Slope displacement

The slope-displacement models estimate the permanent displacement of a sliding mass. They are functions of the yield coefficient \(k_y\), the period of the mass, and ground-motion parameters, which are what the ground-motion models of Ground-motion models predict.

Function

Model

calc_disp_rs08()

Rathje and Saygili (2008), from PGA (and magnitude or PGV)

calc_disp_ra11()

Rathje and Antonakos (2011), from PGA and the periods of the mass and of the ground motion

calc_disp_bt07()

Bray and Travasarou (2007), from the spectral acceleration at the degraded period

calc_disp_bea17()

Bray et al. (2017), subduction events

calc_disp_wla06()

Watson-Lamprey and Abrahamson (2006), from PGA and \(S_a(1\,\mathrm{s})\)

calc_disp_cr20, calc_disp_cr21, calc_disp_cr22

Cho and Rathje (2020, 2021, 2022)

calc_prob_disp_bt07, calc_prob_disp_bea17

Probability of a non-zero displacement

calc_rigid_disp()

Displacement of a rigid block from an acceleration time series

The models differ in the ground-motion parameters they take, so the same ground-motion model supplies each of them with a different quantity.

from pygmm import slope_displacement

model = pygmm.ChiouYoungs2014(scenario)
psa_dts = model.interp_spec_accels([1.5 * 0.3])[0]
slope_displacement.calc_disp_bt07(
    yield_coef=0.1, period_slide=0.3, psa_dts=psa_dts, mag=6.5
)

Earth dams

HaleAbrahamson19 is the transfer function of Hale and Abrahamson (2019) from the input motion to the average acceleration of a sliding mass in an earth dam. It is a function of the height and the shear-wave velocity of the dam, and takes the 5%-damped spectral acceleration at its nonlinear period. transfer_function(freqs, spec_accel) returns a HaleTransferFunction. The period of a dam can be estimated with calc_dam_period_pk19(). In pyStrata the same quantity is computed for a shear-wedge dam, and example 21 compares the two.

Examples