Trends Winter 2019 | Page 24

Timing is everything A sudden influx of water produced by storms, snow melt, or spring run-off can lead to high water episodes that make it difficult, if not impossible, for inspectors to position themselves to gather data and make accurate assessments of scouring. Increased water volume and velocity also “armor” the river with debris that can easily destroy equipment and threaten inspectors’ safety. Unfortunately, bridge scour is most visible to inspectors during the same extreme conditions that frustrate their attempts to access the bridge. “There’s a limited window of opportunity here,” said Pete Haug, an Ayres water resources engineer and a principal investigator for this project. “Short-term scour can happen in a matter of hours and be visible for only a brief time before the river conceals the damage with a layer of re-deposited sediment.” Under such cover, the potentially compromised footing remains. Enabling real-time scour studies was MDOT’s goal when the agency recently partnered with Ayres’ structural inspection group. At MDOT’s request, Ayres’ bridge inspection experts began research in 2016 to identify technology and equipment capable of providing MDOT with a safe, practical solution to conduct scour inspections in the midst of treacherous high water. 24 | TRENDS Ingenuity, Integrity, and Intelligence.