Onassis Cultural Center, New York

The new, all-glass staircase at the recently renovated Onassis Cultural Center museum is a feat of engineering excellence. Photo: © Agnora
Fabricating the centre wall section of the glass staircase in the clean room at Agnora (laminator). Photo: © Agnora

Stiffness and edge colour of SentryGlas® interlayer key to impressive all-glass staircase at Onassis Cultural Center, New York.

Laminated safety glass with SentryGlas® ionoplast interlayer has played an important part in enabling the design of an all-glass staircase installed at the Onassis Cultural Center museum on Fifth Avenue, New York, USA.

The Onassis Cultural Center NY of the Onassis Foundation (USA) showcases a wide range of cultural and artistic programs that explore all phases of Hellenic civilization – ancient, Byzantine and modern. The museum was recently renovated in order to significantly upgrade and expand the galleries and to give the public space of the Olympic Tower Atrium an enhanced new look. Part of this renovation involved the installation of a new, all-glass staircase that connects ground floors with underground galleries.

The staircase is minimalistic in its design and features a cantilevered middle landing. The vertical stringers were made with four plies of glass bonded together by SentryGlas® ionoplast interlayers. AGNORA, laminator on the project, is the North American leader in high precision, extra-large architectural glass fabrication. With CNC machining, tempering, laminating and insulating equipment, the company is able to process glass up to 130” (3,300 mm) widths and 300” (7,620 mm) lengths.

Louis Moreau, Senior Technologist at AGNORA, commented: “For this project, the structural requirements and loading issues were the primary factors that drove the use of SentryGlas®. Alternative PVB interlayers were considered, but these just didn’t make the cut due to the high stress areas involved in the centre staircase wall and the landing balustrades. In addition, the bright yellow edge colour of some PVB interlayers also prohibited their use, whereas SentryGlas® provided a water-clear edge colour, which was critical in this application.”

According to Mr. Moreau, AGNORA worked extensively on internal R&D, enhancing the requisite skills, tools and materials specifically for the project. “We felt as though we were creating a piece of art rather than a glass staircase. We’ve made a giant leap forwards in terms of developing new techniques and tools to trim and polish the vertical and horizontal edges of the glass. It took us two years, but the resulting edgework of the laminated glass staircase is butter-smooth, without using post-laminate polishing on heat treated parts. In addition, the alignment of the holes and four-ply laminates are accurate to a world class level of glass fabrication.”


  • Floors, Stairs & Bridges


  • USA + Canada


  • SentryGlas®


  • Nick Leahy
  • Perkins Eastman

Glazing Contractor

  • Mistral Architectural Metal & Glass


  • Structural Engineering Eckersley O’Callaghan  Design Engineers Michael Ludvik

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