Post 9/11/01 Architecture

As the nations of the earth have now prioritized finding and crushing international terrorists, the number of mega-attacks has fallen. Yes we had the November 2008 attacks in Mumbai which claimed 164 lives and injured at least 308 others, and smaller attacks have been scattered around the world, but being a terrorist these days is a lot harder than in years past. Funding for such insurgent activities is being traced (and cut off) everywhere, phone lines and Web trails are traced, intelligence moles have been developed to penetrate many of these organizations, and planning and implementing attacks, while definitely still very doable, have become harder. Rogue individuals and smaller groups that are less reliant on links with the outside universe are still operating with relative ease in comparison.

Aside from airport and shipyard screenings, a whole new level of technology is being applied to all aspects of our daily lives, elements that we might not even notice unless someone were to point them out. Just as earthquake-resistant structural technology has long been applied to high rises in seismically-prone zones, entirely new considerations are going into new construction that could become prized targets for future terrorist attacks.

Ask yourself, for example, if you were looking for a large suite of offices in Manhattan currently available or under construction, would you really consider leasing space in 7 World Trade Center, the first high rise constructed (by Tishman Construction Corporation) at the site of the collapsed Twin Towers? Wouldn’t you worry that this structure (or the buildings that will follow) would be a prime target for terrorists hell bent on showing the United States exactly how powerless we are? Other than traffic control issues and reducing the probability of a rogue aircraft repeating the 9/11 attack – whether through hijacking or a small targeted flight with explosives on board – what is it that needs to be built into these structures to make them vastly safer? Somebody has convinced and will convince prospective tenants (and their employees) that working in such a target building is safe. How can they do that?

Structural engineers have clearly established that the collapse of the Twin Towers occurred because of a sequence of interlocking events, most of which could have been prevented with design changes. Experts are virtually unanimous that the impacts of the jet aircraft were insufficient in themselves to bring the buildings down. What happened came from the ensuing fires, the limited escape routes, the severing of electrical and communications lines, the loss of water pressure to trigger the sprinkler systems and the structural vector forces that directed failed beams to collapse down and into the center of the buildings where the major supporting structure was built, triggering a chain reaction of further structural failure (which engineers call “progressive collapse”).

The architectural firm of Skidmore, Owings & Merrill (SOM) brought in by developer Larry Silverstein to build 7 World Trade Center and other office towers, addressed these issues: “These skyscrapers have steel connections capable of redirecting the path of the upper floors’ load downward through other structural members if one should fail. And sprinkler supply lines have been located within an impact-resistant core--a major difference from the Twin Towers. Both innovations are now part of New York City building codes. In addition, the newest SOM buildings have two interconnected standpipes, so that if one should fail, the other can compensate.

“Another issue the Twin Towers’ disaster exposed was the difficulty of evacuating lots of people from very high floors. ‘The survival rate below the planes' impact was very high,’ [Nicholas] Holt [SOM's director of technical architecture] says. ‘Above it was very low. That was entirely linked to the damage to the core; the inability to navigate the stairs; and the heat, flames, and smoke not being mitigated by a sprinkler system.’ Designers knew that if tenants were going to be attracted to the upper reaches of these buildings, they needed to feel that they could get out safely. Now, the best American high-rise designs borrow from existing international thinking on safety. In addition to designing wider staircases and building separate stairs for firefighters (a strategy borrowed from the British, who have long practiced this), SOM is pioneering an elevator-assisted exit system that would help people on the highest floors get out faster…

“The idea is that a building's occupants can take the stairs to designated protected refuge areas on specific floors, at which point they can take elevators-- called ‘lifeboats’ --down to exits on the ground floor.” Fastcompany.com, September 8^th. Every time I go to a big sporting event or enter a large international airport, I can’t help but think of the thousands of vulnerabilities of such massive endeavors. I am, however, grateful, for the creative minds of the problem-solvers who are trying to minimize the obvious risks.

I’m Peter Dekom, and when we give smart engineers difficult problems to solve, the solutions simply confirm the obvious continuity of humankind.