Connection Design And Seismic Performance Analysis Of Substructure Of Segmental Precast Bridges

Prefabricated bridge is a bridge divided into several components,prefabricated in advance in an off-site prefabrication plant,and then shipped to the site for assembly.Compared with the traditional cast-in-place bridge,the prefabricated bridge can shorten the construction period,reduce the total project cost,and reduce the adverse impact on the existing traffic.However,from the perspective of earthquake engineering,prefabricated Bridges have innate disadvantages.Under the action of earthquake load,the maximum bending moment usually occurs at the interface between pier and cap,which makes the connection point more vulnerable to deterioration and damage.In order to better improve the connection performance and seismic performance of prefabricated piers,this thesis takes a prefabricated continuous small box girder bridge in Zhengzhou as the engineering background,and on the basis of the existing achievements,a new connection method combining the socket type and the grouting sleeve is proposed.Finally,the finite element software is used to simulate and analyze the connection performance and seismic performance of the conventional connection type pier and the cast-in-place pier under the two working conditions.The main work is as follows:(1)The types,components,connection forms,engineering applications,advantages and disadvantages of the existing substructure components and connection structures of segmental prefabricated Bridges are summarized and analyzed.Based on the analysis results,a new type of substructure connection of segmental prefabricated bridge is optimized and designed.(2)ABAQUS finite element software was used to compare and analyze the bridge pier with the conventional connection mode and cast-in-place pier.The results show that the horizontal ultimate bearing capacity of the new type of segmental prefabricated bridge pier is increased by 4.15% compared with the traditional cast-in-place pier under cyclic load.Compared with the traditional segmental prefabricated bridge pier,the horizontal ultimate bearing capacity of the new hybrid segmental prefabricated bridge pier is increased by 13.80% and the energy dissipation capacity is increased by 22%.Compared with the traditional grouting sleeve connected segmental prefabricated bridge pier,the horizontal ultimate bearing capacity is increased by 11.11%,and the energy dissipation capacity is increased by 25%.(3)The control variable method was used to set the new type of prefabricated bridge pier and cast-in-place bridge pier under five different working conditions.The mechanical properties of the new type of prefabricated bridge pier and cast-in-place bridge pier under different coaxial pressure ratio and reinforcement ratio were investigated.The effects of different parameters on the seismic performance of the new type of prefabricated bridge pier and cast-in-place bridge pier were analyzed.With the increase of axial compression ratio,the energy dissipation capacity and ultimate bearing capacity of the new hybrid segmental prefabricated piers and cast-in-place piers increase significantly,but the ductility performance decreases.With the increase of longitudinal reinforcement ratio,the structural stiffness and equivalent viscous damping coefficient of the new hybrid segment-based prefabricated piers and cast-in-place piers are significantly increased,while the ductility performance is decreased.