Bridges project on I-93 nears completion

“A little more than a year ago, we stood here looking at the sink hole we had to deal with,’’ said Mullan, referring to a gaping hole in the Valley Street overpass that formed in August 2010. That hole, caused by leaking joints in the concrete, prompted state officials to reexamine the bridges.

“We did an evaluation of all of the decks and they were about all in the same condition,’’ said Frank DePaola, highway administrator with the Massachusetts Department of Transportation.

Each weekend - except July 4 - more than 250 workers labored around the clock to tear down and reinstall the sections of the road, in what amounted to an oversized job of cut and paste. After the old steel girders were separated and torn away from their supports, hulking cranes lowered sections of prefabricated road.

Traffic was diverted each week after Friday rush hour, reducing each direction of the highway to two lanes.

DePaola said the cash-strapped agency saved years in construction time because of the innovative method and will consider using it again.

Richard Davey, the MBTA general manager who is slated to replace Mullan this fall, thanked and congratulated the planners.

“It was pulled off well,’’ Davey said.

Matt Byrne can be reached at mbyrne.globe@gmail.com