Engineers, others urge proper maintenance of high-rise buildings

ederal Mortgage Bank of Nigeria’ head office in Lagos before it was gutted by fire

ederal Mortgage Bank of Nigeria’ head office in Lagos before it was gutted by fire

FOLLOWING the fire disaster that occurred recently at the Mammam Kontagora Building belonging to the Federal Mortgage Bank of Nigeria (FMBN) in Central Lagos, professional structural engineers have advocated for proper maintenance of high-rise structures.
 
Most of the high-rise buildings, according to members of the Nigerian Institution of Structural Engineers (NIStructE), were Class A – buildings, designed and supervised by reputable professionals and constructed by seasoned building contractors, selected through standard processes of design, tender, evaluation, award and construction supervision.
 
They argued that with proper maintenance schedule, especially sticking to maintenance culture of the managers, high-rise buildings could last longer. 

“The design life of buildings is usually 50 years but most buildings if well designed and constructed can last for longer years. The Western House in Lagos is about 55 years old and can last twice as long if properly kept. The Union Buildings in Pretoria, South Africa is about 102 years old,” says Mr. Oreoluwa Fadayomi, Vice President of Nigerian Institution of Structural Engineers.

Fadayomi, who is being referred to as the “doyen of engineering profession”, explained that when political considerations over ride the general interest and caution is thrown to the wind, some high-rise and medium-rise building projects are executed without sound professional input. Construction is carried out shoddily and to no particular standard or specifications. Many of such buildings end up being unserviceable and ultimately collapsing.”

He listed structural state of building structures to depend on many factors. These include how good the structural design was; compliance of the contractor to design specifications during the construction; use the building has been put to through the years; maintenance culture of the managers of the building and location and the regularity of such or other natural disasters.

On the fire disasters in high-rise buildings, a former president of the institution), Dr. Victor Oyenuga said: “High-rise or buildings generally are designed to withstand a minimum of one-hour fire resistance. That is, a fire that lasted less than one hour should not normally have a significant effect on the building. This, however, depends on a quite number of factors including the cover, the durability of the cement component of the concrete, the concrete grade and the quantity of reinforcements in the building.”

He however, suggested that the government should engage qualified structural engineers to regularly assess old buildings in Lagos and the integrity of its members. “A building that suffer fire disaster can only be pronounced non-serviceable by a qualified structural engineer after carrying our non-destructive integrity tests on the concrete elements and coring of some part of the elements may needed to be carried out.

“When the various tests are carried out on the building elements, slabs, beams, columns, shear walls, and staircase walls, and analyzed, the necessary steps of strengthening such structure can commence. When the non-destructive and the destructive tests proved that the elements are weak, that is, their strength are no longer commensurable with the services to be provided, then such buildings are better demolished.

“The most noticeable is the observance of cracks all over the building or in some parts of the building. Cracks may indicate a minor problem or a major/disastrous fault in the building. The structural engineer studies such cracks and the interpretation will reveal the next line of action. High-rise or buildings generally are designed to withstand a minimum of one-hour fire resistance.

That is, a fire that lasted less than one hour should not normally have a significant effect on the building. This, however, depends on a quite number of factors including the cover, the durability of the cement component of the concrete, the concrete grade and the quantity of reinforcements in the building.

A building that suffer fire disaster can only be pronounced non-serviceable by a qualified structural engineer after carrying our non-destructive integrity tests on the concrete elements and coring of some part of the elements may needed to be carried out.

When the various tests are carried out on the building elements, slabs, beams, columns, shear walls, staircase walls etc, and analyzed, the necessary steps of strengthening such structure can commence.

These are tests carried out to determine whether that part of the structure is serviceable or not. These are either non-destructive using Schmidt hammer or destructive, by coring and crushing of the cored concrete. The interpretations of the results determine what is to be done next.

He also said that when the non-destructive and the destructive tests proved that the elements are weak, that is, their strength are no longer commensurable with the services to be provided, then such buildings are better demolished,

In his submission, Mr. Kunle Adebajo, a past President of NIStructE, who lamented the lack of maintenance culture in Nigeria, called for cooperation between the architects and structural engineers in all stages of construction such as foundation, soil test and design to ensure structural stability of high-rise buildings in the country.

According to Adebajo, periodical inspection is paramount in sustaining structural stability of high-rise buildings. “As a matter of fact, regular inspection will reveal if there is crack, corrosion or any form of defect and it is when there is consistent inspection that one would be able to capture the true condition of such building, because one cannot maintain something you don’t know where defects lie”.

He listed the causes of structural deficient include exposure of concrete buildings to certain environmental factors; hiding parts that could not be easily detected and some areas that are not easily accessible.

In the event of fire incident, Adebajo stated that damages has different dimension. “For instance, if boiling water fell on someone, he/she may need little attention. However, another victim with such accident may require a severe operation, even amputation. So with buildings that suffer fire outbreak”, saying the degree of damage depends on how long the fire burnt; the degree or intensity of the burning and the time it takes before the fire was put off.

“In any of these cases, experts would determine whether the building would need partial or complete demolition, citing the example of NIDB building that needed to be totally demolished due to the extent of damage it suffered.

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