Study On Seismic Behavior Of Bolted Joints Between Square Steel Tubular Column And H-beam

Steel structure building has the advantages of assembly,environmental protection,light weight and so on.It is widely used in engineering.But there are still many problems in steel frame beam column joints,such as many welds,difficult construction,poor seismic performance and so on.In this paper,based on the reference to the existing square steel pipe column-H-shaped steel beam joints,by analyzing the stress characteristics of the joints,we propose improvements to the joint construction methods.By using the numerical calculation method,the failure characteristics and seismic performance of the joints under repeated load are studied,and the failure characteristics and seismic performance of the specimens under different parameters are further discussed.The main work and achievements of this paper are as follows:(1)Based on the analysis of the mechanical characteristics and mechanical properties of the joint,and considering the convenience of site construction,this paper puts forward suggestions for improving the joint practice,changing the original joint from bolt welding hybrid connection to full bolt connection,and designing the improved joint.It is found that the improved square steel pipe column-H-shaped steel beam joint meets the seismic design requirements of "strong column weak beam,strong joint weak member".(2)According to the relevant parameters of the existing beam column joint structure test specimens,the corresponding numerical calculation model is established.Through the comparative analysis of the numerical analysis results and the test results,the two calculation results are in good agreement,which verifies the reliability of the numerical simulation.(3)Based on the analysis of the failure characteristics and seismic performance of the improved base model,the influence of different axial compression ratio,wall thickness of the square steel column,bolt preload and yield strength of the square steel tube on the seismic performance of the improved base model are further analyzed.According to the numerical calculation results:The hysteresis curve of the BASE specimen is close to an inverse S shape,the node ductility coefficient is 4.555,and the node ductility and energy dissipation ability are better;With the increase of axial compression ratio,the bearing capacity of the joint decreases slightly,and the influence of axial compression ratio on the ductility of the joint increases first and then decreases;Square steel tube With the increase of the wall thickness of the square steel tube,the initial stiffness of the joint is 9.091%,6.202%,2.190%;The initial stiffness of the joint is greatly affected by the bolt preload,when the bolt preload is increased from 77.5kN to 186kN,the initial stiffness of the joint is increased by 61.44%;The increase of the steel yield strength can significantly improve the bearing capacity of the joint when the yield strength of the joint increases from Q235 to Q390,the bearing capacity of the joint increases by 29.98%.(4)The results of the study on the seismic performance of the above-mentioned bolted joints under repeated loads can provide a reference for similar engineering design.