Significance of elastomeric bearing on seismic response reduction in bridges

Abstract

The seismic design of conventionally framed bridges relies on the dissipation of earthquake-induced energy through inelastic response in selected components of the structural frame. Such response is associated with structural damage that produces direct loss, indirect loss and perhaps casualties. For bridge construction, the typical design goals associated with the use of seismic isolation are, (a) reduction of forces (accelerations) in the superstructure and substructure, and (b) force redistribution between the piers and the abutments. For minimising the effect of increased displacement response in such bridges, damping is typically introduced in the isolator. The paper discusses the importance of elastomeric bearings in the design of seismic resistant bridges with an overview of the present IRC code recommendations. The response modifications of such bridges are also included to strengthen the theoretical implications through parametric studies on the same.