Aseismic Analysis Of Prefabricated Frame With Prestressed Dry Junction Performance Study

Precast Concretestructures(PC structure for short)is a kind of structure which is composed of prefabricated components such as walls,beams and columns through reliable connection.Prefabricated frame structure has the characteristics of flexible space separation and easy standardized production,which is widely used in the construction field.As the most critical part of prefabricated frame structure,beam column connection node can realize the function of distributing internal force,transferring bending moment and ensuring the good overall performance of the structure.If the design of beam column connections is unreasonable,it will affect the normal performance and safety performance of the whole PC structure.Therefore,the research on the seismic performance of prefabricated frame joints is the key to promote the development of prefabricated structure.So far,domestic and foreign scholars have made some achievements on the seismic performance of prefabricated frame joints.On this basis,this paper proposes a new type of prestressed prefabricated beam column joint,that is,the beam column joint is designed as a combination of frame column with concealed corbel and frame beam with notch at the beam end,the connecting steel plates are embedded at the left and right beam ends,and the concave groove is prefabricated at the column corbel,so as to achieve the purpose of positioning and installation of beam and column,and finally run through the direction along the beam axis in the frame The reliable connection of frame joints is realized by the pretension provided by the prestressed tendons.In order to study the seismic performance of this kind of joint,the research contents and main work are as follows:(1)In this paper,a frame structure with this type of joint is designed and manufactured,and the quasi-static test of the new prestressed prefabricated concrete frame is carried out.The experimental data including hysteretic curve,skeleton curve and ductility coefficient are obtained,and the failure mode of this kind of frame is summarized,that is,under the action of horizontal low cycle reciprocating load,the frame is damaged at the end of beam and the bottom of column successively,and plastic hinge is produced,which conforms to the beam hinge failure mechanism.It lays a foundation for further research on the seismic performance and design of this structure.(2)Through the quasi-static test of the new prestressed prefabricated concrete frame,the energy dissipation performance and seismic performance are analyzed.The results show that:the new prefabricated prestressed concrete frame has good energy dissipation capacity and excellent seismic performance under horizontal low cycle cyclic load;the existence of prestressed tendons not only delays the development of cracks,improves the overall resistance to deformation of the frame,but also ensures the reliable connection of beams and columns,and improves the rotation capacity between beams and columns and the overall stability of the frame Before the overall failure,the structure has obvious deformation omen and good ductility,which can give full play to the energy dissipation capacity of each component.(3)Based on the test data,the parametric analysis of the single-layer and single span prestressed Precast Concretestructures is carried out by using the finite element software ABAQUS.The experimental results are in good agreement with the simulation results.On the basis of the experimental frame,the mechanical analysis models of six new prestressed prefabricated concrete frames are established with the joint form(dry joint,wet joint),axial compression ratio coefficient(0.2,0.4,0.6)and the number of prestressed tendons(0,2,4)as parameters.The results show that:under the same conditions,the frames with two kinds of joints have good seismic performance,and the frame with wet joints has higher peak bearing capacity,slower degradation of stiffness and strength,better ductility and energy dissipation capacity;the peak bearing capacity increases nonlinearly with the increase of axial compression ratio,but the greater the axial compression ratio is,the worse the ductility of the frame is;the frame without prestressed reinforcement has better ductility The peak load of prefabricated frame decreases obviously,and the stiffness degrades rapidly,but the increase of prestressed reinforcement has little effect on the seismic performance of this kind of structure.The results also show that the energy dissipation performance increases with the increase of axial compression ratio,and under the same conditions,the more the number of prestressed tendons,the worse the energy dissipation performance.