Beginning the night of Thursday, July 26, workers will begin dismantling the western half of the Commonwealth Avenue bridge in Boston as they finish the job of replacing it.
The accelerated construction is expected to be finished in two weeks — by Saturday, Aug. 11. State officials are confident they'll be able to meet the deadline.
But that doesn’t mean it will be an easy job.
Once workers bring the old bridge down, huge pre-built sections of the new span — currently stored at the Allston rail yard — will be trucked to the site, which runs over the Mass Pike near the BU bridge. Huge cranes will be used to hoist the new steel spans into place. Reinforced steel mesh will be placed on those spans, and then concrete will be poured onto them, creating the new roadway.
This is the final phase of the $110 million replacement of the bridge. Phase 1 took place last summer, on schedule, and officials hope phase 2 goes as smoothly.
But similarly to last year, there will be serious disruption to all vehicular traffic, train and T service in the area, as state highway administrator Jonathan Gulliver explains:
"This is a bridge that impacts all modes of travel. It has everything on it or passing under it,” Gulliver said. ”You have commuter rail, you have Amtrak, you have the turnpike, you have surface traffic, and then you have the green line."
But, Gulliver adds, traffic disruption could have been a lot worse.
"More traditional bridge construction would take somewhere in the neighborhood of 3 to 5 years disrupting traffic. This way it's an intensive two-week process, and once it's done, we're out of here and everything is back to full capacity," he said.
But until, then Gulliver says, if possible, travelers should avoid the area. And he advises if you need to be somewhere at a specific time, "get online, use Waze, use Google maps, Apple maps, use whatever tools you have available to you to really plan out your trip."
MassDOT is also offering detour maps and travel advice. Here are the highlights:
Commonwealth Ave Detour:
Mass Pike Ramp Closures:
BU Bridge Detour:
The biggest effect may be on travel along the Mass Pike, which will be reduced to two lanes in each direction during the day, and to just one lane in each direction at night and during off peak hours.
Commonwealth Avenue will be closed to vehicular traffic between Kenmore Square and Packard's Corner.
Vehicular traffic will also be banned from the BU bridge.
Green Line service will be replaced by buses and bus shuttles will be provided for those riding commuter rail or Amtrak service to Albany, NY on both weekends during the project.
There are many ramp closures and detours that will also be in effect. For more information, visit the project’s website.