By George P. Hassett

A $50 million project to repair a Boston bridge took Somerville officials by surprise this week.

Acting Somerville Police Chief Mike Cabral told aldermen Thursday night that Somerville was given late notice of the construction and its likely traffic effects around Route 93. “We were never thought about,” Cabral told aldermen Thursday. “They never considered what’s going to happen to Somerville. This is going to cause major, major problems.”

The project repairs the Craigie Bridge near Leverett Circle.

Ward Two Alderman Maryann Heuston said the project will slow traffic in Union Square and around Webster, prospect and Hampshire streets. She called the move “a poster-child for Boston and Cambridge projects that have severe impacts in Somerville because we handle traffic from Route 93.”

Cabral predicted gridlock traffic conditions in six to eight locations in the city once construction starts Nov. 6. Construction is expected to be finished by April. “We are going to need officers in six to eight locations to deal with the gridlock, road rage, the drivers who try to find other paths around traffic and drive through our neighborhoods in the morning,” he said.

It is unclear if the state will pay for Somerville police details. Cabral said the state is paying for details associated with the project in Boston and Cambridge.

Ward 1 Alderman Bill Roche said the city’s representatives in the State House should have raised Somerville concerns. “This is unacceptable,” he said. “The state delegation should have been speaking on our behalf. If Alderman Heuston had not discovered this, in a few weeks we’d be saying, ‘where did all this traffic come from?'”