A Localised Strengthening Approach of Carbon Fibre Reinforced Polymer (CFRP) Cables with Self-Anchorage System

Carbon fibre reinforced polymer (CFRP) possesses excellent mechanical properties and has gained popularity in modern applications, offering a potential alternative to traditional steel cables. There are four common anchorage systems for CFRP cables: bonded-type, mechanical-type, composite-type, and self-anchored systems. The self-anchored system is widely used due to its simplified configuration; however, the high-stress concentration around the metal ring always causes premature failure. Hence, this paper explores a localised strengthening approach via inserting extra layers of prepregs. It investigates the effect of extra prepreg positioning, number of layers inserted, extra prepreg thickness, extra prepreg length, and extra prepreg angle. This localised strengthening approach can significantly enhance the load-carrying capacity of the CFRP cable. Results showed specimens with several inserted extra prepregs between the initial prepregs had higher load-carrying capacities than those with extra outside surface strengthening. Inserting three extra prepreg layers increased the load-carrying capacity by approximately 13%. The CFRP cable with five inserted extra prepreg layers increased the load-carrying capacity by 20.82%. For the CFRP cable with a 20° separation angle, 100% extra prepreg thickness had a better localised strengthening effect than 150%, showing that too many extra prepreg layers are ineffective in increasing the load-carrying capacity. Besides, a longer extra prepreg can increase the load-carrying capacity due to larger contact surface areas between the initial and extra prepregs. Furthermore, a smaller extra prepreg angle yielded a higher load-carrying capacity: a 2° extra prepreg angle increased the load-carrying capacity by 13.61%, whereas a 5° angle resulted in only 8.72% improvement.