Effect Of Size On The Axial Compressive Behavior Of Concrete Confined With CFRP Strips

Fiber reinforced polymer(FRP)has been widely used in strengthening of concrete structures in recent years.The advantages of light weight,high strength,corrosion resistance,and convenient construction make the technology develop rapidly.Strengthening concrete by wrapping FRP jackets is an important application of FRP.A large number of scholars have systematically studied the properties of confined concrete,which proves that this method can effectively improve the bearing capacity and ductility of concrete structures.Actually,FRP strip spacing is more widely utilized in real application.In order to make FRP strip restrained concrete more widely used in practical projects,a more accurate stress-strain constitutive model must be proposed,and the effect of size effect is unavoidable.In the present study,axial compression tests of CFRP strip-confined concrete specimens of different sizes were conducted.The concrete strength(C30,C60),specimen dimensions(?100mm×200mm,?150mm×300mm,?200mm×400mm,?300mm×600mm)and CFRP were studied.The influence of these three parameters of the number of layers(layers 1,2 and 3)on axial compression behavior of CFRP-stretched confined concrete results in failure modes,focusing on the axial compression performance of CFRP strip specimens with different sizes of concrete cylinders outsourcing the same jacket volumetric ratio.compressive strength,stress-strain curves,and strain distribution along the height of the specimen.The law of ultimate strain changes with three variables.The test results show that compared with unconstrained concrete,the compressive strength compared with unconfined concrete,CFRP confined ordinary strength concrete,?100mm × 200 mm concrete columns wrapped one,two,three layers of strip fabric strength can be increased by 52.78%,94.83%,respectively,The strength of 145.88%,?150mm×300mm concrete columns wrapped with one layer,two layers and three layers respectively can be increased by14.12%,43.22%,and 72.71%.The concrete cylinders of ?200mm×400mm are wrapped with one,two,and three layers respectively.The fabric strength can be increased by7.35%,19.30% and 48.04%,respectively.The strength of the ?300mm×600mm concretecolumns wrapped with one layer,two layers and three layers can be increased by 5.50%,12.65% and 27.02%,respectively.For CFRP-confined high-strength concrete strips,the strength of one-layer FRP strip wrapped ?100mm×200mm concrete column increased by12.19%,and the strength of one-layer FRP strip wrapped ?150mm×300mm concrete increased by 15.42%,and the strength of one-layer wrapped ?200mm×400mm increased by 4.33%,and the strength of the one-layer FRP strip wrapped ?300mm×600mm concrete column increased by 12.47%.The experimental data show that the size effect has an effect on the axial compression performance of CFRP-stretched confined concrete,but the effect decreases gradually as the size of the test piece increases;the data obtained from the test is used to obtain the CFRP considering the size effect by linear regression analysis.Strip restraint concrete strength model,ultimate strain model and analysis-oriented stress-strain model;...