Design optimization of steel building using MINLP

The paper presents the design optimization of the steel building. The structure consists of the main portal frames, which are mutually connected with the purlins. It is proposed that all structural elements are constructed from standard hot rolled IPE sections. The structural optimization is calculated by the mixed-integer non-linear programming approach, MINLP. The dimensioning of steel members is carried out in accordance with the design specifications of Eurocode 3. The Modified Outer-Approximation/Equality-Relaxation (OA/ER) algorithm, a three-phase MINLP strategy and a special prescreening procedure of discrete alternatives are used for the optimization. In addition to the optimal structural mass, the optimal cross-section sizes of the structural elements, the optimal intermediate distances between the steel frames and the optimal intermediate distances between the purlins and rails were determined. An example of structural optimization is presented at the end of the paper