Seismic Performance Analysis Of Prefabricated SRC Column-steel Beam Composite Structure Based On OpenSees

The prefabricated building has the characteristics of green environmental protection,energy conservation and efficiency,which meets the development needs of building industrialization,and is an effective building form to achieve the goal of ’double carbon’.The beam-column joints in the prefabricated frame structure are the core parts of the structure,which are prone to damage under the action of earthquakes and affect the overall safety of the structure,even leading to the collapse of the entire structure.Therefore,it is necessary to conduct an in-depth study on the seismic performance of beam-column joints in prefabricated frame structures.On the basis of the experimental research on a new modular prefabricated steel reinforced concrete column-steel beam composite joint(PSRCS joint)in the early stage of the research group,through the method of finite element analysis,the bearing capacity and seismic performance of the PSRCS joint and the frame structure containing the joint are studied.The main work is as follows:(1)Based on the experimental study of PSRCS joints,a refined finite element model of 6 joints(3 external joints and 3 internal joints specimens)was established by ABAQUS.The failure modes,stress distribution in the core area of the joint and bending momentcorner curves of 6 PSRCS joints under low cyclic loading were further analyzed.The results show that the plastic hinges appear at the end joint of the beam and the bending failure occurs at the end of the beam.With the increase of the ratio of stiffness of the beam to the column,the failure mode of the middle joint specimens tends to change from the bending failure at the end of the beam to the shear failure at the core area of the joint and the bending failure at the end of the column.The stress concentration area in the joint core area obtained by finite element analysis is consistent with the yield failure location of the test.The hysteresis curves of joints obtained from test and finite element analysis are relatively full,and the skeleton curves have obvious elastic,elastic-plastic and failure stages.The agreement between the two is quite high,which effectively verifies the feasibility and accuracy of ABAQUS finite element model.(2)Based on OpenSees analysis platform,the non-linear finite element model of PSRCS joint is established,and the hysteresis curve,skeleton curve,and cumulative energy consumption curve obtained by finite element analysis are compared with the test results.The results show that both hysteresis curves and cumulative energy dissipation curves are in good agreement as a whole.The skeleton curves show three-stage characteristics of different mechanical properties.Yield bending moment error is within14% and peak bending moment error is within 4%.The correctness of using the rotating spring model of Hysteretic material to simulate mechanical properties of PSRCS joints is verified,which lays a foundation for further establishing and analyzing the assembled frame structure model containing PSRCS joints.(3)OpenSees finite element model of assembled frame structure including PSRCS joints is established.Perform static tests on the prefabricated frame structure with 3 floors,6 floors,and 9 floors and the traditional steel reinforced concrete column-steel beam composite frame structure comparative analysis of elastoplasticity.The results show that under the action of inverted triangular pushover force,the ordinary frame structure tends to fail at the foot of column,forming a ’column-hinge’ failure mechanism,while the PSRCS frame structure mainly fails at the end of beam connection,forming a ’beamhinge’ failure mechanism.As the number of stories increases,the maximum base shear of PSRCS frame structure gradually decreases while the corresponding vertex displacement gradually increases.Different beam-end connections have a great influence on the maximum base shear of PSRCS frame structure.The base shear of PSRCS frame structure with welded connections is the largest,which is 1.0-1.2 times of that of the bolted-welded hybrid connection frame structure and 1.22-1.27 times of that of the bolted connection frame structure respectively.(4)Different seismic waves are selected to analyze the prefabricated frame structures with different storey numbers and beam end connections.As the number of floors increases,the inter-story displacement angle of PSRCS frame structure increases and the maximum acceleration of each layer changes slightly.Different joint beam end connections have little effect on the seismic performance of the frame structure as a whole,and the trends of the inter-story displacement angle,the vertex displacement and the maximum acceleration curve are relatively consistent.The PSRCS frame structure with bolt connection has lower bearing capacity,but has better ductility than the PSRCS frame structure with the other two connection structures.The PSRCS frame structure with welded connection has higher overall stiffness due to the joint connection,and its interstory displacement angle and maximum acceleration value are smaller than those of the frame structure with bolted connection and bolted and welded hybrid connection.Finally,based on the analysis of test and finite element calculation results,a performance-based design method for PSRCS frame structures and related design and construction suggestions are proposed.