CSX Bayou Sara Swing Span Replacement

This accelerated bridge construction project included replacing a 100-year-old railroad swing span bridge on Bayou Sara, just off the Mobile River, to minimize maintenance and allow for remote operation. Accessible only by boat or train, the Bayou Sara Bridge Span in Mobile, Alabama, is exactly where the name suggests: the bayou. Located in a remote, difficult-to-access area, the project involved logistical challenges associated with working on the water. In addition, it was critical that the rail service interruption be limited to only 14 hours during the construction phase.

The work included off-site preassembly of a new 550,000 lb structural steel through-girder bridge, which included track work, hydraulics, electrical power, bridge controls, and bridge-operating machinery. During a 14-hour planned railroad outage, the existing span and top portion of the existing swing pier were removed and replaced with a new structural machinery grillage and the new swing span. A new cast-in-place pier cap was then poured to complete the swing pier modifications.