas.md
index 7dc6f59d3..c0b94abb9 100644
--- a/docs/objects_overview/eurocode/ec3_1993_1_1_2016/formulas.md
+++ b/docs/objects_overview/eurocode/ec3_1993_1_1_2016/formulas.md
@@ -63,8 +63,10 @@ Total of 108 formulas present.
 | 6.36           | :x:  |         |             |
 | 6.37           | :x:  |         |             |
 | 6.38           | :x:  |         |             |
-| 6.39           | :x:  |         |             |
-| 6.40           | :x:  |         |             |
+| 6.39           | :heavy_check_mark:  |         | Form6Dot39ReducedBendingMomentResistance            |
+| 6.39 a_w       | :heavy_check_mark:  |         | Form6Dot39awHollowSections and Form6Dot39awWeldedBoxSections            |
+| 6.40           | :heavy_check_mark:  |         | Form6Dot40ReducedBendingMomentResistance            |
+| 6.40 a_f       | :heavy_check_mark:  |         | Form6Dot40afHollowSections and Form6Dot40afWeldedBoxSections            |
 | 6.41           | :heavy_check_mark:  |         | Form6Dot41BiaxialBendingCheck            |
 | 6.42           | :x:  |         |             |
 | 6.43           | :x:  |         |             |
diff --git a/tests/codes/eurocode/nen_en_1993_1_1_c2_a1_2016/chapter_6_ultimate_limit_state/test_formula_6_39.py b/tests/codes/eurocode/nen_en_1993_1_1_c2_a1_2016/chapter_6_ultimate_limit_state/test_formula_6_39.py
new file mode 100644
index 000000000..84ab2d86e
--- /dev/null
+++ b/tests/codes/eurocode/nen_en_1993_1_1_c2_a1_2016/chapter_6_ultimate_limit_state/test_formula_6_39.py
@@ -0,0 +1,77 @@
+"""Testing formula 6.39 of NEN-EN 1993-1-1+C2+A1:2016."""
+
+import pytest
+
+from blueprints.codes.eurocode.nen_en_1993_1_1_c2_a1_2016.chapter_6_ultimate_limit_state.formula_6_39 import Form6Dot39ReducedBendingMomentResistance
+from blueprints.validations import LessOrEqualToZeroError, NegativeValueError
+
+
+class TestForm6Dot39ReducedBendingMomentResistance:
+    """Validation for formula 6.39 from NEN-EN 1993-1-1+C2+A1:2016."""
+
+    def test_evaluation(self) -> None:
+        """Tests the evaluation of the result."""
+        mpl_y_rd = 5000.0
+        n = 0.2
+        a_w = 0.3
+
+        formula = Form6Dot39ReducedBendingMomentResistance(mpl_y_rd=mpl_y_rd, n=n, a_w=a_w)
+        manually_calculated_result = 4705.882  # Nmm
+
+        assert formula == pytest.approx(expected=manually_calculated_result, rel=1e-4)
+
+    @pytest.mark.parametrize(
+        ("mpl_y_rd", "n", "a_w"),
+        [
+            (-5000.0, 0.2, 0.3),  # mpl_y_rd is negative
+            (5000.0, -0.2, 0.3),  # n is negative
+            (5000.0, 0.2, -0.3),  # a_w is negative
+        ],
+    )
+    def test_raise_error_when_invalid_values_are_given(self, mpl_y_rd: float, n: float, a_w: float) -> None:
+        """Test invalid values."""
+        with pytest.raises((NegativeValueError, LessOrEqualToZeroError)):
+            Form6Dot39ReducedBendingMomentResistance(mpl_y_rd=mpl_y_rd, n=n, a_w=a_w)
+
+    @pytest.mark.parametrize(
+        ("mpl_y_rd", "n", "a_w"),
+        [
+            (5000.0, 0.2, 2.0),  # denominator (1 - 0.5 * a_w) <= 0
+        ],
+    )
+    def test_raise_error_when_denominator_is_invalid(self, mpl_y_rd: float, n: float, a_w: float) -> None:
+        """Test invalid denominator."""
+        with pytest.raises(LessOrEqualToZeroError):
+            Form6Dot39ReducedBendingMomentResistance(mpl_y_rd=mpl_y_rd, n=n, a_w=a_w)
+
+    @pytest.mark.parametrize(
+        ("representation", "expected"),
+        [
+            (
+                "complete",
+                r"M_{N,y,Rd} = \min \left( M_{pl,y,Rd} \cdot \frac{1 - n}{1 - 0.5 \cdot a_w}, M_{pl,y,Rd} \right) = "
+                r"\min \left( 5000.000 \cdot \frac{1 - 0.200}{1 - 0.5 \cdot 0.300}, 5000.000 \right) = 4705.882 \ Nmm",
+            ),
+            (
+                "complete_with_units",
+                r"M_{N,y,Rd} = \min \left( M_{pl,y,Rd} \cdot \frac{1 - n}{1 - 0.5 \cdot a_w}, M_{pl,y,Rd} \right) = "
+                r"\min \left( 5000.000 \ Nmm \cdot \frac{1 - 0.200}{1 - 0.5 \cdot 0.300}, 5000.000 \ Nmm \right) = 4705.882 \ Nmm",
+            ),
+            ("short", r"M_{N,y,Rd} = 4705.882 \ Nmm"),
+        ],
+    )
+    def test_latex(self, representation: str, expected: str) -> None:
+        """Test the latex representation of the formula."""
+        mpl_y_rd = 5000.0
+        n = 0.2
+        a_w = 0.3
+
+        latex = Form6Dot39ReducedBendingMomentResistance(mpl_y_rd=mpl_y_rd, n=n, a_w=a_w).latex()
+
+        actual = {
+            "complete": latex.complete,
+            "complete_with_units": latex.complete_with_units,
+            "short": latex.short,
+        }
+
+        assert expected == actual[representation], f"{representation} representation failed."
diff --git a/tests/codes/eurocode/nen_en_1993_1_1_c2_a1_2016/chapter_6_ultimate_limit_state/test_formula_6_39aw.py b/tests/codes/eurocode/nen_en_1993_1_1_c2_a1_2016/chapter_6_ultimate_limit_state/test_formula_6_39aw.py
new file mode 100644
index 000000000..30c30fe06
--- /dev/null
+++ b/tests/codes/eurocode/nen_en_1993_1_1_c2_a1_2016/chapter_6_ultimate_limit_state/test_formula_6_39aw.py
@@ -0,0 +1,131 @@
+"""Testing formula 6.39aw of NEN-EN 1993-1-1+C2+A1:2016."""
+
+import pytest
+
+from blueprints.codes.eurocode.nen_en_1993_1_1_c2_a1_2016.chapter_6_ultimate_limit_state.formula_6_39aw import (
+    Form6Dot39awHollowSections,
+    Form6Dot39awWeldedBoxSections,
+)
+from blueprints.validations import LessOrEqualToZeroError, NegativeValueError
+
+
+class TestForm6Dot39awHollowSections:
+    """Validation for formula 6.39aw (hollow sections) from NEN-EN 1993-1-1+C2+A1:2016."""
+
+    def test_evaluation(self) -> None:
+        """Tests the evaluation of the result."""
+        a = 7000.0  # updated default value
+        b = 200.0
+        t = 10.0
+
+        formula = Form6Dot39awHollowSections(a=a, b=b, t=t)
+        manually_calculated_result = 0.42857142857  # dimensionless
+
+        assert formula == pytest.approx(expected=manually_calculated_result, rel=1e-4)
+
+    @pytest.mark.parametrize(
+        ("a", "b", "t"),
+        [
+            (-7000.0, 200.0, 10.0),  # a is negative
+            (7000.0, -200.0, 10.0),  # b is negative
+            (7000.0, 200.0, -10.0),  # t is negative
+        ],
+    )
+    def test_raise_error_when_invalid_values_are_given(self, a: float, b: float, t: float) -> None:
+        """Test invalid values."""
+        with pytest.raises((NegativeValueError, LessOrEqualToZeroError)):
+            Form6Dot39awHollowSections(a=a, b=b, t=t)
+
+    @pytest.mark.parametrize(
+        ("representation", "expected"),
+        [
+            (
+                "complete",
+                r"a_w = \min \left( \frac{A - 2 \cdot b \cdot t}{A}, 0.5 \right) = "
+                r"\min \left( \frac{7000.000 - 2 \cdot 200.000 \cdot 10.000}{7000.000}, 0.5 \right) = 0.429 \ -",
+            ),
+            (
+                "complete_with_units",
+                r"a_w = \min \left( \frac{A - 2 \cdot b \cdot t}{A}, 0.5 \right) = "
+                r"\min \left( \frac{7000.000 \ mm^2 - 2 \cdot 200.000 \ mm \cdot 10.000 \ mm}"
+                r"{7000.000 \ mm^2}, 0.5 \right) = 0.429 \ -",
+            ),
+            ("short", r"a_w = 0.429 \ -"),
+        ],
+    )
+    def test_latex(self, representation: str, expected: str) -> None:
+        """Test the latex representation of the formula."""
+        a = 7000.0  # updated default value
+        b = 200.0
+        t = 10.0
+
+        latex = Form6Dot39awHollowSections(a=a, b=b, t=t).latex()
+
+        actual = {
+            "complete": latex.complete,
+            "complete_with_units": latex.complete_with_units,
+            "short": latex.short,
+        }
+
+        assert expected == actual[representation], f"{representation} representation failed."
+
+
+class TestForm6Dot39awWeldedBoxSections:
+    """Validation for formula 6.39aw (welded box sections) from NEN-EN 1993-1-1+C2+A1:2016."""
+
+    def test_evaluation(self) -> None:
+        """Tests the evaluation of the result."""
+        a = 7000.0  # updated default value
+        b = 200.0
+        t_f = 10.0
+
+        formula = Form6Dot39awWeldedBoxSections(a=a, b=b, t_f=t_f)
+        manually_calculated_result = 0.42857142857  # dimensionless
+
+        assert formula == pytest.approx(expected=manually_calculated_result, rel=1e-4)
+
+    @pytest.mark.parametrize(
+        ("a", "b", "t_f"),
+        [
+            (-7000.0, 200.0, 10.0),  # a is negative
+            (7000.0, -200.0, 10.0),  # b is negative
+            (7000.0, 200.0, -10.0),  # t_f is negative
+        ],
+    )
+    def test_raise_error_when_invalid_values_are_given(self, a: float, b: float, t_f: float) -> None:
+        """Test invalid values."""
+        with pytest.raises((NegativeValueError, LessOrEqualToZeroError)):
+            Form6Dot39awWeldedBoxSections(a=a, b=b, t_f=t_f)
+
+    @pytest.mark.parametrize(
+        ("representation", "expected"),
+        [
+            (
+                "complete",
+                r"a_w = \min \left( \frac{A - 2 \cdot b \cdot t_f}{A}, 0.5 \right) = "
+                r"\min \left( \frac{7000.000 - 2 \cdot 200.000 \cdot 10.000}{7000.000}, 0.5 \right) = 0.429 \ -",
+            ),
+            (
+                "complete_with_units",
+                r"a_w = \min \left( \frac{A - 2 \cdot b \cdot t_f}{A}, 0.5 \right) = "
+                r"\min \left( \frac{7000.000 \ mm^2 - 2 \cdot 200.000 \ mm \cdot 10.000 \ mm}"
+                r"{7000.000 \ mm^2}, 0.5 \right) = 0.429 \ -",
+            ),
+            ("short", r"a_w = 0.429 \ -"),
+        ],
+    )
+    def test_latex(self, representation: str, expected: str) -> None:
+        """Test the latex representation of the formula."""
+        a = 7000.0  # updated default value
+        b = 200.0
+        t_f = 10.0
+
+        latex = Form6Dot39awWeldedBoxSections(a=a, b=b, t_f=t_f).latex()
+
+        actual = {
+            "complete": latex.complete,
+            "complete_with_units": latex.complete_with_units,
+            "short": latex.short,
+        }
+
+        assert expected == actual[representation], f"{representation} representation failed."
diff --git a/tests/codes/eurocode/nen_en_1993_1_1_c2_a1_2016/chapter_6_ultimate_limit_state/test_formula_6_40.py b/tests/codes/eurocode/nen_en_1993_1_1_c2_a1_2016/chapter_6_ultimate_limit_state/test_formula_6_40.py
new file mode 100644
index 000000000..bded06230
--- /dev/null
+++ b/tests/codes/eurocode/nen_en_1993_1_1_c2_a1_2016/chapter_6_ultimate_limit_state/test_formula_6_40.py
@@ -0,0 +1,77 @@
+"""Testing formula 6.40 of NEN-EN 1993-1-1+C2+A1:2016."""
+
+import pytest
+
+from blueprints.codes.eurocode.nen_en_1993_1_1_c2_a1_2016.chapter_6_ultimate_limit_state.formula_6_40 import Form6Dot40ReducedBendingMomentResistance
+from blueprints.validations import LessOrEqualToZeroError, NegativeValueError
+
+
+class TestForm6Dot40ReducedBendingMomentResistance:
+    """Validation for formula 6.40 from NEN-EN 1993-1-1+C2+A1:2016."""
+
+    def test_evaluation(self) -> None:
+        """Tests the evaluation of the result."""
+        mpl_z_rd = 6000.0
+        n = 0.3
+        a_f = 0.4
+
+        formula = Form6Dot40ReducedBendingMomentResistance(mpl_z_rd=mpl_z_rd, n=n, a_f=a_f)
+        manually_calculated_result = 5250.0  # Nmm
+
+        assert formula == pytest.approx(expected=manually_calculated_result, rel=1e-4)
+
+    @pytest.mark.parametrize(
+        ("mpl_z_rd", "n", "a_f"),
+        [
+            (-6000.0, 0.3, 0.4),  # mpl_z_rd is negative
+            (6000.0, -0.3, 0.4),  # n is negative
+            (6000.0, 0.3, -0.4),  # a_f is negative
+        ],
+    )
+    def test_raise_error_when_invalid_values_are_given(self, mpl_z_rd: float, n: float, a_f: float) -> None:
+        """Test invalid values."""
+        with pytest.raises((NegativeValueError, LessOrEqualToZeroError)):
+            Form6Dot40ReducedBendingMomentResistance(mpl_z_rd=mpl_z_rd, n=n, a_f=a_f)
+
+    @pytest.mark.parametrize(
+        ("mpl_z_rd", "n", "a_f"),
+        [
+            (6000.0, 0.3, 2.0),  # denominator (1 - 0.5 * a_f) <= 0
+        ],
+    )
+    def test_raise_error_when_denominator_is_invalid(self, mpl_z_rd: float, n: float, a_f: float) -> None:
+        """Test invalid denominator."""
+        with pytest.raises(LessOrEqualToZeroError):
+            Form6Dot40ReducedBendingMomentResistance(mpl_z_rd=mpl_z_rd, n=n, a_f=a_f)
+
+    @pytest.mark.parametrize(
+        ("representation", "expected"),
+        [
+            (
+                "complete",
+                r"M_{N,z,Rd} = \min \left( M_{pl,z,Rd} \cdot \frac{1 - n}{1 - 0.5 \cdot a_f}, M_{pl,z,Rd} \right) = "
+                r"\min \left( 6000.000 \cdot \frac{1 - 0.300}{1 - 0.5 \cdot 0.400}, 6000.000 \right) = 5250.000 \ Nmm",
+            ),
+            (
+                "complete_with_units",
+                r"M_{N,z,Rd} = \min \left( M_{pl,z,Rd} \cdot \frac{1 - n}{1 - 0.5 \cdot a_f}, M_{pl,z,Rd} \right) = "
+                r"\min \left( 6000.000 \ Nmm \cdot \frac{1 - 0.300}{1 - 0.5 \cdot 0.400}, 6000.000 \ Nmm \right) = 5250.000 \ Nmm",
+            ),
+            ("short", r"M_{N,z,Rd} = 5250.000 \ Nmm"),
+        ],
+    )
+    def test_latex(self, representation: str, expected: str) -> None:
+        """Test the latex representation of the formula."""
+        mpl_z_rd = 6000.0
+        n = 0.3
+        a_f = 0.4
+
+        latex = Form6Dot40ReducedBendingMomentResistance(mpl_z_rd=mpl_z_rd, n=n, a_f=a_f).latex()
+
+        actual = {
+            "complete": latex.complete,
+            "complete_with_units": latex.complete_with_units,
+            "short": latex.short,
+        }
+
+        assert expected == actual[representation], f"{representation} representation failed."
diff --git a/tests/codes/eurocode/nen_en_1993_1_1_c2_a1_2016/chapter_6_ultimate_limit_state/test_formula_6_40af.py b/tests/codes/eurocode/nen_en_1993_1_1_c2_a1_2016/chapter_6_ultimate_limit_state/test_formula_6_40af.py
new file mode 100644
index 000000000..6e25c7bbb
--- /dev/null
+++ b/tests/codes/eurocode/nen_en_1993_1_1_c2_a1_2016/chapter_6_ultimate_limit_state/test_formula_6_40af.py
@@ -0,0 +1,131 @@
+"""Testing formula 6.40af of NEN-EN 1993-1-1+C2+A1:2016."""
+
+import pytest
+
+from blueprints.codes.eurocode.nen_en_1993_1_1_c2_a1_2016.chapter_6_ultimate_limit_state.formula_6_40af import (
+    Form6Dot40afHollowSections,
+    Form6Dot40afWeldedBoxSections,
+)
+from blueprints.validations import LessOrEqualToZeroError, NegativeValueError
+
+
+class TestForm6Dot40afHollowSections:
+    """Validation for formula 6.40af (hollow sections) from NEN-EN 1993-1-1+C2+A1:2016."""
+
+    def test_evaluation(self) -> None:
+        """Tests the evaluation of the result."""
+        a = 7000.0  # updated default value
+        h = 300.0
+        t = 10.0
+
+        formula = Form6Dot40afHollowSections(a=a, h=h, t=t)
+        manually_calculated_result = 0.14285714285  # dimensionless
+
+        assert formula == pytest.approx(expected=manually_calculated_result, rel=1e-4)
+
+    @pytest.mark.parametrize(
+        ("a", "h", "t"),
+        [
+            (-7000.0, 300.0, 10.0),  # a is negative
+            (7000.0, -300.0, 10.0),  # h is negative
+            (7000.0, 300.0, -10.0),  # t is negative
+        ],
+    )
+    def test_raise_error_when_invalid_values_are_given(self, a: float, h: float, t: float) -> None:
+        """Test invalid values."""
+        with pytest.raises((NegativeValueError, LessOrEqualToZeroError)):
+            Form6Dot40afHollowSections(a=a, h=h, t=t)
+
+    @pytest.mark.parametrize(
+        ("representation", "expected"),
+        [
+            (
+                "complete",
+                r"a_f = \min \left( \frac{A - 2 \cdot h \cdot t}{A}, 0.5 \right) = "
+                r"\min \left( \frac{7000.000 - 2 \cdot 300.000 \cdot 10.000}{7000.000}, 0.5 \right) = 0.143 \ -",
+            ),
+            (
+                "complete_with_units",
+                r"a_f = \min \left( \frac{A - 2 \cdot h \cdot t}{A}, 0.5 \right) = "
+                r"\min \left( \frac{7000.000 \ mm^2 - 2 \cdot 300.000 \ mm \cdot 10.000 \ mm}"
+                r"{7000.000 \ mm^2}, 0.5 \right) = 0.143 \ -",
+            ),
+            ("short", r"a_f = 0.143 \ -"),
+        ],
+    )
+    def test_latex(self, representation: str, expected: str) -> None:
+        """Test the latex representation of the formula."""
+        a = 7000.0  # updated default value
+        h = 300.0
+        t = 10.0
+
+        latex = Form6Dot40afHollowSections(a=a, h=h, t=t).latex()
+
+        actual = {
+            "complete": latex.complete,
+            "complete_with_units": latex.complete_with_units,
+            "short": latex.short,
+        }
+
+        assert expected == actual[representation], f"{representation} representation failed."
+
+
+class TestForm6Dot40afWeldedBoxSections:
+    """Validation for formula 6.40af (welded box sections) from NEN-EN 1993-1-1+C2+A1:2016."""
+
+    def test_evaluation(self) -> None:
+        """Tests the evaluation of the result."""
+        a = 7000.0  # updated default value
+        h = 300.0
+        t_w = 10.0
+
+        formula = Form6Dot40afWeldedBoxSections(a=a, h=h, t_w=t_w)
+        manually_calculated_result = 0.14285714285  # dimensionless
+
+        assert formula == pytest.approx(expected=manually_calculated_result, rel=1e-4)
+
+    @pytest.mark.parametrize(
+        ("a", "h", "t_w"),
+        [
+            (-7000.0, 300.0, 10.0),  # a is negative
+            (7000.0, -300.0, 10.0),  # h is negative
+            (7000.0, 300.0, -10.0),  # t_w is negative
+        ],
+    )
+    def test_raise_error_when_invalid_values_are_given(self, a: float, h: float, t_w: float) -> None:
+        """Test invalid values."""
+        with pytest.raises((NegativeValueError, LessOrEqualToZeroError)):
+            Form6Dot40afWeldedBoxSections(a=a, h=h, t_w=t_w)
+
+    @pytest.mark.parametrize(
+        ("representation", "expected"),
+        [
+            (
+                "complete",
+                r"a_f = \min \left( \frac{A - 2 \cdot h \cdot t_w}{A}, 0.5 \right) = "
+                r"\min \left( \frac{7000.000 - 2 \cdot 300.000 \cdot 10.000}{7000.000}, 0.5 \right) = 0.143 \ -",
+            ),
+            (
+                "complete_with_units",
+                r"a_f = \min \left( \frac{A - 2 \cdot h \cdot t_w}{A}, 0.5 \right) = "
+                r"\min \left( \frac{7000.000 \ mm^2 - 2 \cdot 300.000 \ mm \cdot 10.000 \ mm}"
+                r"{7000.000 \ mm^2}, 0.5 \right) = 0.143 \ -",
+            ),
+            ("short", r"a_f = 0.143 \ -"),
+        ],
+    )
+    def test_latex(self, representation: str, expected: str) -> None:
+        """Test the latex representation of the formula."""
+        a = 7000.0  # updated default value
+        h = 300.0
+        t_w = 10.0
+
+        latex = Form6Dot40afWeldedBoxSections(a=a, h=h, t_w=t_w).latex()
+
+        actual = {
+            "complete": latex.complete,
+            "complete_with_units": latex.complete_with_units,
+            "short": latex.short,
+        }
+
+        assert expected == actual[representation], f"{representation} representation failed."