Finite Element analysis and experimental study of static performance of multi‐CFRP tendon composite anchorage system

Abstract A novel composite anchorage with dispersed arrangement of carbon fiber‐reinforced polymer (CFRP) tendons was proposed. The bonding length and constraint ratio of the dispersed‐tendon composite anchorage were determined by numerical simulation. Six groups of multi‐CFRP tendon composite anchorage systems (MTCAS) were tested to investigate their static performance. The axial force dispersion coefficient c_v and relative slip ratio coefficient δ were proposed to evaluate the static performance of the MTCAS with variables, including pre‐tension load, the inner inclination angle of the sleeve and the modified bonding medium. Results demonstrated that increasing the bonding length and restraint ratio of steel sleeve could improve the stress state of tendon in the anchorage. The anchorage with a bonding length of 280 mm and a constraint ratio of the sleeve of 0.90 can reliably anchor multiple CFRP tendons arranged in a dispersed arrangement. An inner inclination angle of 3.1° of the sleeve can be adopted on the premise that strength utilization ratio is guaranteed and anchorage diameter meets the requirements. An adequate pre‐tension load can reduce the slips of tendons, and the recommended pre‐tension load value should not exceed 0.7 F_ptk. The 0.25% basalt fiber‐modified epoxy resin anchorage obtained the highest strength utilization ratio. Highlights A novel composite anchorage with dispersed carbon fiber‐reinforced polymer tendons was designed. New mechanical parameters evaluating anchorage performance were proposed. Basalt fiber (BF)‐modified epoxy resin (ER) can improve anchoring performance. The 0.25% BF‐modified ER anchorage obtained the highest strength utilization ratio. Pre‐tension load should not exceed 0.7 times the theoretical tensile load.