Automated design and fabrication framework to enhance steel reuse through structural optimization and metal 3D printing

The environmental impact is currently one of the key issues influencing the construction industry from a production standpoint. For this, structural designers are increasingly adopting circular construction strategies aimed at reducing greenhouse gas emissions. Among the most significant shifts in steel construction is the practice of reuse: especially in countries with a high concentration of historical buildings, steel reuse is emerging as a necessary alternative to demolition and waste disposal. This research proposes a structured methodology to automatically design optimized shell-like structures from a dataset of reclaimed steel members, combining global and local optimization algorithms. First, the components recovered from decommissioned steel structures are stored in a dedicated dataset. From this dataset, elements are randomly selected by an algorithm to compose an optimized gridshell structure. The algorithm assembles the gridshell using the best-performing components available in terms of structural utilization and environmental impact. The objective is to minimize the use of new materials by achieving an optimal structural configuration (best fit) using almost exclusively reused elements. The research also investigates the challenge of connecting reused components, which are often non-standard and geometrically diverse. Through a topological optimization study, custom steel joints are designed and validated for fabrication using large-scale metal 3D printing technology known as Wire-Arc Additive Manufacturing (WAAM), allowing for the efficient and precise assembly of the reused elements within the gridshell structure.