Striking a balance between the speed of steel construction and the stiffness of concrete design is an innovative system of concrete columns interconnected with a three-dimensional steel Vierendeel Truss over the height of the building. This unique system facilitates the aggressive 7:1 height to width ratio and the unobstructed views from 100% of the perimeter offices. The relatively light steel members allowed the erection of the frame to advance rapidly ahead of the massive concrete columns.