Constructed in 1925, the CSX Transportation (CSX) bridge over Chef Menteur Pass in New Orleans, Louisiana, needed significant structural steel repairs after nearly a century of exposure to the surrounding coastal environment. Most of the corrosion in the steel truss swing span was found below the tracks, specifically in the cross frames, floorbeams, bottom lateral bracing, and lower chords. Significant impacts to train service across the bridge would be extremely detrimental to CSX's business because this bridge is the only CSX route between New Orleans, Louisiana, and Mobile, Alabama. Instead, the project team including CSX, STV, Inc. (Engineer of Record), and PCL Civil Infrastructure Division (General Contractor) developed design and construction techniques that limited interruptions/outages to rail service to less than five hours at a time. Some notable techniques used include the following: 1.The repairs were performed from a barge underneath the bridge, reducing the hazard of fouling the tracks and increasing the available time to perform repairs that would otherwise be spent staging and removing track-mounted equipment. 2.The project team eliminated the need for falsework by incorporating a jacking sequence to induce a zero-force condition within the fracture-critical lower chord panel being repaired allowing the repairs to be completed within short-duration train and vessel outages. 3.For the largest lower chord repair, in which an entire chord member was replaced, train outages were eliminated by installing a temporary strut that allowed the loads to bypass the existing member under repair. By focusing heavily on design and planning, the project team greatly reduced the risk of delaying trains.
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