Experimental And Analytical Study On Seismic Behavior Of Self-centering Energy-dissipating RC Column-steel Beam Middle Joint

With the development of modern building structures,RCS(reinforced concrete column-steel beam)frame structures are widely adopted because they make take advantage of the mechanical properties of steel structures and concrete structures.At present,the connection mode of the joints of the RCS structure system is mostly rigid connection with the expected failure mechanism of plastic beam hinges,which will result in large residual drift after the earthquake.The self-centering structure can reduce or eliminate the residual drift of the structure and restore the structure to its original position after the earthquake.There are few studies on the self-centering RCS structure.Therefore,it is meaningful to conduct the self-centering RCS structure study.This paper applied the energy dissipating steel plate presented by the research group to the self-centering energy dissipation beam-column middle joint.Nine sets of selfcentering energy dissipation RC column-steel beam middle joint tests were carried out,including eight sets of joint test with steel plate dampers and one set of control experiments without dampers.And the seismic performance of the joints was analyzed from the aspects of hysteresis curve,skeleton curve,energy dissipation capacity,and selfcentering ability;Finally,the ABAQUS software is applied to simulate and analyze the nodes.The main conclusions are as follows:(1)The joint bearing capacity,stiffness and energy dissipation capacity meet the design requirements,and the hysteretic curve of the joint obtained from the test indicates this joint has small residual displacement.(2)The self-centering parameter(SC parameter)of the joint is related to the initial stress of the prestressed strand and the strength of the steel plate damper.The larger the SC parameter is,the stronger the self-reset ability is and the smaller the residual displacement is.(3)The energy dissipation and damage of the joints is concentrated in the damper,and the beam and column are in the elastic state during the whole test process,reaching the expected damage goal.After the test is completed,the energy dissipation core plate is replaced,and the self-centering ability,energy dissipation ability and bearing capacity of the joint are almost unchanged,and the ‘recoverable’ performance goal can be achieved.It performs well in self-centering energy-dissipating RC column-steel beam joint test with desirable manufacturability and replaceability.The results of the finite element simulation are in good agreement with the experimental results in terms of hysteresis curve,buckling shape of the energy dissipating core plate,tension force of prestressed strand and other aspects,which verifying the influence of self-centering parameters on the seismic performance,indicating the effectiveness of the finite element simulation.