Parametric Study On Shear Performance Of CFRP Reinforced RC Space Frame Beam Columns External Joints

At present,the reinforced concrete frame structure is the most commonly used structural form of the building,and most buildings in China adopt this structure.The joint plays a important role in transmitting,distributing internal forces and ensuring the overall stability of the structure.Therefore,research on joint reinforcement is of vital significance for practical engineering.Carbon fiber reinforced polymer(CFRP)is a new type of reinforcement material and has many advantages,making the application of CFRP in reinforcement more and more common.At present,the research on reinforcement of reinforced concrete frame structures with fiber-reinforced polymer is limited to beam,column and other component levels.And there are few researches on the reinforcement of beam-column joints,and most of them are plane frame joints,space frame joint is relatively poor.Therefore,it is necessary to study the reinforcement of joints of the space frame.The study of the anchorage slip between CFRP and concrete is mainly applied at the component level of beams and columns and has not been applied to the joints.In order to further improve the research of joint reinforcement,the anchorage slip between CFRP and concrete interface was considered in the simulation.This article takes the external joints of reinforced concrete frame with transverse beams as an object of study,and has a serious shortage of distribution hoops in the core area of the joints.In view of this situation,the method of sticking CFRP in the core area of the node is used to reinforce it.In this paper,finite element software ANSYS is used to establish a refined finite element model including transverse beams,which can consider the anchorage slip performance between CFRP and the concrete.A total of 74 reinforcement joint models and 36 unreinforced reference joint model have been built.During the simulation,a certain amount of axial pressure is applied to the column end,and displacement loads are applied to the beam end.Through the finite element simulation,the failure modes,reinforcement effects,and different reinforcement parameters of the node model are analyzed.For the effect of joint reinforcement,the research parameters include the number of CFRP layers,the axial compression ratio,the location of the transverse beams,the number of transverse beams,the height and width of the transverse beams,and whether the transverse beams are damaged.Through simulation analysis,it can be seen that the shear strength of the joints after the CFRP reinforcement is significantly improved,and the deformability of the core region is significantly improved,different reinforcement parameters all have a certain degree of impact on the reinforcement effect of the CFRP.