Closed‐form aftershock reliability of damage‐cumulating elastic‐perfectly‐plastic systems

Abstract

Major earthquakes (i.e., mainshocks) typically trigger a sequence of lower magnitude events clustered both in time and space. Recent advances of seismic hazard analysis stochastically model aftershock occurrence (given the main event) as a nonhomogeneous Poisson process with rate that decays in time as a negative power law. Risk management in the post-event emergency phase has to deal with this short-term seismicity. In fact, because the structural systems of interest might have suffered some damage in the mainshock, possibly worsened by damaging aftershocks, the failure risk may be large until the intensity of the sequence reduces or the structure is repaired. At the state-of-the-art, the quantitative assessment of aftershock risk is aimed at building tagging, that is, to regulate occupancy. The study, on the basis of age-dependent stochastic processes, derived closed-form approximations for the aftershock reliability of simple nonevolutionary elastic-perfectly-plastic damage-cumulating systems, conditional on different information about the structure. Results show that, in the case hypotheses apply, the developed models may represent a basis for handy tools enabling risk-informed tagging by stakeholders and decision makers

Application of a Damage State Method Based on Period Elongation for Time Variant Vulnerability of Degrading Reinforced Concrete Buildings

“…It is shown that the probability increase due to the main shock is the largest in the presented case studies, but it is only a fraction of the cumulative probability of exceedance of a damage state throughout the aftershock sequences. The probability of damage state exceedance in the numerical results for the case studies of the aftershock sequences of the Thessaloniki (1978) and the Northridge (1994) follows a similar trend to the failure probability during the aftershock sequence period as estimated by Iervolino et al [5]. Moreover, the assumption that period elongation of ΔΤ = 60 % corresponds to a state near collapse is in agreement with the empirical estimations by Katsanos and Sextos [10].…”

“…Iervolino et al [5] focused on earthquake clusters (aftershock sequences) and developed a probabilistic damage accumulation model for elastic-perfectly plastic single-degree-of-freedom (SDOF) structures and estimated the failure probability as an increasing function of time. Repeated earthquakes and the subsequent damage accumulation may lead to an increased inelastic displacement demand of SDOF systems and an increased ratio of the inelastic displacement to the maximum displacement of the elastic system [6].…”

Engineering Applications Using Probabilistic Aftershock Hazard Analyses: Aftershock Hazard Map and Load Combination of Aftershocks and Tsunamis

“…The strong aftershocks that occur after a large subduction earthquake will adversely affect recovery activities [29][30][31]. For example, the gas, water, and electricity supply were disconnected over a wide area owing to an aftershock with a magnitude of 7.2 on 07 April, 2011, nearly a month after the Tohoku earthquake.…”

A three-level framework for multi-risk assessment

“…Some recent examples in the literature address the increase in a building's vulnerability to ground shaking due to increased structural load following volcanic ash fall or heavy snowfall or after being subjected to a blast (Lee and Rosowsky 2006;Zuccaro et al, 2008;Asprone et al, 2010;Selva 2013;). Another well-known situation is the increased vulnerability of structures to successive shaking during an earthquake cluster or sequence Iervolino et al, 2014).…”