Seismic fragility curves based on the probability density evolution method

Abstract

A seismic fragility curve that shows the probability of failure of a structure in function of a seismic intensity, for example peak ground acceleration (PGA), is a powerful tool for the evaluation of the seismic vulnerability of the structures in nuclear engineering and civil engineering. The common assumption of existing approaches is that the fragility curve is a cumulative probability log-normal function. In this paper, we propose a new technique for construction of seismic fragility curves by numerical simulation using the Probability Density Evolution Method (PDEM). From the joint probability density function between structural response and random variables of a system and/or excitations, seismic fragility curves can be derived without the log-normal assumption. The validation of the proposed technique is performed on two numerical examples.

Reliability analysis of an inter-story isolated structure under a main-aftershock sequence based on the Laplace asymptotic method

“…The failure mode is any substructure failure that leads to failure of the whole inter-story isolated structure. The performance function of the story isolation structure (Dang et al, 2018;Liu et al, 2019) is…”

“…The appropriate selection of the period ratio, yield/weight ratio, and damping ratio of the isolated structure led to an increase in the overall reliability of the structure. Dang et al (2018) studied the reliability of isolated structures using statistical methods and probability. Although horizontal seismic action was reduced by 60-70%, the fortification targets of "no damage under moderate earthquake" and "no collapse under great earthquake" were not satisfied.…”