This master’s thesis focuses on the structural assessment and retrofit of the Gratasuit Bridge, a bridge built in 1983 in Switzerland, which currently shows signs of deterioration and overuse. With the evolving demands of modern traffic and environmental considerations, this study explores the feasibility and benefits of converting the existing jointed bridge structure into a semi-integral or integral bridge system. The research includes a detailed structural analysis, a review of retrofitting methodologies, and a life cycle assessment to evaluate the sustainability of the proposed interventions. The methodology integrates a thorough literature review on bridge engineering and advanced structural checks using multiple software. By comparing the current floating bridge design with the proposed semi-integral system, the thesis demonstrates the advantages of the latter in terms of durability, maintenance reduction, and environmental impact. The outcome is a strategic plan for rehabilitating the bridge, which could serve as a model for similar projects within Switzerland and potentially globally, emphasizing infrastructure sustainability.