World Trade Center Left Safety Design Legacy in Buildings

The shock of the Sept. 11, 2001, attacks pushed security and safety to the forefront in designs of high-rise and civic buildings from Manhattan to Beijing.

Architects added wider stairwells for emergency evacuation and shatter-resistant glass to the face of office blocks. Sidewalks became collapsible, and closed-circuit TV and stricter access control are now common at many new, secured buildings.

The National Institute of Standards and Technology spent six years investigating the structural causes of the collapse of the World Trade Center and nearby Building 7, resulting in 40 changes to International Code Council guidelines that are the foundation for building codes in the U.S.

Setbacks from the street, “hardened” perimeters, bollards and low-rise obstacles and ventilation and water improvements are among the post-9/11 advances in building safety and design. The costs of security enhancements increase according to the value of the interior contents.

Designing a building from scratch can incorporate the latest practices and is generally “more clever” than retrofits, says Rob Rogers, principal at Rogers Marvel Architects.

“There can be a fairly significant cost increase if you need more land, distance things from the curb and traffic or make greater use of cameras and technology,” says Paul Danna, architecture principal at Los Angeles-based AECOM Technology Corp., which managed the Pentagon’s $1.3 billion renovation and upgrade. “Now a lot of thinking is going into how to accommodate these measures without giving a civic project the feeling of a fortress.”

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To contact the editor responsible for this story: Kara Wetzel at

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