Research On The Performance Of New Joint Of Modular Steel Structure Building

With the proposal of the national " double carbon " strategic economy and the vigorous implementation of the " 14 th Five-Year Plan for Industrial Green Development," the development of modular steel structure buildings has been effectively promoted,which has set off a new wave of domestic scholars ’ research on modular buildings.However,in the existing research results,most of the connection forms are difficult to be fully applied to the middle column,side column and corner column joints.Therefore,this thesis proposes a new type of modular steel structure building node for this problem,and studies its mechanical properties through a combination of test and simulation.Based on this,parameter analysis is performed to optimize the node.The main research contents and results of this thesis are as follows :(1)Modular steel structure design.The industrialization process of modular steel structure building is studied and analyzed,and the industrialization process from original steel processing to modular steel structure building project products is summarized.Taking the modular unit design of civil buildings as an example,the functional rooms are designed,and through the arrangement and combination of different modules,the architectural plane forms are diversified,and the overall layout of the architectural space is diversified.(2)In view of the shortcomings of the existing research,this thesis develops a new type of joint,which can be applied to the joints of middle column,side column and corner column.The new joint connector is composed of bearing plate,positioning steel plate,T-type limit steel plate and screw,which has the characteristics of symmetry and universality.It can be widely used in the joints of middle column,side column and corner column by reasonable interception.The new node assembly is simple and efficient,and the existence of the limit plate and the bearing plate can achieve accurate positioning and improve the accuracy of the assembly.The assembly of beam-column module elements is carried out by hole embedding,and the assembly rate is high.(3)The mechanical properties of the new joints were studied by full-scale test.The quasi-static cyclic loading test was carried out on the joints,and the test phenomena and failure modes were analyzed.The hysteresis curve,skeleton curve,bearing capacity,ductility,stiffness,joint type and energy dissipation capacity were analyzed.The results show that the joint is a rigid joint,and the bearing capacity of the joint domain is higher than that of the beam section.The failure mode of the joint is the deformation and buckling of the bolt hole of the connector,the plastic hinge is generated at the root of the frame beam,and the flange is obviously deformed.The hysteresis curve of the new joint under low-cycle reciprocating load is fusiform,and the hysteresis loop is full.It has good ductility and energy dissipation capacity,and the overall seismic performance of the joint is good.(4)The numerical simulation of the new joint is carried out,and the results are compared with the experimental results,and the parameter analysis is carried out to optimize the joint.A refined finite element analysis model was established,and the accuracy of the numerical simulation results was verified by comparing with the experimental results.In addition,parametric analysis is carried out to explore the influence of parameters such as the number of bolts,the diameter of bolts and the thickness of connectors on the performance of joints.The results are compared and analyzed to explore the factors affecting the performance of joints,so as to further optimize the joints.The results show that the maximum error between the finite element analysis and the test data is 7.22 %,and the overall error is small.The finite element analysis results in this study are consistent with the actual situation,and the test results can be simulated.In the parameter analysis,by comparing the mechanical properties of the new joints under different parameters,the parameters of 8 bolts,bolt diameter of 14 mm and connector thickness of 6 mm are selected as the optimization scheme of the joints.