Experimental Study On Seismic Performance Of Prestressed Segmental Precast And Assembled Double-column Bridge Piers

With the implementation of innovation driven development strategy,the development of precast fabricated bridges has become the focus of accelerating the construction of ecological civilization,promoting the development of new industrialization and building green cities.The establishment of integrated technology of bridge structure factory manufacturing,mechanical assembly and standardized management,to promote the city infrastructure construction methods change,reduce pollutants and waste emissions,is of great significance to improve the labor productivity,is the future development trend of the domestic bridge.The core technology breakthroughs in the application of precast assembly technology for bridges are the research and application of connections between columns and caps,between the substructure and superstructure,and the aseismic performance guarantee.Therefore,this paper based on the actual project,design of assembly double column pier,low cyclic loading tests and numerical simulation based on finite element method to study the seismic performance of prefabricated bridge piers,influence analysis of prefabricated bridge piers in different connection mode of the seismic performance parameters of seismic design,so as to optimize the assembly type bridge pier.This paper focuses on the research of the assembled double column pier,mainly including the following research content and the corresponding conclusions:(1)The experimental research results and application theories of the fabricated piers at home and abroad are summarized.The application status and mechanical characteristics of fabricated piers are analyzed.The purpose,specific methods and technical routes of assembled double column piers are summarized.;(2)In order to investigate the seismic performance of bridge pier assembly double column,test model design of a group of different types of prefabricated bridge piers,introduces the production process and test pier test program the main parameters determining model according to the similarity theory,the assembled prestressed pier segment has two kinds,respectively for single segmental prestressed assembly double column pier and multi segmental prestressed assembly double column pier;(3)The reciprocating load pseudo static test of regularity on the pier model,a detailed description of the specimens directly on the test failure,data analysis and processing,the yield load,specimen yield displacement,ultimate load and displacement,displacement ductility coefficient and residual displacement analysis of seismic performance parameters;(4)The two piers of the final damage,serious parts concentrated in beam and pier,pile cap and pier bottom,pier segment does not appear obvious opening angle in yield before the seismic characteristics of two groups of specimens had little difference,the yield displacement is around 10mm,yield strength in the 280kN left and right after yielding of the specimen show some differences in cast-in-place pier specimens than prefabricated bridge pier specimens 18.72%maximum horizontal bearing capacity of high yield,energy dissipation capacity of cast-in-situ specimens appeared more obvious increases,the residual displacement increases,and the assembly type bridge pier specimens energy dissipation and residual displacement increase is not obvious,the prestressed steel strand is enhanced since the reduction properties of specimens,reduce the residual displacement.The ultimate bearing capacity of the cast-in-place pier reaches 481.91kN,and the ultimate displacement is 84.67mm.The ultimate bearing capacity of the prestressed concrete double column pier is 391.65kN,and the ultimate displacement is 73.34mm;(5)Detailed description of the finite element software ABAQUS based on the nonlinear numerical simulation of assembly double column pier structure,respectively,to test the pier for the establishment of prefabricated bridge piers research object and integral cast-in-situ pier finite element model,the finite element analysis results with the test.The error is less than 15%,verify the validity of the modeling method.From the finite element solid model analysis,the load displacement curve and energy dissipation curve are obtained,and the seismic performance of pier under different structural parameters can be directly understood.The stress characteristics of double column pier are verified by simulation combined with existing tests.