Building at World Trade Center is a showcase of terrorproof technologies
Architects around the world are erecting skyscrapers that use a hollow concrete core surrounded by bomb-resistant glass and other security innovations.
When a documentary crew wanted to film the emergency glow-strips that line the expansive stairwells in 7 World Trade Center, Dara McQuillan called down to the security desk and asked them to flick off the lights. Moments after the stairwell went dark, however, a backup power system switched on and ruined the shot.Skip to next paragraph
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Mr. McQuillan, vice president of communications for the building, called again, but when the security desk shut down the backup system, this time a battery-powered generator flooded the stairs with light. The crew never got its dramatic glow-in-the-dark shot.
It has been hailed as the safest building in the world, its 52-stories of glass elegance belying a concrete core built to be a bunker in the sky. It is the first skyscraper to be completed at the World Trade Center site, and as it approaches its second anniversary, its innovative architecture and endlessly redundant security features – most of them designed from the lessons of the Twin Towers catastrophic collapse – offer a template for high-rise buildings in a post-9/11 world.
"The biggest change in high-rise construction now is this sealed, hardened core," says Dr. Herb Hauser, president of New York-based Midtown Technologies, a firm that specializes in security technologies for
buildings. "This means that the structure around the core can go down, or be on fire, or be invested with a biological or chemical problem, but the actual core itself will be protected." [Editor's note: The original version incorrectly stated that Dr. Hauser worked with architects designing new buildings for the World Trade Center site in New York. He didn't.]
At least three skyscrapers under construction that will surpass the height of the world's tallest building, Taipei 101 in Taiwan, are using the concrete-core technique (as well as a number of others under proposal in Russia and Korea). Indeed, the 1,776-foot high Freedom Tower, the anchor of the World Trade Center site, will in many ways simply be a larger version of the adjacent 7 WTC. The Chicago Spire, at 2,000 feet high, and Burj Dubai, soon to be the tallest building in the world at a staggering 2,700 feet, will also each have hollow concrete spines anchoring floors that will cascade and twist around them.
Making buildings with a concrete core isn't a new idea, but the cost of constructing them in the past has been prohibitive. "The main drawback at one time was that a steel frame was so much faster to build," says Mir Ali, professor of architecture at the University of Illinois at Urbana-Champaign. "It took you approximately three to four days to build a steel-frame floor. With concrete, it used to take 10 to 14 days a floor."
But with advances in construction techniques – better and cheaper concrete, more powerful pumps, easy-to-assemble slip and fly forms – crews can now put up a concrete core as fast as a steel frame. Moreover, very tall steel-frame buildings like the former World Trade Center towers and the Sears Tower often shimmy and sway in the wind. The top floor of a concrete-core high rise is as solid as a first-floor lobby.