Research On Seismic Performance Of High-speed Railway Bridge With Functional Separation Bearing By Connecting The Upper Structure

With the rapid development of China's economy,high-speed railway construction has entered a new stage,all over China's high-speed railway network gradually forming.One of the characteristics of high-speed railways is the large number of elevated railway bridges.In some areas,the proportion of viaducts is as high as 80%.With the high development of China's high-speed railway construction,there are some issues need to be further enhanced and improved.China's vast territory,there are many high-speed railway construction in the earthquake-prone and high intensity areas,and China has no dedicated design specifications for high-speed railway bridge.Therefore,it is necessary to study the failure mechanism of high-speed railway bridge under strong earthquake and improve the seismic performance of high-speed railway bridge.Based on the following,this paper aims at studying the initial theoretical of the mechanism for the destruction of high-speed railway bridge,proposing a new method to improve high-speed railway seismic performance by using functional separation bearings.First,continue the upper structure of the high-speed railway bridge is and change the bearings to functional separation bearings,let the piers are in a basic elastic state under strong earthquakes to ensure the seismic safety of high-speed railway bridges.Then verify the effectiveness of the method by finite element analysis of an existing high-speed railway bridge.The main contents of this paper:1.Establish an finite element model of the existing high-speed railway bridge with a span of 32 meters designed according to the existing railway bridge design specification in SAP2000.In order to improve the seismic performance of the bridge system,continue the upper structure and the continuous span is considered 3,5,6,8 spans to get the optimal number of consecutive spans.Finite element analysis of seismic input takes into account the one-way,two-way and three-way ground motion.The input acceleration is 9 degrees of rare earthquakes with a peak acceleration of 0.64 G.The influence of input direction combination of ground motion on the main control index of the structure is studied by linear dynamic time history analysis.2.In the continuous bridge,the nonlinear dynamic time history analysis is carried out by using the fiber hinge model.The working conditions are 0.2G,0.3 G,0.45 G,0.57 G,0.64 G.1)The seismic response of the pier to the yield state is determined by the seismic response of the pier bottom reaction,displacement of the top of the pier and the upper beam.2)Set up the new type of isolation bearing after parameter optimization,carry on the nonlinear dynamic time history analysis,and determine the optimal optimization span.3.Simulate the functional separation bearing in the existing simply supported high-speed railway bridge,verify the effectiveness of the method by the finite element analysis and the convenience of the functional separation bearing.