Seismic Response of an Isolated Curved Bridge with Lead Rubber Bearing by Considering Design Aspect

Abstract

Studies on the application of the lead rubber bearing (LRB) isolation system to various structures carried out as one of the measures to improve seismic performance. Curved bridges play noteworthy role in the modern transportation system. Due to complex interchange and the desire to conform to existing geometric confinements have made this type of structures more alluring. Horizontally curved bridges make up of a noteworthy portion of the bridge population in various countries. In the present study, Lead rubber bearings have been used in an Isolated Curved bridges. Seismic loadings have been considered for three recorded ground motions from PEER strong motion database (PEER 2014) without scaling viz. (1) Imperial Valley (1940) with two orthogonal horizontal ground motion components (PGA0.313g and PGA0.215g); (2) Kobe (1995) with two orthogonal horizontal ground motion components (PGA 0.83g and PGA 0.63g) and (3) Turkey (1992) with two orthogonal horizontal ground motion components (PGA 0.5g and PGA 0.39g). These three ground motions have been considered to represent conditions close to far-fault, near-fault and forward directivity of earthquakes, respectively. Unidirectional and Bi-directional loading have been considered in the present study. Design aspects of the Lead rubber bearings has been considered by deploying the interaction diagram of bearing displacement between the unidirectional and bi-directional responses. It has been found that the bidirectional loading should be considered while designing the isolators.