feat: concrete material properties and material class for Eurocode 2,…

… 2004 (#77)

* Start implementing material properties for concrete ec2 2004

* Add eps_cu1 and eps_c2

* Add eps_cu2, n, eps_c3 and eps_cu3

* Add concrete implementation of concrete for EC2 2004

* Add EC2 to design code factory

* Add tests for concrete ec2 2004

* Move ec2 2004 tests into new structure

* Update units and docstrings

* Change name of function for calculating n

* Force absolute values for args

* Add fun for calc fcd

* Fix incorrect docstring

structuralcodes/codes/__init__.py

@@ -23,8 +23,8 @@
 # Design code registry
 _DESIGN_CODES = {
     'mc2010': mc2010,
-    'ec2_2023': ec2_2023,
     'ec2_2004': ec2_2004,
+    'ec2_2023': ec2_2023,
 }
 
 

structuralcodes/codes/ec2_2004/__init__.py

@@ -2,6 +2,21 @@
 
 import typing as t
 
+from ._concrete_material_properties import (
+    Ecm,
+    eps_c1,
+    eps_c2,
+    eps_c3,
+    eps_cu1,
+    eps_cu2,
+    eps_cu3,
+    fcd,
+    fcm,
+    fctk_5,
+    fctk_95,
+    fctm,
+    n_parabolic_rectangular,
+)
 from ._reinforcement_material_properties import (
     fyd,
     reinforcement_duct_props,
@@ -59,6 +74,19 @@
     'w_spacing',
     'wk',
     'xi1',
+    'fcd',
+    'fcm',
+    'fctm',
+    'fctk_5',
+    'fctk_95',
+    'Ecm',
+    'eps_c1',
+    'eps_cu1',
+    'eps_c2',
+    'eps_cu2',
+    'n_parabolic_rectangular',
+    'eps_c3',
+    'eps_cu3',
     'fyd',
 ]
 

structuralcodes/codes/ec2_2004/_concrete_material_properties.py

@@ -0,0 +1,220 @@
+"""Concrete material properties according to Tab. 3.1."""
+
+import math
+
+from structuralcodes.codes import mc2010
+
+
+def fcm(fck: float, delta_f: float = 8) -> float:
+    """The mean compressive strength of concrete.
+
+    EN 1992-1-1:2004, Table 3.1.
+
+    Args:
+        fck (float): The characteristic compressive strength of concrete in
+            MPa.
+
+    Keyword Args:
+        delta_f (float): The difference between the mean and the
+            characteristic strength.
+
+    Returns:
+        float: The mean compressive strength in MPa.
+    """
+    return mc2010.fcm(fck=abs(fck), delta_f=abs(delta_f))
+
+
+def fctm(fck: float) -> float:
+    """The mean tensile strength of concrete.
+
+    EN 1992-1-1: 2004, Table 3.1.
+
+    Args:
+        fck (float): The characteristic compressive strength of concrete in
+            MPa.
+
+    Returns:
+        float: The mean tensile strength in MPa.
+    """
+    return mc2010.fctm(fck=abs(fck))
+
+
+def fctk_5(_fctm: float) -> float:
+    """The 5% fractile of the tensile strength of concrete.
+
+    EN 1992-1-1: 2004, Table 3.1.
+
+    Args:
+        _fctm (float): The mean tensile strength of concrete in MPa.
+
+    Returns:
+        float: The 5% fractile of the tensile strength in MPa.
+    """
+    return mc2010.fctkmin(_fctm=abs(_fctm))
+
+
+def fctk_95(_fctm: float) -> float:
+    """The 95% fractile of the tensile strength of concrete.
+
+    EN 1992-1-1: 2004, Table 3.1.
+
+    Args:
+        _fctm (float): The mean tensile strength of concrete in MPa.
+
+    Returns:
+        float: The 95% fractile of the tensile strength in MPa.
+    """
+    return mc2010.fctkmax(_fctm=abs(_fctm))
+
+
+def Ecm(_fcm: float) -> float:
+    """The secant modulus of concrete.
+
+    EN 1992-1-1:2004, Table 3.1.
+
+    Args:
+        _fcm (float): The mean compressive strength of concrete in MPa.
+
+    Returns:
+        float: The secant modulus of concrete in MPa.
+    """
+    return 22000.0 * math.pow(abs(_fcm) / 10, 0.3)
+
+
+def eps_c1(_fcm: float) -> float:
+    """The strain at maximum compressive stress of concrete (fcm) for the
+    Sargin constitutive law.
+
+    EN 1992-1-1:2004, Table 3.1.
+
+    Args:
+        _fcm (float): The mean compressive strength of concrete in MPa.
+
+    Returns:
+        float: The strain at maximum compressive stress, absolute value, no
+        unit.
+    """
+    return min(0.7 * math.pow(abs(_fcm), 0.31), 2.8) / 1000
+
+
+def eps_cu1(fck: float) -> float:
+    """The ultimate strain for the Sargin constitutive law.
+
+    EN 1992-1-1:2004, Table 3.1.
+
+    Args:
+        fck (float): The characteristic compressive strength of concrete in
+            MPa.
+
+    Returns:
+        float: The ultimate strain, absolute value, no unit.
+    """
+    fck = abs(fck)
+    return (
+        3.5 / 1000
+        if fck < 50
+        else (2.8 + 27 * ((98 - fcm(fck)) / 100) ** 4) / 1000
+    )
+
+
+def eps_c2(fck: float) -> float:
+    """The strain at maximum compressive stress of concrete for the
+    parabolic-rectangular law.
+
+    EN 1992-1-1:2004, Table 3.1.
+
+    Args:
+        fck (float): The characteristic compressive strength of concrete in
+            MPa.
+
+    Returns:
+        float: The strain at maximum compressive stress, absolute value, no
+        unit.
+    """
+    fck = abs(fck)
+    return (
+        2.0 / 1000 if fck < 50 else (2.0 + 0.085 * (fck - 50) ** 0.53) / 1000
+    )
+
+
+def eps_cu2(fck: float) -> float:
+    """The ultimate strain of the parabolic-rectangular law.
+
+    EN 1992-1-1:2004, Table 3.1.
+
+    Args:
+        fck (float): The characteristic compressive strength of concrete in
+            MPa.
+
+    Returns:
+        float: The ultimate strain, absolute value, no unit.
+    """
+    fck = abs(fck)
+    return (
+        3.5 / 1000 if fck < 50 else (2.6 + 35 * ((90 - fck) / 100) ** 4) / 1000
+    )
+
+
+def n_parabolic_rectangular(fck: float) -> float:
+    """The exponent in the parabolic-rectangular law.
+
+    EN 1992-1-1:2004, Table 3.1.
+
+    Args:
+        fck (float): The characteristic compressive strength of concrete in
+            MPa.
+
+    Returns:
+        float: The exponent n, absolute value, no unit.
+    """
+    fck = abs(fck)
+    return 2.0 if fck < 50 else (1.4 + 23.4 * ((90 - fck) / 100) ** 4)
+
+
+def eps_c3(fck: float) -> float:
+    """The strain at maximum compressive stress of the bi-linear law.
+
+    EN 1992-1-1:2004, Table 3.1.
+
+    Args:
+        fck (float): The characteristic compressive strength of concrete in
+            MPa.
+
+    Returns:
+        float: The strain at maximum compressive stress, absolute value, no
+        unit.
+    """
+    fck = abs(fck)
+    return 1.75 / 1000 if fck < 50 else (1.75 + 0.55 * (fck - 50) / 40) / 1000
+
+
+def eps_cu3(fck: float) -> float:
+    """The ultimate strain of the bi-linear law.
+
+    EN 1992-1-1:2004, Table 3.1.
+
+    Args:
+        fck (float): The characteristic compressive strength of concrete in
+            MPa.
+
+    Returns:
+        float: The ultimate strain, absolute value, no unit.
+    """
+    return eps_cu2(fck)
+
+
+def fcd(fck: float, alpha_cc: float, gamma_c: float) -> float:
+    """The design compressive strength of concrete.
+
+    EN 1992-1-1:2004, Eq. (3.15)
+
+    Args:
+        fck (float): The characteristic compressive strength in MPa.
+        alpha_cc (float): A factor for considering long-term effects on the
+            strength, and effects that arise from the way the load is applied.
+        gamma_c (float): The partial factor of concrete.
+
+    Returns:
+        float: The design compressive strength of concrete in MPa
+    """
+    return abs(alpha_cc) * abs(fck) / abs(gamma_c)

structuralcodes/materials/concrete/__init__.py

@@ -5,6 +5,7 @@
 from structuralcodes.codes import _use_design_code
 
 from ._concrete import Concrete
+from ._concreteEC2_2004 import ConcreteEC2_2004
 from ._concreteEC2_2023 import ConcreteEC2_2023
 from ._concreteMC2010 import ConcreteMC2010
 
@@ -13,8 +14,15 @@
     'Concrete',
     'ConcreteMC2010',
     'ConcreteEC2_2023',
+    'ConcreteEC2_2004',
 ]
 
+CONCRETES: t.Dict[str, Concrete] = {
+    'fib Model Code 2010': ConcreteMC2010,
+    'EUROCODE 2 1992-1-1:2004': ConcreteEC2_2004,
+    'EUROCODE 2 1992-1-1:2023': ConcreteEC2_2023,
+}
+
 
 def create_concrete(
     fck: float,
@@ -59,6 +67,9 @@ def create_concrete(
         )
 
     # Create the proper concrete object
-    if code.__title__ == 'fib Model Code 2010':
-        return ConcreteMC2010(fck, name, density, existing)
+    current_concrete = CONCRETES.get(code.__title__, None)
+    if current_concrete is not None:
+        return current_concrete(
+            fck=fck, name=name, density=density, existing=existing
+        )
     return None