Evaluation of a large-tonnage FRP cable anchor system: Anchorage design and full-scale experiment

Due to anisotropy of fiber-reinforced polymer (FRP) material, the anchoring of large-tonnage multiple-tendon FRP cable is a challenge. To solve this problem, a large-tonnage FRP cable anchor system (CAS) was designed numerically by optimizing five key anchorage parameters affecting the anchor efficiency and implemented in three full-scale basalt FRP (BFRP) cables with 37 Phi 7 tendons. The numerical results showed that the cable radial displacement increases with the spacing of tendons increasing. The cable radial compressive stress and displacement decrease with the thickness of the load transfer component (LTC) increasing. Increasing anchor length and conical angle have significant reducing effect on the cable axial displacement but a negligible effect on the cable radial displacement. Experimental verification showed that the mean anchor efficiency and ultimate load of the BFRP cables were 95% and 1919 kN, respectively. The maximum axial strain difference of the BFRP cable at the loading and free ends increased with the load. The shear stress of the center BFRP tendon first increased rapidly, then decreased slowly, then increased gradually again, and finally decreased quickly. The axial strains and shear stress of the BFRP cable in the anchor zone were consistent with the FE results, and were proved to follow linear and cubic functions, respectively.