ME6011 fifth floor. Several engineers that had
ME6011 Assignment Sampoong Department Store Introduction The Sampoong Department Store was constructed in Seoul,South Korea. It had been collapsed on the 29th of June in 1995. Thiscollapse is known as the deadliest modern building collapse that has takenplace, up until the attacks that took place in New York.
The reasons behindthis disaster were the numerous errors made by the designers and contractorswho built the store, and the irresponsibility on behalf of the store owner. The structure had been built on top of a landfill, whichwas originally designed for an office building. However, midway throughconstruction, the chairman had desired to construct it into a department store,with an additional fifth floor. Several engineers that had been working on theproject warned the owner, Joon, that the changes were life-threatening.
Theystated that the building had high chances of collapsing. However, Joon did not comprehendwith the fact that this was a high probability, and fired his workers instead. When the disaster had taken place, 1500 people were presentin the building and got trapped, in which over 500 died and 937 underwentnon-fatal injuries. The rescue team was not able to start their search till thenext day due to the risk of further collapses, therefore rescuers would have beenat risk.
Figure 1 illustrates the department facilities for eachstory. Figure 1, Department facilities for each story andcollapsed part (Chris Mclean)Literature Review The construction of the Sampoong started in 1987. It wasfirst designed to be an office, but the future chairman of the building, JoonLee decided that it should to be a department store instead. 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. (Almarwae Mohammed 2017). Joon undermined the safety procedures, thus he had stakedthe lives of the people involved in the event, despite knowing the consequencesthat this could lead but he neglected them.
InApril 1995, cracks began to appear in the ceiling of the south wing’s fifthfloor. The only response by Lee and his management staff involved movingmerchandise and stores from the top floor to the basement. Eventually thecracks increased forcing managers to close the top floor and shut the airconditioning. The store management did not shut the building or make anyoneaware of the situation apart from the executives and chairman, the reason whythey did not want to close the building down was because it was a very busystore and did not want to lose day’s revenues, However, the executives andchairman did leave the premises.
(Guo, H.and others 2010). Civil engineering experts were instructed tointerrogate the structure. They carried a basic cursory check, in which theydiscovered that the building was at a risk of collapsing. About five hoursbefore the collapse had occurred, a destructive uproar had been heard from thetop floors; the vibration of the air conditioning had caused the cracks in theslabs to expand further. After the cracks had already developed 10cm wide, the collapsingof the building was unavoidable, thus an emergency meeting was held. During themeeting, the directors suggested that all members in the building must be evacuatedfor their own safety. However, Joon had inclined this idea, over the fear oflosing revenues.
Joon had been successful in leaving the building himself, butdid not evacuate the customers. On the 29th of June, the northwing of the Sampoong store had collapsed, resulting in the death of over 500people. The large number of fatalities was due in part to a distinct lack ofconcern by the building owners/ occupiers in failing to take note of signs ofserious structural distress before the collapse and evacuating the occupants.The five-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 period of the critical failure, it had only taken around 20 seconds for theentire south wing of the structure to crumple. Figure 2 illustrates the Sampoong Departmentstore after it had collapsed. In addition to this loss, it is estimated thatthe property damage was around $216 million.
Figure 2, SampoongDepartment Store collapse (Cindoche) 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). In 1993, the airconditioning units had been transferred over to the column 5E, where the mostvisible cracks were. The reasoning of this was so that the air conditioning couldcover the cracks.
The cracks were aggravated because of the columns that hadbeen supporting the fifth floor.Witnesses had claimed thatthe collapse had rooted from the fifth floor. The committee that was in-chargeof the inquiry concluded that the collapse started at column 5E on the fifthfloor. The causes for the collapse were taken into account as design errors,construction failures, substandard construction quality control, and reductionin the cross-section of the columns to support the fifth floor. Figure 3 illustrateshow column 5E was damaged. Figure 4 illustrates vibrations for AC units. Figure 3, How Column 5Ewas damaged (Chris McLean)Figure 4, Vibrations fromAC units cause further damage to column 5E. (Chris Mclean).
At around 5.00 p.m.
of the localtime, the fifth-floor ceiling had started to sink, and so the store workers hadblocked access to the fifth floor. Prior to the incident, the store was occupiedwith countless customers. However, Joon did not desire to close the store orcarry out any repair during that time.
When the building started to produce cracking sounds at about 5:52 p.m.The workers began to alert the building with sound alarms and evacuate thebuilding, but it was too late to be able to take any action. Around 5:52 p.m.,the roof gave way, and the air conditioning units crashed through into thealready-overloaded fifth floor. The main columns weakened to allow theinsertion of the escalators, collapsed in turn, and the building’s south wingpancaked into the basement. Within 20 seconds of the disaster, all of thebuilding’s columns in the south wing gave way, killing 502 people and trappingmore than 1,500 inside.
(Almarwae Mohammed 2017).It is evident that thewhole tragedy could have been avoided if they evacuated the customers on time,but Joon Lee did not consider such an approach to be necessary. Joon Lee wasaware that the collision was unavoidable, therefore he did a self-serving actby saving his own life and putting others at a risk. After the disaster, LanChung, a professor of civil engineering and Professor Oan Chul Choi, head ofdepartment of Architecture, started a thorough interrogation of why the building’sstructure had been a failure. The first thing they observes was that the structure of thestore was 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, this means that frameworkmust be constructed perfectly.
Secondly, they started to look at the site onwhich the building was constructed and the materials used. Research revealed that even though the superstructure was built on alandfill, the foundations and basement rested on rock and survived the collapsewell. (Chris McLean and others 2010). The investigation revealed that cuttingholes in every slab had weakened the structural integrity of each slab. Thecolumns should have been around 31-35 inches thick, but that wasn’t the case asthey were less than 24 inches thick. In addition to that, the distance betweeneach column was around 36 feet which was hazardous. Figure 5,Example of Slab Construction (Chris McLean 2010) 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. Figure 6, Diagram of forces moving airconditioning units (Chris McLean 2010) The Sampoong Department had collapseddue to the ignorance of safety issues, and punching shear failure, which isillustrated in figure 7. The construction of a flat-slab permitted the entirebuilding to collapse. Figure 7, Diagram of PunchingShear on Column 5E.
(Chris McLean) The rescue team made anappearance during the event within minutes, however, the search had not begun untilthe next day due to the life-threatening risks for the rescue team. After twodays, some officials assumed that any member trapped would be dead, but oneindividual survived for 16 days, with the help of drink rain water dropletsfalling in. While the investigation in thetrials had taken place, Joon was charged with criminal negligence and receiveda prison sentence of 10 years, which was later deducted to 7.5 years after anappeal in April 1996.
His son, Lee Han-Sang, underwent 7 years for accidentalhomicide and corruption. Two city officials and chief administrator had alsoparticipated in taking bribe, and so they were also jailed. Other parties thathad been participating included Sampoong Department Store executives and thecompany who had had a responsibility for constructing the building. Thesettlement involved over 3000 cases (3,293 precisely), in which the overallcost was around $300-350 million. All in all, the factors thathad had the gravest impact on the collapse were the changes in the designing,and also the fact that these changes were carried out without any approval inthe process of building maintenance.
Furthermore, a heavy load was topped andthe structure was cut and damaged which damaged the entire structure. In theprocess of the construction, there had been a poor management and supervision,which resulted in poor construction, and so it had been the main factor of thebuilding’s collapse. These factors had been a contribution to the disaster, asthe safety factors were not secured.
The collapse could have been avoided inseveral occasions throughout the construction, and there could have been a lifespan of the building. References Chris,McLean and others. (2016). Sampoong Department Store. Availableat: https://failures.wikispaces.com/Sampoong+Department+Store. (Accessed:09/01/18).
Cindoche(2017) In 1995, the Sampoong Department Store collapsed killing morethan 500 people. Available at:https://www.reddit.com/r/CatastrophicFailure/comments/49vv26/in_1995_the_sampoong_department_store_collapsed/(Accessed: 11/01/18). Gardner,N, J and others. (2002) Lessons from the Sampoong department store collapse.
pp1-7. Guo, H., Zhang,B., Lei, L., Zhang, L., & Chen, Y.
(2010).Spatial distribution and inducement of collapsed buildings in Yushu earthquakebased on remote sensing analysis. Science China Earth Sciences, 53(6), 794-796.(Accessed:09/01/18). This Dayin History (2016)Available at: http://divorcelawyersteam.com/blog/this-day-in-history-june-29th/(Accessed: 9/01/17). Mohammed,Almarwae.
(2017) ‘World Scientific News’, Structural Failure of Buildings:Issues and Challenges, pp 3-Won Park,Tae and others. (2012) ‘Inspection of collapse cause of Sampoong DepartmentStore’, pp1-8.