By assembling each 500-ton steel bridge leaf offsite and floating it by barge to the bridge site, the team aims to limit planned transit service outages to just 12 days, substantially less than with conventional techniques. Installation of the first leaf is set to take place in mid-October, while the second leaf will be placed next spring.

Per federal regulations, including those of the U.S. Coast Guard, at least one bridge leaf must remain functional and in operation throughout the project.

Granite’s approach echoes contractors’ efforts to minimize rail impacts during the structure’s construction between 1914 and 1916 around an existing double-decked center-pier swing bridge.

According to historical records, both of the then-new bascule leaves were built in the “up” position so that trains could continue to pass through on the old bridge until that structure could be demolished. The bascule bridge was officially placed into service in March 1916.

Although a well-known part of local history, the bridge has presented numerous challenges to the project team, which also includes construction manager HNTB and engineer-of-record AECOM. Many of those involve elements or conditions not accounted for during the design phase.

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“There have been figurative skeletons that continue to be unearthed as work progresses and items are removed or uncovered,” says Granite project manager Jack Canale. Primary challenges have involved additional replacement of structural steel components as well as the reconstruction of the bridge control houses utilizing the existing footprint of the original house, he points out.

“The project team has had to work through missing design details by coordinating with structural, movable and architectural design disciplines to provide solutions for the client while maintaining the overall project schedule,” Canale adds.

The entire rehabilitation project is expected to be completed in December 2027.