Finite Element Analysis On Static Behavior Of RHS K-joint Strengthened By Carbon Fiber Reinforced Polymer

With the development of the times,the steel structure plays a very important role in the bridge construction.Especially the steel tube,due to its excellent performance,makes up the tubular truss bridge which always used in the viaducts and urban landscape bridge due to its spanning capacityAs for the steel tubular truss structure,the joints can be regarded as the connections for the tubular members,but also the weak parts in the structure.That is why more attention should be focus on the tubular joints.At present,there are two kinds of methods for strengthening the joints,which can be divided into external reinforcement and internal reinforcement.The use of carbon fiber reinforced polymer(CFRP)method retrofitting the tubular joints can make up for the shortcomings of existing methods.In this paper,a reasonable finite element model is established to investigate the static performance of the tubular joints strengthened with CFRP sheets.The results of research could be stated as:1.Selecting constitutive relationship and element type for steel and CFRP,setting boundary condition and loading method according to the experimental research,considering material and geometric non-linearity,the finite element model is established to verify with the experimental results,which provide theoretical foundation for the research of K-joint strengthening by CFRP.2.The static performance of the rectangular gap K joint strengthened with CFRP sheets is studied and analyzed by using finite element method.It is found that the bearing capacity of the rectangular tubular K-joint reinforced with CFRP sheet is significantly improved compared with the unreinforced K-joint,and the deformation of the joint is effectively limited.3.The influence of the parameters of CFRP(the number of layers,length of plies and orientation of plies)and geometrical parameters of K-joint(diameter ratio,chord thinness ratio angle between brace and chord and gap)on the bearing capacity and the efficiency isinvestigated systematically4.A finite element model of the unreinforced tubular truss is established according to the experimental results.By comparison,the model of tubular truss retrofitting by CFRP sheets is also established,it is found that the mechanical performance of the steel tubular truss strengthened with CFRP sheets are better than the unreinforced steel tubular truss.