FRP约束UHPC圆形短柱轴心受压性能研究OA北大核心CSTPCD

In order to study the influences of the number of fiber reinforced polymer(FRP)layers,the type of FRP,and the volume of steel fiber on the axial compression performance of ultra-high performance concrete(UHPC)circular stub columns,21 FRP-confined UHPC circular stub columns were tested under axial compression.The typical failure characteristics and stress mechanism of the specimens were analyzed.In addition,the influence of various parameters on the ultimate strength and ultimate strain of the specimens was studied.The experimental results show that the ultimate strength of UHPC circular stub columns can be improved by increasing the number of FRP layers.The ultimate strength of C12,C22,and C32 is 17.8%,25.4%,and 23.4%higher than that of C11,C21,and C31,respectively.With the increase in the volume of steel fiber,the ultimate strength and ultimate strain,and the ductility of UHPC circular stub columns are improved.The ultimate strength and ultimate strain of C31 are increased by 2.9%and 15.1%,respectively,compared with C21,as well as 4.7%and 50%,respectively,compared with C11.Under the same FRP layers and volume of steel fiber,the improvement of the ultimate strength of confined UHPC circular stub columns by carbon fiber reinforced polymer(CFRP)is significantly better than that by glass fiber reinforced polymer(GFRP).The ultimate strength of C11,C12,and C13 is 9.7%,7.8%,and 7.2%higher than that of G11,G12,and G13,respectively.In view of the constraint of the steel fiber,calculation models of compressive strength and ultimate strain of FRP-confined UHPC circular stub columns are proposed.Furthermore,the constitutive model of FRP-confined UHPC is given.