Calculation Analysis And Experimental Study Of GRP-confined Concrete Cylinders

FRP, the fiber reinforced composite material, is a kind of material with highmechanical properties materials. It is made of polymer matrix and fibres bondingtogether by extrusion and drawing of special mould. Compared with traditionalmaterials, FRP is light-weight with good resistance to fatigue damage, corrosion,environmental abrasion. It also has low thermal expansion, easily transportation andinstallation, water resistant, absorption radar microwaves. With the continuing drop inthe cost of FRP material, it is being widely used for structural strengthening, repair andrehabilitation work. The paper is investigated the behaviour of concrete cylindersconfined by glass fibre reinforced polymers (GRP).Firstly, through the theoretical study, the calculation formulas of the displacements ofGRP confined concrete column and yielding stresses, yielding strains in three direction(radial/hoop/axial) direction were proposed.Then, ABAQUS software was used to do the numerical simulation. The purpose ofthe modeling was to investigate the mechanism and behavior of columns confined withGRP. Simultaneously, by changing the fibre wrapped orientation and the thickness offibre, the parameter analysis was done. The confined mechanism between GRP andconcrete core was also discussed deeply.Finally, in order to verify validity of formula and feasibility of the finite elementmethod, specimens were tested in the experiment.2glass fiber reinforced polymers(GRP) confined concrete cylinders with same dimensions and materials and1unconfined concrete cylinder was set up. The first column was confined with±45°layers of GRP from the axial direction while the second column was with an orientationof±55°. The numerical results showed good agreements with calculation andexperiment.The study results showed a substantial increase in the axial compressive strength,ductility, yielding stresses and strains of the GRP-confined concrete cylinders ascompared to the unconfined one. With the larger thickness and fibre orientation fromaxial direction, the axial compressive strength, yielding stresses and strains becomeincreasingly high. And the confined mechanism is worked after yielding of concrete.