Optimization based cost comparison between reinforced concrete and steel beams

Abstract

This paper presents the optimization based cost comparison between reinforced concrete and doubly-symmetrical welded steel I beams. The task of the research was to define the spans at which each of two different considered structures would show its advantages. The optimization/comparison was performed for simply supported beams for spans between 5 and 30 meters and for a uniformly distributed variable imposed load of 5 kN/m. The structural optimization was performed by the nonlinear programming (NLP) approach. The cost objective function was defined for the optimization and subjected to structural analysis constraints. The structures were designed in accordance with Eurocodes for both the ultimate and serviceability limit states. Beside the optimal self-manufacturing costs, the results also include the optimal masses for the different considered structures.