Cardboard arch, Museum of Modern Art, New York: Shigeru Ban with Buro Happold
The MoMA Arch, located in the Abby Aldrich Rockerfeller Sculpture Garden of the Museum of Modern Art (MOMA) in New York City, New York, is the work of architect Shigeru Ban and engineers Buro Happold. Shigeru Ban: A Paper Arch was commissioned as part of the exhibition “Making Choices”, the second cycle of MOMA2000 which runs until August 1st.
Covering a third of the Sculpture Garden, Ban's arch creates an outside room, with a massive trellis or roof proportional to the size of the trees and surrounding buildings. The nine-ton arch stretches 87 feet across the Museum's Sculpture Garden.
Cardboard is a relatively common material, but its structural properties have been untested until recently. Buro Happold engineers in New York were able to call upon the extensive research and experience of Buro Happold's Berlin office, where engineers worked with Ban on the immense card tube gridshell for the Japan Pavilion at the Hanover World Fair, scheduled to open on June 1st 2000.
To minimize time on site and the associated disruption to the Museum Garden, the arch structure was fully fabricated off site. Cardboard tubes manufactured in Germany were shipped to New York in 40 foot lengths, ready for assembling off site in Queens over a scaffolding mould structure that allowed the tubes to naturally deform to their final shape. The structure was then cut into 16 pieces for transport on flatbed trucks. The pieces were connected together on a side street behind the museum and then hoisted over the museum wall with a crane and spreader beam. Once they were all in place the grid tubes were spliced back together. The installation process was completed in a week of continuous rain, in time for the Exhibition's opening party.
The arch is totally self supporting, bracketed to the wall of the garden on one side and the MOMA building itself on the other. The structure is made up of a series of eight, 600mm (2ft) deep, cardboard arch trusses spanning 27m (87ft) with a rise of 9m (30ft). Trusses laid out at 2.4m (8ft) centres are laterally stabilised at mid-depth by a lattice grid of the cardboard tubes which span between the arches. A series of tie cables underneath the arches stiffen the structure and control buckling under asymmetric loading conditions.
The cardboard tubes are formed of spirally wound sheets of cardboard which build up to the required thickness. The truss chords are fabricated from 120mm (4-3/4") diameter tubes that are flexible enough to curve into their preformed shapes, prior to fabrication yet sufficiently stiff to carry their structural loads.
Cardboard arch, Museum of Modern Art, New York: Shigeru Ban with Buro Happold/2
The connection between truss and grid elements is through a series of steel rods. Precision detailing was essential for the complex interlocking geometry of circular truss segments and elliptical grid members. Buro Happold used 3-D modelling techniques to aid with the detailing and to generate construction drawings for the fabricator. Standardised components were developed to avoid custom fabrication and to save time.
The Arch was designed as a temporary structure and will be dismantled after closure of the Exhibition on August 1st. All building material from the arch will be recycled.
