The 33rd annual International Bridge Conference (IBC) was held earlier this month at the Gaylord National Resort and Convention Center in National Harbor, Maryland. The conference is a source for continuing education and networking opportunities for members of the bridge industry. The technical sessions were broken into different groupings, including construction/fabrication, design, foundations, rehabilitation, innovation, and others. One of the more popular sessions covered topics associated with accelerated bridge construction (ABC), during which I presented my paper on a project that Dewberry recently completed.

The Route 9 Green Street Bridge

The paper, "Superstructure Replacement of U.S. Route 9 Southbound over Green Street Utilizing Accelerated Bridge Construction," discussed a federally funded, $6,000,000, New Jersey Department of Transportation (NJDOT) project located in Woodbridge Township, New Jersey. The Route 9 southbound bridge over Green Street was a component of a three-quarter mile roadway improvement project that aimed to improve safety and address recurring drainage issues in a heavily congested section of U.S. Route 9. The circa 1937 bridge that carries an estimated 31,000 vehicles per day was initially identified for deck slab replacement. However, during preliminary engineering, it was determined that conventional staged construction with a cast-in-place deck slab would disrupt traffic for at least a year.

Creating an Alternative Plan

ABC techniques were explored to reduce the construction duration. In order for an ABC project to be effective, the type of bridge, complexity of geometry, anticipated detour routes, road-user costs, and utility and right-of-way impacts must be considered. For the Route 9 Green Street bridge, the geometry of the existing substructure presented challenges, however, other factors offered a strong case to utilize ABC, including the fact that a majority of the construction could be done in one weekend, cutting the overall duration by almost ten months. My team presented a cost comparison between the deck replacement alternative utilizing conventional staged construction and an ABC superstructure replacement alternative to NJDOT and the Federal Highway Administration (FHWA). Even though the ABC alternative would add almost $500,000 in construction cost, NJDOT and FHWA both valued the benefits of the reduced construction duration, so the alternative plan was approved.

Beginning at 9 p.m. on Friday, October 17, 2014, the contractor (IEW Construction Group of Trenton, New Jersey) shut down the southbound lanes and began demolition. By 6 a.m. on Monday, October 20, the bridge was reopened to traffic in time for the morning commute. Parapet and sidewalk construction, as well as the final surfacing, were completed in a subsequent stage with limited traffic disruptions.

Minimizing Risk

Demolishing an existing superstructure and replacing it within a weekend includes significant risks. However, simplified detailing and appropriate planning done before the road was closed minimized the risks associated with this type of construction and enabled the contractor to complete the work effectively. The combination of ABC techniques, early and ongoing discussions with key project stakeholders, sufficient advance notice to the public via mass media, and certain project requirements, contributed to the success of the project and provided a new superstructure that will extend the service life of this structure for NJDOT and the community.

WATCH A SHORT VIDEO OF THE SPAN BEING INSTALLED