Time-dependent reliability analysis of RC beams shear and flexural strengthened with CFRP subjected to harsh environmental deteriorations

Time-dependent reliability analysis of existing reinforced concrete (RC) beams strengthened with externally bonded carbon fiber reinforced polymer (CFRP) wraps is conducted. Corrosion effect in terms of remaining cross sectional area of steel reinforcement is modelled as a non-stationary Gaussian process and the probability of failure is estimated as a solution to the first passage probability from the safe domain. Moreover, flexural and shear limit states are modeled in a series system formulation. It was found that the steel stirrup ratio strongly influenced the reliability of beams subject to harsh environments and in some cases beam may experience brittle fracture during its service life. Furthermore, it is found that the upper bound of the system probability of failure is significantly higher than its corresponding individual limit states due to correlation between flexural and shear failure modes.