Effects of Ground Motion Characteristics on Seismic Response of Rocking- Foundation Bridges

Past studies have revealed that the different characteristics of near- fault pulse-like and far-field broadband motions have varying effects on the response of structures. In this paper, a suite of pulse-like and broadband motions are utilized to investigate the response of rocking-foundation and hinging column bridges including large deformation effects. Incremental Dynamic Analyses were carried out on simplified models of which the following parameters were varied: the rocking strength, the column height, and the fundamental period. Results show that, in a probabilistic sense, rocking systems are more susceptible to tip-over in pulse-like motions than in broadband motions. The re-centering effect of rocking systems makes them relatively immune to damage in motions that consist of many small inelastic pulses. Elastic-perfectly plastic hinging systems have less re-centering capability and hence they are more susceptible to accumulated deformation and eventual collapse in many small cycles that might occur in long duration broadband motions.