Dynamic characteristic analysis and fatigue life estimation of bridges with considering the shear residual stress

Abstract

Firstly, this paper established a finite element model of the steel bridge and applied movable vehicle loads measured by experiments into the finite element model so that stress and strain distribution characteristics in detail structures of bridges were computed. The change process in the direction of detailed element of diaphragm plate after the shear residual stress was taken into account. Results showed that the direction of its principal tension stress was vertical to the actual crack direction of cracks. To analyze the inner relationship between the internal force of diaphragm plate and local stress amplitude, vehicle loads moved horizontally to record the change trend of principal stress at the arc hole and shear force and bending moment in the cross section. Through making a comparison, this paper found that stress amplitude at the arc hole was mainly affected by shear force and local wheel pressure. Stress amplitude at the arc hole close to diaphragm plate was larger than that at the arc hole close to the middle line, which was easier to crack and consistent with actual damage. Finally, the fatigue life of bridges which took into account the shear residual stress was estimated according to stress and strain to compare with the result which did not take into account the shear stress. Comparison results showed that the shear residual stress had an obvious effect on fatigue life of the steel bridge, so it cannot be neglected during numerical computation.