Study On The Anchorage Perfromance And Application Technology Of Carbon Fiber Cables Under High Stress

Carbon Fiber Reinforced Polymer tendon(Carbon Fiber Reinforced Polymer Tendon)is a new kind of high-performance cable material.Compared to steel cable,CFRP has superior properties such as high strength,light weight,good corrosion resistance and fatigue resistance,etc.,it is suitable for large-span bridges and other structures.The high efficiency anchorage system is the key technology of CFRP cable in engineering application.The existing prestressed CFRP cable anchorage system which is more mature is still the bond-type anchorage.The wedge-type anchorage with small size,high anchorage efficiency and stable long-term performance,especially the cable group anchors is the technical bottleneck that has been researched at home and abroad in recent decade and needed to be break through.This paper focuses on the new type of wedge-type group anchors with staggered grooves and its performance in long-span concrete bending members prestressed with unbonded CFRP cables.The main research in this paper are as follows:(1)The forced mechanism of the wedge-type anchorage has been studied.At the same time,according to the stress characteristics and requirements of CFRP tendon,the radial compressive stress of the tendon is taken as the main research parameter,The numerical simulation tool was used to analyze the influence on the surface compressive stress of the tendon by modifying the multiple parameters of this kind of anchorage,including: the length of barrel,the inclination of the barrel,the force of pretightening,different friction coefficient between clip and tendon,different friction coefficient between barrel and clip,and the different diameter of tendon.The influence of various key parameters on the anchorage performance were mastered,The suggestions of the disign of the wedge-type anchorage were given based on the results of simulation.A three-hole wedge-type anchorage of prestressed calbe was designed based on the results of the simulation,and the three-hole barrel was verified to meet the requirements of the experiment by calculating its maximum principal tensile stress.(2)The static tensile test of the three-hole wedge-type anchorage of CFRP cable was carried out,and the anchorage efficiency coefficient of the group anchor was obtained,which can reach up to 68.3%.(3)The experimental study on the flexural performance of 4 external prestressed concrere beams prestressed by CFRP cables has been designed and completed,the external prestressed cables' s layout scheme is three deflection lines and two deviators.The main parameter is the degree of prestress ? and the external deflection angle? of the tendon.The whole process of the test memers was analyzed by nonlinear static analysis.The stress increment of the external CFRP cables was calculated based on the deflection of the beams,and the cracking moment and ultimate bearing capacity of the test beams were calculated.The ductility of the test beams were calculated based on the energy method.(4)Te finite element software ABAQUS was used to simulate the whole process of the test beams,the development of the crack simulated by using the concrete damaged plasticity model is accordance with the actual situation.The rationality of the simulation was verified by comparing the simulation results with the test results.