Keystone Construction plans to break ground next week on a $7.6 million senior apartment building at 10th Street and Keystone Avenue. The 33-unit building dubbed St. Clair Senior Apartments also will include 3,600 square feet of retail and office space. The project, which sits in the Super Bowl Legacy development area, received state and local tax credits. The developers are Indy-East Asset Development and Riley Area Development Corporation. It was designed by Halstead Architects.