Effect of synthetic ground motions on the liquefaction induced settlements
Résumé
In the methodology of the Pacific Earthquake Engineering Research (PEER) Center in the performance-based earthquake engineering, four stages must be studied: the hazard analysis, the structural analysis, the damage analysis and the loss analysis. Each stage has its own relation with the design model. The liquefaction apparition leads to several disastrous damages that are divided into four levels based on the crest settlement of the embankment and the peak ground acceleration (PGA) of the input signal. In this work, the effect of soil liquefaction-induced failure to a levee due to varied earthquake loading was assessed. A 2D finite element model of an embankment founded on a layered soil/rock profile was considered. An elastoplastic multi-mechanism model was used to represent the soil behavior. To account for the natural hazards, both real and synthetic input motions were used. To quantify the damage induced of the embankment the relative crest settlement was calculated and fragility curves were drawn in order to study a level of performance and to analyze the ground response. The Pacific Earthquake Engineering Research (PEER) Center is a federally funded earthquake engineering research centers that developed a performance-based methodology for risk assessment. This methodology addresses the performance of the engineering model in terms of risk of collapse, repair costs and post-earthquake loss (Porter, 2003; Causse et al., 2014, among others). It aims at estimating the frequency of a particular performance to exceed various level of the design. It takes into account a probabilistic and a determin-istic approach that are treated in four stages: the hazard analysis, the structural analysis, the damage analysis and the loss analysis. Each stage has its own relation with the design model via a performance parameter that is linked to the previous stage. Moreover, nowadays liquefaction is considered as a disastrous phenomenon that causes damages to the soil and the structures, in addition to human and economic losses. It is defined as the loss of the soil of its shear strength due to the excess of pore water pressure (Castro et al., 1982; Ishihara, 1993; Kramer, 1996, among others). The soil particles will lose their bonds and will behave like liquids. Moreover, the damage quantification due to liquefaction depends on the type of the studied structure. For an embankment for example, the crest settlement is the mode of failure to consider in order to conduct a damage analysis (Wu, 2014). Based on literature, for the case of an embankment, the liquefaction apparition has been divided into four damage levels based on the crest settlement of the embankment that is linked to the peak ground acceleration (PGA) of the input signal (Swaisgood, 2003). Hence, the effect of the ground motions is necessary to identify specially for the case of non 1
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