Experimental Research on Stress Relaxation Properties of CFRP Rods
In order to determine the relaxation loss of prestressed carbon fiber reinforced polymer(CFRP)rods in the ground anchor abutment of Danjiangkou Reservoir Bridge of Shixi Expressway in Hubei Prov-ince,the stress relaxation of CFRP rods under different stress ratios was experimentally studied.Based on the axial tensile test of CFRP rod specimens anchored by bonded anchorage and mechanical crimping an-chorage,the influence of different anchorage forms on the failure mode of CFRP rods and the material prop-erties of CFRP rods were clarified;based on the 1 000 h stress relaxation test of CFRP rod specimens,the development laws of stress relaxation of CFRP rods at different stress levels were obtained.The results showed that the specimens anchored by bonded anchorage had an ideal bursting tensile failure under axial tension,but the strain of the specimens changed greatly during the stress relaxation test;the specimens an-chored by mechanical crimping anchorage failed prematurely with the mode of the spallation and peeling of the CFRP rods under axial tensile,but the strain of the specimens changed little during the stress relaxation test,which could meet the relevant requirements of the stress relaxation test in GB/T 21839-2019.The stress relaxation of the CFRP rods increased with the increase of the initial stress ratio.The relaxation rates of specimens with initial stress ratios of 0.53,0.63 and 0.82 were 1.06%,1.65%and 2.31%after 1 000 h,respectively;the development of stress relaxation of CFRP rods converged rapidly and tended to be more stable with the increase of initial stress.The stress relaxation of specimens with initial stress ratios of 0.53,0.63 and 0.82 at 24 h were 45.3%,58.8%and 59.7%of that at 1 000 h,respectively.The stress relaxa-tion of specimens with initial stress ratios of 0.53,0.63 and 0.82 at 200 h were 78.3%,81.2%and 82.7%of that at 1 000 h,respectively;based on the test results,the prediction model of stress relaxation in CFRP rods was established with high prediction accuracy,and the relaxation rates of prestressed CFRP rods in ground anchor abutment of Danjiangkou Reservoir Bridge in 10,30,50 and 100 years were 1.91%,2.18%,2.32%and 2.52%,respectively.
stress relaxationcarbon fiber-reinforced polymer(CFRP)rodanchorage formsinitial stress ratioprediction model
万方数据
维普
