999 17th Street
This 3-dimensional façade stands out in downtown Denver due to its unique folded geometry. The glazing consists of fully tempered insulated glass units, with a laminated outer lite, a highly reflective low-e coating on the #4 surface and a fritted band to camouflage the floor slab behind the facade. The unique geometry, combined with the highly reflective low-e coating, creates a stunning effect as it presents a distorted reflection of the surrounding city. The support structure consists of rectangular HSS tubes spanning in a primarily vertical direction, each individually custom-fabricated with “kinks” to follow the flow of the glass façade. The glass is attached back to the support structure with a continuous silicone gasket behind the glass and a series of patch plates at the front of the glass to support it against wind suction. In addition, supplemental stainless steel point supports were used to attach the glazing to the support structure.
The façade is supported by stainless steel cables 24mm (0.94”) in diameter spanning horizontally. To reduce the span of the cables, and minimize the amount of pretension required, small diameter stainless steel “wind needles” brace the cables to carry the wind loads back to the concrete building columns. At the corner of the façade, the cables are braced by a vertical truss made up of 10.75 diameter pipes. 30mm (1.18”) stainless steel tension rods carry the weight of the glass up from the lowermost cable to a rectangular HSS tube hidden in the ceiling. The glazing consists of low iron laminated insulated glass supported by stainless-steel corner clamps. To manage deflections and reduce the thickness of glass required for the long rectangular panels, additional “corner” clamps have been modified and added at the centre of each long edge.
This project consists of an approximately 23’ tall cable façade, L-shaped in plan, that grows vertically to over 141’ tall at the south end and extends up to a simple glazed skylight to create a majestic, open atrium. The wall is as transparent of a wall as is possible supported only by cables such that the supporting structure disappears behind the 25mm vertical and horizontal butt glazed joints and the spacer bar that runs around the insulated glass units. All that can be seen from the inside and outside of the facade are the clamps. In addition to a transparent appearance, this bespoke system enables there to be minimal structure within the useable space of the lobby, creating a maximum amount of useable space for the lobby.
Location: Denver, Colorado, USA
Size: 13,000 sq ft / 1,210 sq m
Systems Used: Architecturally Exposed Steel, Edge Clamped Glass, Point Supported Glass
Architect: Davis Partnership Architects
General Contractor: GE Johnson Construction Co.