Monitoring During Bridge Widening

The Huey P. Long Bridge spans nearly 2,400 feet over the Mississippi River in New Orleans. This cantilevered steel through-truss bridge opened to traffic in 1935 and is owned and operated by the New Orleans Public Belt Railroad. The bridge currently carries dual rail lines between the trusses and 2 lanes of vehicular traffic cantilevered to the exterior of each truss. The Louisiana Department of Transportation and Development (LDTD) decided to widen the bridge rather than replace it, based on the need to improve vehicular traffic flow and constraints due to uninterruptible rail traffic. Throughout the duration of the widening, the existing truss members will be monitored with an array of more than 800 strain gauges designed to measure axial and bending load effects. This article provides an overview of the Huey P. Long widening project, and focuses on the LDTD's structural health monitoring program, included in the construction contract as a proactive measure to assess whether the anticipated amount of load is being transferred from the widening truss members to existing truss members.