April 2014

Creating tension

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Birdair Inc. installs a tensioned fabric membrane roof on a Kuwait stadium

by Krista Reisdorf

Photos courtesy of Birdair Inc., Buffalo, N.Y.

The roof on Jaber Al-Ahmad International Stadium displays 450 illuminated holographic glass cupolas.

In Safat, Kuwait, temperatures during the summer often exceed an unforgiving 130 F. One can barely imagine moving in such heat, let alone playing soccer.

However, the city is now home to the largest soccer and Olympic-standard sports venue in Kuwait, Jaber Al-Ahmad International Stadium. When the 64,000-seat stadium was being planned, the desert heat was a significant consideration, leading to a canopy design that would allow daylight on the field but effectively shade spectators.

The State of Kuwait Public Authority for Youth and Sports chose Birdair Inc., Buffalo, N.Y., to help design, engineer, fabricate and install a tensioned fabric membrane roof for the stadium.

Keeping it light

Construction of the stadium and adjacent grounds began in September 2005 and occupied more than 1.3 million square feet.

Birdair began constructing the roof system's skeletal structure during February 2006 using compressed steel and heavy-duty cable framework from Bridon Structural Systems, South Yorkshire, United Kingdom. Four-inch diameter radial cables were used, weighing more than 385 tons and covering an area of 137,795 square feet. An inner ring, constructed with compressed steel, weighed about 1,950 tons.

Photos courtesy of Birdair Inc., Buffalo, N.Y.

The roof in progress

The company unfurled 523,500 square feet of Merrimack, N.H.-based Saint-Gobain Performance Plastics' TeflonĀ®-coated fabric. It was placed in 282-foot spans from the roof's outer edge to the open inner ring, which measured 348 feet in diameter.

"Custom tension 'sleds' were fabricated to handle the tension process for the cable structure," says Kevin Mayer, Birdair's vice president of business development. "The sleds were designed specifically to fit the requirements for the project."

The company used woven fiberglass material coated with Teflon because it is inherently translucent, and light can come through it to brighten the interior of the stadium and reduce the need for supplemental electric lighting. The membrane's coating also is durable, reportedly offering an expanded lifespan.

In addition, the canopy shape of the roof was cost-effective, says Wesley R. Terry, professional engineer for Birdair.

"With its concave, load-bearing profile, it required only a minimal, single-layer cable net to support the fabric membrane," he says.

At the fabric peaks, 450 illuminated holographic glass cupolas were installed to help transmit light.

Mayer says the company faced typical challenges for cable-supported roof structures using a compression ring design.

"Most of the challenges were related to construction methods and how to coordinate cable structure in a manner that provides required tension during installation," he says.

The company followed standard safety methods for tensile membrane structures based on Occupational Safety and Health Administration guidelines and internal methods developed at Birdair.

Keeping it cool

The owner wanted a structure that used a tent or cone shape, connecting the roof to Kuwait's Middle Eastern heritage; it was a success, with the stadium resembling a traditional dhow sailing vessel used by Arabs.

Photos courtesy of Birdair Inc., Buffalo, N.Y.

The finished stadium roof resembles a traditional dhow sailing vessel.

And fans will be impressed with the effective shading in the stadium, Terry says.

"The difference for fans will be dramatic," he says. "I sat in the stands after the membrane was installed, and it does an outstanding job of lowering the temperature inside the stadium."

Mayer believes the hard work and challenges paid off, producing a unique structure.

"The project is an ideal model for lightweight efficiency in cable-supported roof structures for long-span stadium applications," he says. "Overcoming the construction requirements for the roof structure was the most rewarding part of the project."

Krista Reisdorf is Professional Roofing's director of online communications.

Project name: Jaber Al-Ahmad International Stadium
Project location: Safat, Kuwait
Project duration: February 2006-February 2007
Roof system type: Tensioned fabric membrane
Roofing contractor: Birdair Inc., Buffalo, N.Y.
Roofing manufacturers: Bridon Structural Systems, South Yorkshire, United Kingdom, and Saint-Gobain Performance Plastics, Merrimack, N.H.


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