OPTIMUM PROBABILITY-BASED DESIGN OF PLASTIC STRUCTURES

Abstract

This paper is concerned with probabilistic optimum limit design. The problem is formulated as a weight minimization with a constraint on the probability of system failure. A reliability optimum design procedure is described in which the inter-dependene among any two random loads and the inter-dependence among any two random plastic moments are accounted for through the coefficients of correlation between these variables. Computer programs were written to analyse the sensitivity of the optimal solution with respect to different parameters. As an example, the optimum probability-based formulation is illustrated in the context of plastic design of a simple portal frame. Considerations of the discrete optimal-design solution resulting in practice by the selection of members from a set of standard available profiles are given in the final part of the paper.