On the morning of 24 April 2013, Rana Plaza, an eight-storey commercial building in Savar on the outskirts of Dhaka, collapsed while thousands of garment workers were inside. More than 1,100 people died, with the widely cited final count at 1,134, and around 2,500 were injured. The Rana Plaza collapse is the deadliest disaster in the history of the global garment industry and one of the deadliest accidental building failures anywhere.
This article sets out what the Bangladesh government’s probe committee found, explains the structural mechanisms in plain terms and describes the safety reforms that followed. Most of those who died were young garment workers, many of them women. The engineering facts are presented here because understanding them is part of making sure such a failure does not happen again.
The building and how it was used
Rana Plaza was completed in 2006 and housed shops and a bank on its lower floors and five garment factories above. It was a reinforced concrete frame structure. Garment production is a heavy industrial use: rows of sewing machines, stock, cutting tables, large numbers of workers on each floor, and diesel generators to keep production running during power cuts.
Buildings intended for shops and offices are designed for lighter floor loads than industrial buildings and are not normally designed for the sustained vibration of heavy machinery. The building’s architect has said publicly that it was planned for shops and offices, not factories. Using a building in a way it was not designed for is, in engineering terms, overloading it, even if nothing is added to its structure.
Warning signs on 23 April
On the day before the collapse, large cracks appeared in the building and were shown on local television. The building was evacuated, and the bank and shops on the lower floors stayed closed the following day. Workers in the garment factories, however, were told to return. On the morning of 24 April a power cut led to the generators on the upper floors being started. Within minutes the building collapsed, leaving only part of the ground floor standing.
Visible cracking in a reinforced concrete frame, particularly in columns, is a sign that the structure is under distress. It is precisely the moment at which a building should be closed and assessed by a qualified engineer, as discussed in our guide to types of concrete cracks.
What the official probe into the Rana Plaza collapse found
The committee appointed by the government of Bangladesh identified several causes acting together:
- Unsuitable ground. The building stood on land that had been a pond and was filled in. The committee found that the site was not suitable for a multi-storey building of this kind.
- Floors added without permission. According to the committee, approval existed for fewer floors than were built, and the additional upper floors were constructed without permission.
- Substandard materials. The committee reported that poor quality reinforcing bars and cement had been used.
- Heavy machinery and vibration. Industrial machinery and the generators on the upper floors imposed loads and vibration the structure had not been designed to carry.
The committee recommended prosecution of the building’s owner and the owners of the factories. Criminal proceedings in Bangladesh have been slow and, at the time of writing, have not fully concluded. This article does not go beyond the committee’s findings in assigning responsibility.
The engineering mechanism in plain terms
Each finding of the probe attacks the same thing: the margin between the load on a column and the load it can carry.
Load went up
Extra floors added dead load to every column below them, and the heaviest increase fell on the ground-floor columns, which carry the accumulated weight of everything above. A change to industrial use added live load and dynamic load from machinery.
Capacity went down
The strength of a reinforced concrete column depends on the quality of its concrete and steel and on how well they are placed and compacted. Poor materials reduce that strength directly. Our article on reinforced concrete explains why the two materials have to work together to perform.
Support became uncertain
Filled ground over a former pond is often soft and variable. It can settle unevenly, which introduces additional stresses into a frame that is already close to its limit. Understanding soil bearing capacity and designing foundations for it is the first step in any building.
Vibration was the final trigger
When the generators were started on the morning of the collapse, the vibration they introduced into a structure already showing distress is understood to have been the final load it could not bear. Once columns began to fail, there was no reserve to redistribute their load, and the collapse spread through the building.
Reforms that followed
The disaster brought international attention to building and fire safety in garment factories. Within weeks, global brands, retailers and trade unions signed the Accord on Fire and Building Safety in Bangladesh, a legally binding agreement providing for independent inspections of supplier factories, remediation of hazards and worker safety committees. A parallel initiative was formed by a group of North American companies. The government of Bangladesh, with the support of the International Labour Organization, also expanded factory inspection, and a fund was established to compensate victims and their families.
Thousands of factory buildings were subsequently inspected for structural, fire and electrical safety, and many required strengthening, load reduction, or the relocation of heavy equipment and storage. The inspections confirmed that the conditions at Rana Plaza were not unique.
Lessons for building owners everywhere
The Rana Plaza collapse may seem distant from a regulated building environment, but its lessons are universal. A building is designed for a particular use, and changing that use, adding floors or installing heavy plant changes the structure’s demands. These are matters for a professional engineer, not for an owner or tenant to decide alone.
In Singapore, the Building Control Act requires structural changes to be designed by a professional engineer, and the periodic structural inspection regime exists to identify distress in existing buildings. For older buildings, a structural inspection is the proper response to visible cracking or a proposed change of use. The case sits alongside others in our overview of famous structural failures where warning signs were visible before the collapse.
Frequently asked questions
What caused the Rana Plaza collapse?
The government’s probe committee found that the building stood on filled ground unsuitable for it, that upper floors had been added without permission, that substandard materials had been used, and that heavy machinery and generators imposed loads and vibration the building was not designed for. Together these left the columns without enough capacity, and the building collapsed on the morning after cracks were found.
How many people died in the Rana Plaza collapse?
More than 1,100 people died, with the most widely cited final count being 1,134, and around 2,500 were injured. Most of the victims were garment workers employed in the factories on the upper floors.
Were there warnings before the building collapsed?
Yes. Large cracks were found on 23 April 2013 and the building was evacuated that day. The shops and bank on the lower floors remained closed, but garment workers were instructed to return the next morning, when the building collapsed.
What changed after Rana Plaza?
Brands, retailers and unions signed the Accord on Fire and Building Safety in Bangladesh, leading to independent inspections and remediation of thousands of garment factories. The government expanded its own factory inspection with ILO support, and a compensation fund was set up for victims and their families.
Related reading
- Hyatt Regency Walkway Collapse: The Connection That Failed
- Sampoong Department Store Collapse: What Went Wrong
- Tacoma Narrows Bridge: Why It Failed and What It Taught
- Nicoll Highway Collapse (2004): Engineering Lessons
Planning a change of use or new equipment in an existing building, or concerned about cracking? Talk to our consultancy or get in touch for an accountable structural assessment.
