US 190 MISSISSIPPI RIVER BRIDGE, A COMBINED AILROAD/HIGHWAY BRIDGE REHABILITATION

摘要

The U.S. 190 Mississippi River Bridge crosses high above the Mississippi River between Port Allen and the capital City of Baton Rouge, Louisiana. The combination bridge carries four travel lanes and a single track of railroad that services Union Pacific Railroad and Kansas City Southern. The bridge, completed in 1940, consists of 8,887 feet of railroad approach spans, 2,571 feet of highway approach spans, and 3,326 feet of five cantilever steel through-truss main spans for a total length of 12,213 feet. The highway travel lanes are supported by floorbeams cantilevered on either side of the truss, and the railroad travels through the center of the trusses. This project included the rehabilitation, complete cleaning and painting, and general structural rehabilitation of various bridge members, including cross frame chord members and connection angles, top lateral bracing members, replacement of main truss vertical and diagonal lacing bars, deteriorated interior stiffeners of main truss verticals, deteriorated diagonals at portals, anchor bolt and column rehabilitation for approach bents, bearing pins and corroded complex stirrup bearings, rehabilitation of false chord expansion devices, replacement of cracked gusset plates, and patching of concrete spalls at bearings and retaining walls. Schemes for jacking and temporary support of members under live loads from highway traffic and Cooper E-80 railway load during rehabilitation were evaluated. Structural analysis that included traffic reduction during phases of construction was also considered. Traffic control and phasing for maintenance of traffic during various phases of construction were addressed.