Architectural SuretySM program aims to make buildings more resistant to insult
Deadly attacks on US targets: Two US embassies in Africa, the US Capitol Building, Khobar Towers, the Oklahoma City federal building, the World Trade Center.
Costly natural disasters: Hurricane Andrew, $16 billion; Northridge, Calif., earthquake, $25 billion; the northeast-US blizzard of ’93, $1.6 billion. Add in fires, mud slides, tornadoes, riots, vandalism, and deterioration due to aging, and you’ve got what amounts to a significant, and growing, national concern.
What do these catastrophes have in common? Skyscrapers, bridges, dams, tunnels, public buildings, homes — structures that are supposed to protect us but too often don’t, says Rudy Matalucci of Security Systems and Technology Center 5800.
In the Oklahoma City bombing most of the victims were killed not by the blast but by the building, he says, either by sharp wedges of flying glass or by falling concrete as the building’s nine floors fell one on top of another like a house of cards.
"People evacuate when disaster strikes," he says. "You’d like people to feel compelled to run into a building rather than out of it during an emergency."
Raising public expectations
Rudy leads a group of Sandians who are working with an alphabet soup of regulatory agencies, professional associations, contractors, universities, and governments to help raise current construction-industry standards of safety, security, and reliability so that future structures can better withstand the kinds of insults that aren’t planned for but nevertheless are within the realm of real possibility.
The Architectural SuretySM program, as the Sandia effort is called, aims to use Labs risk management methodologies and technical capabilities to examine the vulnerabilities of public buildings and other structures and identify changes in architectural design, building codes, or construction standards that would improve their performance in natural disasters, terrorist attacks, or other out-of-the-ordinary situations.
It involves applying the exacting "surety" principles required in nuclear weapons work to the business of building buildings, many of which are by definition high-consequence systems.
"We aren’t trying to turn all buildings into bunkers," says Rudy. "What we want is for people to go through the thought process, to ask, ‘What are the vulnerabilities of this structure and what can be done about them given the costs?’ "
A broadening range of threats
At his arrest Ramzi Yousef, convicted in the 1993 World Trade Center bombing, told authorities he had intended to kill 55,000 Americans by causing the building’s south tower to topple onto its north tower. "These attacks have forced a wider focus on the vulnerabilities of some government buildings to terrorist bombings," Rudy says. "It has caused designers to look at the principle of having a whole structure depend on one structural element."
Still, he says, much more examination needs to be done of many more types of structures — malls, post offices, dams, highway overpasses, corporate centers. "Someone needs to ask, ‘If I’m a crazy guy or a disgruntled employee, can I get to that?’ "
The vast majority of threats to buildings and infrastructures don’t come from terrorists, however.
In 1978 the engineer who created the new 59-story Citicorp Center in Manhattan, then the world’s seventh tallest building, realized that a last-minute design change made during construction, coupled with a preexisting design weakness, made the skyscraper vulnerable to high quartering winds, the likes of which might be seen in a storm occurring about every 16 years. If the winds came, the building could crumble. It was human error.
An army of welders quickly corrected the problem, but the apparently minor change, compliant with New York City building codes, could have been disastrous.
Public works engineers in older cities like New York, Philadelphia, and Chicago worry about another threat: aging infrastructures. Deteriorating buildings and bridges, leaking tunnels, and unreliable levees and pipelines may be ripe for catastrophic failure. Even in newer cities such as Los Angeles, storm drains and pavement are crumbling faster than they can be repaired.
Getting beyond building codes
Despite the many recent high-profile disasters and near misses, though, a recent survey showed that 68 percent of building design professionals have not changed their design processes or considerations in response to the ever-broadening range of threats, new and old, to public structures and government facilities.
The problems are complacency, cost consciousness, and a "building-code mindset," Rudy says. The architect will produce the least expensive effort for his cut of the design fee. The engineer will stick to tried-and-true practices learned in school. The regulator’s goal is to make sure a building "meets code" — a minimum set of requirements grounded in engineering fundamentals but seldom mindful of abnormal threats, he says.
Once the building is up, the owner buys insurance to protect himself, legally and financially, from unexpected catastrophes. The insurance company may look at a few potential threats, but it’s too late — the building’s vulnerabilities are literally set in concrete, he says.
Rudy’s goal is to "have it all on the table" when the architect, engineer, owner, regulator, and attorney sit down to design the building. "They should look at layouts, types of concrete, types of glass, consider tradeoffs, and make informed decisions," he says.
Meeting the prescriptive legal requirements is not enough anymore, he says. "We need to think beyond the building codes. No city has a code for terrorists."
What can a national laboratory do?
Already Sandians have tackled a range of technical problems toward safer, more secure, and more reliable buildings and city infrastructures. A series of Sandia explosives tests since 1997 at the New Mexico Institute of Mining and Technology has looked at how different types and configurations of window panes fracture in a bombing and how they transfer blast loads to the surrounding structure. Future tests may lead to new types of glass that disintegrate into blunt, granular particles early in a blast when overpressure is at its lowest, thereby producing slow-moving, sand-like fragments that would cause the fewest and least severe injures. (Ed Beauchamp, 1833)
Last year Labs security experts consulted with the architect who designed the new federal courthouse in Albuquerque on ways to make the building more resistant to attack. The seven-story building, scheduled to be occupied in November, features controlled underground parking, maximum standoff distance from the street, planter-barriers that prevent parking near the structure, smallest windows lowest to the ground, and a variety of access-control technologies inside the building to prevent bombs and weapons from being carried in. (Rudy Matalucci, 5848)
For the state Highway and Transportation Department Sandia has helped check intentionally damaged steel girders in a now-removed I-40 bridge over the Rio Grande using nondestructive inspection techniques. The tests showed that measurement of how a vibration changes as it propagates through a superstructure can reveal hidden flaws without having to tear the bridge apart. Similar techniques could help reveal potentially catastrophic deterioration in flawed or aging infrastructures. (Randy Mayes, 9119) To provide data about structural response to bad weather or other insults, Sandia has developed a relocatable instrumentation package called the Autonomous Structural Event Recorder. ASER includes a central computer, telemetry equipment, and sensors to measure and record subtle structural movements, such as roof lift and material fatigue, that can help identify hidden weaknesses in most building types. An ASER proto- type is now being tested on an outbuilding in Area 1. (Tom Baca, 9119)
Testing structures with supercomputers
Today’s computing capabilities are providing an unprecedented opportunity to design better buildings, as well, Rudy says.
Sandia computer scientists already have combined two existing computer codes originally developed for nuclear weapons work — one that simulates hydrodynamic (blast) physics and another that simulates the physics of structural response — into a single code that, with the help of a supercomputer, can model in three dimensions what happens to a wall or multistory building subjected to a bomb blast. This prediction capability could help designers quickly and cheaply test many new building layouts, construction materials, and blast-mitigation approaches. (Dale Preece, 6117)
Using existing computer codes that model the physics of fire propagation, engineers also may soon be able to see how fire spreads through a building given different layouts and materials. (Lou Gritzo, 9116)
"We want to use supercomputers to test under what pressure a roof would fly off a building, see why its walls come apart, understand why levees break, model how floors collapse in a gas explosion," adds Rudy. "We ought to be able to tell you whether you’d survive a blast 10 floors below you in a hotel. This is technology that exists today."
An 80×60-ft., four-story building is being constructed at White Sands Missile Range in preparation for a DoD-sponsored test to better understand how a typical reinforced-concrete building responds in a bomb blast. The building will be instrumented with a variety of sensors and then subjected to a terrorist-type bomb blast. Sandia plans to use readings from the test to refine the "cyberblasts" being modeled on Labs supercomputers. (Steve Attaway, 9117)
Rudy also wants to see modern-day virtual reality tools put to use making buildings safer. "Using computer-aided design drawings, you could put yourself inside a building during a bombing," he says. "You could test emergency response plans. You can train for special teams operations. You can place and test security measures." (Sharon Stansfield, 5905)
Other untapped opportunities
Perhaps one of the biggest contributions Sandia can make to safer, more secure, and more reliable buildings is to help develop a set of risk management methodologies tailored specifically for architectural issues, he says. That would help architects and owners identify design deficiencies and prioritize changes that would bring the greatest surety benefits for the lowest cost based on the likelihood of threats to each new building. "Risk management can help designers bring high-consequence or high-probability events into the equation to make sure new buildings perform in acceptable ways," he says.
Future explosives tests could gather data on such unknowns as how far away from a blast a person would suffer ear injuries, how cinder block walls fail, how key structural supports can be placed to ensure a building won’t collapse, and how windows shatter.
Sandia has done some early work modeling how shock isolators can mitigate the damage to buildings from earthquakes. Many such devices, such as the one installed on San Francisco City Hall following the 1989 Oakland quake, haven’t yet been put to the test. "The state of California is just waiting to see how well its earthquake retrofitting worked," Rudy says. "Computer testing and validation of the retrofits would reassure the public."
Ultimately, he says, you’d like to see technologies being developed at the national labs become part of "intelligent structures" in which the heating, cooling, lighting, electrical systems, water supplies, and computer networks are checked continuously. Microsensors could alert building occupants of water or air duct contamination by harmful chemicals or gases. Inexpensive microelectromechanical systems (MEMS) could be embedded in concrete or attached to steel girders to record stresses, temperatures, and other significant structural histories. (Mike Valley, 6352)
Rudy believes there’s a lot of other untapped expertise at Sandia with the potential to contribute to Architectural SuretySM.
Building a national constituency
But Sandia’s contribution to Architectural SuretySM must go beyond applying technologies to structures, Rudy says. It won’t happen until those in the building business are convinced of the need to adopt Architectural SuretySM principles.
"We need to build a national constituency of people who see the benefit of this," he says.
Last year Sandians taught a course on infrastructure surety to grad students in the University of New Mexico’s Civil Engineering Department. The course attracted enough positive feedback from students and faculty that a similar course will be taught in UNM’s School of Architecture and Planning and CE Department in spring 1999.
Rudy wants to develop a standard Architectural SuretySM course outline and provide it to faculty "anywhere there are active and progressive architecture and civil engineering programs," he says. Faculty members at MIT, Stanford, the University of Toledo, Arizona State, and NYU have expressed interest in such a course, he says.
Sandia has hosted and participated in a series of conferences with Architectural SuretySM as a theme, he says. In May 1997 Sandia, the American Society of Civil Engineers, and the American Institute of Architects co-sponsored a two-day conference on "Assuring the Performance of Buildings and Infrastructures." Sessions were presented on such topics as protection of federal buildings, decaying infrastructures, blast threats, containing flood damage, and risk assessment and cost-benefit analyses. A second conference focusing on disaster mitigation is scheduled for October 1999 at Georgetown University.
The Labs also has hosted and attended several meetings with high-level leaders of such organizations as the Federal Emergency Management Agency (FEMA), Electric Power Research Institute (EPRI, the research arm of the electric power industry), Institute for Business and Home Safety, and the General Services Administration (GSA) to develop strategies for incorporating preventive Architectural SuretySM issues into their disaster-relief efforts.
Disaster-resistant cities, dams
FEMA has pledged to provide $1 million to one city in each state to encourage local businesses and governments to begin turning their cities into "disaster-resistant communities."
Sandia also is working through EPRI’s Disaster Recovery Business Alliance program to identify problems that an Architectural SuretySM approach might contribute to solving. "The cost of damages from a disaster itself typically is small compared to the lost revenue coming into a city as a result," Rudy says. "EPRI wants businesses and local governments to work together on disaster relief. We want to help the communities do that."
The Labs is involved in a project with the US Bureau of Reclamation, the US Army Corps of Engineers, Lawrence Livermore National Lab, the Tennessee Valley Authority, and Bonneville Power Authority to evaluate threats to the 1,000-plus federal dams in the United States and develop better security approaches to protect them. Three dams will be chosen as pilot projects to demonstrate the new security methodologies. Sandians have written an initial white paper to outline goals for the project.
And most recently Sandia hosted GSA Office of Federal Protective Service leaders in an effort to identify Sandia technologies and security approaches that might be used to protect federal buildings, give GSA officials an overview of Sandia’s surety work and vulnerability analysis capabilities, and understand FPS needs.
"We are starting to make inroads with the agencies that are expected to deal with these new threats," Rudy says. "This is something Sandia can do in the national interest."