Investing in quicksand as buildings collapse across Kenya
By Peter Theuri | September 30th 2021
Nearly a month ago, a five-storey residential building in Kinoo, Kiambu County, sank while under construction and leaned so precariously it drew similarities to the famous Tower of Pisa in Italy.
The building had suddenly put lives at risk, but it was ultimately flattened under the supervision of engineers from the National Construction Authority (NCA) and officers from the county government.
Institution of Engineers of Kenya president Nathaniel Matalanga attributed the collapse to a weak foundation.
“You cannot build a five-storey structure on a narrow foundation without the service of a structural engineer. It will collapse,” he told Real Estate.
Just over a week later, a two-storey building under construction collapsed in Mamboleo, Kisumu County. Three bodies were retrieved from the collapsed building.
This is not the first time bad contractors have been exposed, with amateurish work leading to loss of lives. Who, exactly, has been sleeping on the job?
Tom Oketch, chairman of the Institution of Construction Project Managers of Kenya, piles the blame on inspectors and county governments, which he says have abdicated duty.
“People will want to take shortcuts when building so as to cut on costs and time, and so if there is not enough supervision of structures they are all condemned to fall,” he says.
“Such constructions should be nipped in the bud, but those responsible for it seem to be reluctant to do their job.”
Dr Oketch says it is time for authorities to be held to task over their failures.
NCA is also partly to blame for the collapsed buildings, industry experts say, with people involved in the construction sometimes not certified by the authority.
The Institute of Quantity Surveyors of Kenya said that, in the Kinoo building’s collapse, the developers had sought the services of unlicensed people to cut costs.
A lot goes into construction, with the law providing the steps for development control and enforcement.
At the outset, the developer, or their agents, should submit a development proposal in form of building plans to the county government for approval.
“Vetting by a physical planner within the county government then follows, with invoicing for payment of the necessary applicable approval fees,” says Joseph Njomo, Principal Physical Planner with the County Government of Nyeri.
Upon payment, the application is registered and booked for consideration by the approval committee.
After approval of the building, plans are released to the applicant together with a card bearing the name of the building inspector who is supposed to ensure that all the listed steps of construction are monitored and followed.
“Registration of the approved plan with the NCA is done. During construction, right from the setting out of the site to completion, the developer is expected to engage the building inspector at every stage,” Mr Njomo says.
For construction at an environmentally-sensitive area, National Environment Management Authority approval is mandatory.
Further, high-level developments such as multi-dwelling units and industries are also subjected to the same.
“Upon completion of the project where the inspection card is duly signed by the building inspector and the developer’s consultant, a completion certificate and a subsequent occupation certificate are issued,” Njomo says.
In case of an approved project where the developer fails to engage the building inspector as guided, the enforcement notice is issued to stop further construction until a structural integrity report is submitted by a private registered structural engineer.
The structural integrity report indemnifies the county government in case of any eventuality.
But the county government should not be absolved from blame if such buildings collapse without the report.
“In case of non-approval, the above procedure also applies but subject to payment of regularisation fees. In case of defiance to an enforcement notice, prosecution is instituted through the county government legal office,” says Njomo.
In case of a dangerous or hazardous eventuality, assessment is based on the compliance to approval conditions and whether the building was being inspected as guided.
Brian Kambona, an assistant engineer at Rhines Engineering Services, says a building collapses when it fails to bear its own weight, called the dead load, and the imposed pressure, known as the live load.
“Oftentimes, a building collapses when the key structural members, that is roof, slab, beam, column and foundation, fail,” he says.
The problem stems from the “do-it-yourself” mentality where developers turn a blind eye on professionalism, the engineer says.
“Developers are embracing quackery in the construction sector to save a few coins, without understanding the compounded negatives effects of their actions,” says Mr Kambona.
But engaging a quack for one’s design only leads to poor, underwhelming work.
“There is often cases of incorrect analysis of loads, which leads to poor sizing of members (beams and columns) and hence providing an avenue for imbalances in load distribution within the building,” says Kelvin Maina, an engineer at Losai Management.
“This leads to structural failure.”
Additionally, a building could be correctly designed but the developers sometimes feel the urge to add storeys, hence extra loads, during the implementation phase without consulting the design engineers.
“Developers also fail to pay attention to the geotechnical factors of areas they are building in, affecting the building’s foundation,” Kambona says.
Two things should govern choices made for the type of foundation, he says; the solidity of the soil and the heaviness of the building and its contents.
“Oftentimes, developers use shortcuts because adequate foundations can cost up to half the cost of the building depending on the factors mentioned earlier and this leads to differential settlement,” says the engineer.
“In differential settlement, failure originates from the sub-structure of a building and extends its impact to the entire structure, leading to collapse.”
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