Prestressed Continuous Composite Bridges under Dynamic Load

Abstract

The dynamic and fatigue responses of continuous composite bridges with prestressed concrete deck slabs are investigated. The dynamic analysis of such continuous slab‐on‐steel girder bridges is based on the orthotropic plate theory using reliable estimates of the orthotropic rigidities of the bridge. Experimental results from tests on four 1/4‐scale models of continuous composite bridges verify and substantiate the analytical results. Two of the bridge models are tested under repeated loading at the resonance frequency of the structures. The dynamic strain variations due to repeated loading are determined for various components, such as the prestressing steel, the steel girders, the concrete deck slab, and the shear stud connectors. It is shown that prestressing the concrete deck slab in the vicinity of the pier supports eliminates transverse cracking of the slab, enhances the natural frequencies, and increases the fatigue life as well as the ultimate load‐carrying capacity.