Tsunami fragility curves of a RC structure through different analytical methods

Recent tsunami events have stimulated research activity into tsunami fragility functions which have been largely based on empirical data. However, empirical fragility functions are biased because the influence of earthquake and tsunami damage are difficult to separate. We develop a new theoretical framework to assess the structural performance of a building due to tsunami inundation by drawing on recent experimental and theoretical progress at UCL on building. Different nonlinear static analyses, i.e. constant-height pushover (CHPO) and variable-height pushover (VHPO), are compared with nonlinear dynamic analysis in assessing the fragility curves of a case study structure for a set of realistic tsunami wave traces. The results of VHPO provide a good prediction of collapse fragility curves obtained from the dynamic analysis under a wide range of tsunami time-histories. On the other hand, CHPO provides a larger, i.e. about 10% in median value, fragility in case global failure is considered and a smaller fragility for local shear failure. On the basis of these results, it is recommended that VHPO be used in future fragility analysis of buildings subjected to tsunami.