| The emergence of the urban overpass is the inevitable requirement of the urban road traffic development,the urban overpasse of the curved beam bridge is adapt to a variety of terrain strongly,also it can compromise the surrounding environment well and increase the visual aesthetic feeling,which is used in the construction of city overpass widely. Compared with the straight bridge,the curved beam bridge which bears complex forces,because of the mechanical properties is not comprehensive,and the distribution regularities of the internal forces are not understanded clearly in the structural design,Leading to the operation of some curved beam bridges occurred such as the bearing separation,the beam body sway,and the beam body fliping collapse accident etc. The curved beam bridge which is severer than the straight bridge in all previous earthquake damage,therefore the mechanical properties of the curved beam bridge need to understand correctly and reduce the operation period disease and strengthen the seismic performance and take structural measures to ensure the safety of the curved beam bridge,which become very important.This paper based on the engineering background of Lanzhou Xiao xihu lake overpass traffic reconstruction project,which mainly revolves around the static characteristics, dynamic characteristic,seismic response analysis three aspects of contents then carrys out the following works.Firstly,analysis the curved beam bridge static characteristic focuses on comparison the calculation methods and established two kinds of calculation models:the space beam gird model,the plate element model. The plate element model as the reference and comparison for the space beam gird model. Discuss under different load conditions the curve beam internal force and deformation research,summarize the corresponding laws,finally though the experimental results to prove the beam gird method analysis the curved bridge force performance accuracy.Secondly,analysis the curved beam bridge dynamic,this paper based on the dynamic measurement test of the natural frequency of vibration to revise the finite element model and calculate the dynamics,then as the foundation for the seismic response analysis.Thirdly,analysis the curved beam bridge of response spectrum,using the two mutually vertical in horizontal direction and input the two-way ground motion,and discuss the ground motion input along different directions on the curved beam bridge’s internal force and the influence on the pier top displacement.Using the 0 ° ~ 180 ° rotating method,to determine the most unfavorable input direction of the curve beam bridge seismic response.With 《Code for seismic design of urban bridges》recommend method to compare for the pier response.Lastly,analysis the curved beam bridge of elastic time history analysis and discuss the EL-centro seismic wave under the action of the main girder span and pier top displacement time history. Compared the two different seismic waves on the influence of the internal forces of the piers,finally the analysis of the elastic time history results and the response spectrum results are contrast.Through analyzing the static and dynamic of the curved beam bridge,using the grillage method to analysis the curved beam bridge’s mechanical performances,the calculation results which can satisfy the engineering design requirements. In order to ensure the security of the curved beam bridge structure design,the response spectrum calculation results should be checked with the time history analysis results each other. |
