Why is deck drainage inspection important under NBIS?

• A. Drainage is not part of NBIS.
• B. To reduce noise.
• C. To ensure water is properly directed to prevent deck deterioration and corrosion.
• D. To improve aesthetics.

Answer: (C)

Water management on a bridge deck is essential for long-term safety and reliability. Deck drainage inspection is part of NBIS because properly directing water away from the deck and its joints prevents water from pooling and seeping into cracks, which can cause concrete deterioration and corrosion of reinforcing steel. When drainage systems (gutters, scuppers, downspouts, and drainage channels) are functioning and the deck is sloped correctly, water is kept away from critical components, reducing freeze-thaw damage and slowing deterioration. That focus on preventing damage and maintaining structural integrity is why this option is the best choice. The other ideas—noise reduction or aesthetics—are not the purpose of NBIS, and drainage is indeed a required consideration in NBIS inspections.