Failure analysis for overall stability against sliding and overturning of a girder bridge

In recent years, several similar girder bridge failures due to the overall instability have occurred one after another in China, and the crucial factor of the failures was reported to be the overturning. However, girder bridge sliding, an unusual failure mode for the overall instability, has been rarely mentioned. The Chunhui E-ramp bridge, which failed and collapsed under the joint action of four trucks with a total weight of 389.3 ton, was a typical case. Thus firstly, this paper aims to evaluate the response of girder to the passing eccentric heavy vehicles over the bridge. Secondly, this paper intends to analyze the process of overall instability against sliding and overturning. In order to achieve these two aims, we employed a nonlinear finite element model and the step-by-step method to obtain the dynamic response of girder bridge; and established a transverse anti-slip equilibrium equation. Analysis of the result showed that the failure began with the uplift and ended up with the sliding, rather than a rigid body overturning. Additionally, the specification limitations and the friction coefficient of bearings were both discussed based on the results of numerical analysis.