Emergency Underwater Bridge Inspections
Norfolk Southern Corp.
Systemwide, United States
Norfolk Southern Railway operates approximately 19,500 route miles in 22 states and the District of Columbia. Along that route, there are nearly 10,000 bridges that span more than 300 miles. The railroad makes significant investments to keep each bridge safe for employees and the public. In 2019, Marine Solutions was contracted to provide emergency underwater inspections of 13 structures. These inspections were the result of vessel impacts, observed structure movements, scouring, or other events affecting daily operations. Services included nondestructive ultrasonic steel thickness (UT) measurements on steel supported structures, installation of crack monitors on concrete structures, underwater sonar imaging, and recommended remediation actions, if any, for each structure inspected. Crews were able to respond within 24 hours to these emergencies.
Tombigbee River Bridge (Structure 88.20), Jackson, AL - Marine Solutions performed multiple emergency inspections on this vertical lift span bridge following multiple impacts. Sonar imaging, a structural assessment, and repair recommendations were provided following a barge collision with a steel bridge bent during flood conditions. Sonar imaging was used to evaluate piers and fenders for potential damage following an impact. An underwater inspection and sonar imaging was done to evaluate potential damage to a concrete pier that had been struck by a barge and/or tug. And underwater imaging using MS-1000 imaging equipment was done after a bridge fender system was hit by a barge during flooding.
Grand River Bridge (Structure S-189.19), Brunswick, MO - The railroad carries grain out of Chariton County over the Grand River Bridge. With lots of flooding in the area, Marine Solutions was originally called in to provide underwater imaging of substructure damage on the 22-pier railroad bridge. After arriving on site, the structure had collapsed due to a logjam underneath the bridge. The railroad had cut the rails to control the collapse. Services were amended to providing underwater sonar imaging to help lay out new substructure units for immediate bridge replacement.
Tenbridge (Structure 331.2-CNO&TP), Chattanooga, TN - The Tenbridge is a vertical-lift railroad bridge over the Tennessee River, with a main span of 310 feet. Marine Solutions was originally contracted to perform acoustic imaging services on five bridge piers to verify the quantity of steel sheet piling installed by another contractor. Divers observed scouring, and subsequently were requested to perform an underwater inspection of two bridge piers to further investigate the scour conditions.