Repositioning of the Cumberland River Swing Bridge

The movable bridge crossing the Cumberland River in Nashville, TN has an overall length of 695ft with a center swing span that is 275ft out-to-out. Two fixed-position spans on each side of the swing span are 206ft from center-to-center of bearings. It was found that during routine operations the swing span would not completely close. Inspections noted that the adjacent ‘fixed’ span had started moving toward the swing span and creating points of interference. Additionally, it was concluded that the reason for the encroachment was deterioration of the pier’s core caused by scour. Since the location is subject to both heavy river and heavy rail traffic, there is effectively no downtime for the structure. Thus, all construction work was required to be performed within two 12-hour outages. Included herein are an overview of the bridge history, the sources of the span movement, the pier repairs, and the integrated geotechnical and structural collaboration used to reposition the span.