When structural failure reflects societal failure
08 March 2016
Author: Sean Brady is the managing director of Brady Heywood. The firm provides forensic and investigative structural engineering services and specialises in determining the cause of engineering failure and non-performance
On April 23, 2013, large cracks were noticed in some of the floors, walls and columns of the eight-storey Rana Plaza complex in Dhaka, Bangladesh. An engineer inspected the damage and declared the building unsafe. Workers were sent home and the story made the local TV news – another garment factory in Bangladesh with safety concerns.
The following morning, the employees of the bank and shops comprising Rana Plaza’s lower three levels stayed away from work, but the workers from the garment factories on the upper five storeys arrived. Many believed they would simply be sent home. Instead, they were told that the structure had been reinspected and was safe.
Amid allegations of threats regarding the withholding of wages, the workers entered the building. At 9am there was a power outage – not an unusual event in Dhaka. The diesel generators on the roof kicked in to compensate. Vibrations shook the structure. It is reported that the building’s upper storeys had been constructed illegally, without the necessary permits, leaving the structure vulnerable. It collapsed.
Intense rescue efforts continued for days and weeks, and more than 2,500 people, some horrifically injured, were pulled from the devastation – one woman 17 days after the collapse. The death toll makes Rana Plaza one of the most shocking structural collapses in recent times. There were 1129 fatalities.
Some failures are caused by the most insidious of human factors: corruption and greed. The events surrounding Rana Plaza are eerily reminiscent of the collapse of the Sampoong Superstore in South Korea in 1995.The five-storey, bright pink superstore was originally conceived as an office development, and its beginnings were not without controversy. It was built on landfill, and the building’s foundations and basements were constructed by Woosung Construction.
But problems arose when Woosung resisted proposed alterations to the building’s use – it would be changed from office to retail and a fifth storey would be added. Woosung was dismissed and replaced by Sampoong’s in-house contractors, and in December 1989 the superstore was opened after inspections apparently confirmed it complied with all the necessary standards.
For five and a half years all was well, but by mid-1995 it become clear something was very wrong with the structure. On the morning of June 29, significant cracking was discovered in the roof slab. At some point previously, heavy air conditioning units, which were originally located on the east side of the building, had been moved to the west side because of noise complaints.
Rather than being lifted by crane, the units were simply pushed across the roof slab. It would transpire that the slab had only one-quarter of the required capacity to support the units and the roof was badly damaged. Cracks up to 25mm wide had opened up at column locations.
Engineers were called to inspect, and they advised the building be evacuated. The company executives decided otherwise. Over the course of the day, the cracks worsened and spread. The air conditioning units were switched off – vibration appeared to be making matters worse. By that afternoon the senior executives had fled the building.
Notoriously, they didn’t raise the alarm, and people continued to use the superstore, unaware of the events unfolding above them. At 6pm the building could take no more, and the 91m long north wing of the store suddenly collapsed. Only the two end walls of the structure remained standing. There were 498 fatalities.
Cause of failure
While the Sampoong Superstore failure may have been set in motion by the damage caused by relocating the air conditioning units, bribery and corruption had ensured a deficient structure from the beginning. One of the key issues was the decision to change the building’s use from office to retail without also re-evaluating its structural system, which was comprised of columns and flat slabs with no supporting beams.
The change to retail resulted in significant weaknesses being introduced, such as the installation of escalators necessitating large openings being cut in the flat slabs. But it was the replacement of the planned skating-rink on the fifth floor with a traditional Korean restaurant that posed the real problem.
Traditional Korean restaurants have no seating – patrons sit directly on the floor.
So the decision was made to install in-floor heating, which required the construction of a 900mm deep concrete floor. This additional concrete added significant mass to the structure, and increased the dead load of the fifth floor by 35 per cent. To make matters worse, columns were either simply omitted or moved to fit the restaurant’s architectural needs, leading to a situation where columns were no longer coincident with those on the level below.
The flat slab was now playing a critical structural role in transferring column loads between the floors. Ultimately, the cause of the collapse was these changes, brought about by the “illegal alteration of the architectural design and usage of the building”. 
While they may have led to the collapse, these illegal alterations were only the tip of the iceberg when it came to the building’s non-compliance. For example, columns specified as 890mm thick were actually 610mm thick. They had only eight, as opposed to 16, bars of reinforcement. In other places, reinforcement had been simply omitted.
Concrete strength was only 18MPa where 21MPa was specified. And these changes were made possible by corruption – 12 local building officials were found guilty of taking bribes for approving changes and providing provisional use certificates. They had been paid over US$17,000 .
The collapse and loss of life caused outrage in Korea, leading to an investigation of the construction industry. The investigation found an endemic level of corruption, which was historical. Throughout the 1980s Korea’s construction industry was booming, and the pressure on contractors to deliver was intense – a situation exacerbated by a government veto preventing overseas contractors signing contracts.
Then Seoul was awarded the 1988 Olympic Games, further stressing the situation. Such an environment was ripe for abuse, and the construction of the Sampoong Superstore occurred in the midst of this rush. While it would become its most visible casualty, the problem was much broader: the South Korean government’s survey of high-rise buildings would find that only 2 per cent complied with the standards; 84 per cent would need repairs, and 14 per cent were declared unsafe and required rebuilding .
The Sampoong Superstore disaster reminds us that every once in a while a failure occurs that has impacts far beyond the rubble and the tragic loss of life. Such failures force us, as a society, to take a closer look at ourselves. While Sampoong exposed widespread corruption, Rana Plaza highlighted an ugly affliction that had escaped mainstream discussion: modern day slavery.
The fallout quickly spilled over Bangladesh’s borders to land on our high streets. All the five garment factories in Rana Plaza – New Wave Bottoms, Phantom Apparels, Phantom Tac, Ether Tex and New Wave Style – produced clothes for Western clients .
The ramifications of April 24, 2013 are still being felt throughout the Western world: clothing retailers have had their ethical obligations thrust before them, there have been rallies in the streets, and the UK has passed the Modern Slavery Act, which will force companies with a turnover of £36 million or more to be accountable for the links in their supply chain .
The journey will be long and is far from complete, but the tragedy of Rana Plaza should remind us that every time we open our wallets in today’s globalised economy, the transaction is not only a monetary one. It is a moral one.
This article first appeared in The Structural Engineer in December 2015. It is reproduced with kind permission from the Institution of Structural Engineers.
Web: www.bradyheywood.com.au; Twitter:@BradyHeywood
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