Targeted deployment of scour monitoring sensors for at-risk bridges

This paper presents a methodology on prioritizing deployment of scour sensors at high-risk bridges using a holistic approach. Specifically, stream geomorphic data, bridge design information, and bridge scour ratings are used to intelligently identify and prioritize bridge sites for remote scour monitoring. Scour is the leading cause of bridge failure, with 309 bridges in the State of Vermont rated as scour critical. Using Vermont as a case study, this work looks to correlate bridge structural design data with hydraulic and stream geomorphic information to identify bridges at high risk of scour processes, and specifically for bridges more structurally susceptible to scour damage. Including additional stream and hydraulic indicators in the analysis, rather than relying on structural evaluations alone, enables areas of geomorphic instability to be identified; and bridges in these areas can be outfitted with scour monitoring devices. Lowcost monitoring devices are proposed to monitor at-risk bridges and to provide additional information in scour-prone areas. A sensor under development would allow for direct installment into stream beds at existing bridges, and incorporate accelerometer-based monitoring, with wireless data transmission. The device would allow for real-time measurement of streambed degradation and aggradation during high flow events, thereby providing timely information regarding critical scour events. This work aims to aid State transportation engineers in identifying, which bridges in the transportation network are at risk, of scour processes, provides useful insight into scour rating systems, and assesses the value of the geomorphic assessments to improve our existing bridge rating system. The compilation of results from geomorphic assessments, scour ratings, and bridge design information will be presented.