CHICAGO—The city has approved the construction of 625 W. Adams, a 20-story office tower expected to cost about $150 million.

A partnership of Alter Group and White Oak Realty Partners LLC is developing the 20 story tower in the city’s West Loop. The building was first proposed by Alter in 2010. There are still no tenants announced for the building.

The building is currently a parking lot at the southeast corner of Adams and Des Plaines Streets, said Tom Saletta, principal with White Oak, in a statement. “The project will include a 400-car parking garage, a conference center for up to 800 people and fitness center as well as exterior terraces at both the seventh and 20th floors.” Saletta is marketing the building for the partnership.

Matthew Ward, senior vice president with Alter, said in the statement that there’s no large blocks of office currently available in the area. “The building is uniquely positioned to attract the sophisticated, cost-effective corporate user that understands the numerous economic benefits of being in a high-performance office building with large floor plates,” he said.