Study On Seismic Behavior Of Prestressed Assembled Concrete Frame Structures

The prestressed assembled concrete frame structure with unbonded mode has the advantages of small residual deformation and easy repair after earthquake,no bond slip between prestressed tendons and concrete,and has the advantages of assembled structure and prestressed structure,but the energy consumption capacity of the structure is weak and the construction is difficult.Therefore,this paper studies the prestressed assembled concrete frame structure which uses angle steel to dissipate energy,which is in the form of cow leg column and missing beam,and the notched beam is laid on the cow leg column during construction,which is convenient to construct and improves the safety of prestressed concrete structure construction.Using angle steel as energy dissipation element,diagonal steel is convenient to replace and the price is low.In this paper,the finite element simulation method is used to analyze the prestressed assembled concrete frame joints with angle steel connections under low cyclic reciprocating load by using ABAQUS software,and the Pushover analysis of a two-story and two-span prestressed assembled concrete frame is carried out,the main research contents and conclusions are as follows:(1)Five groups of beam-column joint models with common angle steel,vertical opening angle steel and transverse opening angle steel are established respectively.the effects of angle steel opening on seismic performance of beam-column joints are studied from the aspects of hysteretic curve,skeleton curve,stiffness degradation,energy dissipation capacity,residual displacement and bolt stress.It is found that with the increase of the opening width of the angle steel,the force of the angle steel decreases,the maximum stress of the bolt decreases,the initial stiffness of the joint decreases,the stiffness degrades rapidly,the energy dissipation capacity decreases,and the residual displacement decreases.Compared with the ordinary angle steel joint,the maximum bearing capacity of the three groups of transverse angle steel joints decreases 2.1%,4.2% and 10.2%,respectively.The ultimate load or yield load of diagonal joint with transverse opening of angle steel is reduced,but the ultimate load of angle steel joint can be adjusted by transverse opening,but the vertical opening is meaningless.The prestressed assembled joint of angle steel connection has good seismic performance and can be applied to frame structure.(2)The cast-in-place and prestressed assembled one-frame frames models were established and analyzed by Pushover.The analysis shows that the cast-in-place frame has stronger bearing capacity than the prestressed assembled frame,but the prestressed assembled concrete frame has better deformation capacity.The prestressed prefabricated frame has good ductility,and the displacement angle between the layers of the structure meets the requirements of the code.(3)The design process of prestressed fabricated concrete structure is summarized.Combined with an example of prestressed fabricated structure,the component fabrication and construction process are illustrated,and its application value is analyzed.It is shown that the structural system has broad application prospect.