Impact Behaviour of Carbon Fibre-Reinforced Polymer (CFRP) Cables with Protective Sheaths

Carbon-fibre-reinforced polymer (CFRP) cables have attracted the attention of people as a corrosion-free substitution of steel cables serving in aggressive environments. The production of CFRP cables generally refers to that of steel cables at the present, but as CFRP cables do not have corrosion risk, the step of greasing the external surface of the tendon bundle of steel cables is sometimes omitted. This results in various bond states between the outermost protective sheath and the tendon bundle, which affect the impact load transfer and thereby affecting the impact behaviour of the CFRP cable but has never been properly considered when developing the protective sheaths. To understand the effect of the bond state on the impact behaviour of CFRP cables, and to find the optimal type of protective sheaths, the present study designed three types of protective sheaths (Type 1, free-sliding sheaths; Type 2, fixed sheaths; and Type 3, semi-fixed sheaths) and simulated them with achievable materials. Drop-weight impact tests were carried out on 2-meter-long CFRP cables with protective sheaths. The test results showed that the semi-fixed type of sheaths performed the best among all three types in delaying the fracture, improving the achievable maximum impact force and tension, and enhancing the energy dissipation capacity of the CFRP cable. Therefore, the semi-fixed type of sheaths is the recommended type for CFRP cables.