Influence of Elastomeric Bearings on Traffic-Induced Vibration of Highway Bridges

Elastomeric bearings (rubber bearings) have been used in highway pseudo-continuous bridges without joints changed from simple girders to reduce the environmental influence of traffic-induced vibration. In addition, elastomeric bearings have been adopted in simple girder bridges for base isolation systems of earthquakeproof structures. Three-dimensional analysis of dynamic response of bridges under moving vehicles is carried out to examine the change of dynamic response in bridges caused by replacing steel bearings with elastomeric bearings. Analytical results are compared with experimental results in urban highway bridges. It is not shown clearly in experiments that natural frequencies are changed slightly in analysis by replacing steel with elastomeric bearings. Although vertical displacements of main girders at the span center do not almost change between steel and elastomeric bearings, horizontal displacement in the bridge axis direction becomes larger with elastomeric bearings. For the evaluation of the experimental acceleration of the ground motion, the dynamic reaction force is analyzed and the dynamic influence is investigated.