The Sampoong Department Store Collapse
Collapse of Faultily Constructed Department Store in Korea Killed Over 500
|Post-collapse photograph of the Sampoong Department Store|
On June 29, 1995 a mall in Seoul, South Korea collapsed with an estimated 1,5000 people inside. In less than 20 seconds, a section of the five-story building came crashing down into the basement, killing over 500 people. 1 The collapse of the building, which was constructed using steel-reinforced concrete pillars, was blamed on faulty construction. 2
The building had a number of structural modifications during its lifetime which contributed to the collapse. It was originally designed as an office building with four floors, and constructed in 1987. When it was later converted to a department store, support columns were cut away to accommodate escalators. The owner, Lee Joon, carried out these modifications over the objections of the original contractors, whom he fired and replaced.
A fifth floor was eventually added to house a restaurant. It involved installation of a heavy concrete slab. A heavy air conditioning unit was added to the building's roof, exceeding the design loads by a factor of four. Haphazard relocation of the air conditioning unit damaged the roof structure.
Prior to its collpase, the building showed cracking due to the overloading produced by the faultily-engineered fifth floor and air-conditioning unit placement. 3
Sampoong Collapse Cited to Explain WTC Collapses
In response to a requests for peer review of a draft paper by physics professor Steven Jones challenging the official explanations for the collapses of the Twin Towers and Building 7 ( Why Indeed Did the WTC Buildings Collapse?) a civil engineer cited the Sampoong department store collapse as an example of a symmetrical structural collapse not induced by explosives. The reviewer uses the above photograph to make the following claim:
In the picture, it is easy to see that there is very little debris on the street, and note how uniform the width and depth of the debris is along the street, reinforcing the symmetry of the failure. This structure was 9 stories tall (5 above ground and 4 below). At the lower center, in the space between the beams and columns you can see how fine the rubble is. This type of debris field and limited adjacent structural damage can only exist if the collapse occurred in a highly symmetric manner.
Here the reviewer appears to make over-reaching conclusions, both on the nature of this collapse, and its comparability to the collapse of a skyscraper such as Building 7.
- The sources of this photograph do not indicate how long after the incident it was taken, and whether much of the rubble had already been removed.
- The Sampoong building was apparently framed with reinforced concrete, not steel columns and beams.
- The Sampoong building was not properly engineered, and showed signs of failure before the collpase. Being a short building, it did not have to withstand wind-loading events that any skyscraper has to withstand on a regular basis.
- The Sampoong building was not even a high-rise, let alone a skyscraper. The reviewer's assertions that the failure was symmetric, if true, would not be remotely applicable to the collapse of a skyscraper such as the three World Trade Center towers, each of which had height-to-width ratios of over five.
The collapse of the Sampoong Superstore in Seoul, South Korea, represents an example of a structural collapse attributed in large part to corruption.
The Sampoong department store opened in December 1989. It was a nine-story building with four basement floors and five above grade. The building was laid out in two wings (north and south) connected by an atrium lobby. By the mid-1990s the store’s sales amounted to more than half a million U.S. dollars a day (Wearne 2000, pp. 99-100).
Unfortunately, the store had been built on a landfill site that was poorly suited to such a large structure. Woosung Construction built the foundation and basement and then passed the project onto Sampoong’s in-house contractors. Woosung had apparently resisted some proposed changes to the building plans, such as the addition of the fifth floor (Wearne 2000, p. 100).
Sampoong made significant changes to the structure. The most important were the conversion of the original use as an office block to that of a department store. Other changes included changing the upper floor from a roller-skating rink to a traditional Korean restaurant. Stricter standards had to be met for fire, air conditioning, and evacuation. Although the structure apparently met all building code requirements, the revised design was radically different from the original (Wearne 2000, p. 100).
The building was put into service.
“For five and a half years business thrived. In June 1995 the store passed a regular safety inspection. But within days there were signs something was seriously wrong: cracks spidering up the walls in the restaurant area; water pouring through crevices in the ceiling. On June 29 structural engineers were called in to examine the building. They declared it unsafe. Company executives who met that afternoon decided otherwise. They ordered the cracks on the fifth floor to be filled and instructed employees to move merchandise to the basement storage area “(Wearne 2000, p. 100).
Some employees heard rumors of the structural damage and impending collapse but remained in their departments to work. At 6:00 p.m. on June 29, the center of the building collapsed, similar to a controlled implosion, in about 10 s. The five-story north wing, about 91 m (300 ft) long, fell into the basement, leaving only the facade standing (Wearne 2000, pp. 100-102).
Customers were concentrated in the basement and in the fifth-floor restaurant. The customers and employees had no time to run. Some survivors were found in the wreckage, and one was brought out 17 days after the collapse. The overall death toll was 498 (Wearne 2000, pp. 100-107).
The final report was delivered by the Seoul District Prosecutors Office, entitled The Final White Book of Finding Out the Real Truth of the Collapse of the Sampoong Department Store. The public was outraged. In particular, the news that the senior executives had fled the building without warning others was disturbing. The report on the collapse, as well as earlier structural and construction failures, suggested a widespread pattern of corruption in the country’s construction business. A government survey of high-rise structures found 14% were unsafe and needed to be rebuilt, 84% required repairs, and only 2% met standards. Joon Lee, the chairman of Sampoong, and his son Han-Sang Lee were convicted and sent to prison for 10 1/2- and 7-year terms, respectively. Twelve local building officials were found guilty of taking bribes of as much as $17,000 (U.S. equivalent) for approving changes and providing a provisional use certificate (Wearne 2000, pp. 111-112).
The cause of the Sampoong collapse, then, was not a technical issue as much as outright fraud. The Korean construction industry, protected by government regulation from outside competition, had become complacent. Bribes were used to get around the usual government checks and balances that serve to protect public safety.
This case study is discussed in chapter 10 of the book Beyond Failure: Forensic Case Studies for Civil Engineers, Delatte, Norbert J., ASCE Press. This case study is discussed by Wearne (2000, pp. 99-113) in Chapter 5, entitled Crooked Construction: Sampoong Superstore. A technical paper on the collapse entitled Lessons from the Sampoong Department Store Collapse (Gardner et al. 2002) was published in the Cement & Concrete Composites journal.
Wearne, P. (2000). Collapse: When Buildings Fall Down, TV Books, L.L.C. (www.tvbooks.com), New York. (This book is a companion to The Learning Channel’s television series “Collapse.”)