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Eurocode 8 module: ec8

Overview

The ec8 module provides tools for seismic design according to EN 1998-1. It generates elastic and design response spectra, retrieves national annex parameters for both the standard Eurocode and the Portuguese National Annex, and exports spectra to CSV.

Response spectra — ec8.spectrum

get_spec_params

Returns the raw spectrum shape parameters for a given locale, code, importance class, soil type, and seismic zone.

from eurocodepy.ec8 import get_spec_params

S, ag, TB, TC, TD = get_spec_params(
    locale='PT',        # 'EU' (standard CEN) or 'PT' (Portuguese NA)
    code='PT-1',        # see table below
    class_imp='II',     # importance class: 'i', 'ii', 'iii', 'iv'
    soil='C',           # soil type: A, B, C, D, E
    zone='1_2',         # seismic zone (code-dependent)
)

Available codes

locale code Description
EU CEN-1 Standard Eurocode type 1 spectrum
EU CEN-2 Standard Eurocode type 2 spectrum
PT PT-1 Portuguese NA — continental Portugal (type 1)
PT PT-2 Portuguese NA — continental Portugal + Madeira (type 2)
PT PT-A Portuguese NA — Azores

Seismic zones

  • PT-1: 1_1, 1_2, 1_3, 1_4, 1_5, 1_6
  • PT-2 / PT-A: 2_1, 2_2, 2_3, 2_4, 2_5
  • CEN-1 / CEN-2: .1g, .2g, .3g, .4g, .5g, .6g, .7g, .8g, .9g, 1_0g

get_spectrum_ec8

Builds the full horizontal design spectrum as a dict of arrays.

from eurocodepy.ec8 import get_spectrum_ec8   # also: ec8.spectrum.get_spectrum_ec8

spec = get_spectrum_ec8(
    locale='PT',
    code='PT-1',
    imp_class='II',
    soil='C',
    zone='1_2',
    behaviour=3.0,   # behaviour factor q (1.0 for elastic spectrum)
)

# Keys in the returned dict:
# 'T'   — period array [s]
# 'Sd'  — design spectral acceleration [g]
# 'Se'  — elastic spectral acceleration [g]
# 'ag'  — reference peak ground acceleration [g]
# 'S'   — soil factor
# 'TB', 'TC', 'TD' — corner periods [s]

get_spectrum_user

Generate a spectrum from arbitrary user-supplied parameters without needing a national annex entry.

from eurocodepy.ec8.spectrum import get_spectrum_user

spec = get_spectrum_user(ag=0.2, S=1.15, TB=0.1, TC=0.6, TD=2.0, behaviour=4.0)

get_spectrum_parameters

Low-level function; returns the parameter dict for a given combination.

calc_spectrum

Computes the spectral ordinates from already-extracted parameters.

draw_spectrum_ec8

Plots the spectrum using matplotlib.

from eurocodepy.ec8 import draw_spectrum_ec8

draw_spectrum_ec8(spec, show=True, title='Design spectrum — Lisbon')

write_spectrum_ec8

Exports the spectrum to a CSV file (two columns: T [s], Sd [g]).

from eurocodepy.ec8 import write_spectrum_ec8

write_spectrum_ec8(spec, filename='spectrum_PT1_II_C_1_2.csv')

Compliance

Calculations follow EN 1998-1:2004 and the Portuguese National Annex (NP EN 1998-1).

Further reading