Underwater Bridge Integrity

Applying Technology to Bridge the Safety Gap
DP-97 Scour Monitoring and Instrumentation
DP-98 Underwater Evaluation and Repair of Bridge Components

In 1987, New York State lost 17 bridges because of scour, and 10 people were killed when the Schoharie Creek bridge collapsed. In 1989, when the Hatchie River bridge failed in Covington, Tennessee, another eight lives were lost. These and other less dramatic bridge failures point to an urgent need to improve the overall quality of the nation's bridges. Although the National Bridge Inspection Program, established in the 1970s, took significant steps toward improving the condition of bridge elements above water, the inspection of bridge elements below the water's surface was not similarly achieved.

In recent years, the NBIS has been revised to address this situation and now stipulates that all bridges be inspected underwater on a regular basis, not to exceed 5-year intervals. FHWA has also assisted the States in setting up underwater inspection programs through technical advisories, policy documents, and in particular, the Demonstration Project "Underwater Inspection of Bridges" (DP-80). The project was very successful, exposing State personnel to state-of-the-art inspection equipment and enabling them to learn first-hand the criteria for a successful underwater inspection program.

During this time, and partially due to the success of DP-80, new technology to inspect, evaluate, and repair bridge components underwater has continued to emerge. There is an immediate need to transfer this technology to State highway agencies and other municipalities.

The four major goals of this high-priority area are:

  1. To make presentations of DP 97 "Scour Monitoring and Instrumentation" to the highway community to give personnel "hands-on" experience with state-of-the-art instrumentation to measure and monitor bridge scour. Fixed and portable instrumentation, including geophysical methods, are demonstrated.

  2. To make presentations of DP 98 "Underwater Evaluation and Repair of Bridge Components"to showcase the latest technology available for evaluating and repairing bridge components underwater

  3. To work with the states to obtain and install instrumentation, collect data and to provide technical assistance to better maintain their highway structures.

  4. To work with the states to develop an underwater inspection and repair program.

U.S. Department of Transportation
Federal Highway Administration