Study On Seismic Performance Of New Joints Of Modular Steel Structure

With the increasing prosperity of social economy,the construction industry will inevitably develop towards the direction of low pollution and assembly in the future.Modular building is a form with the highest assembly rate in prefabricated buildings,which has the advantages of fast construction speed,less on-site operation and less environmental pollution.However,there is still a lack of research on module unit connection and structural integrity.Therefore,on the basis of the existing research,this paper proposes a modular combined connection node of inner sleeve and buttonthrough bolt.The main research contents are as follows:1.The corner column model of modular building had been analyzed by finite element method;The results show that the joints are damaged due to the fracture of the weld at the floor beam and the large extrusion deformation of the floor beam;The shear deformation of the bolt at the end of the beam occurs due to the extrusion of the connecting plate,but the bolt and the connecting piece do not reach the ultimate strength of the material;The new type of sleeve bolt joint is semi-rigid;The ductility coefficient of the joint is greater than 2,and the equivalent viscous damping coefficient is greater than 0.2,which indicates that the new joint has good seismic performance.2.In this article,the axial compression performance of modular steel structure composite columns is studied,and the influence of the changes of the parameters such as the hole at the end of the column and the bolt preload on the axial compression bearing capacity of the columns is analyzed;The results show that the axial bearing capacity of the column decreases with the weakening of the column section,and the bearing capacity of the side column decreases by 7% compared with that of the side column with the opening diameter of 24 mm.When the sleeve and bolt are inserted at both ends of the column,the stiffness of the composite column is increased by 8%.Under the condition of no extrusion deformation at the end of the column,the bolt preload has little effect on the ultimate bearing capacity of the column.3.The seismic performance of the new joints under different parameters had been analyzed;The results show that the ultimate bearing capacity gain is less than 2% with the increase of bolt radius and axial compression ratio,while the initial stiffness increases by 6% and 19% respectively;Increasing the gap between sleeve and column wall will reduce the bearing capacity by 17%,but increase the ductility coefficient by5%;The results show that the ultimate bearing capacity and energy dissipation capacity are increased by 10% and 26%,respectively;After weakening the two sides of the box beam,the plastic hinge at the end of the beam can move to the weakening position,and the ultimate bearing capacity can be reduced by 12%,but it can effectively prevent the plastic failure of the beam column connection.4.The reliability of the new joint in modular building had been analyzed,and the differences between the new joint,the rigid joint and the articulated joint had been compared.The results show that the effect of sleeve bolt joints and hinge joints in the structure is similar,and the energy dissipation capacity of the structure under earthquake action is better when sleeve bolt joints are used,but the maximum use height should not exceed 6 stories,Compared with the rigid connection model,the elastic interlayer displacement angle of sleeve bolt connection can meet the requirements of relevant specifications.