Experimental Study On The Seismic Performance Of A Prefabricated Column-column Connection Joint With “π” Replaceable Connector

Considering the characteristics of the prefabricated structure,here proposes a new type of column-column joint with replaceable connectors,which can be replaced and repaired after suffering the earthquake.This new type of joint is composed of cross-welded steel columns,prestressed tendons and "π-shaped" replaceable connectors.As a replaceable structure,the joint limits the plastic deformation to the connector,while the rest of the part remains elastic during the earthquake.This joint has the characteristic of "staying tough under moderate earthquake,keeping replaceable under severe earthquake." As a prefabricated structure,the components of the joint can be precast in the factory,which shrinks the construction period.A total of4 groups of specimens are involved in the pseudo-static test to study their seismic performance.On the basis of the test results,a hysteretic model is derived.The test involves 4 specimens,and the parameters include the strength grades(Q160,Q235),the thickness of the web(6mm,10 mm,14mm)and the section form of the π-shaped limbs(with opening or without opening)of the connector.3 specimens are loaded twice to evaluate the replacement of the connector after suffering the earthquake.The main work and conclusions are as follows:(1)For the strength of the connector,it is found that the energy consumption of the joint with Q160 steel connector is 6.9% higher than the joint with Q235 connector under minor earthquake(corresponding to 1/500～1/150 displacement angle).However,compared with the joint using Q160 steel,the energy consumption of Q235 steel connector joint increases by 14.5% under moderate and severe earthquake(corresponding to the 1/150～1/18 displacement angle).(2)For the web thickness of the connector,the test includes the specimen with6 mm,10mm,and 14 mm to analyse the impact.It is found that increasing the web thickness of the connector can increase the peak load,initial stiffness and energy dissipation of the joint,while it accelerate the deterioration of the stiffness of the specimen.(3)For the section form of the π-shaped limbs of the connector,it is found that the joint with non-opening connector has higher initial stiffness and energy dissipation than that with opening connector.But similar as the web thickness,joints with non-opening connector show higher speed of deterioration of the stiffness.Based on the test results,this paper proposes the hysteretic model of this new type of joint.The model enables to calculate the yield load point,peak load point and load failure load point.The calculated results are in good agreement with the test results,which provides the basement for the later design method.