Research On The Seismic Behavior Of Long-span Suspension Bridge With Central Buckle

Suspension bridge is mainly composed of bridge tower, main girder, main cables, hangers, and ancillary structural parts. From the structural perspective, the girder weight and the load transferred to the main cable by boom between the main cable and the stiffening girder, the main cable transfer to the tower and anchorage by tensile stress, so the suspension bridge is very clear. In the middle position, installing the central buckle between the main girder and the main cable is one of the effective measures to improve the structural stiffness of the long-span suspension bridge.Scholars at home and abroad in view of the dynamic and seismic performance of suspension Bridges was carried out by a lot of work, but to study on the central suspension dynamic properties and seismic performance of the research work is relatively small. Based on the actual suspension bridge engineering, this paper studies the different forms of central buckle regularity of influence on seismic performance of long-span suspension Bridges. The main research content is as follows:First of all, this paper discusses the vibration of the suspension bridge upper structure system theory, the structure vibration balance equations are derived, and its overall is decomposed into vertical, horizontal and torsional vibration differential equations of equilibrium of the three kinds of vibration and vibration character; Introduce several common bridge seismic analysis method, and expounds in detail the basic theory of time history analysis method and numerical solution method.Then, based on the ANSYS software platform set up three finite element models of suspension bridge with different forms of central buckle, modal analysis, by comparing the different forms of central buckle model of the vibration characteristics of suspension Bridges, summed up the central buckle for long-span suspension bridge the influence law of dynamic performance, do foundation for further seismic time history analysis.Finally, according to the site conditions of the bridge and the vibration characteristics of the structure itself, select the appropriate seismic waves. By adjusting the peak acceleration to implement structure in the frequency of seismic wave in elastic time history analysis under earthquake excitation and the elastic-plastic time history analysis under earthquake excitation. Analysis and comparison of each model in the corresponding internal force and displacement response under earthquake excitation, summed up the frequency under the action of severe earthquake and earthquake under the action of the central buckle regularity of influence on seismic performance of long-span suspension Bridges.