Analysis Of Dynamic Characteristics And Seismic Response Of Long-span Suspension Bridge During Construction Period

Along with the reform and opening up and modernization needs of the development in the early1980s, domestic large-span bridge construction, has opened a newone, the large span and large-span suspension bridge emerging and refresh the record at home and abroad. As the span increases, the structure external to the role will become more sensitive,especially during the construction period. Equipment, personnel and structural safety issues due to the construction of the bridge has not yet formed a final structural system in a relatively unstable state,structural rigidity is low, easy to seismic loading under large displacementsand internal forces.To address the problem, this paper is in the construction ofNanxi Yangtze River Bridge as project background, I studies its main construction phase of the bridge structure dynamic characteristics and seismic responseand a number of conclusions including:(1) According to the construction drawings, the Nanxi Bridge to more than three-dimensional finite element dynamic calculation model are established for thesimulation of the South Bridge to the construction phase, on this basis the dynamic characteristics analysis of the construction process is carried, and drawlarge span suspension bridge construction dynamic characteristics of the process oflaw.(2) Completion of these three states of the tower that pylon supported thelargest cantilever， tower construction completed and the main cable completedbased finite element program for earthquake response spectrum analysis and seismictime history analysis showed that on the placement of the beams and the erection ofthe main cable is completed to improve the security of the bridge tower.(3) Inputting the full-bridge model, vertical, longitudinal-vertical and three ofthe seismic waves，with the ground vibration excitation, the maximum displacementand internal force of the critical points of stiffening girder section and pylon iscompared, draw some useful conclusions.(4) The results of comparing the construction of state and the bridge state ofNanxi Bridge to pylon displacements and internal forces, the erection of thestiffening girder of the seismic performance of the whole bridge plays a role inpromoting.