The main objective of this study is to implement and evaluate the National Cooperative Highway Program (NCHRP) Project 21-3 “Instrumentation for Measuring Scour at Bridge Piers and Abutments” (Lagasse et. al., 1997) designated system(s) for monitoring bridge scour.

The proposed project determines the method(s) and procedure(s) that most accurately identify the severity of scour in bridge foundations.

Two systems were considered: 1) Magnetic Sliding Collar (MSC) and 2) Sonar systems. For this purpose, more than ten bridge sites that are rated “scour critical” by New Jersey Department of Transportation (NJDOT), have been inspected for possible installation of equipment.

Two bridge sites were selected: Route 35 over Matawan Creek in Aberdeen, NJ, and Route 46 over the Passaic River in Elmwood Park, NJ. Both bridges were selected based on scour activity, accessibility, and streambed conditions as noted in bridge inspection reports.

On each bridge, both MSC and sonar systems were installed. Continuous scour data monitoring was initiated.

It was observed that both instruments could be easily installed with the proper equipment and some technical skills by the inspection personnel of NJDOT. Research also found that the MSC and sonar devices complement each other, and provide a clear and accurate picture of the scour activity at each site.