Bending Behavior of Deformed Steel Bridge Girder

AbstractThe first author was asked to evaluate the safety of a steel bridge on the municipal road with which the load of a truck running on the expressway underneath appeared to have collided. The bridge consists of two main girders and the orthotropic deck, and one of the main girders was found severely damaged. The damage includes the out‐of‐plane displacement of the lower part of the web, the bend/buckling of the transvers stiffeners and the separation of the transvers stiffeners from the web, the fracture of the bolted connections between the transvers stiffeners and the lateral struts. In the investigation, the deformation of the main girder due to collision is reproduced by the finite element analysis first. The result is quite satisfactory with the residual displacement in good agreement with that measured in situ. The steel girder deformed by the collision is then loaded to see its bending behavior. The result indicates that the initial stiffness is reduced by 14% and the reduction in the bending strength is 0.8%. The bending behavior is further investigated by removing the transverse stiffeners, since many of the transverse stiffeners were damaged rather badly. The results indicate that the contribution of the transverse stiffeners to the bending behavior is very little and that the damages of the transverse stiffeners is not a problem at all. Hence it may be concluded that the damaged girder due to collision doesn't threaten the safety of the bridge.