关键词: 振动与波, 吊杆, 中, 下承式拱桥, 摄动, 张力, 位移

Abstract: Suspenders are important force-transmission components of through and half-through arch bridges. Their mechanical situation is closely related to the safety of the arch bridges. Since suspenders can only withstand tension, their tensile forces and the safety of the arch bridge will change when a suspender damages. In this paper, based on perturbation theory, the changing laws of the tensile forces and displacements of the suspenders due to the suspender damage are studied by means of a three-dimensional finite element model. Taking Liujiang Bridge in Beijing-Hong Kong-Macao expressway as an example, this model is verified. Results show that when a suspender damages, its internal force will reduce, but the reduction ratio is less than its damage extent. The forces of the other suspenders of the same arch rib with the damaged suspender increase, but the increasing reduces rapidly as the suspender getting far away from the damaged one. The forces of the suspenders of the opposite arch rib essentially keep unchanging. The displacements of suspender joints also change due to the suspender damage, but the change ratio is less than the damage extent and gradually reduces as the distance between the undamaged hanger and the damaged one increased. As the damage extent of suspender increases, the rates of changes of both forces and displacements of suspenders increase too.

Key words: vibration and wave, suspender, half-through and through arch bridge, perturbation, force, displacement