Reliability Updating of Deteriorating Concrete Floor Slabs

The main objective of this paper is to propose a method to estimate the probability of failure of building concrete floor slabs using a probabilistic treatment of the most influencing geometrical, material or environmental variables. The estimation of probabilty of failure results through a stochastic simulation of the material degradation of the slab with time and the variation of the loads applied. Consequently, the progressive increase of the probability of failure is pictured. This value is the additional information to decide the appropriate level for the reparation. The presented method treats as random variables these basic ones taking part in the carbonation process, chloride penetration and corrosion. Distribution functions are used to, by means of simulation, applied upon the mathematical models of degradation, obtain the ultimate response of the slab at any time and then compare it with the acting loads, which are at their turn obtained through a stochastic treatment. The employment of the first order reliability moment (FORM) is used to estimate the probability of failure either for a part of for the entire slab.