Influence of Span Length and Radius on Isolated Steel I-Girder Bridge under Different Ground Motion

Abstract

Abstract: Bridges are essential for transportation from many years, out of them Steel I-girder bridge is very old and frequently used in many parts of the world. The current practice of bridge required reduction in bridge demand and proper stability of bridge girder specially at horizontally curve bridge, these are more critical during earthquake. Therefore, it is crucial to understand the seismic behaviour of the Steel I- girder bridge under ground motion. This study investigates the effect of different span length and Radius of bridge, under seismic forces. 3D model of three span, two lane steel I-girder bridge having five number of longitudinal girders, which are interconnected by X-bracing used for analysis. Seismic performance of bridge has been improved by using Lead Rubber Bearing (LRB) as isolator. Time history analysis has been performed to carry out seismic analysis under different ground motion. Study compare both isolated and non-isolated bridge performance. Result help to establish relationship between base shear, span of bridge, radius of bridge, transverse displacement and time period with and without isolator. Result shows that base shear is 60-77% reduce by using LRB.