Scalar- and Vector-Valued Fragility Analyses of Gravity Quay Wall on Liquefiable Soil: Example of Kobe Port

Abstract

The crucial role of intensity measure (IM) selection in the seismic fragility analysis of gravity quay walls is demonstrated in this paper. Scalar- and vector-valued fragility functions are presented for seismic vulnerability and performance-based evaluation of a well-documented gravity quay wall. Nonlinear dynamic analysis by an advanced constitutive model, UBCSAND, was performed to capture earthquake-induced permanent displacement of the quay wall. The estimated permanent displacement and tilting of the wall are in good agreement with its performance observed during the Kobe 1995 earthquake. Numerous dynamic analyses were then performed to compile a database of permanent displacements. Subsequently, a refinement process was conducted to classify the IMs, based on their interdependency and also their efficiency, sufficiency, and predictability. Eventually, the most appropriate IMs along with the most applicable ones were selected as the nominate parameters for seismic fragility analyses. The results demonstrate that the probability of exceedance from a given damage state is strongly dependent on the IMs selected for the fragility analysis. Appropriateness of the selected IMs is discussed through the comparison of the observed damage and the probabilities given by the fragility functions. The fragility functions developed by vector-valued IMs obtain more realistic probability of the quay wall damage compared with the scalar-valued fragility curves.