Research On Carbon Fiber Cable Anchorage And The Influence Of Water Immersion Environment On Its Fatigue Performance

Cables in steel cable-bearing systems or steel cables in long-span structures are susceptible to corrosion under reciprocating loads and the environmental effect,affecting the service life of the structure.Fiber-reinforced composites have good design,light weight,high strength,corrosion resistance,and good fatigue properties,and are considered to be alternatives to steel cables.However,the domestic and foreign researches on the anchorage of fiber-optic cables are relatively lagging.At the same time,the durability research of cable-anchor structures under the action of multiple coupling fields is still blank.In order to promote FRP materials,these problems need to be solved urgently.In this paper,a new type of multi-cone anchoring structure is developed on the basis of the existing single inner cone bonded anchorage.The effectiveness of the structure is analyzed by theoretical analysis,numerical simulation and static load test.Fatigue performance of FRP tendons and the influence of the water-soaked environment on the cable-anchor structure under fatigue loading were obtained under the fatigue test of the cable-anchor structure of the tendons.The specific research content and results of this article include:(1)The new multi-level cone anchorage is analyzed based on the single-inner-bonded anchor.The results show that the multi-level cone can adjust the compression stress of the CFRP in the anchor and reduce Stress concentration at the front end of the anchorage;at the same time,the multi-level cone anchorage can also effectively reduce the outer diameter of the anchor.For double inner cone anchors,the outer diameter of the anchor can be reduced by 10-20 mm,and the multi-level cone anchorage can reduce the outer diameter of the anchor greater.The numerical simulation of the new multi-stage cone anchor has shown that the multi-stage cone structure can adjust the compression stress on the CFRP,and the elastic modulus of the bonding medium,the friction coefficient between the bonding medium and the anchor cup,and the anchor cup are analyzed;the anchorage performance of the anchorage is good,and the anchoring efficiency coefficient reaches more than 90% and meet the standard.The data of the peripheral strain gauge of the anchorage indicates that the multi-level cone anchorage structure effectively reduces the impact of the front end of the anchorage.Squeeze stress.(2)The fatigue test of a single CFRP tendon anchor structure under water immersion environment was carried out.The results show that the fatigue test under water immersion environment does not destroy the CFRP in the water immersion part,and the fatigue load degrades the stiffness of the reinforcement.The stiffness degradation law conforms to the yang stiffness degradation model.Fatigue load causes stress redistribution in the anchorage area.Water immersion will aggravate the stress redistribution in the cable anchor structure.The stress redistribution mainly occurs in the front end of the anchor and in the first 100000 cycles.(3)The fatigue test of the new multi-level cone anchorage under water immersion environment did not damage,the wavelength change of the measuring point at the water immersion end is greater than that at the Unprocessed end,the residual strength test exerts the strength of the base material of the CFRP,and the reinforcement exhibits divergent failure,Anchorage static load test and fatigue test can meet the requirements of the standard,and it is expected to be applied in engineering practice.