Experimental study on the influence of the preload in RC structures strengthened with CFRP

Concrete buildings represent a large part of the world’s structures. Long-term effects represent a critical issue for this kind of construction making it necessary to develop reinforcement systems (i.e. composite materials). A large part of nowadays research is focused on composite materials study in terms of durability, resistance increase, and good practices. The present work investigates the influence of CFRP sheets reinforce in terms of global behavior and crack opening. Using digital image correlation technology, crack development is studied after beam retrofitting in a no-damaged stage and in a cracked stage respectively. The study points out the influence of the pre-load in reinforced beams in terms of crack width, taking into account steel strain level equal to 80% of the elastic limit strain.