Research On Seismic Performance Of Steel Tubular Nested Fabricated Concrete Bridge Piers

With the acceleration of urbanization,the shortcomings of the overall construction of cast-in-situ bridges are continuously enlarged,and the improvement of prefabricated technology and the advantages of energy saving and environmental protection,controllable quality,convenient construction,and low interference to traffic make prefabricated bridges widely popularized.And application.However,the existing literature mainly focuses on the research on the hysteretic performance of the traditional grouting sleeve and grouting corrugated pipe connection and the prestressed steel reinforced connection pier,and there are few reports on the steel tube nested connection pier.Therefore,in this paper,three types of bridge piers,including in-situ cast,grouting sleeve connection and steel tube nest connection,are used as research objects.Hysteretic performance tests and finite element expansion parameter analysis are performed.model.(1)The horizontal low-cycle repeated load test of the three types of bridge piers with integral cast-in-place,grouting sleeve connection and steel pipe nesting connection was carried out,and the hysteresis curve,skeleton curve,ductility,residual displacement,energy consumption and strength of the specimen were analyzed The failure performance and laws of degradation,stiffness degradation,etc.were discussed,and the failure mode of the specimen was discussed.The results show that the cumulative energy dissipation capabilities of the three types of concrete bridge piers are close to each other,and there is no obvious stiffness degradation.The horizontal peak load of the steel pipe nested assembled pier is close to the overall cast-in-place pier;the ultimate displacement is increased by 11.18% compared with the integral pier;the displacement ductility coefficient is increased by 11.87% compared with the integral cast-in-situ bridge pier specimen.The horizontal peak load of the concrete-pier specimens of steel pipe nesting connection assembly is 13.41% higher than that of the grouting sleeve connection assembly pier;the limit displacement is 5.57% higher than the grouting sleeve connection assembly pier;the displacement ductility coefficient grouting sleeve connection assembly type The bridge pier specimens increased by 5.89%.(2)Use ABAQUS finite element software to establish three different connection types of pier models.Based on the good fitting of the finite element fitting conditions and the test results,the comparison found that the steel pipe nested connection pier has different slenderness ratio and axial compression ratio.The seismic performance under other parameters is superior to the traditional grouting sleeve connecting bridge pier.Taking the steel pipe nested connection type pier as the research object,the extended parameter analysis was carried out.The research results show that the elastic stiffness of the pier increases with the increase of the embedded depth of thesteel tube,the strength of the steel bar,the diameter of the steel tube,the thickness of the steel tube,and the strength of the concrete,and decreases with the increase of the slenderness ratio;the peak load increases with the axial compression ratio and the slenderness ratio,Steel pipe embedding depth,steel pipe diameter,steel bar strength,concrete strength increase and increase,and decrease as the slenderness ratio increases.Axial compression ratio,slenderness ratio,steel pipe embedding depth,and steel pipe diameter parameters are the main parameters that affect the seismic performance of steel pipe nested connected concrete bridge piers.(3)Based on the finite element parameter analysis,drawing on the calculation framework of the concrete-filled steel tube pier-column skeleton curve,the steel pipe embedding depth and the ratio of the length of the side of the pier and the ratio of the length of the side of the steel pipe diameter pier are introduced to fit the skeleton curve of the steel pipe nested connection The calculation formulas of elastic stiffness,horizontal peak load,peak load displacement,descending section stiffness and restoring force model,the eigenvalues and the finite element calculation results are in good agreement,and the error is basically controlled within 15%.And get the verification of engineering examples.Finally,a reasonable and practical calculation method for the restoring force model of steel pipe nested connection pier is given,which provides a theoretical basis for the engineering application of steel pipe nested connection pier and the improvement of calculation theory.