Corrosion mc2020

docs/_example_code/usage_corrosion.py

@@ -0,0 +1,29 @@
+"""Example code to calculate the velocity_of_corrosion and the area_after_corrosion of rebars."""
+
+from structuralcodes.codes.mc2020._corrosion import calculate_velocity_of_corrosion,calculate_minimum_area_after_corrosion
+
+# Calculate the representative velocity of corrosion (defined Pcorr_rep according to MC2020)
+Pcorr_rep=calculate_velocity_of_corrosion(corrosion_type="carbonation_induced",exposure_class="Unsheltered")
+Pcorr_rep=calculate_velocity_of_corrosion(corrosion_type="carbonation_induced",exposure_class="Sheltered")
+Pcorr_rep=calculate_velocity_of_corrosion(corrosion_type="chloride_induced",exposure_class="Wet")
+Pcorr_rep=calculate_velocity_of_corrosion(corrosion_type="chloride_induced",exposure_class="Airborn_seawater")
+Pcorr_rep=calculate_velocity_of_corrosion(corrosion_type="chloride_induced",exposure_class="Submerged")
+Pcorr_rep=calculate_velocity_of_corrosion(corrosion_type="chloride_induced",exposure_class="Tidal_zone")
+Pcorr_rep=calculate_velocity_of_corrosion(corrosion_type="chloride_induced",exposure_class="Cyclic_dry_wet")
+Pcorr_rep=calculate_velocity_of_corrosion(corrosion_type="chloride_induced",exposure_class="Cyclic_dry_wet",fractile=0.5) #should give 30
+Pcorr_rep=calculate_velocity_of_corrosion(corrosion_type="chloride_induced",exposure_class="Cyclic_dry_wet",fractile=0.8413) #should give 30+1*40=70 (1 stdev)
+Pcorr_rep=calculate_velocity_of_corrosion(corrosion_type="chloride_induced",exposure_class="Cyclic_dry_wet",fractile=0.9772) #should give 30+2*40=110 (2 stdev)
+print("Calculated velocity of corrosion Pcorr_rep = "+str(round(Pcorr_rep,2))+" μm/yr")
+
+# Calculate the minimum area after corrosion of a rebar of diameter 16mm.
+InitialArea=8*8*3.141592
+print("Area before corrosion = "+str(round(InitialArea,2))+" mm2")
+# MethodA: by indicating the mass_loss
+Minimum_area_after_corrosion=calculate_minimum_area_after_corrosion(uncorroded_area=InitialArea,pitting_factor=1.2,mass_loss=0.3)
+# MethodB: by indicating the velocity_of_corrosion and the time_of_corrosion
+Minimum_area_after_corrosion=calculate_minimum_area_after_corrosion(uncorroded_area=InitialArea,pitting_factor=1,velocity_of_corrosion=100,time_of_corrosion=10)
+
+print("Calculated Minimum_area_after_corrosion = "+str(round(Minimum_area_after_corrosion,2))+" mm2")
+
+
+

structuralcodes/codes/mc2020/__init__.py

@@ -5,3 +5,7 @@
 __title__: str = 'fib Model Code 2020'
 __year__: str = '2024'
 __materials__: t.Tuple[str] = ('concrete', 'reinforcement')
+
+from ._corrosion import kc, pcorr_fractile, pcorr_rep
+
+__all__ = ['pcorr_rep', 'pcorr_fractile', 'kc']

structuralcodes/codes/mc2020/_corrosion.py

@@ -0,0 +1,174 @@
+import typing as t
+
+import numpy as np
+from scipy.stats import lognorm
+
+corrosion_type = t.Literal['carbonation', 'chloride']
+exposure_class = t.Literal[
+    'sheltered',
+    'unsheltered',
+    'wet',
+    'cyclic_dry_wet',
+    'airborn_seawater',
+    'submerged',
+    'tidal_zone',
+]
+exposure_class_corrosion_type = {
+    'carbonation': ['sheltered', 'unsheltered'],
+    'chloride': [
+        'wet',
+        'cyclic_dry_wet',
+        'airborn_seawater',
+        'submerged',
+        'tidal_zone',
+    ],
+}
+
+
+def _validate_corrosion_exposure(
+    corrosion_type: corrosion_type, exposure_class: exposure_class
+) -> bool:
+    """Returns True if corrosion_type and exposure_class are valid."""
+    corr_type = corrosion_type.lower()
+    exposure = exposure_class.lower()
+    if corr_type not in ['carbonation', 'chloride']:
+        return False
+    return exposure in exposure_class_corrosion_type[corr_type]
+
+
+_table_30_1_6 = {
+    'carbonation': {
+        'sheltered': {'mean': 2, 'std': 3},
+        # the table shows "t", but 7 is correct
+        'unsheltered': {'mean': 5, 'std': 7},
+    },
+    'chloride': {
+        'wet': {'mean': 4, 'std': 6},
+        'cyclic_dry_wet': {'mean': 30, 'std': 40},
+        'airborn_seawater': {'mean': 30, 'std': 40},
+        'submerged': {'mean': 4, 'std': 7},
+        'tidal_zone': {'mean': 50, 'std': 100},
+    },
+}
+
+
+def pcorr_rep(
+    corrosion_type: corrosion_type, exposure_class: exposure_class
+) -> dict:
+    """Returns corrosion rate properties in micrometer/year.
+
+    This implements MC 2020 table 30.1-6a and 30.1-6b.
+    The return is a dictionary containing mean and standard deviation of pcorr
+    in micrometer/year.
+
+    Note:
+        There is a typo in MC2020 Table 30.1-6a. In unshelterd conditions, the
+        pcorr standard deviation is indicated as "t" while it should be equal
+        to 7 micrometer/year according to fib Bulletin 111.
+
+    Args:
+        corrosion_type (str): The type of corrosion. Can be either
+            "carbonation" or "chloride".
+        exposure_class (str): The exposure class. Can be one of the following
+            for "carbonation": "sheltered", "unsheltered".
+            Can be one of the following for "chloride":
+            "wet", "cyclic_dry_wet", "airborn_seawater", "submerged",
+            "tidal_zone".
+
+    Returns:
+        dict: A dictionary containing the mean and standard deviation of the
+            corrosion rate in micrometer/year.
+
+    Raises:
+        ValueError: if the corrosion type is not valid.
+        ValueError: if the exposure class is not valid for the relative
+            corrosion type.
+    """
+    if not _validate_corrosion_exposure(corrosion_type, exposure_class):
+        raise ValueError(
+            'Invalid corrosion_type or exposure_class.\n'
+            'corrosion_type must be either "carbonation" or "chloride".\n'
+            'exposure_class must be one of the following for "carbonation": '
+            '"sheltered", "unsheltered".\n'
+            'exposure_class must be one of the following for "chloride": '
+            '"wet", "cyclic_dry_wet", "airborn_seawater", "submerged", '
+            '"tidal_zone".'
+        )
+    return _table_30_1_6[corrosion_type.lower()][exposure_class.lower()]
+
+
+def pcorr_fractile(
+    corrosion_type: corrosion_type,
+    exposure_class: exposure_class,
+    fractile: float = 0.5,
+) -> float:
+    """Returns the fractile of the corrosion rate in micrometer/year.
+
+    This functions uses data from MC 2020 table 30.1-6a and 30.1-6b to
+    calculate the corrosion rate at a given fractile. The return is a float
+    representing the corrosion rate in micrometer/year.
+
+    Note: according to fib Bulletin 111, the corrosion rate can be assumed to
+        follow a lognormal distribution.
+
+    Args:
+        corrosion_type (str): The type of corrosion. Can be either
+            "carbonation" or "chloride".
+        exposure_class (str): The exposure class. Can be one of the following
+            for "carbonation": "sheltered", "unsheltered".
+            Can be one of the following for "chloride":
+            "wet", "cyclic_dry_wet", "airborn_seawater", "submerged",
+            "tidal_zone".
+        fractile (Optional[float]): The fractile for which to calculate the
+            corrosion rate. The default value is 0.5, which corresponds to the
+            median corrosion rate. The value should be in the range ]0,1[
+
+    Returns:
+        float: The corrosion rate at the specified fractile in micrometer/year.
+
+    Raises:
+        ValueError: if the corrosion type is not valid.
+        ValueError: if the exposure class is not valid for the relative
+            corrosion type.
+        ValueError: if the fractile value is not valid.
+    """
+    if fractile <= 0 or fractile >= 1:
+        raise ValueError(
+            'The value of fractile is not valid, use a value between 0 and 1.'
+        )
+    pcorr_dic = pcorr_rep(corrosion_type, exposure_class)
+
+    # Lognormal distribution
+    s = np.log(1 + pcorr_dic['std'] ** 2 / pcorr_dic['mean'] ** 2) ** 0.5
+    scale = (
+        pcorr_dic['mean'] ** 2
+        / (pcorr_dic['mean'] ** 2 + pcorr_dic['std'] ** 2) ** 0.5
+    )
+    lognorm_dist = lognorm(s=s, scale=scale)
+    return lognorm_dist.ppf(fractile)
+
+
+def kc(fc: float) -> float:
+    """Compute kc reducing compressive strength factor.
+
+    MC2020 30.1.10.3.2.1
+
+    It does depend only on fc and not on corrosion level, even if it is valid
+    for low to moderate corrosion values.
+
+    Moderate and low corrosion levels have been defined to apply approximately
+    for medium bar diameters with 5% weight loss and 0.25 depth of corrosion.
+
+    Args:
+        fc (float): Compressive strength of concrete in MPa.
+
+    Returns:
+        float: The reducing compressive strength factor kc.
+
+    Raises:
+        ValueError: if fc is not positive.
+    """
+    if fc <= 0:
+        raise ValueError('fc must be a positive value.')
+    eta_fc = min((30 / fc) ** (1 / 3.0), 1)
+    return 0.75 * eta_fc