Finite Element Analysis Of Seismic Behavior Of Two Story Two Span Precast Concrete Frame Under Horizontal Low Cyclic Loading

Prefabricated beam and column components are adopted,in which the beam and column are reserved with holes,and the column end is provided with concealed corbel.The prestressed reinforcement is passed through the reserved holes,then tensioned and grouted,and then sealed with epoxy resin to form a preloaded prefabricated concrete structure.This beam column joint structure is a popular joint form in recent years.It not only retains the advantages of prefabricated structure and responds to the call of national green construction,but also overcomes the defects of poor connection performance of beam column joints of prefabricated structure by using the characteristics of prestressed structure.However,there is little research on the influencing factors of preloaded prefabricated concrete structure.Therefore,based on the quasi-static test of two-story and two span preloaded prefabricated concrete frame,this paper uses pushover static elastic-plastic analysis and finite element software ABAQUS for finite element parameter analysis.The main research results are as follows:(1)A quasi-static test is carried out on a two-story,two-span pre-pressed prefabricated frame,and its seismic performance in terms of hysteretic performance,ductility,energy dissipation capacity and stiffness degradation is mainly studied.The results show that the ductility of the frame is better,and the ductility of the second layer is better than that of the first layer;the energy consumption capacity of the frame in the early stage is small,the energy consumption capacity in the yield stage is significantly improved,and the growth rate of the energy consumption capacity in the failure stage slows down or even decreases;The stiffness of the frame begins to degrade rapidly at the yield stage,and the final stiffness is not conducive to its continued bearing capacity.(2)The pushover analysis of the frame is carried out by SAP2000,and the calculated base shear vertex displacement curve of the frame is obtained.Compared with the test data,the vertex yield displacement,the vertex limit displacement and the displacement angle between yield layers are slightly smaller,and the errors are 11.1%,24.0% and11.2% respectively.The inter story displacement angles of both are less than 1/50 of the limit value specified in the code,and the frame deformation meets the seismic requirements.In addition,according to the sequence and position of the frame hinge obtained by pushover analysis,it is found that the plastic hinge mainly appears at the beam end and column bottom,indicating that the failure mechanism of the frame is the overall yield mechanism,which meets the design requirements of "no collapse in large earthquake".(3)The finite element software ABAQUS is used to analyze the parameters of the frame,focusing on the effects of the tension control stress of prestressed reinforcement,the cracking load of epoxy resin cement slurry,the strength grade of concrete and the axial compression ratio on its seismic performance.The results show that increasing the tension control stress in a certain range can improve the ultimate bearing capacity,ductility and energy dissipation capacity of the frame,but the stiffness degradation rate of the frame will be accelerated accordingly;Increasing the cracking load of epoxy resin cement slurry will improve the ultimate bearing capacity and energy dissipation capacity of the frame,but at the same time,the ductility of the frame will become worse and the degradation rate of stiffness will accelerate,which is not conducive to the continuous bearing after the earthquake;With the increase of concrete strength grade,the ultimate bearing capacity and energy dissipation capacity of the frame are significantly improved,but the ductility will become worse and the degradation rate of stiffness will accelerate;Increasing the axial compression ratio of the frame will lead to the obvious deterioration of the ductility of the frame.Due to the brittle failure,the stiffness degradation speed is accelerated.In addition,the energy dissipation capacity of the frame is also reduced.Therefore,the axial compression ratio must be reasonably controlled.The research results of this paper provide a certain reference for the subsequent design of precast concrete structure.