New Boston Crossing Will Open Up Room for Dredging

by Johanna Knapschaefer, enr.com, January 9, 2012, ENR

Replacement of the historic 76-year old, 120-ft-long Chelsea Street Drawbridge in East Boston will smooth the journey not only of 20,000 daily motorists but of barges supplying fuel for Logan International Airport and the northeast region.

The project will double the width of the Chelsea River Federal Channel and provide 175 ft of vertical clearance. The old bridge restricted shipping to a 96-ft section of the channel.

The $125-million Massachusetts Dept. of Transportation project began in 2009. It was originally slated for completion this month, but was rescheduled for April due to overall scope, says Dan Casalleto, MassDOT Boston-area construction engineer. “This is our first time,to install a permanent lift bridge,” he says.

After demolishing the old bridge last summer, crews rolled two steel segments of the new 450-ft, 1,200-ton lift span onto temporary transfer rails between two 212-ft-tall towers, says Jack Pecora, project manager for J.F. White, Framingham, Mass. “Other lift spans have been floated in using the tides, but this is likely the first time in New England to launch a 450-ft span with a 140-ft cantilever,” he adds.

“We pushed the bridge up with a hydraulic jack 3 .5 ft at a time, blocked the ends and used a steel wedge to engage the rollers,” Pecora says. “Once the lift span was in final position, we connected its four corners to bridge wire ropes that ran over an enormous sheave to bridge counterweights, and raised the bridge.”

The old Chelsea Street Bridge was one of only four bascule designs developed by Joseph Strauss and may have been the only Strauss heel trunnion bascule bridge in the state, according to the Historic American Engineering Record. The new bridge, designed by HNTB Corp.’s Boston office, will link the cities of Chelsea and Boston over Chelsea Creek. Read more…

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