U.S.-based Accordia Partners, a commercial real estate projects developer, has got a green light to develop the 20-acre Bayside Expo Center site, which could yield up to 3.5 million square feet of new mixed-use waterfront development.

Accordia got the approval from The University of Massachusetts board of trustees and the university’s building authority.

The company and its capital partner, U.S. specialty finance company Ares Capital Corp., will pay $235 million for the site’s ground lease.

The companies have agreed to a guaranteed minimum price of $192.5 million, and will also invest $25 million in infrastructure upgrades.