Type: Process Essays
Sample donated: Rebecca Fox
Last updated: September 12, 2019
On 29th of June, 1995, the Sampoong DepartmentStore in Seoul, South Korea, completely collapsed. The collapse is thedeadliest modern building collapse until the attacks in New York city and is thedeadliest non-deliberate building that collapsed until Savar building collapsedin 2013. The tragedy occurred due to multiple errors made by the designers andcontractors who built the store and the negligence of the store owner. The structure was built on top of a landfill, it wasoriginally designed for an office building but midway through construction thechairman wanted to make it into a department store. Many engineers that wereworking on the project warned the owner Joon that the changes were dangerousbut he fired them.
In the disaster occurred, they were 1500 people that weretrapped in which over 500 died and 937 received non-fatal injuries. The rescuecrews did not start to search until the next day and the search was called offbecause of unstable remains and rescuers would be at risk. In figure 1 itillustrates the department facilities for each story. Literature Review The construction of the Sampoong started in 1987, it wasoriginally designed to be an office but the future chairman of the buildingJoon Lee midway through the construction, wanted it to be a department store. The process involved cutting the numbers ofsupport columns to be able to install the escalators. The contractors refusedto carry these changes as they were not safe, Lee Joon the future chairmanignored their concerns and hired another building company for the construction.
The Sampoong Department Store opened to the public on July 7, 1990, attractingan estimated 40,000 people per day during the building’s five years ofexistence. The store consisted of north and south wings, connected by anatrium. (Almarwae Mohammed 2017). Lee Joon ignored the safety procedures and risked thelife of all those people involved in the incident even after knowing the possibleconsequences. In April 1995, cracks beganto appear in the ceiling of the south wing’s fifth floor. The only response byLee and his management staff involved moving merchandise and stores from thetop floor to the basement. On the morning of June 29, the number of cracks inthe area increased dramatically, prompting managers to close the top floor andshut the air conditioning off.
The store management failed to shut the buildingdown or issue formal evacuation orders as the number of customers in thebuilding was unusually high, and it did not want to lose the day’s revenue.However, the executives themselves left the premises, as a precaution. (Guo, H.and others2010). Civil engineering experts were asked toinspect the structure but they only carried a cursory check in which theystated that the building was at risk of collapse. Around five hours before thecollapsed occurred, several loud bangs were heard from the top floors, as thevibration of the air conditioning caused the cracks in the slabs to widenfurther. After the cracks already grown 10cm wide, it was realised that thecollapsed was unavoidable and an emergency meeting was held.
In the meeting.The directors suggested that all costumers should be evacuated. However, JoonLee refused over the fear of losing revenues. Joon Lee did leave the buildinghimself as he was aware of the dangers but did not evacuate the customers. On the 29th of June, the northwing of the Sampoong store collapsed, the disaster killed over 500 people. The largenumber of fatalities was due in part to a distinct lack of concern by thebuilding owners/ occupiers in failing to take note of signs of seriousstructural distress before the collapse and evacuating the occupants.
Thefive-storey building was a flat plate structure with elevator shafts andservices located in rigid shear wall structures between the two wings and atthe building extremities. (N.J Gardner and others 2002). Fromthe point of the critical failure, it only took around 20 seconds for the entiresouth wing of the structure to collapse. In figure 2 it illustrates theSampoong Department store after collapsed. In addition, it is estimated thatthe property damage was around $216 million.
The restaurant floor had a heated concrete base referred to as “ondol”,which has hot water pipes going through it; the presence of the 4-foot-thick(1.2 m) “ondol” greatly increased the weight and thickness of the slab. As aresult of the fifth floor’s presence, the columns held up four times themaximum weight that they were supposed to support.
In addition, the building’sair conditioning unit was also installed on the roof, creating a 45-tonne(50-ton) load that was four times the design limit. (Guo, H.andothers 2010). In1993, the air conditioning units were moved over the column 5E, where the mostvisible cracks were, the purpose of the air conditioning was to cover thecracks, the cracks worsened due to the columns supporting the fifth floor.
According to thewitnesses, the collapse started from the fifth floor. The committee that was incharge of the inquiry concluded that the collapse started at column 5E on thefifth floor. The reasons for the collapse were noted as design errors,construction faults, poor construction quality control, reduction in thecross-section of the columns support in the fifth floor.
In figure 3 itillustrates how column 5E was damaged and in figure 4 it illustrates vibrationsfor AC units. At around 5.00 p.
m. of the localtime, the fifth-floor ceiling began to sink, the store workers blocked theaccess to the fifth floor. Before the incident, the store was packed withhundreds of customers, however, Joon Lee did not feel the need to close thestore or carry out any repair during that time. When the building started to producecracking sounds at about 5:52 p.
m., workers began to sound alarms and evacuatethe building, but it was too late. Around 5:52 p.m., the roof gave way, and theair conditioning units crashed through into the already-overloaded fifth floor.The main columns weakened to allow the insertion of the escalators, collapsedin turn, and the building’s south wing pancaked into the basement. Within 20seconds of the disaster, all of the building’s columns in the south wing gaveway, killing 502 people and trapping more than 1,500 inside. (Almarwae Mohammed2017).
It is evident that thewhole tragedy could had been avoided if they evacuated the customers on timebut Joon Lee did not consider such approach necessary. Joon Lee was aware thatthe collision was unavoidable therefore, it was very selfish to not do anythingabout it and put the life of so many people at risk.After the disaster, LanChung, a professor of civil engineering and Professor Oan Chul Choi, head ofdepartment of Architecture, started investigating the reason why the structurecollapsed. The firstthing they noticed in their investigation was that the structure of the storewas a flat-slab structure as illustrated in figure 5, there are no cross beams or steel framework; without crossbeams, there is a form of load transmission missing, which means the framework must be constructed perfectly. Secondly,they began to look at the site on which the building was constructed and thematerials used.
Research revealed thateven though the superstructure was built on a landfill, the foundations andbasement rested on rock and survived the collapse well. (Chris McLean andothers 2010). The investigation revealed that cutting holes in every slabweakened the structural integrity of each slab. The columns were supposed to bearound 31-35 inches thick but were less than 24 inches thick. In addition, thedistance between each column was around 36 feet which was very dangerous. The air conditioning unitswere placed on the roof in order to keep the noisy machinery away fromsurrounding skyscrapers. Investigators soon learned that the air conditioningunits on the roof hadbeen moved due to noise complaints from surrounding buildings anyway.
Insteadof hiring cranes and professional moving teams, the units simply had been dragged across the roof, creating huge cracks.Figure 6 illustrates diagram of forces moving air conditioning units. ChrisMcLean and others 2010). The constant vibration of the AC caused the cracks to widenin column 5E leading it to a critical failure. The rescue team was on thescene within minutes of the incident, however, rescue crew did not beginsearching until the next day due to the risk for the rescue team.
Theauthorities called off the search because of the risks involved for the safetyof rescues over the fear that the remains of the store could come down. Aftertwo days, some officials assumed that anybody left is dead but one individualsurvived for 16 days in the collapsed with just few scratches of drink rainwater to survive. During the interrogation in thetrials. Lee Joon was charged with criminal negligence and received a prisonsentence of ten years which was later reduced to seven and half after an appealin April 1996. His son, Lee Han-Sang, received seven years for accidental homicideand corruption. Two city officials and chief administrator were also involvedin taking bribe which as a result were jailed. Other parties involved includedSampoong Department Store executives and the company who was responsible forcompleting the building.
The settlement involved 3,293 cases in which the totalcost was around $300-350 million. All in all, the factors thathad the most critical impact on the collapse were the changes in the design andthat these changes were carried out without any approval in the process ofbuilding maintenance, in addition, a very heavy load was added and thestructure was cut and damaged which damaged the structure. In the process ofconstruction, there was a very poor management and supervision which causedpoor construction, which was one of the factors that impacted the collapsed.The factors mentioned so far lead to the disaster as the safety factors werenot secured.
The collapse could had been avoided in many different timesthroughout the construction and life span of the building.