The AFL-CIO Housing Investment Trust said on Monday it is investing $20 million to help finance the redevelopment of a landmark downtown building.

The trust said it purchased $20 million of taxable bonds as part of the financing package for the $148.2 million redevelopment of the Randolph Tower, a Gothic Revival-style skyscraper in the West Loop.

The vacant building will be converted into the Randolph Tower City Apartments with 310 apartments and more than 20,000 square feet of retail, restaurant and office space. About 20 percent of the rental units will be reserved for affordable to low-income housing.

The project also will use $34 million in city assistance from TIF funds.

The developer, Village Green Cos., bought the building out of bankruptcy in 2005. Since then, the project has had a number of setbacks, including the early departure of an early partner, that have pushed up the cost the project by about $60 million.

AFL-CIO said the redevelopment will create about 690 construction jobs for union members.