By Jerome Weeks - Art&Seek.org
http://stream.publicbroadcasting.net/production/mp3/kera/local-kera-783639.mp3
Dallas, TX – An unusual metal structure is going up on the Winspear Opera House. It's a solar canopy. KERA's Jerome Weeks has the latest in our series of reports on unique design elements in the Dallas Center for the Performing Arts.
Last week, the Margot and Bill Winspear Opera House began to sprout wings.
The most eye-catching feature of the new opera house will undoubtedly be the red glass that's being installed on the auditorium itself.
But the other noticeable feature is the solar canopy under construction. It's like a giant window shutter -- set horizontally, five stories off the ground. Made of aluminum and steel, it will stretch out from the Winspear as far as 98 feet.
Spencer de Grey is senior partner at Foster & Partners, the Winspear's architects. In the past 15 years, the company has included solar canopies on a half-dozen of its projects. De Grey says the Winspear's canopy will be the biggest they've done. It will cover nearly three acres all around the opera house.
That may seem rather flamboyant. But, de Grey says, the canopy is really a traditional Texas response to the blistering sun.
DE GREY: "If you go back to 19th century architecture in the Southern states and Texas, we are used to seeing deep verandahs as a natural response - and this is before air-conditioning was invented - a natural response to the climatic conditions."
De Grey believes that air-conditioning isn't a response to Texas weather -- it's more like a denial of it. As long as we pump enough energy into office and condo towers, we can pretend the outside heat doesn't exist. Yet the wings' on the Winspear can reduce that heat by 20 degrees.
Calling the canopy wings' isn't simply a figure of speech. The canopy will have 630 louvers - they're like giant blades 28 feet long. They're set at precise angles to cut the sunlight.
But it wasn't just the light the engineers had to consider with the canopy. It was the wind.
Jeff Innmon is project manager for the Winspear. He's standing on the lobby roof with the canopy under construction.
INNMON: "We modeled the canopy in a wind tunnel. And originally studied the building for wind pressures to make sure that we weren't going to get any extreme wind pressures."
The wind pressure could build up because the louvers act like airplane wings. They catch the wind and increase the air pressure under them for lift. But these particular wings happen to be attached to a steel frame weighing more than 850 tons. They're not about to achieve liftoff. But with a strong wind, they could rattle or whistle. And the Dallas Opera wouldn't appreciate the accompaniment. So the louvers are specially stiffened and bolted in place to prevent any unwanted noise.
The canopy covers so much ground around the opera house because it will shade the lobby as well as part of Annette Strauss Artist Square. That's the outdoor venue that will be nestled right next to the Winspear.
Because it's so large, the solar canopy will also create a precious rarity in downtown Dallas: a public, outdoor space - with shade. A comfortable plaza in which to sit and drink and watch. Even under the noonday sun.
DE GREY: People don't normally walk out of doors in Dallas, particularly in downtown Dallas. The ability just to walk out and sit under the shade, provided by the solar canopy, will make a substantial difference to people's perception of public space.
The Dallas Center for the Performing Arts plans on making that public space a pleasant gathering spot - with trees and fountains and a cafe. The hope is that, during the day, it will attract even those Dallasites who'd never set foot inside an opera house.
They'll come just for the coolness of the shade.