Study On Creep Of Composite Members Of Reinforced Concrete Filled With GFRP Tubular

Because of FRP’s lightweight, high strength and corrosion resistance, it is widely concerned by the scholars at home and abroad since it was born. Among different kinds of FRP, the pipe of FRP is the most representative. FRP pipe is the most representative. composite members of reinforced concrete filled with GFRP tubular is a new kind of composite components, which putting longitudinal working reinforcement (steel cage) and then pouring concrete in the GFRP tube.On the one hand, GFRP tube improve the force performance of concrete by Confined concrete, increased the bearing capacity and the earthquake resistance ductility of the composite Members, especially, the GFRP tube played the protective function to the internal steel bar and the concretes; on the other hand, the stability of the the thin GFRP tube is improved by internal concrete. At present, many experts and scholars of domestic and foreign domestic stuy on the component’s mechanical properties of composite members of reinforced concrete filled with GFRP tubular, who mainly research on its Axis of compression member、Eccentric compression and flexural properties, etc.but the influence of concrete to the creep is hardly reported。Based on the before research, this paper research on the Study on creep of composite members of reinforced concrete filled with GFRP tubular, the main research work is as follows:Through the analysis on the reinforced concrete circled by the GFRP under axial compressive force, the method for computing the compression members restrained by GFRP was deduced. In the process of deduction, the theory of performance flow and concrete’s creep theory under multi-axial stress state were used. The computer language was used for programming the simulation part of nonlinearity. On the basis of concrete examples, influences of the ratio of GFRP, concrete strength grade, imposed load and temperature were considered. And then, effects of creep on the axial stress of core concrete, pipe GFRP and stirrup’s force were taken into concern as well as the influence of the temperature on the bearing capacity of the members.Based on the Performance flow theory for concrete creep, The flexural members constructed by reinforced concrete filled in the GFRP tube under long-term load were researched.For the mechanical characteristics of concrete filled in the GFRP tube, the model of it is simplified, and then a one-dimensional creep formula was presented. The Computer language was used for programming the simulation part of nonlinearity. On the basis of concrete examples, influences of the GFRP ratio, concrete strength grade, imposed load and temperature were considered. And then, effects of creep on the axial stress of core concrete, pipe GFRP and stirrup’s force were taken into concern as well as the influence of the temperature on the bearing capacity of the members.After the analysis of the members formed by reinforced concrete filled in GFRP tube under eccentric compression and the core concrete’s creep, the creep of the GFRP tube under eccentric compression was studied. Theories used in this study include theory of the concrete’s creep under multi-axial stress, theory of concrete’s performance flow applied to concrete’s creep in a continuous unload condition. By establishing the creep model of the concrete and initial conditions, a method for calculating the member’s creep was found. In addition, it is applied to discuss the GFRP ratio, the eccentricity and the tightening of the stirrups. The timeliness of the concrete’s creep was simulated by means of the Computer language. Results calculated in this way proved to be reasonable.