The basics: Architects aimed to maximize transparency with the grand glass entrance addition to the General Motors Renaissance Center, or RenCen, in Detroit. Completed in January 2005, the $500 million renovation includes the 43,100-square-foot football-shaped entrance of point-supported glazing and all-glass circulation ring.
The players: Architect, Skidmore, Owings & Merrill LLP, New York City; general contractor, Turner Construction Co., New York City; stainless steel structure, Novum Structures LLC, Menomonee Falls, Wis.; glass suppliers, Viracon, Owatonna, Minn., Figla USA, Pine Brook, N.J.; PDC Glass Michigan, Plymouth, Mich.; curtain wall supplier and installer, Exterior Wall Specialties, Northville, Mich.; aluminum skylight supplier and installer, Harmon Inc., Eden Prairie, Minn.; glass railings, Soheil Mosun, Toronto; structural steel installer, Contour Steel Inc., Lakeview, N.Y.; point-supported glass installer, R.E. Krug Corp., North Tonawanda, N.Y.; sloped glazing system and installation, APG-America Inc., Glassboro, N.J.
The glass and systems: Laminated glass attached via point supports into all-glass roof and wall systems, with a welded, stainless steel roof truss with curved bottom chord set atop of two pre-tensioned columns at both ends of a 96 foot span, and walls framed out using vertical stainless steel tension trussing with horizontal cables for lateral stability. The geometry of the tension trusses is set by a vertical out chord cable, parabolic inner chord cable and cigar shaped horizontal king posts connecting them.