A Novel Anchorage System Of CFRP Cables And Its Performance

Carbon fiber reinforced polymer(CFRP)cable may be a potential alternative for steel cable to solve the corrosion problem.The anchorage of CFRP rod bundle is a big issue due to the anisotropic property and relatively high strength in fiber direction.Up to now,the bond-type anchorages are the most widely used anchoring configuration in CFRP cables.However,anchoring failure and pre-mature fracture due to the anchorage damage of CFRP rods occur frequently in bond-types anchorages.To avoid anchoring failure,increasing the anchorage length as well as the selection of deformed CFRP rods are the most usually adopted,which makes the anchorage and cable diameter much bigger than the conventional one.On the other hands,the pre-mature fracture of CFRP cable is resulted by the unproperly designed anchorage system that excessive damage on the radial direction of CFRP rods will generated when CFRP cable is loaded.In this study,a novel bonding anchorage system characterized by the diverged arrangement of CFRP bars inside socket with resin-based adhesive was proposed for CFRP cable.The ultimate bearing capacity and fatigue performance of this novel bonding anchorage system was experimentally tested to verify its applicability in bridge.(1)The bonding behavior between CFRP bar and resin-based adhesives are experimental investigation by pull-out test.And the observed pullout responses are modeled by numerical simulation to obtain the bond-slip relationship that represent the bonding behavior.On this basis,relationship between bonding length and bonding capacity is established for the determination of minimal bonding length in this novel anchorage system.(2)The anchorage system was experimentally tested to verify its performance and numerical simulations were conducted to investigate the influential factors in proposed anchorage to cable bearing capacity and failure mode.The effect of the adhesive stiffness on the uniformity of the tensile stress distribution of CFRP bars in cable,as well as the effects of the adhesive wedge action on the cable fracture mode were investigated with the finite element simulation.(3)The acoustic emission(AE)technique is employed to evaluate the performance of anchorage in the fatigue test and post-fatigue ultimate bearing capacity test.The obtained AE signals are analyzed by using wavelet packet transform and a cluster-based pattern recognition is adopted to associated the AE signal with damage pattern?(4)The length effect on the tensile strength of CFRP bar was studied in the macroscale.The tensile strengths of CFRP wires with different lengths were obtained experimentally and analyzed by using the several strength models considering length effect such as random strength field model,asymptotic weakest-link Weibull model.And the log-likelihood ratio test and the Bayesian information criterion(BIC)are used as the criteria for the validation of these strength models.Based on the prediction of strength distribution with different lengths,Monte Carlo simulation is adopted to predict the strength distribution of CFRP cable.(5)The environmental determental effects on CFRP cable,especially the anchorage system is simulated by means of high-temperature corrosion medium immersion of CFRP cable under laboratory condition.Then,the anchorage performance under fatigue loading and post-fatigue ultimate bearing capacity is examined to verified its long-term durability.Besides,the fatigue limit of CFRP cable using this novel anchorage is experimentally investigated and some useful information on fatigue life and fracture mode were obtained and they were helpful to extend a wide range of applications especially in the environment under high levels of fatigue loading.