Experimental Study On Reinforced Concrete Frame Beam-column Joints Strengthened By Sprayed GFRP

Reinforced concrete frame structure is a widely used structure form in our town houses,in the different levels of earthquake disasters,in addition to a small number of damaged or destroyed,the most concrete frame structure building as mild or moderate damage,belong to "repairable","strengthening" category,the seismic damage of reinforced concrete structure has very important meaning in seismic strengthening.Injection of glass fiber reinforced composite material(Sprayed GFRP)is Europe and the United States,Japan and other countries in the latest technology in the field of structure strengthening research,with the help of the injection machine cut short fiber and resin mixture of high speed jet injection material layer to the structure surface to form certain thickness,and the reinforced structure to work together to form the overall,has the characteristics of light weight,high strength,convenient construction,can the vibration damage of fast repair and reinforcement concrete structure.In order to study the seismic effect of reinforced concrete frame "T" beam-column joints after reinforcement,four "T" beam-column joints are studied in this paper.By setting the axial pressure ratio(0.2,0.3,0.4),the low level of four components for weeks under reciprocating load pseudo-static aseismic test to study the injection of glass fiber reinforced polymer(GFRP)seismic performance of t-shaped reinforced concrete beam-column joints and reinforcement effect.Through the destruction of all specimens form,load-displacement hysteresis curve and hysteretic performance,skeleton curves,energy dissipation capacity and ductility coefficient test result analysis,comparing reinforced and unreinforced seismic performance of the specimens,the following conclusions:1.The same axial compression ratio is 0.2,and the bearing capacity of the reinforced component JJD-2 is 7.4% lower than that of the unreinforced component JJD-1,and the ductility is 8.9% higher.2.Under the same reinforcement condition,with the continuous increase of axial compression ratio,the bearing capacity of 0.3axial compression ratio component JJD-3 is 11.5% higher than that of 0.2 axial compression ratio component JJD-2,and the ductility is 12.0% higher.The bearing capacity of 0.4 axial compression ratio component JJD-4 decreased by 14.8% compared with 0.4 axial compression ratio component JJD-3,and its ductility increased by 7.7%On the OpenSEES finite element software platform,GFRP reinforced T beam is built Column node model,without considering axial compression ratio of specimen earthquake situation,the model the simulation study of low reversed cyclic loading,OpenSEES can effectively simulate the GFRP on the "T" type of beam-column joints constraint function.