Finite element investigation of fatigue performance of CFRP-strengthened beams in hygrothermal environments

摘要

The effectiveness of reinforced concrete (RC) external bonded with carbon fiber reinforced polymer (CFRP) laminates is bound by the negative effect of hygrothermal environment and cycle load. In order to prove the durability of CFRP-strengthened RC beams in hygrothermal environment, this paper concentrates on a numerical and experimental research of the failure modes and fatigue life of CFRP-strengthened RC beams under the coupling action of hygrothermal environment and cyclic load. Considering that two main failure modes of CFRP-strengthened RC beams are debonding of CFRP-concrete interface and main reinforcement fracture, the failure criterion of interface debonding and main reinforcement are involved in finite element method (FEM). Based on the fatigue damage accumulation, the failure mode which occur first can be predicted. The results show that the main failure mode of CFRP-strengthened RC beams in indoor environment is main reinforcement fracture. With the increase of temperature and humidity, interface debonding become the main failure mode. The fatigue life corresponding to failure mode under different hygrothermal environments can be calculated, which is in good agreement with experimental results.