Seismic Performance Of Double Column Bridge Bents With Buckling Restrained Brace

As an important part of the bridge structure system,the pier plays an important role in bearing all the load of the superstructure and transferring the load to the foundation.The strength of the bridge's seismic performance depends largely on the pier.The traditional integral cast-in-place piers usually rely on their own plastic deformation to dissipate the seismic energy,so that after the earthquake,there is often a large residual displacement,which affects the basic functions of the bridge,and thus hinders the implementation of the rescue work.Although the self-centering bridge pier with energy-consuming steel bars can overcome the problem of excessive residual displacement after the earthquake,once the energy-consuming steel bars are damaged,it is difficult to replace,and then the seismic performance will be greatly reduced.In order to solve the above problems,this paper proposes a self-centering double-column pier with Buckling Restrained Brace(BRB for short).In this paper,the research work done on this self-centering double-column pier is as follows:(1)Through reviewing the domestic and foreign related literatures,analyzing the research history and current status of self-centering piers and BRB,summarizing the research methods and results of the predecessors.Based on the deficiencies of previous studies,this paper proposes a self-centering double-column pier structure system with BRB.(2)Theoretical analysis of the seismic performance of self-centering double-column piers with BRB.Firstly,the structure and basic mechanical properties of BRB are introduced.Then,the hysteretic behavior,bending resistance and lateral stiffness of self-centering double-column piers with BRB are theoretically analyzed.(3)Based on the Opensees,establishing a numerical model of the self-centering double-column piers with BRB.The numerical model of the self-centering double-column pier of BRB is established according to the reasonable selection of material constitutive,unit type and constraint method.And the accordance between the numerical simulation results and the existing experimental results indicate that the simulation method can simulate well the self-centering double-column piers.(4)Study on seismic performance of self-centering double-column piers with BRB set under low cyclic repeated horizontal loads.The BRB self-centering double-column pier with two different layouts of herringbone and single oblique are designed as the research object,and the whole cast-in-place double-column pier and the self-centering double-column pier without energy-consuming components are used as the comparison object.The hysteresis loop,skeleton curve,residual displacement and cumulative energy consumption are used as evaluation indexes by which the seismic performance of samples are compared and analyzed.The results show that the self-centering double-column pier with BRB has better energy-consuming capacity,stronger self-centering ability and superior seismic performance;and the herringbone arrangement is more reasonable than single-slanting.(5)Study the influence of various parameters on the seismic performance of self-centering double-column piers with BRB.The effects of BRB stiffness ratio,core length ratio,core material type,axial compression ratio,prestressed tendon reinforcement ratio and initial tensile force on seismic performance were studied.