CASE STUDY - Vicksburg Bridge Strike


Detecting a Bridge Strike 

As the only railroad bridge over the Mississippi River between Memphis and Baton Rouge, the Old Highway 80 bridge in Vicksburg, Mississippi, is a vital link in our country’s transportation infrastructure. Constructed in 1930, the aging structure not only endures rail traffic from the Kansas City Southern Railway, but also sees significant boat traffic underneath. In August 2016, a SENSR structural monitoring system was installed on the bridge to detect marine bridge strikes.

The Challenge

On November 25, 2016, barges in the Yazoo River broke loose of their moorings and drifted into the Mississippi River upstream of the Old Highway 80 bridge. Exacerbating the situation, a towboat collided with the loose barges, which in turn caused some of the barges it was towing to break loose.

Even though emergency services were notified of the accident, neither the Coast Guard nor the barge operators notified the bridge operator of the potential danger.

The Solution

Despite barge operators stating otherwise, SENSRsi detected two barge strikes shortly before midnight. By comparing the time of the reported strikes with surveillance video, the bridge operator was also able to get visual confirmation of the strikes.

Had SENSRsi not been installed on the bridge, decision makers may never have known a strike had occurred that evening. Instead, SENSRsi quickly alerted those in charge to the collisions and provided them insight into the severity of the impact.

The Result

Despite recording a large dynamic tilt on two of the piers, SENSRsi showed that they had quickly returned to their original positions without any permanent damage. The incident shows that barge operators are not always reliable when it comes to reporting bridge strikes. A continuous structural monitoring system can be on guard for strikes even when no one is watching.