| The expansion of the old buildings has great development prospects and space.Because it can increase the usable area under the condition of not disturbing the original structure,and can also effectively protect the cultivated land resources,which meets the strategic requirements of China’s sustainable development.Meanwhile,it can solve the problems of leakage and heat insulation of the original building roof.How to ensure the coordinated work of the RC frame-light steel layer-mixed structure under earthquake and effectively transmit the horizontal load of earthquake to the vertical anti-side force member,which put high requirements on the connection joints of the old and new structures.Therefore,the analysis of the mechanical properties of the add layer structure joints is the key to the seismic design of hybrid structures.In this paper,the finite element numerical simulation of the new outsourced joint was proposed by the research group was carried out to study the seismic performance and failure mechanism of the joint and to carry out parameter analysis and optimization design.This study put forward reasonable design suggestions and provided reference value for future engineering design.The main work of this paper are as follows:(1)Reading a large number of references,summarizing and analyzing the research status of RC framework-light steel layer-added hybrid structure at home and abroad,and presenting the research direction and content of this paper.(2)Based on the test of the new joint under the low-cycle reciprocating load,the finite element model was established by ABAQUS software to analyze the force performance of the joint under horizontal unidirectional and cyclic reciprocating loads.By compared with the experimental results,the correctness of the finite element model was verified and its seismic performance was studied deeply.(3)Changing the reinforcement ratio of the beam,the hoop ratio of the column,the height of the outer concrete and the depth of the anchor bolt.Meanwhile,studied the influence of relevant parameters on the seismic performance of the joint,and determined the optimal range of design parameters of the new joint to propose rational design suggestions for new joint.(4)According to the results of parameter analysis,the original joint form was optimized and the related model was established.The seismic performance and energy consumption capacity were compared and analyzed before and after optimization,and reasonable design suggestions were summarized.Results show that the new outsourced joint was finally damaged at the beam under the horizontal load.The effect of the outer concrete on the steel column can enhance the lateral stiffness of the upper structure.The longitudinal reinforcement and the reinforcement can ensure the load effective transfer between the upper and lower structures,which made the test pieces have better bearing capacity and energy consumption;Increased the reinforcement ratio of the beam can improve the bearing capacity of the new outsourced joint,and made it more energy-consuming;With the increase of the height of the outer concrete,the reinforcement effect on the steel column can be strengthened,the lateral stiffness of the upper structure can be increased,the synergistic work between the upper and lower structures can be strengthened and the horizontal seismic load can be effectively transmitted,and the energy consumption of the test piece can be improved.However,the impact on bearing capacity was not obvious;with the change of the width of the outer concrete,the rigidity of the core area can be strengthened,and the plastic hinge on the beam can be moved outward,effectively protecting the core area,Improve the bearing capacity of the test piece;the depth of the anchor bolt can ensure the reliable connection of the upper and lower structures,and had little effect on the seismic performance of the joint;The optimized joint had higher carrying capacity and stronger energy consumption than the one before optimization. |
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