Seismic Evaluation of a Bridge with Different Isolators at Different Locations

Abstract

In this analysis, we investigate the role of the location of isolators on the seismic behaviour of an RCC bridge with three different isolator systems. The isolation system in the structure will reduce the external ground motion approaching the structure, so that the structural elements do not behave in a nonlinear fashion, and no damage is caused or cracks develop to structural elements as all the deformations are absorbed by the isolator system. To study the role of isolation location on seismic response, an upcoming five-span RCC village road bridge across a canal crossing in Belgaum district is considered. To analyse the influence of the isolation location on different isolators systems, each isolator was modelled with three different cases: The first model was with isolators at the top of the piers, the second at the middle and the third at the bottom. Three types of isolators, i.e., Lead Rubber Bearing (LRB), High Damping Rubber Bearing (HDRB) and Friction Pendulum System (FPS) were modelled as bilinear link elements. The analysis role of isolation location on modal time period, base shear and displacement of structural elements. The analysis shows that the best location for the isolator to provide full functional benefit is at the bottom of the pier.