‘Cement quality not responsible for building collapses’

Victor O. Oyenuga was the president of the Nigerian Institution of Structural Engineers between 2009 and 2011. He was the best graduating student of 1978, at Yaba Polytechnic and a first-class degree holder at the University of Lagos. In this interview with ODINAKA ANUDU, the Imperial College graduate and designer of Teslim Balogun Stadium debunks the rumour that cement quality is responsible for ceaseless building collapses in Nigeria. Excerpts:

There is this insinuation that cement quality is responsible for incessant building collapses in the country. How do you react to that, from a professional point of view?

Well, this is definitely not true. It is actually the mixture that gives you the quality of concrete or mortar. What is actually the problem is the proportion of the cement used, not the cement itself.

What then are the causes of building collapses?

One is the foundation. When we talk of foundation, we refer to soil test. Once soil test is not done, the engineer cannot physically determine the strength of the soil required. Once he does not know the strength, the foundation could be faulty. Then we can also have a faulty design; that is, the engineer did not design the way he ought to. This often occurs if the task is not given to a structural engineer.

But the major problem is construction, either in terms of materials or production of concrete itself. Since we often refer to the strength of the concrete, if the engineer, for example, designed to grade 25 concrete, and the mixing after tests showed something much less, you find out that the proportion required would probably be more. So, once the building is loaded, you end up having a collapse because the strength of the concrete is not as adequate as he had already thought. So, where cement comes in is in the mixture. You know people often want to cut corners because they believe cement is expensive. So, where two bags are required, they use one. When you use one, you cannot expect the same strength because this is all about binding.

Is this an indictment on professionals?

No, it is not an indictment because none of the buildings collapsed has ever been handled by a structural engineer. I can categorically say this anywhere. The only thing we are not happy about is that people are dying but nobody is paying compensations.

What then can be done to curb recurring building collapses?

One, government should be ready to curb building collapse. Yes, there must be that political will. After collapse, the whole place would be cleared over night in such a way that nobody would know something had happened. After a building collapse, there must be lessons to be learnt.

Our recommendation is that once there is a collapse, the whole place should be cordoned off. Let Council for the Regulation of Engineering in Nigeria (COREN) and a body called Engineering Regulatory Monitoring (ERM) contact the specific association, especially Institution of Structural Engineers. We move to the site and find out the cause.

What is worrisome here is the types of building that are collapsing. Buildings that collapse overseas are major ones, but here we talk about two or three storey buildings and even bungalows collapsing.

The second aspect of it, which the Lagos State government has been implementing since my regime, is that there must be soil test for every site, especially if it is two or three storey buildings. It is helpful to the owner because he will know exactly the type of soil he is dealing with, and to the engineer to enable him know the exact strength. Most of the problems occur at the bottom; once it fails there, the building collapses.

Number three is that buildings should be given to structural engineers for the design so that if there is a problem, we know who to hold responsible. Another one is that we must allow professionals to supervise, because a professional structural engineer will not allow the owner or contractor to go against specifications.

The problem in terms of raw materials is iron rod. They will say ‘half inch, not full’ but I don not understand that. It is either it is half an inch or it is not. This is why I recommend that iron manufacturers should attach certificate of delivery to every consignment. This will indicate the strength of the materials, the diameter, so that it can be measured when taken to the site.

Are collapses mainly associated with old or new buildings?

You see, every building has a life span. On the average, buildings are designed for 50 years. But you find out that most of the times, old buildings are modified. If you modify a building meant for residential to commercial, there may be collapse. This was the case with the Oshodi incident.

What then are the roles of cement manufacturers in curbing the menace?

I know that no cement manufacturer in Nigeria produces fake cement. Lafarge, Dangote and others are recognised beyond Nigeria. But I expect that cement manufacturers to give certificates of consignment, showing the strength of cement. You know we have different classes of cement, so they have to specify.

What roles could government play to arrest the situation?

The government can work through the seven regulatory bodies of engineers, technologists, etc. Again, it is the role of the Standards Organisation of Nigeria (SON) to ensure that manufacturers meet the standards. They can go in there, take samples, test and report back. But the problem is that the government does not believe its citizens. I designed Teslim Balogun, five years before my graduation. The stadium is used by FIFA now. I went to Imperial College, best in Europe and second in the world. We were 23 and three of us, two Nigerians from University of Lagos, and one white person who finished from here. Let the government give us jobs because we know what we do beyond the shores of this country.