Risk assessment of an interacting structure–soil system due to liquefaction

Abstract

SUMMARYThe present study deals with the non-linear stochastic dynamic analysis of a soil-structure interacting system. The ultimate objective is to determine the risk of damage to the system due to liquefaction under a wide range of earthquake intensities. A Monte Carlo simulation approach is followed in conjunction with advanced ÿnite element procedures. The stochastic spatial variability of soil properties and the randomness of the seismic excitation are taken into account in order to estimate the statistics of the response, measured in terms of uniform foundation settlement and tilting. Speciÿcally, soil properties are modelled as non-Gaussian random ÿelds and seismic excitations as non-stationary random processes. The probabilistic characteristics of the stochastic ÿeld modelling soil properties are established from in situ tests. The risk of damage to the soil-structure system due to liquefaction is assessed by establishing fragility curves, which are of paramount importance for risk assessment and management studies of such systems. Fragility curves express the probability of exceeding various thresholds in the response. The relative e ect of the variability of various soil parameters on the variability of the response is also examined.

Numerical simulation of liquefaction effects on seismic SSI

“…8 to 10m) with a max bed greater than 0.12g (Figure 8 d). These conclusions agree with those found by Koutsourelakis et al [19] and Popescu [20].…”

“…This phenomenon of SSI added to the foundation type [32] can explain the response of collapsed structures observed during the recent earthquakes, as it is reported by Tokimatsu et al [28] and Juang et al [31] among others. A similar response has been reported in numerical and physical tests [37,38,19,26,35,36].…”

“…These works regard principally the degradation of soil rigidity in clays [33,34]. Among numerical works studying effects of soil liquefaction on the structure response we can mention Koutsourelakis et al [19], Popescu [20], Chakrabortty et al [35] and Popescu et al [36]. According to these works the local subsoil conditions influences the seismic response of structures changing the characteristics of the strong motion.…”

Parametric studies and quantitative assessment of the vulnerability of a RC frame building exposed to differential settlements

“…The choice of such a structure is governed by the observation that the building height is not critical in assessing building response due to ground failure, observation which has been confirmed analytically by Koutsourelakis et al (2002).…”

Apport de la modélisation numérique dans l’analyse des risques sismiques liés à la liquéfaction

“…On peut remarquer que le spectre de réponse médian est compatible avec le spectre de réponse du sol type A de l'Eurocode8 ajusté à la valeur médiane de l'accélération maximale en rocher affleu rant. Les statistiques sur quelques caractéristiques des signaux d'entrée sont résumées dans le tableau I. Ces caractéristiques sismiques sont l'accélération maximale au rocher affleurant (PHA), l'intensité d'Arias (IA rias), la période prédominante (Tp), la période moyenne (Tm) (Rathje et al, 1998), l'intensité spectrale (Si), la vitesse maximale (pgv), l'intensité mis (Irm s) (Koutsourelakis et al, 2002), la densité d'énergie spécifique (SED) et la durée significative (t5 95). Pour les définitions des para mètres voir l'annexe A.…”