The Relation Between Dynamic Characteristic Parameter And Damage For Rigid Tied-bar Arch Bridge

The rigid tied-bar arch bridges are the special stress system composed of three main stress members such as arch ribs, suspenders and rigid tied-bars. The structural dynamical performances have close relations with the stiffness, the mass and the damp of the bridge structure, no matter what damages produced by arch rib and suspenders and tied-bar, once the damage degree of bridge structure reaches a certain value, it will produce an effect on the change of the stiffness and the damp of the whole structure or the part structure, thus affecting the change of the whole dynamic characteristic parameters of the bridge structure. As a result, the corresponding relation exists between the change of dynamic characteristic parameters of the rigid tied-bar bridge and the possible damage of the structure, utilizing the relation between the dynamic characteristic parameters and the damage, the damage of the rigid tied-bar bridge can be distinguished.First, the methods of the theory of the damage identification based on dynamic characteristic parameters are presented in the thesis, such as the methods of the trace of dynamic characteristic based on the change of the frequency, the curvature mode and the element strain energy. Then, the possible damage of the arch bridge and the cause of the production are presented, besides, the main points of establishing the finite element simulated mode based on non-existent damage and existent damage for the rigid tied-bar arch bridge are also presented, finally, utilizing the dynamic analytical data of the damage structure, the relation between the structural damage and the change of the structural natural vibration frequency, the change of the curvature mode, the change of the different value of the curvature mode is respectively studied, it is stated clearly by the analysis that the damage of the suspenders and the arch ribs and the rigid tied-bar can cause the decrease of the value of the natural vibration frequency, the existence of damage can be investigated, but the position of the damage cannot be determined; the status of the damage of the arch ribs and the rigid tied-bar can be quite effectively judged by the method of the different value of the curvature mode, the status and the degree of the damage of the suspenders can be effectively judged by the different value of the strain energy indirectly.Through the achievement of the study in the thesis, a certain base is established for the study of the damage identifications and the damage locations of the rigid tied-bar arch bridge.