Concept Terzo Tempo transforms an unfinished concrete structure at Scalo San Cristoforo into a civic infrastructure for sport, landscape and collective life. The abandoned frame is not treated as a ruin to be completed, but as an open matrix capable of hosting new spatial generations. context The site is compressed between the railway to the north, the Naviglio Grande to the south and the viaduct to the west. Within these severe boundaries, the unfinished building has become the custodian of a spontaneous landscape. The project works with this condition, preserving the presence of the existing structure and the ecology that has grown around it. reticular ecosystem The exposed concrete skeleton becomes the project's wireframe. A new steel structure operates as a reversible prosthesis: a sequence of independent units is inserted within and around the existing grid, producing changing constellations of spaces for sport and public activity. urban strip An orthogonal system of paths extends beyond the building and reorganizes the surrounding ground. The strip connects gardens, clearings, water, sports areas and new crossings towards the Naviglio, turning the former industrial enclosure into an open urban park. program The ground floor acts as a public membrane between the curated park facing the Naviglio and the open landscape towards the railway. Exhibitions, events, a bistro, pools and climbing spaces occupy the lower level. Training rooms and flexible sports halls are suspended above, while an elevated square and terrace offer new viewpoints over the park and the city. structure The new construction is formed by a sequence of long-span steel trussed portals. Functional volumes are suspended by vertical rods and connected to the trussed columns, minimizing the number of supports perceived at ground level. Longitudinal bracing stabilizes the system while keeping its structural hierarchy visible and legible. credits Project team: Cristian Casiraghi, Federico Martorana, Anita Rizzi, Chiara Tabladini. Professors: Filippo Orsini, Estefania Cuenca Asensio. Tutors: Michele Deconti, Carlotta Oliosi, Michelangelo Sicari. Politecnico di Milano, Architectural Design Studio, A.A. 2025/2026.