Researchers from the National University of Singapore (NUS) have developed a new form of ultralight arch that could make it far easier to build large-scale column-free structures such as airport hangars, factories, stadiums, and concert halls.
The Cloud Arch is a long-span structure made using Expanded Polystyrene (EPS) foam – an ultra-lightweight material most commonly used for packaging purposes. The material is 95 per cent air, conferring it with an extraordinarily low mass.
The NUS research team, led by Shinya Okuda, an assistant professor of architecture at the NUS School of Design and Environment, and Tan Kiang Hwee, a professor from the NUS Faculty of Engineering, spent two years developing and testing long-span arches using composite materials that incorporate the EPS foam.
During the stage of initial development, the team developed several prototypes, the first of which was an arch with a modest four-metre span. The NUS researchers eventually succeeded in building a pavilion with arches whole span measure 14 metres. This structure was given the moniker of the “Cloud Arch” by the researchers, due to its vague resemblance to a mass of airborne moisture.
According to Okuda, the key to using the foam as a component material for the arches was the application of digital technology during the fabrication process.
“Structurally optimised forms are often doubly curved,” said Okuda. “By applying digital fabrication technology on the EPS foam, we could shape complex forms in a fast and cost-efficient manner.”
The extremely low mass of the product could tremendously increase the ease and convenience of building large-scale structures that use arches to create extensive, column-free spaces.
“As the material is extremely lightweight, we could achieve significant savings in terms of transportation cost as well as the time taken to set up and dismantle the structures,” said Okuda. “We hope to reduce the construction cost by one-third and construction time by half, compared by conventional construction materials, such as concrete.”
According to Tan Kiang Hwee, in addition to its extremely low weight, EPS’s high strength makes it an excellent ingredient for use in composite building materials.
“EPS foam has almost similar compression strength to weight ratio as concrete and is currently used as landfill for landscape works,” he said. “We are also testing its composite properties when reinforced with bonded fabric as a possible material for permanent construction. “
The research team have already obtained a provisional US patent for the technology, while the first prototype made its debut at the Archifest 2014 Pavilion Competition where it was one of two joint winners, and placed on display from September 26 to October 11, 2014.
The next step is the development of a 25-metre span roofing prototype for factories, a project which is being supported by both NUS and JTC Corporation via the NUS-JTC Industrial Innovation Centre.