Probabilistic assessment of fatigue crack propagation in concrete

It is well known to engineers that fatigue accounts for a majority of structural failures. In plain and reinforced concrete structures, fatigue may lead to excessive deformations, excessive crack widths, de-bonding of reinforcement and rupture of the reinforcement or matrix leading to structural collapse. It is learnt from the available literature on fatigue behavior of concrete that the rate of fatigue crack growth depends on a number of parameters, such as, the tensile strength, stress history, stress intensity factor range and fracture properties. Furthermore, these parameters are random in nature. These factors together with the wide variations in material properties of concrete suggests that a statistical/probabilistic framework is required for fatigue life prediction in concrete. In this work, the probability of failure of concrete beams under fatigue is computed through Monte Carlo simulation and by considering the different parameters responsible for fatigue failure as randomly distributed. The sensitivity of different parameters involved in fatigue process pertaining to failure is also studied using stochastic sensitivity analysis.