Preliminary Definition of Fragility Curves for Pile-Supported Wharves

Significant damage has been caused by past earthquakes to pile supported wharves, nevertheless a rigorous analytical vulnerability and risk analysis of pile-supported wharves has not yet been performed. Efforts so far are mainly based on pushover analyses, which do not capture dynamic phenomena during the earthquake excitation. Moreover, most methods for dynamic analyses of pile foundations focus on soil nonlinearities, but not also on the nonlinear structural response of the pile (formation of plastic hinges), which is inevitable as a mode of failure in the case of pile-supported wharves. The primary objective of this research is to propose a methodology for performance-based fragility analysis of pile-supported wharves on the basis of nonlinear dynamic analysis. A model which accounts both for soil and pile nonlinear response was investigated. A wharf section of representative geometry was subjected to parametric analysis, for which variables are input motion, its intensity, and soil properties. A two-parameter lognormal distribution was implemented for the preliminary definition of fragility curves for pile-supported wharves. Increasing the number of analyses will allow for a more refined definition of fragility curves for pile-supported wharves, in the future, that can be used for cost-efficient management of pile-supported wharves against losses due to seismic excitation.