Mechanical Analysis Of Joints Between Concrete-Filled Square Steel Tubular Column And Laminated Composite Slim Beam

The use of laminated composite slim beam in prefabricated steel structures can reduce the structural height,shorten the construction period and reduce the project cost.it has good economic and social benefits.Combining the laminated composite slim beam and the concrete-filled square steel tubular column into a new structural system has a good application prospect in the building structure.However,there are few studies on the performance of the laminated composite slim beam and the concrete-filled square steel tubular column joints.There is no corresponding design theory.In this paper,a combination of numerical simulation and theoretical analysis is used to perform bending analysis and punching analysis on the concrete-filled square steel tubular column with laminated composite slim beam connections.Complete work is following:(1)The finite element software ABAQUS was used to establish joints refinement finite element model.Through the comparison of the analysis results and the experimental results,the validity and rationality of the analysis model is verified.(2)Using the established finite element model,numerical simulation of the new joints bending and impact punching is performed.The influence of the parameters of different axial compression ratio,plate thickness,steel dark beam height,steel dark beam web width,steel dark beam flange thickness,square steel tube thickness,concrete strength and steel beam strength on the flexural and shearing bearing capacity,energy dissipation capacity,stiffness degradation,strength degradation,ductility and other indexes of joints were analyzed.The main parameters affecting the flexural and punching shear bearing capacity of the new joint are defined.(3)Three type joints of equal beam and column,strong beam weak column,strong column weak beam are designed.The influence of different strong column coefficient on the bearing capacity,stiffness,ductility,failure mode,and the internal force distribution ratio of the steel dark beam and concrete in the floor of the new type of joint are analyzed.Combined with the analysis results,the stress mechanism of the core area is of the joint obtained.The shear capacity of the core zone is mainly provided by the steel pipe web in the core zone and the infill concrete.The flange and inner baffle plate in the core zone are mainly used to transmit the beam end bending moment.(4)Established a theoretical calculation formula for the flexural and punching shear bearing capacity of the new joints.Based on the numerical analysis data,the formula for calculating the flexural capacity of the joint in the positive bending moment region and negative bending moment region is obtained by regression.And the calculation formula of joint punching shear bearing capacity under the action of punching force.The results of the calculation formula for the bearing capacity established by the two methods are verified and are in good agreement.(5)The system design method of the new joint is proposed,and the construction requirements of each component of the joint and verification examples are given.Combined with the experimental results of the joint and the numerical analysis results,this new joint design proposal is given,which provides a reference for practical engineering application.