For the second consecutive summer, the Massachusetts Dept. of Transportation has completed substantial work on an accelerated bridge project early.

The project to replace the deteriorating 52-year-old Commonwealth Avenue Bridge began last July, when crews demolished and replaced the eastbound portion of the bridge, including the Massachusetts Bay Transportation Authority Green Line B portions of the bridge. The $82-million project went so smoothly that MassDOT was able to resume preconstruction traffic patterns three weeks early. 

This summer, after the $110-million project to replace the westbound portion of the bridge started on July 26, the Green Line resumed normal service across the Commonwealth Avenue Bridge on Aug. 10—one day ahead of schedule, according to MassDOT. The bridge reopened to motorists, cyclists and pedestrians the following day. All lanes across the nearby Boston University Bridge also reopened by midday on Aug. 11.

Walsh Construction Co. is serving as MassDOT's contractor for the project.

"Our crews are continuing to work 24/7 and we are pleased to be restoring MBTA Green Line B trolley service ahead of schedule this afternoon, and lifting vehicular travel restrictions on the Commonwealth Avenue Bridge and the BU Bridge tomorrow," said Jonathan Gulliver, the state's highway administrator, in an Aug. 10 statement.

The fast-track demolition and replacement of the westbound side of the bridge involved the utilization of three cranes to place 45 steel beams and 214 prefabricated concrete deck panels. The project included 680 cu yd of concrete and 520 tons of hot mix asphalt, according to MassDOT. It also involves installing granite curbing, waterproofing the bridge deck, paving, putting in place traffic signals and completing utility and other work.

The project, which would have taken an estimated four to five years using conventional techniques with significant lane-takings and service disruptions, is scheduled for full completion in 2019 under the accelerated plans, MassDOT said. While the major westbound construction activities on the Commonwealth Avenue Bridge are now compete, punch-list items will be finished in the upcoming weeks during off-peak hours, including work completing sidewalks, final pavement and markings, and finishing a parapet wall.

Stephanie Pollack, MassDOT's secretary and CEO, said in a statement that hundreds of hours of engineering went into the design and construction. "All of the pre-planning and design elements were thoroughly vetted and then the logistics were implemented in sequence," she said.