Architects: Enhancing Security and Aesthetics by Al Heavens
In February 2002, I was at a meeting of the Counselors of Real Estate in Washington -- the first time that esteemed group had gathered since the terrorists attacks of the previous autumn. It was warm for late February, so a lot of Washingtonians were out and about. Yet the atmosphere in the capital was understandably tense, almost eerie. A police siren would sound, and everyone the street would immediately turn in the direction of the siren, fearful of the worst. After 9/11, there were a lot of predictions that the back to the city movement that had been gathering steam throughout the 1990s would shift into reverse. The belief was that the big cities would be easier targets for terrorists than the suburbs. There was a lot of doom and gloom, especially among the smart-growth advocates who had been betting the farm on the cities. I don't know if you know about the Counselors, but these men and women, who number no more than 1,000, are the tops in the real estate field. They know what they are talking about. Thus, after listening to the speakers they had assembled for their three days of meetings, the only conclusion I could draw was that the cities would continue to thrive, drawing on those young professionals and empty nesters that had been the fuel of their revitalization. It reminded me of what my wife said after she had been mugged a few blocks from our city house when she was seven months' pregnant with our older son back in 1982. "This is my city, too, and they'd just better get used to me being here," she said. That son, who grew up in Philadelphia and went to college in Chicago, was not as sure as his mother. He was two weeks' late -- probably wondering how safe the world outside really was. Does that mean security concerns are important in the urban setting. Of course not. Just as city dwellers have always needed to develop street smarts to reduce the threat to our safety as we walk the streets, architects have been coming with their version of street smarts when designing buildings after 9/11. The American Institute of Architects has developed a primer for its members and clients that show how to make a building secure without designing something that looks like a fortress. The AIA recognizes that the architect has to make buildings safe, functional, comfortable, "and even inspirational" while making them secure. Building and "life safety" codes require that buildings provide minimum levels of health and safety performance requirements, including structural integrity, fire protection and safe access and egress. Design strategies and measures that address security issues "respond to the client's judgment of the threats and related risks to a facility." An architect and his or her client have to define what the building's security requirements are before the design is started. Trying to overlay security strategies and measures after a design concept has been set can result in delays, change orders and extra costs. This may compromise any efforts to achieve the level of protection that the client believes is necessary. Some buildings are potentially more vulnerable to attack than others. The design of these buildings may require the use of techniques that are seldom applied to other building projects. For example, the AIA talks about "building hardening techniques" that increase the structure's ability to withstand an explosion with minimum loss of life or property. The goal is to avert or delay total structural failure -- progressive collapse -- permitting safe evacuation. There are structural and nonstructural ways to do this, according to the AIA. Blast-resistant structural analysis and design require considerable computer-modeling skills and engineering judgment, the AIA says. Among the factors to consider are the tendency of a system to collapse progressively, "structural redundancy," which refers to components in the structural system to carry the load if one or two columns are lost; the behavior of the ductile framing systems; the length of spans; the weight of the material, especially the nonstructural components; and the strength of the cladding on the exterior of the building (brick, marble, limestone, metal) and its effect on the structural system. In the nonstructural design category, design and operation strategies can help mitigate the effects of bomb and ballistic attacks by maximizing the "stand-off" distance between possible detonation points and the buildings (such as a car bomb across the street). These strategies can include securing the perimeter around the building site -- the Jersey barriers in front of the Capitol, for instance – using building shapes that resist blast shock waves better, controlling the patterns of approach to a building, and eliminating or strictly controlling parking beneath these buildings. | 
