Effect of earthquake ground motions on fragility curves of highway bridge piers based on numerical simulation

Fragility curves express the probability of structural damage due to earthq uakes as a function of ground motion indices, e.g., PGA, PGV. Based on the actual damage data of highway bridges from the 1995 Hyogoken-Nanbu (Kobe) e arthquake, a set of empirical fragility curves was constructed. However, th e type of structure, structural performance (static and dynamic) and variat ion of input ground motion were not considered to construct the empirical f ragility curves. In this study, an analytical approach was adopted to const ruct fragility curves for highway bridge piers of specific bridges. A typic al bridge structure was considered and its piers were designed according to the seismic design codes in Japan. Using the strong motion records from Ja pan and the United States, non-linear dynamic response analyses were perfor med, and the damage indices for the bridge piers were obtained. Using the d amage indices and ground motion indices, fragility curves for the bridge pi ers were constructed assuming a lognormal distribution. The analytical frag ility curves were compared with the empirical ones. The proposed approach m ay be used in constructing the fragility curves for highway bridge structur es. Copyright (C) 2001 John Wiley & Sons, Ltd.