SEISMIC RESPONSE ANALYSIS OF BRIDGES ISOLATED WITH FRICTION PENDULUM BEARINGS

A systematic method is developed for the dynamic analysis of the struc tures with sliding isolation which is a highly non-linear dynamic prob lem. According to the proposed method, a unified motion equation can b e adapted for both stick and slip modes of the system, Unlike the trad itional methods by which the integration interval has to be chopped in to infinitesimal pieces during the transition of sliding and non-slidi ng modes, the integration interval remains constant throughout the who le process of the dynamic analysis by the proposed method so that accu racy and efficiency in the analysis of the non-linear system can be en hanced to a large extent. Moreover, the proposed method is general eno ugh to be adapted for the analysis of the structures with multiple sli ding isolators undergoing independent motion conditions simultaneously . The superiority of the proposed method for the analysis of sliding s upported structures is verified by a three-span continuous bridge subj ected to harmonic motions and real earthquakes. In addition, the side effect of excessive displacement of the superstructure induced by the sliding isolation is eliminated by replacing one of the roller support s on the abutments with hinge support. Therefore, both reductions in t he forces of the substructure and the displacements of the superstruct ure can be achieved simultaneously. (C) 1998 John Wiley & Sons, Ltd.