Research On Seismic Performance Of Self-Centering Mortise-Tenon Segmental Pier Based On Cyclic Pseudo-Static Test

Most of the traditional bridge structures are mostly constructed by cast-in-place concrete.However,the production conditions of concrete,concrete pouring environment,maintenance conditions and other factors have a great impact on the pouring and maintenance quality,construction difficulty and construction period of concrete structure.With the rapid development of bridge modernization,rapid construction has become a research hotspot of bridge construction.Many theories and construction methods of prefabricated structures have been put forward.Prefabricated structures have gradually become the mainstream of green construction at this stage.The rapid construction of substructure is possible due to the development of theories and practices on prefabricated segmental pier.However,there are some seismic performance problems such as poor energy dissipation capacity in practical application.It have not been widely used in high seismic intensity areas.Therefore,developing a self-centering segmental pier to enhance energy dissipation capacity and making full use of the advantages of segmental pier to research seismic performance are of great significance to the development of prefabricated structures.In this paper,a self-centering mortise-tenon segmental pier is proposed.Three 1:3large-scale specimens are designed and manufactured for cyclic pseudo-static test analysis.The finite element model of self-centering mortise-tenon segmental pier is established based on ABAQUS software.Through the analysis of the damage phenomenon,the results of the test data,the comparison and parameter analysis of the finite element model,the time scale response analysis of the earthquake,the seismic performance of cast-in-place piers and self-centering mortise-tenon segmental piers with different parameters are compared and analyzed.The main research contents and conclusions of this paper are as follows:(1)Three test pieces of cast-in-place pier(CP),self-centering mortise-tenon segmental pier with 70% standard value of ultimate strength of the pre-tension stress(MTSP1)and self-centering mortise-tenon segmental pier with 80% standard value of ultimate strength of the pre-tension stress(MTSP2)with a model scale of 1:3 were designed and manufactured.The three are designed according to the principle of equivalence.That is,the parameters such as section size,longitudinal reinforcement ratio,axial compression ratio and stirrup ratio are the same.Through the comparative analysis of its seismic performance in terms of horizontal bearing capacity,stiffness,energy dissipation capacity and residual displacement,it is found that the horizontal bearing capacity and self-centering capacity of the self-centering mortise-tenon segmental pier are strong,which proves the self-centering mortise-tenon segmental pier designed in this paper has seismic performance no less than that of cast-in-place pier.(2)Based on ABAQUS,the finite element models of self-centering mortise-tenon segmental pier and cast-in-place pier are established.And the establishment of constitutive model and finite element modeling method are described.The models are verified and compared by experiments.The analysis results show that the simulation results of finite element model are consistent with the test results in terms of the horizontal bearing capacity,the self-centering capacity,the energy dissipation capacity is in good agreement.It proves the accuracy of the model.(3)The finite element model of MTSP1 specimen model is analyzed.It includes the reinforcement ratio of longitudinal reinforcement,the initial prestress of prestressed reinforcement,whether the prestressed reinforcement is sticky and its layout position,dead load axial compression ratio and shear span ratio,whether to add external energy dissipation damper,etc.The seismic performance of structures with different parameters under cyclic pseudo-static load is analyzed and compared.The conclusion is drawn through hysteretic curve,skeleton curve and cumulative energy dissipation.And the reasonable parameter range is given.(4)The seismic vulnerability analysis of the two types of pier models based on the displacement ductility coefficient is carried out.The seismic vulnerability curves of the two types of piers are calculated,so as to give the evaluation results for setting the seismic damage probability of the two types of piers under earthquake.