Nonlinear static procedure for fragility curve development

This study examines the fragility curves of a bridge by two different analy tical approaches; one utilizes the time-history analysis and the other uses the capacity spectrum method. The latter approach is one of the simplified nonlinear static procedures recently developed for buildings, in this resp ect, a sample of 10 nominally identical but statistically different bridges and 80 ground-motion time histories are considered to account for the unce rtainties related to the structural capacity and ground motion, respectivel y The comparison of fragility curves by the nonlinear static procedure with those by time-history analysis indicates that the agreement is excellent f ur the state of at least minor damage, but not as good for the state of maj or damage where nonlinear effects clearly play a crucial role. Overall, how ever, the agreement is adequate even in the state of major damage consideri ng the large number of typical assumptions under which the analyses of frag ility characteristics are performed.