By Ademola Adegbamigbe
As the year 2021 inches to a close, a tragedy that Nigerians can never forget in a hurry was the collapse of the 21- storey building on Gerald Road, Ikoyi, Lagos on Monday, 1 November 2021. It has, so far (as the excavation goes on), claimed over 40 lives, including that of the developer, Femi Osibona.
As the families of the bereaved mourn, those that narrowly escaped death thank their God, lies, conspiracy theories and subtle innuendoes have gone viral on the Internet. One of these was that Chief Michael Ade-Ojo sold the land on which the Ikoyi property was built to Vice President Yemi Osinbajo.
However, Ade-Ojo quickly issued a public statement, debunking that. See the statement here:
Beyond these, however, there are lessons to be learnt within and outside by Nigerian civil engineers.
Cocoa House in Ibadan, Oyo State, and the Ikoyi collapsed building on Gerald road, Ikoyi, Lagos, provide a great study in binary analysis. While it is clear that the building collapsed because it could not withstand the forces of nature or gravity or as a result of substandard materials or a combination of the three factors, Cocoa House still stands like the rock of Gibralter.
Not a few Nigerians believed (and still do) that what happened in Ikoyi was the result of not sticking to the specification approved. See the relevant document below:
The 26-storey Cocoa House was built by the old Western Region and commissioned in 1965. The Obafemi Awolowo/Ladoke Akintola government did it. That was with proceeds from cocoa exports. The edifice was built by Cappa and D’Alberto. Despite that fire gutted some of it’s floors at a point, peeling off the paints and plaster, the superstructure remains unaffected till today.
Nigerian builders can take their cue from the foreign builders who use a lot of steel reinforcements for their structures. See more photos under.
Skyscrapers that sway horizontally to wind force
On a visit to Nigeria from his base at the University of New Orleans, United States, Professor Niyi Osundare told this reporter about tall buildings that rock or sway to the wind.
Citing the example of The Chrysler Building in New York City, science.howstuffworks explains:
“In addition to the vertical force of gravity, skyscrapers also have to deal with the horizontal force of wind. Most skyscrapers can easily move several feet in either direction, like a swaying tree, without damaging their structural integrity. The main problem with this horizontal movement is how it affects the people inside. If the building moves a substantial horizontal distance, the occupants will definitely feel it.
The most basic method for controlling horizontal sway is to simply tighten up the structure. At the point where the horizontal girders attach to the vertical column, the construction crew bolts and welds them on the top and bottom, as well as the side. This makes the entire steel super structure move more as one unit, like a pole, as opposed to a flexible skeleton.”
Wind Resistance
In addition to the vertical force of gravity, skyscrapers also, as the report indicates, have to deal with the horizontal force of wind. “Most skyscrapers can easily move several feet in either direction, like a swaying tree, without damaging their structural integrity. The main problem with this horizontal movement is how it affects the people inside. If the building moves a substantial horizontal distance, the occupants will definitely feel it.
The most basic method for controlling horizontal sway is to simply tighten up the structure. At the point where the horizontal girders attach to the vertical column, the construction crew bolts and welds them on the top and bottom, as well as the side. This makes the entire steel superstructure move more as one unit, like a pole, as opposed to a flexible skeleton.”