Research On The Application And Theory Of Non-metallic Anchorage System Based On FRP Materials

With the durability of prestressed reinforced concrete structure being increasingly prominent, Fiber Reinforced Plastics or Fiber Reinforced Polymer (short for FRP) as non-metallic materials are favored by people, because of their advantages such as light weight, high tensile strength, noncorrosive, excellent fatigue performance, nonmagnetic and recycling. FRP are modern composite materials with composition of fiber as mainly material, resin as the matrix and adequate auxiliaries. The existing anchorage system for prestressed tendons and cables of steel is no longer appropriate for that of FRP due to their low transverse shear strength and crushing resistance. It is necessary to develop a new anchorage system for FRP, if FRP materials apply to cable structure or concrete structure as prestressted tendons. Many analysis and experimental researches related to bond-type anchorage and wedge-type anchorage have been conducted by domestic scholars in area of anchorage system for FRP. In those researches, anchorage barrels are made of steel, which does not solve the problem of durability. The paper researches on the application and theory of non-metallic anchorage system based on FRP materials, providing foundation of realization and further practical application in the sense of non-metallic material reinforced concrete structure.Based on current domestic and international researches and development of FRP anchorage system, as well as the existing anchorage system of steel and FRP prestressed tendons, the paper studied the stress state, tension process, anchoring characteristic of FRP prestressed tendons and relative standards, to conclude the features of non-metallic anchorage system with FRP materials. After that, paper advanced the structure form of non-metallic anchor and studied mechanical performance of this anchor by theory analysis. With finite element software, non-metallic anchor was simulated and analyzed. Considering the production, ranges of error control were concluded in the reasonable values of this anchorage system which influenced the anchorage efficiency, based on the previous research. With the result of analysis, It is suggested that error of obliquity of anchorage(6°) should be controlled between range of -1°~ +0.5°, and angle difference between anchorage barrel and clips should be controlled between range of 0.1°~ 0.4°. The non-metallic anchorage for FRP prestressed tendons (φ16mm GFRP andφ25mm CFRP) were developed in addition. The load of anchorage was also analyzed by experiment, which showed that anchorage efficiency of the non-metallic anchorage forφ16mm GFRP was 138%, larger than 95% and satisfied the requirement; the conservative ultimate bearing capacity of the non-metallic anchorage forφ25mm CFRP was 1300kN ~ 1400kN, which was 32% ~ 43% larger than designed ultimate load. Besides, combined with actual production, manufacturing process and influence factors of these non-metallic anchorages were expounded, and some problems that need paying attention to in the production were brought forward.