Research On The Seismic Performance Of Precast Concrete Frame Joint With Replaceable Energy Dissipation Connector

The development of prefabricated concrete structure can effectively promote the process of building industrialization in China.In recent years,the principle of “equal cast-in-place” has been adopted in the practice of China’s prefabricated structural engineering,and great progress and development have been made.However,the “equal cast-in-place” precast concrete frame structure system has the advantage of industrial production,but also inherits the problems of scattered damage and unsatisfactory yield mechanism in cast-in-place structures.A type of the single-side yield beam-column joints with replaceable energy dissipation connector of precast concrete frame(REDC-SPCF),which can give full play to the advantage of precast concrete frame structures and achieve excellent seismic performance and rehabilitation performance,is proposed in this dissertation.The precast concrete frame structure with the joint is not only convenient in construction,but also has excellent ductility and energy dissipation performance.Under the earthquake excitation,the damage of the structure is only concentrated in the energy dissipation connector,so the rapid repair of the structure can be realized by replacing the connector after the earthquake.what’s more,its flexural capacity is controlled by the energy dissipation connection,so it is easy to realize the seismic principle of “strong column and weak beam”,and to guarantee “strong shear and weak bending” and “strong node and weak component”.In this paper,the structural mechanism,energy dissipation characteristic,shear transfer characteristic,stiffness characteristic and flexural capacity of the new joint will be studied in detail,and the theoretical basis and design principle of the new joint seismic design method will be proposed.The main research contents and achievements are as follows:(1)Summaring the main connection mode of the precast concrete frame structure and existing problems in cast-in-place frame structures,a type of REDC-SPCF joint is proposed in this dissertation.(2)The structural mechanism and the force transfer path of REDC-SPCF joint are studied.This paper reveals the load transfer mechanism at the elastic and elastoplastic stages,and puts forward the theoretical basis and design principles for the design of the upper and bottom longitudinal reinforcement design,solt design and shear transfer design of the new joint.Furthermore,the energy dissipation characteristics and the arrangement form of energydissipating components of the new joint are studied,and the internal influence relations between connection stiffness and structural parameters,as well as the relations between Interstorey drifts,joint rotation and plastic strain of energy-dissipating members are deduced.(3)Low-cycle reversed loading test and the seismic rehabilitation test are carried out on the new type of joints,which the mechanical properties,deformation characteristics and energy dissipation capacity of the joints are the key study objects.The test results reveal that the plastic deformation was concentrated in the REDCs and concrete and longitudinal reinforcement at“top-hinge”,while the beam and the column remained elastic,revealing that the damage concentration and single-side yield could be realized.Stable hysteretic curves without pinch or negative stiffness were observed in the test,while a high energy dissipation capacity could be obtained.Comparing the mechanical and seismic property between the initial working condition and the condition after the seismic rehabilitation,the feasibility of the seismic rehabilitation is verified.(4)Based on the test results,a refined model of the component level and the joint level was established to simulate the test phenomenon and performance of the specimens by ABAQUS.Furthermore,the parametric analysis of the key factors was carried out to study mechanical properties and seismic performance of the new joint.