Design of a 7-story office building above an underground parking lot. The supporting frame of the structure contains a regular grid of columns and three cores. Composite column sections were used to carry the loads from the upper floors that do not go down. The floating columns on the east and west elevations and the north extension are held by SuperBrace steel trusses. To allow for lighter construction, waffle concrete slabs were used in the construction of the upper floors. Lightweight steel was used on an existing IDC9 underground parking building.