Failure Analysis of a Girder Bridge Collapse under Eccentric Heavy Vehicles

Abstract

In recent years, several accidental collapses of girder bridges have occurred under the influence of eccentric heavy vehicles in China. To explore the causes and mechanisms of the collapses, a collapsed six-span, RC, continuous box-girder bridge was introduced and analyzed. By gathering onsite information about the accident, different failure forms were determined. Simplified mechanical calculations and finite-element simulations were used to determine the characteristics of the structural response caused by the load on the bridge during the accident. Finally, the sequence of the accident was reproduced, and the controlling factors leading to the structure failure were clarified. This study suggests that bridge accidents are caused not only by instability issues of integral overturning but also by strength failures of the components. Under the circumstances caused by an extreme eccentric vehicle load, the large deformation resulted in an apparent second-order effect. Noticeable lateral horizontal interaction forces between the piers and girder appeared, which led to bending failures in the piers that later caused the collapse of the superstructure.