Research On Seismic Behavior Of Assembled Square Steel Tube Concrete Column-H-Shaped Steel Beam Joints

The assembled building is an important symbol of building industrialization.For assembled buildings,the "factory prefabricated,on-site installation" construction method is used,which has the advantages of low pollution,high efficiency,and low energy consumption,and is more in line with the green development concept of energy savings and emission reduction,low carbon,and environmental protection.In the structure,the beam-column joint is crucial to internal force transmission between members and the overall seismic performance of the structure,whose complicated force situation makes connection design a major challenge in current research.Due to the influence of welding quality and construction site conditions,the joints are prone to brittle damage.For the popularization of such structures,it is critical to optimize the connection method of steel column-steel beam joints and master their seismic performance.Therefore,in this paper,a fully bolted assembled square steel pipe concrete column-H-beam joint is designed based on the widely used outer ring plate type joint,and its seismic performance is investigated by means of proposed static tests and numerical simulations.The main work and conclusions are as follows:(1)A fully bolted assembled square steel pipe concrete column-H-beam joint is proposed,which consists of a steel pipe concrete column and an H-beam spliced by separating the hoop type joint connection plate,and then connected by high strength bolts.(2)The proposed static tests were conducted on four assembled square steel tube concrete column-H-beam joints,the damage characteristics and various seismic performance indexes of such joints were obtained.The results indicate that the hysteresis curve of the joints shows a “Z-shaped”,the average equivalent viscous coefficient is 0.1606,the energy dissipation coefficient is above 0.95,and the ductility coefficient is 2.545～2.985,which has better energy dissipation capacity and ductility compared with ordinary reinforced concrete joints.(3)ABAQUS was used to perform finite element analysis of the joints,and the errors of the joints’ damage characteristics and load-displacement curves were within the permissible limits compared with the experimental results,which verified the validity of the joint modeling approach.Further,parametric analysis was carried out to obtain the influence law of different parameters on the seismic performance of the joints.The results indicated that the increase of axial pressure ratio,beam-column linear stiffness ratio and steel pipe wall thickness will increase the joint bearing capacity and energy consumption capacity,and to a certain extent,the increase of axial pressure ratio will decrease the joint ductility,as well as the increase of beam-column linear stiffness ratio will reduce the increase in joint bearing capacity.While the changes of concrete strength grade and bolt preload will have less effect on the seismic performance of such joints.