Sustainable Foundations for Small-River Bridges: A Comprehensive Review

Bridges spanning small rivers are vital for rural connectivity and flood management, yet their foundations often face challenges of unstable alluvial soils, scour, and limited budgets. This review examines sustainable foundation strategies for small river bridges, focusing on environmentally sensitive materials, economic efficiency, and climate resilience. We survey common foundation types (e.g. pile, well, raft, box culvert) and their applicability in alluvial regions, noting that traditional well foundations remain widespread in India due to soil conditions and cost. Contemporary sustainability criteria—such as minimizing carbon footprint, reusing waste materials, and ensuring long-term performance—are emphasized. Case studies from India (e.g. Uttar Pradesh alluvium) demonstrate the effectiveness of using precast concrete box culverts as a cost-effective alternative to deep wells, while international examples (e.g. arid U.S. streams) highlight scour-resistant deep foundation design. We identify gaps in current practice, including insufficient integration of life-cycle assessment and climatic change adaptation in foundation design. Finally, we outline research directions—such as novel low-carbon materials, adaptive design for flood resilience, and foundation reuse—to advance sustainable bridge foundations.