Coastal and river bridge scour mitigation using hybrid solutions

Bridge piers, foundations, and abutments in coastal areas or across rivers often face heightened risk of detrimental scour development under wave and/or current loading. Along our coastlines bridges are part of essential evacuation routes, saving lives ahead of predicted storm impacts with life-threatening consequences if compromised. Further inland, many bridges across creeks and rivers that are part of rural transportation systems and low volume road networks afford equally important transportation connections. When disaster strikes and these structures are compromised – as was painfully demonstrated in the recent Central Texas flash flood disaster – entire communities are cut-off from relief help or means to recover quickly. In most instances, bridge failure is initiated through hydraulically-induced scour formation and growth at the interface of the structural components and the surrounding sediment. If scour issues can be predicted and mitigated early, catastrophic failure can be avoided. The problem is that traditional mitigation techniques are costly or, in the case of rural bridges, may not even be included in the design. Here, we plan to test low-cost hybrid mitigation techniques that can help reduce scour impact to bridges caused by wave or current impact by using bio-cementation (such as Microbially-Induced Calcium Carbonate Precipitation - MICP) and/or geosynthetics in combination with the in-situ sediment.