If a bridge is identified as scour-critical, which action is typically required?

• A. No immediate action; monitor during next inspection.
• B. Only routine maintenance on the deck.
• C. Special attention to foundation stability and erosion around piers/abutments, potentially triggering remedial actions.
• D. Immediate closure to all traffic.

Answer: (C)

When a bridge is scour-critical, the threat is the erosion around the foundation, especially around piers and abutments, which can undermine stability. This calls for moving beyond routine maintenance to a focused assessment of foundation stability and the eroded area. You’d inspect for scour depth, assess how well protective works are performing, and determine if current measures are adequate. If conditions show that the foundation could be compromised, remedial actions are triggered to protect or repair the foundation, such as adding or improving scour protection, implementing stabilization measures, or other engineering fixes. Immediate closure to all traffic is not the standard step unless the risk is extreme, and routine maintenance or mere inspection without addressing erosion would not be sufficient.