Models of R.C. structures for probabilistic serviceability analysis

Abstract

Crack appearance or excessive deflection in a structure depends on multiple variable parameters, and the structural serviceability estimate may be improved with the aid of probabilistic analysis, which calls for suitable models. Members are subdivided into finite elements with distinct characteristics. For cracking and deflection analyses different thicknesses of the finite elements are taken, according to the behavior of the structure. Probabilities of crack appearance in a member are evaluated as function of the variable lengthwise strength of the concrete, its mean strength within the structure population, and the live load. The probabilities of member deflections are evaluated in the same manner as for cracking, the deflections are evaluated by summation of products curvature-abscissa for each finite elements. Some numerical analyses show very differing reliability of different real concrete structures. Proposed models allow the real behavior of structure as well as the variation of material characteristics and loads to be taken into account.