Building Collapse: Engineers Speak On Causes, Preventive Measures

Recently, reports of building collapse have been on the rise in Nigeria.

Some engineers who spoke with AllNews Nigeria  shared some of the reasons why such a tragedy occurs and measures that can be put in place to avert future occurrences.

Femi Adedokun, a building contractor explained that there are various reasons that could cause buildings to collapse, identifying some of them include human errors, mistakes during installation of the building foundation, inappropriate construction and performance failure.

“Failure to a waterproof foundation is the biggest foundation mistake around and can cause the collapse of a building if left unchecked because it can destroy the foundation over time.

“Most foundations are made of cement or concrete, which is extraordinarily durable but porous. This means that water can penetrate the foundation. 

“Over time, water inside the foundation will contract and expand as it freezes. 

“Even if the building is situated in an area which does not experience regular freezing temperatures, water will still weaken and slowly break down the foundation.

He also identified pouring a foundation in inappropriate weather or not giving the foundation enough time to dry up as a factor responsible for the collapse of buildings

“Concrete and cement are extremely durable materials. However, a big part of their strength depends on being allowed to dry properly. 

“Immediately after pouring, a cement or concrete foundation needs adequate time to dry

“The period required to dry varies, depending on the particular mix used.

“Not giving a foundation adequate time to dry can cause the foundation to settle, crack, sag and not be able to support as much weight as it would if it had been allowed to dry properly, which is one of the most grievous errors that can be made during the installation of a foundation.” 

Adedokun, therefore, advised that a foundation be poured on a pleasant day with no threat of rain. 

Commenting on inappropriate construction as a cause of building failure, he said, “Failure to build in accordance with drawings and specifications can also add to failure of structures.

“Extra loads due to unauthorised change of use or additions and alterations to the structure can intensify an under-designed building and can contribute to its failure.”

Adedokun also said the use of inferior or substandard building materials is another reason buildings fail.

He further explained that the collapse of buildings can be due to human error, especially from the structural engineer.

“Sometimes, buildings collapse due to obvious negligence or gross human error, especially on the part of the structural engineer.

“When the structural engineer fails to account for loads the structure is expected to carry, it might later lead to the collapse of such buildings. 

Adewale Odewale, a civil engineer identified the use of inferior materials, improper measurement, inadequate supervision, unskilled workers and poor pre-production as factors that might be responsible for the collapse of buildings.

“Engaging unskilled workers in building projects is one of the factors that affect the collapse of buildings because they don’t have the in-depth knowledge of building constructions.

“Managing materials such as cement, sand, granites, etc can also lead to the collapse of buildings later in future, therefore having more than enough materials is suggested than to manage on construction sites.

“If proper measurements are not used it can lead to structural failure. 

“For instance, using 300mm for spacing a bar that should be in 200mm or extending a floor of which is supposed to be 30msq to 45msq. 

“Therefore, it is advisable to work with the designed measurements to avoid excessive spans. 

“Excess load or additional load is also one of the most important areas to take note of in construction. 

“If a building is initially designed to be four floors and the structural element for such a building has been planned to be a four-storey building, probably during construction the owner of the house might instruct the contractors to make it seven stories.

“Therefore, it is obvious that the structural element has been overloaded, which might result in the collapse of such building.”

Speaking on how it can be avoided, Odewale said it is better to make decisions before the execution of a structure or do a new structural design for the new load imposing on the structure.

“Also, another factor that could lead to the collapse of a building is when workers fail to follow the normal time of construction, that is when they try to hasten the process.

“For instance, during construction,  it is advisable to wait for about 28 days for a concrete floor to get dry before the removal of props, but some workers won’t wait for the number of days probably because they want to complete the project faster and this might weaken the structure of such building and might lead to collapse.”

Odewale suggested that before the commencement of any building project, it is important to check the defects on the existing buildings to know how to avoid those defects on newly proposed structures, such as checking the topography of the road, gutters and so on. 

He also emphasised investigating the soil-bearing capacity to know the kind of load to impose on the soil and the type of foundation to be chosen for the particular proposed building and design the foundation based on the load and soil capacity.

An architect, Olanrewaju Ogunsekan, also speaking on factors that might lead to the collapse of a building shared, “The foundation is the most important aspect of any building. 

“For a building to be structurally stable, the foundation needs to be solid because a lot of buildings collapse because of foundation errors.

“He also identified causes of foundation errors to include inappropriate foundation type, improper concrete mixture, lack of supervision and poor ground preparation.

A building contractor who pleaded anonymity mentioned poor foundation, non-skilled labour, use of sub-standard materials and improper supervision as factors that could lead to the collapse of buildings.

Speaking on a poor foundation, he said, “If the foundation is not adequately planned, it means there will be problems in the building itself sooner or later. 

“For instance, some might have a plan of constructing a two or three-floor building then they start with the foundation that would carry such.

“At the end of the day, probably because the owner of the building has more funds or for some other reason, the person wishes to extend the buildings to five or six floors, he would still use the foundation planned for three or four floors for five and six, which is wrong because the foundation won't be strong enough to bear such load.

“Sometimes, the poor foundation could also involve the use of materials.

“When it comes to foundation, there are standards at which it should be made.

“Some use beam, some use formwork, some use binding, so it depends on the structure of the building and the number of floors you build.

“It  also depends on the kind of foundation you are given.”

He further harped on the importance of having a good labour head during construction.

“Having a good labour head will make it possible to point out the tiniest mistake during construction and make necessary adjustments immediately, which will prevent the building from collapsing because when people are skilled enough at what they do, they do the job perfectly."