Experimental Study On Damaged Prefabricated Frame Joints Strengthened By Prestressed Steel Wire Rope

Although the assembly building started late in China,the assembly concrete structure is favored by the industry for its superior environmental protection advantages and structural performance.At present,the country is vigorously promoting prefabricated buildings,the proportion of new prefabricated buildings is gradually rising.However,the seismic resistance of prefabricated concrete structures has always been the focus of research.The prefabricated frame structure is assembled on site,which makes the steel bar discontinuous and concrete discontinuous in the core area of the joint point,and then makes the special interface between the precast members and between the precast members and the post-cast concrete,and becomes the weak link of stress under the action of earthquake.In theory,the traditional reinforcement method is effective for the reinforcement and repair of assembly structure,but the traditional joint reinforcement method generally has the problem of stress lag,and the reinforcement effect is not ideal.In order to solve the above problems,a new prestressed steel wire rope reinforcement method of assembled frame joints is proposed.In order to study its reinforcement effect,the damaged integrated frame was strengthened and the pseudo-static test was carried out.Through comparing the test phenomenon and seismic performance of the frame before and after reinforcement,the following main conclusions were drawn:1.The construction process of the prestressed steel wire rope reinforcement method is simple,and the key components of the reinforcement device,such as special anchoring steel plate,can be mass-produced in the factory,which greatly improves the reinforcement efficiency.The results of pseudo static test show that the prestressed steel wire rope reinforcement method can effectively improve the seismic performance of the damaged assembled frame,especially in the rigidity and bearing capacity.The test results are as follows:(1)The reinforcement method of prestressed wire rope can greatly improve the joint stiffness.Compared with the damaged frame,the stiffness of the strengthened frame joint is increased by 267%,and the initial stiffness is restored to 128% of the initial stiffness of the original member.(2)The overall development trend of the skeleton curve of the strengthened assembled integral frame is similar to that of the undamaged frame.At the later stage of the test,under the same displacement condition,the bearing capacity of the strengthened integral frame is slightly higher than that of the undamaged frame.(3)After reinforcement,the hysteretic loop curve of the frame is relatively full,and it has good energy dissipation capacity.Although the energy dissipation capacity of the frame is weaker than that of the similar frame without damage,it can also meet the basic seismic requirements.3.The finite element software was used to carry out the numerical analysis of the reinforced assembly frame,and the simulation value was compared with the experimental value,and it was found that the two were consistent,which verified the feasibility and rationality of the numerical simulation.4.Combined with the current reinforcement design code,the design calculation method and construction technology points of the new prestressed steel wire rope reinforcement method applied in the project are put forward,which provides reference for the subsequent application of the prestressed steel wire rope reinforcement method in the project.In the paper,there are 60 pictures,3 tables,and 87 references.