BANGOR — Detours will be put into effect Monday in Bangor and Brewer in the areas where construction for the new bridge connecting the two cities across the Penobscot River is under way.

In Bangor, Washington Street will be closed between Oak and Exchange streets. The portion of Hancock between Exchange and Oak that is now one-way will be changed to a two-way street. This detour will remain in effect for the duration of the bridge project. The new bridge is due to open June 14, 1997.

A couple of six-week detours have been planned for Brewer.

The first one, to begin Monday, will close a small piece of State Street between Penobscot and North Main streets. The old bridge will remain open, but traffic coming off the bridge or headed for it will be rerouted around the closed part of the street for six or seven weeks.

“There’s a ton of work to do in there, and the city has agreed to let us close that,” said Bob Zimmerman, engineer for the bridge project for the Maine Department of Transportation.

In Bangor, crews from Reed and Reed began work on an abutment and a pier last fall. Construction continued throughout the winter.

One of the projects completed last fall was the relocation of the Penobscot interceptor sewer, a 27-inch pipeline serving most of the east side of the city.

Closing a section of Washington Street now will save the project four months and $500,000. It will remove traffic from 80 percent of the construction area, and will give contractors space to store equipment and materials.

The city’s municipal operations committee approved the detour last October, while urging officials to make sure the change on Hancock Street is well-marked when traffic is changed to two-way.

A traffic signal was hung at the intersection of Hancock and Exchange streets during the winter, and was set on flashing recently to get motorists used to the coming change.