Probability of failure of a box beam using simulation techniques

Abstract

Though structures designed according to codes do not generally fail, it is interesting to know their true probability of failure in view of the economic consequences.A simply supported uniformly loaded box beam is considered. Based on real statistical data derived from tests or adequate and realistic assumptions, the factored moment Mf and the resisting moment Mr are calculated using Monte Carlo simulation. In order to take into account some important phenomena for prefabricated beams, such as residual stresses, initial crookedness, and end conditions, the random variable α, which multiplies Mr, and its variation coefficient Vα are introduced. The α coefficient is defined as the tested capacity divided by the code predicted capacity. After interpolation, the variable Z = Mr − Mf is assigned a normal (Gaussian) frequency distribution. Then, the probability of failure is evaluated using a well tested mathematical technique.