The council is expected to approve zoning changes that would allow the building variances in setback and height rules. The changes have been approved by the city's planning commission and recommended by city staff.

Construction, however, won't start tomorrow, Carleton Rise, project manager for Hines, tells GlobeSt.com. "The next step is to get an architect on board and to figure this thing out a little further because basically all we've got right now are very, very conceptual plans," he says. "So we need to do a little A&E work and start marketing the project."

The project would call for demolishing the low-rise building at Fifth and Congress and constructing the new building on that spot. The new building and the existing tower next door would be connected by skybridges, Carleton says. When completed, "They should function as one building and feel like one building." The new building would have office, parking and retail.