Mechanical Behaviors Study On GFRP Tube Filled With Reinforced Concrete Members

In recent years, (Fiber Reinforced Polymer, shorten as FRP) is widely concerned by the scholars at home and abroad since it was born. The most representative composite material is FRP tube. Concrete-filled FRP tubes not only can provide an excellent alternative for concrete effectively subjected to corrosive environments, but also can raise the bearing capacity as a permanent formwork for the concrete, as a result, concrete-filled FRP tubes may adapt to the development of modern structures toward long-span, high rise and heavy-load. In this paper, based on the achievements in FRP tube filled reinforced concrete and steel reinforced concrete, author used experimental, numerical and theoretical methods to study the properties of GFRP tube filled with steel reinforced concrete. The major contents are the following:Experimental study on composite columns under axial compression of GFRP tube filled with concrete. The research on mechanism and failure mode, analysis on composite column's bearing capacity, deformation. Compare and analysis on the GFRP confined concrete component in different wall thickness of GFRP tube. A nonlinear analysis program of axial load is created, which is used to predict main parameters of wall thickness, steel ratio, concrete strength on the load-deformation curves. Superposition method is used to calculate the bearing capacity subjected to axial load. On the foundation of uniform theory, the formula of ultimate bearing capacities is worked out.Experimental study on composite columns under axial compression of GFRP tube filled with reinforced concrete. The research on mechanism and failure mode are studied through experiments. Compare and analysis on the GFRP confined concrete component in different wall thickness of GFRP tube and different steel ratio. A nonlinear analysis program of axial load is created, which take the effects of wall thickness, steel ratio, concrete strength into account. In addition, the calculation formulas of bearing capacity of GFRP tube filled with reinforced concrete columns subjected to axial load are created based on both superposition method and uniform theoryExperimental study on flexural behavior of the GFRP tube filled with reinforced concrete. The analysis on the influence of different wall thickness and different steel ratio to study the bearing capacity of composite component is carried out through experiments. With fiber model method, the nonlinear program of GFRP tube filled with reinforced concrete under pure bending compression is developed, which take the effects of wall thickness, steel ratio, concrete strength into account. Using ultimate balance theory, ultimate bearing capacities of pure-bending components under different failure models are given. On the foundation of uniform theory, the formulas of ultimate bearing capacities of pure-bending components are worked out.Experimental study on the composite column's eccentric compression of GFRP tube filled with reinforced concrete. The different wall thickness of tube, different eccentricity and different cross-section are compared. A nonlinear program is developed to study the properties of eccentric load column by using fiber model method, which take the effects of wall thickness, steel ratio, concrete strength, slenderness into account. In addition, superposition method is used to calculate the cross-sectional capacity subjected to eccentric load. On the foundation of uniform theory, the formulas of ultimate bearing capacities of eccentric compression components are worked out.Based on finite element software ABAQUS, the whole the carrying capacity of GFRP tube filled with steel reinforced concrete under axial compression, pure bending, eccentric loading are analysised. Feature points from a typical load - deformation curve of cross section stress are analysised. Besides, the interaction between GFRP tube and concrete, steel and concrete are taken into account in this paper.