A Restoration Plan for Damaged Bridge that Takes Into the River Environment and Waste Reduction

The chapter delves into the restoration of the Kesengawa Bridge, which was severely damaged by the 2011 Tohoku Earthquake and Tsunami. The bridge, a critical infrastructure along the Ofunato Line, required a restoration plan that balanced structural integrity, environmental sustainability, and flood risk reduction. The text evaluates two primary restoration plans: one involving the removal and new construction of all bridge members, and another focusing on reusing the remaining structures. The chapter highlights the challenges and solutions associated with reusing the existing superstructure and substructure, including the integration of a reinforced concrete slab for BRT vehicles and the optimization of new superstructure designs to reduce material usage. A significant focus is placed on minimizing environmental impacts, such as reducing CO2 emissions and construction waste, while ensuring the bridge's functionality and safety. The restoration plan ultimately chosen emphasizes the reuse of existing structures, innovative solutions for substructure reinforcement, and the adoption of a steel sheet pile foundation to minimize river turbidity. The chapter concludes with a comprehensive evaluation of the environmental impacts and disaster risks associated with each plan, underscoring the importance of considering both structural and environmental factors in restoration projects.