Breaking point: South Korea’s department store disaster

Alarming structural flaws caused five floors of a department store in Seoul’s Gangnam District to collapse.

It began with a months-old crack. Then another. Then, on the morning of 29 June 1995, in the heart of Seoul’s upscale Gangnam District, hairline fractures snaked across the ceilings of the top floor of the busy Sampoong Department Store.

At first, managers cordoned off the floor. The situation was manageable. But by midday, those cracks had widened to up to 10 cm across.

Customers reported hearing several loud bangs from the top floors as the vibration of heavy air conditioning units on the roof radiated through the cracks. Just one day before, a worker heard a strange noise, which was later revealed to have been the sound of a reinforcing steel bar slipping through concrete.

Still, management ignored the advice of onsite engineers and refused to issue evacuation orders. They switched off the humming air conditioners, moved merchandise down to the basement and closed off the fourth floor.

At 5:57pm, time ran out. In just 20 seconds, the entire south wing of the store crumbled in an avalanche of concrete and steel. In total, 502 people were killed (including six whose bodies were never found) and nearly 1000 were injured.

Following investigations into the disaster’s cause and mass public outcry, two people were sentenced for criminal negligence, corruption and accidental homicide convictions, and multiple city officials were charged with bribery.

Latent errors

In the immediate aftermath, the cause of the disaster was unclear. The investigation committee suspected a gas leak as the most likely reason. However, scenes of the rubble showed the building hadn’t thrown debris outwardly as with an explosion; it had compacted downwards like a stack of cards. With gas ruled out, attention turned to the building’s construction.

The Sampoong Department Store, consisting of five upper floors and four basement levels, with an atrium connecting the north and south wings, was made of reinforced concrete and built as a flat slab construction. Using this technique, concrete columns bear the load of the floor slab above, doing away with the need for cross-beams when the load is calculated accurately.

In an article published in Forensic Science International, Tae Won Park, from the Department of Architectural Engineering at Dankook University, wrote: “[Sampoong Department Store] had the structure that collapse of one pillar support led to breakdown of an entire structure in a moment. Therefore, such [a] structure requires a precise design and construction.”

However, the final design was not as precise as it needed to be, as frequent changes to its function and design, and construction deficiencies, put the building at risk of catastrophic failure and were ultimately to blame for the disaster.

The first cause originated in the building’s planning stage when owner Lee Joon converted the initial plans for a four-floor residential building to a commercial shopping centre.

According to approved drawings, the unplanned-for fifth floor would be a rollerskate rink, a decision made to bypass zoning regulations that restricted the number of trading floors a department store could have. Joon remodelled the top floor, again, to a food court.

This had major ramifications. Heavy kitchen appliances were installed, new wall partitions were added, and hot water pipes were run along the reinforcing bars in the upper floor slabs. Park found only 40 per cent of the original flexural strength was retained.

While this construction flaw was not enough to precipitate the building’s collapse, it contributed to structural weakness which was compounded by the omission of drop panels identified in at least one column on the fifth floor.

“In [a] flat slab structure, [a] drop panel plays [the] role as a beam in frame slab structures that consists of pillar and beam,” Park wrote. “Consequently, no construction of [the] drop panel could be a direct factor to [the] collapse of [the] building.”

The combination of the mislocation of the reinforcing top bars, undersized diameters of the top columns and the lack of a supporting drop panel severely compromised the structure’s ability to counteract the high shear forces being directly applied to the concrete columns, which were additionally excessive to those assumed by the original design engineer. Each of these would reduce its safety factor, investigations concluded.

Critical point

Despite these alarming structural flaws and construction deficiencies, the department building stood for five years. The final blow was the installation of air conditioning units on the rooftop in 1993.

Three cooling towers, weighing a combined 45 t, were originally placed towards the residential end of the roof. Residential complaints of noise eventually led to their relocation on the other side. However, rather than carefully lifting or disassembling them into smaller units to minimise structural damage, they were placed on rollers and dragged across the roof.

Importantly, they were moved directly over a column in the fifth floor; column 5E, which investigations found to be the originating point of collapse when the fifth floor slab around it gave way to punching shear force.

Over the next two years, each time the air conditioning units clicked on, vibrations would gradually widen cracks around the column, and by the morning of the disaster, it overloaded, culminating in the department store’s progressive collapse.

Crackdown

Construction of the building began in 1987, in the middle of South Korea’s infrastructure boom and one year before Seoul would host its first Olympic Games.

Against this backdrop of major socioeconomic growth, court investigations found evidence of corruption among local planning officials, including accepting bribes to approve frequent design changes, which enabled Sampoong’s owner to circumvent safety provisions. Perfunctory inspections sandpapered over the early warning signs, with cracks already observed in April 1995.

This was summarised by the chairman of a special investigation committee organised by the government: “The accident was the result of poor management caused by a lack of construction [and] building inspection, maintenance and management, and a lack of supervision from the administrative office.”

The response to the collapse also revealed gaps in emergency rescue protocols; namely, a lack of a command and control system to coordinate the response across emergency personnel, inadequate rescue equipment and a delay in rescue. As a result, new disaster management laws were created, including:

• The establishment of the Disaster Control Act on 18 July 1995. This strengthened emergency infrastructure around response, recovery and relief following human-caused disasters at the national and local government level.
• The creation of the National 119 Rescue Service on 19 October 1995, provisioning rescue resources directly to major national accidents.

This story was originally published in the November 2025 edition of create.

Sources

Tae Won Park, Inspection of collapse cause of Sampoong Department Store, Forensic Science International, 2012.

Yong-kyun Kim and Hong-Gyoo Sohn, Disaster Response Policy Change in the Wake of Major Disasters, Labeled Focusing Events, Disaster Risk Management in the Republic of Korea, 2018.

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