Design of RC columns subjected to safety constraint

Minimum cost design of reinforced concrete columns subjected to reliability constraints is a multi-level optimization problem because both the analysis of minimum cost design, and the estimation of the reliability are nonlinearly constrained optimization problems. A procedure for reliability constrained optimal design of columns is described in this study. It seems that such a design approach is allowed by the current CSA A23.3-94 design code and will become more relevant for an objective-based design code. This design approach ensures that the designed columns meet specified reliability levels, and that the construction materials having probabilistic characterizations which are different from those used for design code calibrations are used economically. The procedure is demonstrated through example designs of short and slender columns.