Construction Control And Seismic Response Analysis Of The High-pier And Long-span Continuous Rigid Framed Bridge

Continuous rigid frame bridge is a bridge structure which widely used in high-pier and long-span bridge. In order to reduce the secondary internal force caused by shrinkage and creep of concrete, temperature, braking force, etc. This type of bridge usually requires piers to have sufficient flexibility in the longitudinal direction of the bridge. So hollow high-pier is one of the main structural forms of the lower part of the structure. Balanced cantilever construction method is the main construction method of high-pier and long-span continuous rigid frame bridge. Because of many construction stages, long period and structure system transformation in the process of construction, ensure that the bridge linear and comply state accord with the design requirements and the reliable construction control of bridge is very necessary. The seismic system currently used in the continuous rigid frame bridge is mainly ductile seismic system, which uses local damage of bridge piers to ensure the overall seismic performance of the structure, but repairring the damage is more difficult after earthquake. So proposing the seismic isolation design of high-pier and long-span continuous rigid frame bridge, and improving the seismic performance of the bridge is very necessary.Taking a(60+90+90+60)m high-pier and long-span railway continuous rigid framed bridge as the research object in the paper, to control the construction process, analysis the seismic response and present the seismic isolation design of the bridge. the work is completed content:(1) In order to ensure the bridge can smooth closure, bridge alignment and stress state meet the design requirements. A finite element simulation model is established by Dr. bridge to react each construction stage. Combining with the adaptive construction control theory to provide accurate formwork elevation for the construction of the bridge and ensure the safety and the construction quality of the construction process.(2) Using the finite element simulation model of construction stage, the main factors(elastic modulus of concrete, bulk density, control stress for prestressing, etc.) that affect the alignment control of the bridge are analyzed systematically. The influence of various influencing factors on the structural deformation is summarized, and laying the foundation for the accuracy of the bridge alignment control.(3) Through the structural analysis model established, studying reasonable value of jacking force of the high-pier and long-span continuous rigid framed bridge from the cumulative effect of the bridge, the shrinkage and creep effect and temperature effect.Discussing the influence degree of the size of jacking force on the deformation and internal force of main girder and pier.(4) A whole bridge space dynamic calculation model is established by the finite elementanalysis software Midas/civil to analysis the dynamic characteristic value of the the high-pier and long-span continuous rigid framed bridge, analyze linear elastic seismic response of the bridge under the rare earthquake, and summarize the characteristics of internal force distribution of the main piers.(5) In order to improve the seismic performance along the longitudinal direction of the high-pier and long-span continuous rigid framed bridge, proposes a damping scheme which setting up the viscous damper on both ends of the abutment of rigid framed bridge. By onlinear time-history analysis, discusses the damping effect of the damping scheme and the mechanical parameters reasonable values of fluid viscous damper.