| In recent years, with the rapid development in infrastructure construction, a number ofbridges have been built. In order to make bridges look beautiful, the structure of them bedesigned in various. As an old style bridge, the suspension bridge was always been built.Under the seismic load, the bridges often be destroyed, it makes the rescue very difficultand causes people great inconvenience. So make the analysis of bridges on the seismicresponse are necessary. We could take the earthquake-reduction or seismic isolation measuresaccording to the analysis results.This paper makes Liujiaxia suspension bridge as the engineering background, and uses thefinite element analysis software MIDAS/CIVIL build whole bridge model, analyze thedynamic characteristics, calculate the seismic response, and shock absorption measuresaccording to the results of the seismic response and evaluate the effect of shock absorptionmeasures.The main work content is as follows:(1) The literature, analyze the destruction of the bridge structure under seismic action, thebridge bearing is often destroyed at first, as an important part of infrastructure whichconnecting substructure and superstructure of bridges, it would make the slip, fall off orcapsize of the upper structure and cause the destruction of the lower structure.(2) The dynamic analysis of finite element model of Liujiaxia suspension bridge wasestablished by the finite element analysis software MIDAS/CIVIL, considering the interactionof soil and pile foundation, using the method of beam on elastic foundation, and simulate theeffect of pile-soil. Analyze the natural vibration characteristics of the model, and making thepreparation for the back of the seismic response analysis.(3) According to the earthquake requirements and the geological conditions, anddetermine the spectrum function of entering to of bridge structure, and then analyze theseismic response which under different input direction of model.(4) According to the field geological conditions, determining three groups of the differentclassic seismic wave as the input seismic load to the bridge structure, to adjust the three setsof wave, make it meet the requirements of the proposed site then analyze the seismicresponses of the structure model under the three groups seismic wave.(5) According to the result of seismic response, decided to add fluid viscous dampers tostructure as shock absorption measure. Choose the appropriate fluid viscous dampers andanalyze the damper technical parameters like damping coefficient and damping exponent,then put these parameters into the finite element model of the bridge. (6) After add the shock absorption measure to the structure and make the analysis on theseismic response, like the internal force and displacement values. Then compare these valueswith the response of not adding earthquake-reduction measures on the structural.(7) By the force and the displacement of contrast, the structure after adding dampingmeasure, under the seismic load, the displacements and the force at the top of the tower andthe beam bearing significantly reduced. Its show that the shock absorption measures effect isgood. |
