Seismic Response Analysis Of Long-span Continuous Rigid Frame Bridge

The society nowadays,with the rapid economic development,the traffic line plays an increasingly important role in economic development,and the bridge is an important part of the traffic line.With its beautiful appearance and economical budget,the rigid bridge is widely used in traffic engineering bridge construction.So it is necessary to analyze the seismic capacity of the bridge under earthquake action.With the paper takes a(65 + 110 + 65)m bridge in Guangzhou as the engineering background,this thesis has focused on the seismic response of this bridge.The main contents are as follows:(1)In order to study the effect of pile-soil-structure interaction on the dynamic characteristics of bridge structures,Midas civil is used to establish the base consolidation model(model I)and consider the pile-soil-structure model(model II).After the calculation of the dynamic characteristics of the two models,we find that that the self-vibration period difference between the two models is significantly different.It is evident that if the pile is not rigid enough,the consolidation of the pier is considered to have a great effect on the structural analysis,and the two models are given.Therefore,this thesis has focused on the analysis of the seismic response based on the second mode.(2)The seismic response analysis of the finite element analysis model was carried out by using the response spectrum method and the linear time history method under the action of the E1 earthquake.The results of the analysis were consistent and the difference between the calculation result of these two methods is less than 20%,which meets the specification requirements.So the response spectrum method is well fitted for seismic response analysis.The time history analysis method can be used to check the results obtained by the response spectrum analysis method.In the seismic analysis,the results of the two methods can be combined to obtain a reasonable seismic design.(3)The seismic response analysis of the established finite element analysis model is carried out by linear and nonlinear time-history method under the action of E2 earthquake.The nonlinear internal force response value is much smaller than the linear internal force response value.Therefore,the linear time history analysis method cannot truly reflect the internal force of the bridge.The seismic response analysis of the bridge under the E2 earthquake should consider the nonlinearity of the material.(4)In order to further study the seismic response mechanism of the plastic hinge under the action of the E2 earthquake,and probe the order of the potential plastic hinge after the elastoplastic stage,the yield state of the plastic hinge is achieved by adjusting the peakacceleration of the ground motion.We come to the conclusion that the peak of earthquakes increases,plastic hinges appear shorter,and the number and deformation of plastic hinges are increasing.With 2 # left pier first appearing plastic hinge,special attention should be paid th its reinforcement in seismic design in the bridge to avoid a sudden brittle damage.