Finite Element Analysis On Mechanical Performance Of GFRP Tube Confined Concrete Members

Fiber Reinforced Polymer or plastics (FRP), as a new type of materials, have received many attentions from scholars both home and abroad for their outstanding characteristics such as high-strength, corrosion resistance and light weight; among materials of this type, FRP filament winding pipe is the most representative one. The existence of the outmost FRP filament winding pipe can not only help the composite structure which consists of FRP filament winding pipe, concrete and reinforcing steel bar (steel tube) to effectively resist the erosion to concrete caused by severe environment so as to improve the durability of the structure; but it can also restrain the lateral deformation of inlayer concrete to improve the mechanical performance of concrete and enhance the load bearing capacity of the concrete. These advantages make the composite structure of this kind a current research focus home and abroad. Based on the researches of the composite structure consisting of FRP filament winding pipe and concrete as well as the composite structure consisting of FRP filament winding pipe and reinforcing steel bar (steel tube), the mechanical properties of these composite structures have been studied using the general finite element software ABAQUS, and the main focuses of this thesis are as follows:Based on finite element software ABAQUS, the whole the carrying capacity of GFRP-concrete-steel double-skin tubular columns under axial compression are analysised. Feature points from a typical load - deformation curve of cross section stress are analysised. Besides, the interaction between GFRP tube and concrete is taken into account in this paper. Filament winding pipe and concrete, the composite structure consisting of FRP filament winding pipe and reinforcing steel bar, and the composite structure consisting of FRP filament winding pipe and reinforcing steel tube were simulated using finite element method. The failure mechanisms of the component were studied through load-strain curve and the stress distribution of the component at each characteristic point were given. In order to validate the correctness of the model, the simulation results were compared with the experimental results from literatures, and the comparison shows good agreement between them. Based on the validated model, the effects of the thickness of the GFRP tube, the filament winding Angle of the GFRP tube, strength grade of the concrete and the length to diameter ratio of the component on the load bearing capacity of components were studied, concluded that the bearing capacity with the variation law of these design parameters.The eccentric compression property and the bending resistance of the composite structure consisting of GFRP filament winding pipe and concrete, the composite structure consisting of FRP filament winding pipe and reinforcing steel bar, and the composite structure consisting of FRP filament winding pipe and reinforcing steel tube were simulated. The failure mechanisms of the component were studied through load-deformation curve and the stress distribution of the component at each characteristic point were given. The correctness of the model was validated through comparison of simulation results and the experimental results from literatures. In addition, the influence of the structure parameters such as the eccentricity, the thickness of the steel pipe, hollow ratio and structure span on the load bearing capacity were mainly investigated, concluded that the bearing capacity with the variation law of these design parameters.