Mechanical Performance Analysis Of New Assembled Reinforced Concrete Joints

Prefabricated concrete structure is an important structural form of building structure entering industrialization.Its advantages of green environmental protection and short construction period have attracted more and more attention at home and abroad.The assembled concrete frame system has become the most widely used assembled structural system due to its high precast rate of beam and column components.Through the investigation of seismic damage of prefabricated buildings,the damage of precast beams or precast columns is relatively light in the earthquake.The structural failure is mainly due to the failure of the joints of beam-column joints.Therefore,the reasonable connection form of beam-column joints is very important.In this paper,a new type of connection method is proposed for the beam-column joints of the assembled concrete frame.The assembled precast beams,precast columns,steel and end plates are connected by bolts.ABAQUS software was used to complete the design and reinforcement of beam-column joints of assembled concrete structures.The finite element model was established and the quasi-static analysis was carried out.Through the finite element analysis of cast-in-place beam-column joints and assembled beam-column joints,the shear performance of assembled joints and cast-in-place joint beams under different concrete strength grades and different bolt strength is studied.The seismic performance of assembled joints and cast-in-place joints under different concrete strength grades,different bolt strength and steel strength.The main research is as follows :(1)Based on the research status at home and abroad,this paper proposes a new type of fully assembled beam-column joint,and explains the connection structure and assembly process of the new joint.In order to make the results of the paper more convincing,this paper uses ABAQUS software to establish the finite element model of the assembled beam-column joint with the same bolt connection as the existing test,and applies the same cyclic reciprocating displacement to the beam end of the model as the test.By comparing the numerical simulation results and the test results,it is found that the peak load simulation error is 10.46 %,the peak displacement simulation error is 13.63 %,and the displacement ductility coefficient simulation error is 5.21 %.The feasibility of ABAQUS finite element software simulation calculation is proved.(2)The shear performance of the assembled beam-column joint model is analyzed,and the influence of concrete strength grade and bolt strength on the shear performance of the assembled beam-column joint is analyzed.The numerical analysis results show that the increase of concrete strength grade has little effect on the shear performance of beam-column joints because the bolts and steel at the beam end can bear large shear stress in the assembled model.The increase of bolt strength can effectively improve the shear performance of beam-column joints.(3)In the seismic analysis of cast-in-place beam-column joint model and fabricated beam-column joint model,the positive bearing capacity of cast-in-place beam-column joint is higher than that of fabricated beam-column joint,and the negative bearing capacity of fabricated beam-column joint is higher than that of cast-in-place beam-column joint.When analyzing the parameters of assembled beam-column joints,it is found that the increase of bolt strength has the greatest influence on assembled beam-column joints,followed by the increase of concrete strength grade,and the increase of steel strength has the least influence on assembled beam-column joints.