A five-story mixed-use building with a 60,000-square-foot fitness center, a 30,000-square-foot grocery store and 120 luxury apartments is planned for the next phase of the OneNorth development in Bayside.

OneNorth is a mixed-use development northeast of I-43 and Brown Deer Road, developed by Milwaukee-based Cobalt Partners, which includes apartments and a library.

The planned five-story mixed-use building, called Building E of the OneNorth project, would be located along I-43. It would replace a two-story office building on the site.

Plans for the building have been modified since they were first unveiled by Cobalt last year. There are fewer apartments and the size of the grocery store has been reduced. The original plans called for 180 apartments and a 50,000-square-foot grocery store.

Scott Yauck, president and CEO of Cobalt Partners, declined to disclose the names of the potential fitness center or grocery store tenants in Building E.

“No users have been confirmed for the new building,” he said. “We are in discussions with both fitness users and grocery users, but there is nothing at this point that can be confirmed. We still have a long way to go relative to typical user due diligence, including sales projections, lease economics, and timelines.”

The apartments in the building would include one-bedroom units, with rents starting at $1,800 a month, two-bedroom units starting at $2,500 a month and three-bedroom units, with rents starting at $3,500 a month.

BizTimes Milwaukee reporter Hope Moses contributed to this report.