Experimental Research On Seismic Behavior Of Joints Of Fabricated Steel-concrete Composite Frames

Prefabricated building has many advantages,such as high construction efficiency,high construction precision,high construction quality,low labor cost,energy conservation and environmental protection,etc.These advantages well meets the needs of the domestic construction market.The development of prefabricated buildings has become an inevitable choice for the development of domestic construction industry.Prefabricated reinforced concrete joints have also become the focus of research,but according to the current research results,most of the prefabricated joints have more or less short plates in economic benefits,social benefits,mechanical properties or structural forms,which are difficult to be extended to engineering applications.In order to solve the above problems,the fabricated steel-concrete joint specimens are designed and manufactured,aiming to develop a simple structural form,good seismic performance,low cost,easy to promote the fabricated reinforced concrete joint form.In this paper,two fabricated steel-concrete composite frame joints and one common concrete cast-in-place joint are designed and fabricated,and they are numbered as ZJ-1,ZJ-2 and PJ-1 respectively.The failure modes of three specimens are analyzed.The bearing capacity,hysteretic performance,skeleton curve,energy consumption capacity,rigidity degradation,strength degradation,ductility and strain of steel plate are studied.The seismic performance indexes of fabricated joints and cast-in-place joints are compared.The results show that: Compared with cast-in-place joints,the bearing capacity and energy consumption capacity of the two kinds of fabricated joints are significantly enhanced,showing stronger seismic performance;The initial stiffness of the proposed fabricated joint is large,but the stiffness degradation is obvious in the middle and later stage of the test.After reaching the ultimate bearing capacity,the bearing capacity decreases rapidly,and the ductility is slightly poor;The failure mode of ZJ-2 is better than that of cast-in-place joint.After the failure of the specimen ZJ-2,the column still remains most of the bearing capacity,which conforms to the structural design concept of strong column weak beam and strong joint weak component.The hysteretic curve of ZJ-1 is fuller than that of ZJ-2,which shows stronger energy consumption capacity.The finite element analysis of two fabricated joints and one cast-in-place joints is carried out by ABAQUS finite element analysis software.The simulation results are in good agreement with the experimental results.Under this premise,the influence of steel strength,steel plate strength,concrete strength,axial compression ratio and steel plate thickness on the seismic performance of fabricated joints are studied.The results show that:The thickness of steel plate and the strength of steel plate are the key factors affecting the seismic performance of the specimens.With the increase of the thickness of steel plate or the strength of steel plate,the bearing capacity and energy consumption capacity of the two kinds of fabricated joints are greatly enhanced;The strength of concrete has a great influence on the bearing capacity of the fabricated joint.With the strength of the concrete increases,the bearing capacity of the fabricated joint is greatly improved,but the energy consumption capacity is less improved;The axial compression ratio also has a greater impact on the seismic performance of the specimens;The strength of reinforcement has a relatively small impact on the seismic performance of the fabricated joints.