Tuesday night the Portland planning board voted unanimously to approve an expansion of Maine Medical Center’s campus in Portland’s West End neighborhood.

The project, which will run about $512 million, is expected to begin in May and will force a one block section of Congress between Weymouth and Forest streets to close for 8 weeks while the construction is going on. Traffic will be re-routed from Weymouth Street to Park Avenue and to St. John Street. This will continue until June 28th.

City officials said there is no other option than to close that block of Congress Street because the crane being used is too wide to allow traffic to flow. This means the detour will will also wreak havoc by Hadlock Field during Sea Dogs home games in May and June as well as the annual Mother’s Day race scheduled for Sunday, May 13, in which they need to close a portion of Park Ave.

This first phase of a 5 year project will move the hospital’s helipad and add two floors with 64 new oncology patient rooms on the East Tower, while also adding 225 spaces to the visitor parking garage.