Susquehanna River Bridge

CSX Transportation decided to repair the Susquehanna River Bridge bearings and supporting masonry pier cap at MP BAK 56.9 on the Philadelphia Subdivision. The bridge is approximately 6108 feet long, consisting of a combination of two through truss, 11 deck truss, and 27 deck girder spans that cross over the Susquehanna River near Havre De Grace, MD.

The bridge currently carries a single track on an open timber deck. Most of the structure is in a tangent alignment, with a curved alignment beginning on the final span on the west end of the bridge (Span 40). The substructure consists of stone masonry abutments. The bridge was originally constructed in 1908, with portions rebuilt in 1939. This bridge was showing signs of deterioration at the bearings supported by Piers 34 and 35, along with the bottom flanges of the 27 girder spans.

Benesch provided design and details for two truss bearing locations and 23 girder span locations. Benesch also included repair details for the bottom flanges of the girder spans by splicing in new plates/angles with additional cover plates. There are seven different girder span lengths within the bridge, though repairs were only completed for three span types. The bottom flange repair locations were determined per CSX’s inspection report, and the primary area of concern was the spans over the river island.

Benesch also designed and detailed lifting assemblies in order for a contractor to jack the truss and girders spans to perform the bearing repairs. Benesch performed a two-day field investigation of the site to gather relevant data such as field measurements, and to take bridge photos.

A preliminary repair plan was developed that will highlight the repair types, locations, and proposed construction staging. Once approved by CSXT, final repair plans were developed. Construction crews utilized four-hour track outage work windows, and construction was staged accordingly.