Research On Seismic Behavior Of Connections Of Modular Steel Structures

With its many advantages,steel structure module construction plays a good application prospect in the process of industrialization in China.The beam-column joint is the core of the steel module and plays a decisive role in the strength,rigidity and stability of the steel module.Therefore,the study of the mechanical behavior of steel-beam beam-column joints is the key to the seismic design of modular building structures.In this paper,the beam-column joints of the HBS module system in Australia are used as the research object.The hole opening,Axial Compression Ratio,column wall thickness,The influence of parameters such as the thickness of the baffle,the thickness of the curved plate and the thickness of the force-transmitting plate on the mechanical properties of the joint is to explore the mechanism and design method of the joint failure.The main contents are as follows:(1)Method verification;using the same modeling and analysis method,the quasi-static analysis of the beam-column end plate connection nodes is carried out.The results show that the finite element calculation results are in good agreement with the test,and the accuracy of the finite element analysis method is verified,which can simulate the true stress state of the node.(2)Analysis of the influence of node opening;establishing the unopened model JJD-T0 and the node opening model JJD-TH of the node domain under the same parameters,considering the influence of different Axial Compression Ratios on the mechanical properties of the joint,the research results show that:(1)Under the same axial compression ratio,the failure modes of the two specimens are basically similar,and there is no significant difference between the bearing capacity,initial stiffness and ductility of the specimens.(2)The mechanical properties of the two nodes are greatly affected by the axial pressure.It is recommended that the Axial Compression Ratio of the joint column should not exceed 0.2.(3)Analysis of node parameters;changing the column wall thickness of the joint and the thickness of the baffle,curved plate and force-transmitting plate,and studying the influence of various parameters on the mechanical properties of the joint.The finite element analysis of the node specimens with 9 different parameters shows that :(1)The failure mode of the node is the drum failure,which basically meets the design principle of “strong node and weak rod”.The initial stiffness is basically 1841.4~2035.8 N/mm,belonging to a semi-rigid node.(2)When the thickness of the column wall is small,the ductility of the joint is poor,and the column is damped;when the thickness of the column wall is less than 2 mm of the thickness of the baffle,the ductility and energy dissipation performance of the joint are better.(3)When the thickness of the baffle is large,the bearing capacity of the joint is large,but the energy consumption is weak.When the thickness of the baffle is greater than 2 mm,the energy consumption of the joint is better.(4)When the thickness of the curved plate is larger,the initial stiffness of the joint is larger and ductile.Better,but the energy consumption is weak.(5)The thickness of the force-transmitting plate mainly affects the ductility and energy dissipation coefficient of the node.When the thickness of the force-transmitting plate is large,the node has good ductility and strong energy consumption.(6)According to the conclusion of parameter analysis,the basic method of node design is proposed.(4)Conclusion verification;according to the parameter analysis results,the JJD-YH node specimens are optimized and designed.Compared with other similar steel nodes,JJD-YH has higher bearing capacity,larger initial stiffness and ductility good,the energy consumption performance is better;the stress distribution in the node domain is more uniform.(5)Node optimization;based on the JJD-YH test piece,the concrete-filled steel column node JJD-YC is designed.The calculation results show that the bearing capacity of JJD-YC is improved by 11.9%,the energy consumption performance is good,the stiffness decays slowly,and the ductility coefficient reaches 3.2.