MINLP cost optimization of industrial steel building

Abstract

This paper presents the cost optimization of a single-storey industrial steel building structure. The optimization is performed by the Mixed-Integer Non-linear programming approach, MINLP. The structure consists of the main portal frames, which are mutually connected with the purlins. All structural elements are proposed to be built up of standard hot rolled I sections. The MINLP performs the simultaneous cost, topology and discrete sizes optimization of the building structure. Since the discrete/continuous optimization problem is non-convex and highly non-linear, the Modified Outer-Approximation/Equality- Relaxation (OA/ER) algorithm has been used for the optimization. Alongside the optimal structures costs, the optimal number of main portal frames and purlins as well as all standard cross-section sizes have been obtained.