Building Destruction and Collapse
Building Destruction and Collapse
BUILDING DESTRUCTION AND COLLAPSE
Engineers and architects design buildings to stand, and the vast majority of them do so without major incident. Yet occasionally a building does collapse, bringing with it questions about the science, technology, and ethics of structures. Though they happen for a variety of reasons, collapses can be clustered into three groups: those resulting from natural disasters (earthquakes, mudslides, tornadoes, and the like); inadvertent collapses (because of flaws in design, use, and/or maintenance); and intentional destruction (including both planned demolition and malevolent attacks). Each type raises different, if related, ethical questions.
Two types of explanation exist for collapses. The first is focused on the mechanics or physics of the destruction; it asks what forces were acting on (and being produced by) what parts of the structure and in what fashion. The lessons drawn from such analyses will be, necessarily, structural or mechanical in nature. Matthys Levy and Mario Salvadori (2002), for instance, declare that collapses are always due to structural failure, though this failure may come about in a variety of ways (and, though they do not explicitly say so, may or may not be accidental).
A second type of explanation focuses on what might be termed social—rather than physical—dynamics. Here, the forces are those of the designers and others involved in determining whether and how to erect (or destroy) a structure. Such forces are more difficult to analyze and impossible to quantify, but they are as much a part of building success and failure as are the physical laws that allow them to stand or fall. These two kinds of explanations often have different relative weights in examinations of natural, inadvertent, and intentional destructions.
Building destructions caused by natural disasters are the most deadly and devastating kind. The 1923 earthquake near Tokyo, Japan, measured 8.3 on the Richter scale and left 100,000 dead; the 1995 Kobe, Japan, earthquake, rated 7.2, was the costliest ever, causing an estimated US$150 billion in damage and destroying nearly 100,000 structures. Tornadoes (including the 148 that formed the Super Outbreak of 1974, killing 315) and hurricanes (such as Camille of 1969, which killed 200 and caused billions of dollars in damage) can cause massive devastation as well.
Although the basic cause of the building collapses in these disasters is structural failure (as is true in any collapse), such widespread collapses pose the immediate challenge of disaster response in the face of damaged (or even nonexistent) infrastructure. Is the community able to cope (on its own or with outside assistance) when communication, rescue, and medical systems have been damaged or destroyed?
Secondary challenges emerge as investigators study which structures failed and which survived, in an effort to learn lessons for future construction. These studies may confirm existing knowledge (e.g., the Kobe Report's confirmation that newer structures survived because of their more sophisticated designs), may point to a need for new knowledge or regulation (as in the 1923 Tokyo quake, which led to Japan's first building code), or may uncover flaws in applying existing knowledge, either because that knowledge is not sufficiently detailed or because it has been inexpertly applied (as turned out to be the case with earthquakes in Mexico City in 1985 and Turkey in 1999). The causes of devastation here are clearly beyond the scientific; cultural and economic factors play significant roles, as do settlement and development patterns. Resulting questions have to do with building standards and where (and how well) they are applied, and economics (decisions about how much safety is worth).
Once an immediate crisis has passed and investigations have been completed, then comes the most challenging phase: deciding what to do next. When the lessons are scientific, they can be codified and shared. When the lessons are cultural or economic, they are harder to learn or apply. Often the issue becomes one of conflict between governmental control and citizen freedom. How much control should local or national governments have over private construction, and how many federal dollars should go toward relief if, say, people build in known flood plains or tornado alleys, while failing to take precautions (or neglecting to purchase appropriate insurance)?
The effects of the power of nature may be more deadly, but the effects of the fallibility of human nature provoke a stronger urge to assign responsibility. In 1922 the Knickerbocker Theatre in Washington, DC, suffered a partial collapse, killing ninety-five people. A severe snowstorm that evening both precipitated the collapse and prevented a larger death toll, but was not the underlying cause of the collapse. Subsequent investigations uncovered shoddy design and materials, but charges against the designers and builders were dismissed, and the resulting call to institute district-wide licensing requirements for architects and engineers went unheeded until 1950 (after every other state in the union had adopted licensing laws for engineers). Twenty other states had already passed such laws at the time of the Knickerbocker collapse, seventeen of them in the four years prior to that disaster. New York—home of the American Society of Civil Engineers (ASCE)—was one of those states, passing its law in 1920, after a decade of heated debate and resistance by the ASCE.
When two walkways in the lobby of the Hyatt Regency Hotel in Kansas City, Missouri, collapsed in 1981 during a crowded dance contest, 114 people died. The Hyatt disaster challenged the resolve of a profession that, in its codes of ethics, had recently declared public safety to be the paramount goal. Licensing laws had been in place for over thirty years, but the Hyatt case posed the first test of such regulation in the face of a collapse. Disasters such as the Knickerbocker had encouraged the call for licensing, but once passed, such laws were used primarily to deal with unethical business practices. After five years of investigations and negotiations, two engineers who had supervised the design of the hotel lost their licenses, a decision decried by many of their colleagues as inappropriately harsh given the complex chain of events and professionals involved in the design and collapse of the structure. That criminal charges had been dismissed for lack of evidence strengthened such opposition.
If news of the Hyatt collapse challenged the engineering profession, the story of the Citicorp building in Manhattan renewed its faith and confidence. A 1995 New Yorker magazine article revealed that in 1978—a year after Citicorp Center opened—the structural engineer discovered a fatal flaw in the fifty-nine-story building. William LeMessurier blew the whistle on himself and in collaboration with the building owners, insurance agencies, and city officials devised a plan for retrofitting the building to ensure its safety. To avoid a public panic, the building tenants were not informed of the repairs being made to the structure. The case is frequently cited as an exemplar of ethical behavior on the part of those involved, most notably LeMessurier himself, yet the secrecy of the case raises questions about the public's right to know the risks they face and to decide what risks they are willing to assume.
When mercifully vacant buildings collapse, as in the cases of the Hartford Coliseum (1978, Connecticut) and Kemper Arena (1979, Kansas City, Missouri), the effects are dramatic, but far less wrenching for the public as well as for the building profession. In these two collapses, multiple factors combined in unexpected and unfortunate ways. Heavy rains and high winds exploited previously unnoticed weaknesses in the Kemper Arena roof design. In the Hartford collapse, early deformations in the structure were dismissed as insignificant for years, only to compound into the collapse of the roof just hours after an event that had drawn some 5,000 spectators. Hundreds of roof and structure collapses occurred during that winter of record snowfalls, but none so memorable as the one in Hartford. These cases (and the snow-induced Knickerbocker collapse) point to the interplay of natural and human causes in some major collapses, which complicates the matter of assigning responsibility.
As with natural disasters, accidental collapses lead to investigations. Designers strive to derive lessons about design in an attempt to extract some good from the rubble. The easier lessons to learn or reinforce about design and building practice are the scientific ones. Updating building codes and reminding designers of the need for structural redundancies are straightforward actions. The harder lessons are those related to responsibility. How far should the responsibility of a designer extend and to whom? Changes in liability and licensing in the United States over the past century have at once increased designers' authority and their obligations. That tradeoff is the underlying principle of modern professional ethics—professionals possess highly specialized knowledge, which can be used for good or ill, and the public invests professionals with the authority to make decisions and to self-regulate in exchange for a promise to serve the public granting that authority.
In contrast to natural and human disasters are building destructions brought about intentionally, whether through intent to protect or to harm. As buildings age and congestion increases, some owners opt for planned demolition, often to clear the way for newer, safer, or larger structures. Controlled Demolition, Inc., operated by The Loizeaux family of Maryland has become famous for its skill at bringing a structure the size of Three Rivers Stadium (2001, Pittsburgh) down to the ground without harming people or the new stadium rising next door. Robert Moses was perhaps the most prolific developer of the twentieth century, yet he was, reflexively, the most prolific demolisher as well, and has as a result been both praised and vilified for his role in altering the New York cityscape. Whether controlled demolition is large or small, the collapse of each structure marks the end of potentially heated negotiations over preservation and land use.
Whether or not general agreement exists on such demolitions, they are at least planned publicly. Covert acts of intentional destruction exist as well—in the forms of arson, war, and terrorism. Ironically, the World Trade Center (WTC, 1993 and 2001, New York City) and the Murrah Federal Building (1995, Oklahoma City, Oklahoma) act as links between the public and the secret types of building destruction. The WTC began with the planned demolition of the commercial district known as Radio Row and was itself demolished by terrorists. The birth and the death of the WTC both produced victims—those in the former were fortunate to escape with their lives, if not their livelihood. The Murrah building, damaged beyond repair by U.S. terrorists, was eventually brought down by the Loizeaux family firm.
Intentional destruction, though it may be less deadly than other types, is most unsettling because it pits one group of people against another. Although the collapse of the WTC towers was probably an unplanned result of the terrorist airplane attacks, the military does study how to destroy buildings and is even designing "bunker-busting" bombs to attack special fortifications. Yet even in the civilian arena, it is common to debate who properly controls or decides acceptable tradeoffs. In both publicly and privately planned demolition, those making the decisions are rarely those who will be affected by them.
The Oklahoma City bombing ushered in a new era of concern for building standards, though it was not the first terrorist attack on U.S. soil (which dates at least to the deadly 1920 bombing of the Morgan Bank in New York City). If the Murrah bombing was a chink in the armor of U.S. confidence, that crack became a gaping hole with the destruction of the WTC. The investigations into the Oklahoma and New York cases were unusual in that they began by exploring nonmechanical causes, focusing appropriately on the role of the terrorists. But in the WTC case, behind the calls for vengeance and war were whispers asking whether the towers should have stood longer once they had been attacked. The comparatively minor damage suffered by the Pentagon during the same attack vividly demonstrated how important a role building design plays in building performance. How far does a designer's obligation to build a "safe" building extend? The two investigations converged around questions about how best to design future structures to preserve freedom and access while protecting building integrity and security.
Several stages of response are common across these three types of building destruction: the search for lessons, the discovery of complexity in the causes, the proposal to change current practice, and the reluctant acceptance that actual changes will be less sweeping than those proposed. Among the challenges faced by those responding to building collapses, two are continual. The first is that, hard as it may be to identify the causes of a particular collapse, it is inestimably harder to identify solutions that will prevent a whole category of future collapses. The second challenge is to achieve a balance between studying past failures and designing for future successes.
SARAH K. A. PFATTEICHER
Caro, Robert A. (1975). The Power Broker: Robert Moses and the Fall of New York. New York: Vintage. Pulitzer-prize winning biography of developer Robert Moses detailing his far-reaching effects on the infrastructure of the city and state of New York.
Herring, Susan Davis. (1989). From the Titanic to the Challenger: An Annotated Bibliography on Technological Failures of the Twentieth Century. New York: Garland. Detailed, reliable guide to key primary and secondary sources on wide range of failures.
Levy, Matthys, and Mario Salvadori. (2002). Why Buildings Fall Down: How Structures Fail, rev. edition. New York: Norton. Accessible introduction to the physics of building destruction, written for a lay audience; sequel to Why Buildings Stand Up.
Liss, Helene. (2000). Demolition: The Art of Demolishing, Dismantling, Imploding, Toppling, and Razing. New York: Black Dog and Leventhal. The story of the Loizeaux family and their company, Controlled Demolition, with extensive photographs.
Morgenstern, Joe. (1995). "The Fifty-Nine-Story Crisis." New Yorker 71(14): 45–53. The article that broke the story of the averted crisis at Citicorp, after nearly twenty years of secrecy.
Petroski, Henry. (1994). Design Paradigms: Case Histories of Error and Judgment in Engineering. One of several books by Petroski using historical case studies to demonstrate the technical lessons engineers learn from failure. New York: Cambridge University Press.
Schlager, Neil, ed. (1994). When Technology Fails: Significant Technological Disasters, Accidents, and Failures of the Twentieth Century. Detroit: Gale Research. This encyclopedia of more than one hundred technological disasters includes sixteen building and structural collapses, each with a brief bibliography.
Wearne, Phillip. (1990). Collapse: When Buildings Fall Down. New York: TV Books. An introduction to the findings of forensic engineering investigations into 11 major structural collapses of the last half-century.
"Why the Towers Fell." NOVA Online. Available from http://www.pbs.org/wgbh/nova/wtc/. This Internet site supplements the PBS program of the same name, exploring the reasons for the collapse of the World Trade Center.