Design and mechanical properties of anchorage system with variable stiffness and bending angle for CFRP cables: Experiment and simulation

Owing to the shear and compressive properties of CFRP perpendicular to the fiber direction are much lower than the tensile properties along the fiber direction, which leads to the anchoring of CFRP is difficult and limits its application in engineering structures. In the present paper, a new type anchorage system with variable stiffness of bonding medium and bending angle of CFRP bar is developed, to solve the problems of low anchoring efficiency and easy slip of traditional anchorage system. The design, mechanical properties, stress distribution and parameter optimization of anchorage are conducted through experiment and simulation. The results show that the optimal bending angle of CFRP bar is 4° for anchorage design. The stress distribution inside the anchorage zone obtained by the simulation analysis is consistent with experimental test, and the setting of variable stiffness of bonding medium and bending angle of CFRP bar can reduce the stress peak by 50.9 %-67.3 % in the loading end, which avoid the premature local shear and slip failure of traditional anchorage, and the anchoring efficiency is greater than 95 %. Uniformity of stress distribution improved with the increase of the number and the evenly of length of bonding media, and the optimal average modulus (Ea) and difference of modulus (ΔE) of bonding medium are 12 GPa and 4 GPa, which provide the key design parameter for anchorage.