Glass Bunker in the Sky

As four large towers begin to take shape at Ground Zero in Lower Manhattan, architects must balance post-9/11 safety with art, commerce and community interests.

The first building to go up at the World Trade Center site is a veritable showcase of ‘terrorproof’ technologies. Dubbed 7 WTC, the 52-story office structure is already being lauded as the world's safest building because of its innovative architecture and redundant security features. Indeed, 7 WTC features a sealed, hardened concrete core.

Herb Hauser, president of Midtown Technologies, observes, ‘This means that the structure around the core can do down, or be on fire, or be invested with a biological or chemical problem, but the actual core itself will be protected.’

Beyond the core, 7 WTC has an array of other features. Its skin is made almost entirely of glass, and its foundation is designed like a diamond parallelogram so that the overall structure gives off a crystalline appearance.

The glazing process incorporates new bomb-resistant technologies into the glass that eliminate flying shards and even shield the building from an explosion by deflecting a blast's energy. The majority of 7 WTC's windows are double-paned, laminated, and layered with a new plastic polymer.

Meanwhile, the windows closest to the lobby are reinforced with inner cables that would absorb a blast and snap right back like a rubber band.