Research And Improvement On Seismic Performance Of Precast Segmental Concrete-filled Tube Bridge Piers

With the advancement of urbanization and the implementation of sustainable development strategy,new requirements for modern bridge construction have been put forward,and engineering construction has developed in a new direction.The construction time should be shortened to reduce the damage of ecological environment and the pollution of the city.Precast segmental assembly technology complies with the development of industrialization,and it is good for the process of urbanization.Now,more and more bridge construction adopts prefabricated components.Segmental assembling pier is a new type of pier,which can shorten the construction period,reduce damage and residual deformation.But there are few researches on segmental piers,which limits their development.Compared with cast-in-place piers,segmental piers have great disadvantages on energy consumption and need to be improved.The author takes a group of typical segmental concrete filled steel tube bridge piers test as the research object in the paper,and then analyses its seismic performance of the segmental concrete bridge pier is analyzed.To improve the seismic performance of the segment pier,the author proposes a new type of connection-flange connection.The main contents of this paper are as follows:(1)Clarifying the function and mechanical properties of each part of the pier,then analyzing the vertical bearing capacity,bending resistance and shearing resistance.The failure mechanism is understood.Theoretical analysis shows that bending failure is the main form of destruction,which leading to the joint opening between segments,and the self reset performance of the prestressed reinforcement makes it close.(2)Establishing the ABAQUS finite element model,and carring out the static loading,then verifing the reliability of the simulation method by comparison with the existing test results.The seismic performance of the cast-in-place pier and the section bridge pier is further analyzed,and the influence of the pre-stress,axial pressure ratio and the thickness of the bottom steel pipe is analyzed too.Analysis results show that improving the pre-stress and axial compression ratio can improve the seismic performance of the segmental piers,and properly raising the thickness of the bottom steel pipes can also improve the performance of the piers.(3)Based on the weakness of seismic performance of segmental assembling piers,a new connection form-flange connection is proposed in this paper.Flange connection can be used as energy dissipation device,and can be used as a mold.for pouring,avoiding the partial casting of joints at the scene,simple process and convenient operation.The mechanical analysis and numerical simulation of the flange joint segment pier are carried out,and the mechanical properties and failure mechanism are analyzed,and the improvement of various parameters of the seismic performance is analyzed.The results show that the energy dissipation of the bridge pier with flange connections is greatly improved.