Eurocode 2 module: `ec2`

Overview

The ec2 module provides tools for the design of reinforced and prestressed concrete structures according to EN 1992-1-1 and, for slabs and shells, EN 1992-2 Annex LL. It supports the 2004 edition and the 2023 edition (second generation) where functions have been updated; see Editions and National Annexes.

Page	Content
this page	conventions, materials, helper functions, limitations
EN 1992-1-1:2004	beam bending and shear, anchorage, punching, SLS crack, creep, shrinkage, fire
EN 1992-1-1:2023	shear (8.2), torsion (8.3), detailing (12), creep and shrinkage (Annex B)
Membranes, slabs and shells	Annex G (2023), EN 1992-1-1 Annex F and EN 1992-2 6.109 and Annex LL (2004), sandwich model, out-of-plane shear
Clause map	every function of `uls2023` by clause and equation (generated from the docstrings)

Conventions

Functions written for the second-generation code (uls2023, time_dependent2023, and the shell, slab and membrane checks) use kN, m and MPa unless the docstring says otherwise. The older 2004 functions were written one by one and mix units; the table below is what each family expects.

Family	Lengths	Areas	Forces / moments	Stresses
`uls2023`, `uls.shell_check`, `uls.slab_check`, `uls.membrane_check`	m	m² (per m: m²/m)	kN, kN/m, kNm, kNm/m	MPa
`uls.beam` (`calc_mrd`, `calc_asl`)	m	cm²	kN·m	MPa
`uls.shear` (`calc_vrd`, `calc_vrdc`, `calc_asws`)	m	m² per m	kN	MPa
`uls.shell` (`calc_reinf_plane`, `calc_reinf_shell`)	m	forces, see the docstring	kN/m	—
`uls.punch`	mm	—	kN, kNm	MPa
`uls.anchorage`	mm	mm²	N	MPa
`sls.crack`	m (bar diameter too)	m²	kNm	MPa; `crack_opening` returns mm
`time_dependent2023`, `sls.creep`, `sls.shrinkage`	`hn` in mm	—	—	MPa; ages in days

Signs. Tension and sagging bending are positive in the code of 2023 (Annex G): the bottom layer of uls2023 is in tension for positive m. EN 1992-2 Annex LL and uls.shell.calc_reinf_shell take positive m as tension on the top face. uls.shell_check hides this by returning asx_bot, asy_bot, asx_top, asy_top for the physical faces. Axial force is positive in tension, except in sls.crack.crack_opening (compression positive, see its docstring).

Materials

`Concrete`

Code reference: materials.Concrete, materials.get_concrete

from eurocodepy.ec2 import Concrete

c = Concrete('C30/37')
c.fck      # characteristic compressive strength [MPa]
c.fcd      # design compressive strength (fck / γc)
c.fctm     # mean tensile strength
c.Ecm      # secant modulus of elasticity [MPa]

Available grades: 2004, C12/15 to C90/105; 2023 (Table 5.1), C12/15 to C100/115.

EN 1992-1-1:2023

c = Concrete('C30/37', edition='2023')                  # k_tc = 1.0 (late loading)
c = Concrete('C50/60', edition='2023', loading='other') # k_tc = 0.85
c.eta_cc, c.k_tc, c.fcd   # fcd = eta_cc * k_tc * fck / gamma_c  (Eq. 5.3)
Concrete('C30/37', edition='2023', situation='accidental').gamma_c   # 1.15 (Table 4.3)
Concrete('C30/37', edition='2023', k_cip=1.1)           # cast in the ground (4.3.3(4))

from eurocodepy.ec2 import material_partial_factors, prestress_partial_factors
material_partial_factors('2023', 'fatigue')   # gamma_s, gamma_c, gamma_ce, gamma_v
prestress_partial_factors('2023')             # Tables 4.1 and 4.2

loading='late' is t_ref ≤ 28 d (CN/CR) or 56 d (CS) with the design loading not expected for 3 months after casting; 'other' is every other case, including fck(t). Reinforcement and Prestress take edition and situation as well. The edition=None default is 2004.

The check inputs (PunchInput, ShearInput, SlabInput, MembraneInput, ShearTorsionInput) take the partial factors of a design situation with from_partial_factors:

from eurocodepy.ec2.uls.punch_check import PunchInput
inp = PunchInput.from_partial_factors("2023", "accidental", d=0.25, bx=0.4, by=0.4, fck=30, fyk=500)
inp.gamma_v, inp.gamma_c, inp.gamma_s, inp.edition   # 1.15, 1.15, 1.0, '2023'

Convenience instances are pre-created: C20_25, C25_30, C30_37, …, C90_105.

`Reinforcement`

Code reference: materials.Reinforcement

from eurocodepy.ec2 import Reinforcement

r = Reinforcement('B500B')
r.fyk     # characteristic yield strength [MPa]
r.fyd     # design yield strength (fyk / γs)
r.Es      # elastic modulus [MPa]

Available grades: B400A/B/C, B500A/B/C, B600A/B/C, B700A/B/C, A400NR, A500NR, A400NRSD, A500NRSD, A500EL.

`Prestress`

Code reference: materials.Prestress

from eurocodepy.ec2 import Prestress
p = Prestress('Y1860S7 12.5')   # class and nominal diameter
p.fpk     # characteristic tensile strength [MPa]
p.fp0_1k  # 0.1% proof strength [MPa]

Helper functions

# Partial safety factors
from eurocodepy.ec2 import GammaC, GammaS, GammaCT, GammaP   # 1.5, 1.15, 1.5, 1.15 (floats)

# Time-dependent concrete strength factor
from eurocodepy.ec2 import beta_cc
s = beta_cc(t=28, s=0.25)   # βcc(t) of Eq. 3.2: 1.0 at 28 days, s = 0.25 for class N cement

# Creep and shrinkage (EN 1992-1-1:2004, Annex B)
from eurocodepy.ec2 import calc_creep_coef, calc_shrink_strain

# Creep and shrinkage (EN 1992-1-1:2023, Annex B): same model as ec2.time_dependent2023, validated
from eurocodepy.ec2 import creep_coef, shrink_strain

Not implemented

EN 1992-1-1:2023: uls2023.column is the 2004 column code with the 2023 fcd; SLS crack width (sls.crack) and anchorage and lap lengths (uls.anchorage) are still 2004.
EN 1992-2 Annex LL: the general eccentric case of (108) (zn ≠ zt) and the eccentric reinforcement of (115)c.
EN 1992-1-1:2004 slabs: the chord force of the shear truss is not added to the Wood-Armer bars (the sandwich model adds it).
Minimum reinforcement is never added to membrane, slab and shell designs unless min_reinf asks for it (default "demand": a face with no tension gets zero).

Eurocode 2 module: ec2