Commerce Tower is an office complex consisting of 150,000 square feet of leaseable office space over 130,000 square feet of parking in an 18-story concrete framed structure.
Twelve inch deep long spanned cast-in-place, post tensioned floor joists achieved a 40'-0" clear span allowing the architect to give the developer column free office floor space. Using post-tensioned joists in lieu of precast prestressed double-tees, and a flat plate parking structure, allowed us to squeeze 11 floors of office and 7 floors of parking into a 200' height limit. Accommodating the specified number of floors for office and parking avoided the addition of a costly basement which would have required dewatering during
the construction of the foundation. New city ordinances required a building envelope that resulted in the structure stepping back 18'-6" on both ends of the building along the north-south axis and 6'-6" on both ends of the building along the east-west axis. The step banks occurred in 6'-6" intervals starting at level 14. In order to keep the floor to floor dimensions and the floor framing typical, vertical stepped frames were utilized in lieu of transition girders which allowed for economical construction.
