Research On Seismic Performance Of Segmental CFST Pier With External Energy Dissipating Elements

With the rapid development of society and economy,the construction of infrastructure is in full swing all over the world,and bridge construction,as an important part of the infrastructure network,is also booming.With the rapid development of society and economy,the construction of infrastructure is in full swing all over the world,and bridge construction,as an important part of the infrastructure network,is also booming.In order to reduce the impact of bridge construction on the environment,segmental assembling technology comes into being and is gradually applied to bridge substructure.However,segmental assembling pier has some problems such as insufficient horizontal bearing capacity and poor energy dissipation capacity under the action of earthquake,so it is particularly critical to improve the seismic performance and bearing capacity of segmental assembling pier.At present,the research concept of earthquake engineering starts from the study of earthquake resistance,earthquake reduction and earthquake isolation.The structural system with functional recovery is to first satisfy the functional integrity under normal use,then ensure that the damage under earthquake can be controlled,the energy dissipating device can be concentrated energy dissipation,and finally ensure that the pier has the ability to self-reset after earthquake and the energy dissipating device is easy to replace.Therefore,this paper proposes a kind of segmental concrete-filled steel tubular pier(PSCFST pier)with external energy-dissipating elements that can be controlled by damage,have excellent self-resetting performance and can be repaired.The main work content of this paper is as follows:(1)Based on the failure mode and theoretical analysis of PSCFST pier,the PSCFST pier with external energy dissipating components designed in this paper is proposed.Through the checking calculation of shear capacity,it is verified that the designed pier will not suffer irreversible shear failure.The feasibility of the proposed PSCFST pier with external energy dissipating elements is verified by a simple finite element analysis.(2)Carry out pseudo-static test of pier with PSCFST,analyze the damage difference by opening size,deformation of energy dissipating element and obvious buckling of steel pipe during the test,and analyze hysteretic curve,stiffness characteristic,residual displacement and energy dissipation capacity obtained from the test.To further verify the feasibility of the designed PSCFST pier,the improvement effect of energy-dissipating components on the seismic performance of PSCFST pier and the replaceable performance after earthquake were evaluated.(3)The finite element analysis of PSCFST pier with external energy dissipating element is carried out.Firstly,the finite element analysis is carried out to verify that the finite element can accurately simulate the hysteretic behavior of pier under horizontal reciprocating action.By changing axial compression ratio,section ratio and initial prestress level,the influence law of different parameters on the seismic performance of PSCFST pier was explored,and its seismic mechanism was grasped.(4)Based on the above test and finite element results,the PSCFST pier with open joints in plastic hinge area is proposed.The influence of open joints position on the seismic performance of PSCFST pier is studied through pseudo-static test.Then,the finite element analysis of PSCFST pier with open joints in plastic hinge area under different parameters is also carried out.At the same time,it is compared with the finite element analysis of the pier with slit in the middle to find the difference.(5)By analyzing the flexural capacity of the PSCFST pier with external energy dissipating elements proposed in this paper,and grasping the differences with other scholars’ studies,the flexural curvature and force-displacement formulas suitable for the pier in this paper are proposed.The hysteretic model obtained from the theoretical formulas is compared with the finite element results to verify its accuracy.In this paper,a detailed analysis of the proposed new PSCFST pier structure is carried out by comprehensive use of the experimental and finite element methods,and the stress mode of the pier is deepened theoretically,which can provide ideas for the subsequent practical engineering.