Structural optimization of a parametric arch structure: comparison between three metaheuristic algorithms

Over the last few decades, sustainability and efficiency have become increasingly important in the architecture, engineering, and construction (AEC) industry due to the large amount of resources consumed. In view of this scenario, the primary requirement for designing large-scale structures is efficiency, achieving performance targets with the least amount of structural material. Since the advent and development of computational tools, structural optimization based on mathematical computation has become one of the most commonly used methods for designing sustainable and efficient buildings. Metaheuristic algorithms can be applied to a wide range of situations, especially in the engineering field, where they have been extensively used. Due to the complexity of optimization problems, classical and traditional techniques will not always be able to provide a global optimum solution efficiently. This thesis aims to investigate the efficiency of various metaheuristics algorithms, such as Genetic Algorithm (GA), Simulated Annealing (SA) and Estimation of Distributed Algorithm (EDA), when applied to large-scale size and shape optimization problems. Experimental results are obtained from the case study of a parametric arch structure. In particular, the optimization process is treated with the three different metaheuristic single-objective algorithms, by minimizing the structural weight and imposing a constraint condition on the Von Mises stresses along the arch. Cases with 2, 3, 4, and 5 parameters were studied depending on the type of section used. There have been 20 analyses conducted for each case and each algorithm. Minimum, average, and standard deviations and comparison graphs between the algorithms have been reported. In this thesis, the phases of parametric modelling, structural analysis and optimization have been developed entirely in the virtual environment provided by Rhino, Grasshopper, Karamba and Galapagos software packages. This interoperable software is chosen for this study due to its high versatility and customizability and, at the same time, the fact that it is widely used within engineering and architecture offices, so that procedures and results provided here can be helpful to design practitioners.