State transportation officials are advising motorists that the bridge carrying Woerd Avenue over the Charles River in Waltham will be closed to all traffic for nearly two years starting on Monday, July 31, because the span is being replaced.

The closure will remain in place 24 hours a day through the spring of 2021 to allow construction crews to operate safely. During that period, a detour will be in place for vehicles that would normally cross the bridge.

The detour route will use Crescent Street, Moody Street, Lexington Street, and Rumford Avenue. Officials are advising the public that Woerd Avenue will remain open for abutters only north of the bridge between Crescent and Cove streets, and south of the bridge up to Rumford Avenue.


Access to the nearby state Department of Conservation and Recreation boat launch also will remain open during construction.

Those traveling through the area should expect delays, reduce speed, and use caution, officials said. Appropriate signage, law enforcement details, and advanced message boards will be in place to guide drivers through the work area.

The $3.1 million bridge project, which got underway last month, involves demolition of the existing bridge and replacing it with a new concrete span that will include sidewalks on both sides. The project, set for completion in 2021, also involves some work on the approaches to the bridge.

John Laidler can be reached at laidler@globe.com.