Housing sector

Expert denounces the proliferation of soil tests in the housing sector

The outgoing President of the Nigerian Institute of Construction (NIOB), Mr. Kunle Awobodu has condemned the proliferation of soil testing in the housing sector, saying it is one of the main factors behind the the frequent collapse of buildings or structural failures in the country.

According to him, with the prevalence of cheap and dummy soil testing in the industry, structural design based on such geotechnical reports could lead to structural failure.

Speaking at the 2022 Engr. (Dr) TM Olatunji Distinguished Annual Lecture organized by the Nigerian Institution of Civil Engineers in Lagos, Awobodu, pointed out that a symbiotic relationship exists between geotechnics and structural design.

He explained that the subsoil investigation reports were used for the design of the foundations and that if the information provided by the ground from the soil test was inaccurate, the calculations and analysis of the engineer geotechnical engineer would not be correct.

In his presentation on “The Role of Professionals in Preventing Building Collapse in Nigeria”, where participants included front-line engineers, builders, urban planners and professionals under the auspices of the Building Collapse Prevention Guild ( BCPG), Awobodu said it is high time for professionals to take action to end the incidents of building collapses in the country rather than protracted talks.

The BCPG report shows that as many as 508 buildings collapsed in Nigeria between October 1974 and July 13, 2022 (48 years).

Of these, Lagos State recorded 320 incidents of building collapse during the period.

This means that Lagos State accounts for 63% of collapsed buildings in Nigeria, despite its small area.

Building collapse is a global phenomenon, according to Awobodu, but the frequency with which buildings collapse in Nigeria has sparked global concern over the need to help the country improve its safety performance.

Painting the sad state of soil testing business in the country, Awobodu said the prevalence of cheap and fake soil testing has forced major soil testing companies to fold as they cannot compete. in an unregulated business.

He said: “The importance of soil testing in preventing building failures led the Technical Committee led by Reis to recommend mandatory soil testing at sites of buildings with two stories and above. But what the commission did not contemplate was the unintended creation of jobs for charlatans.

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“The prevalence of cheap and bogus soil testing has forced major soil testing companies to fold. There was no way they could compete in an unregulated business.

“Unfortunately, because state materials testing laboratories are directly involved in soil testing activities, there is no neutral government agency regulating soil testing standards.”

According to Awobodu, observations from many soil testing sites revealed insufficient accessories, uncalibrated cone penetrometer (CPT) testing machines and poorly performed standard penetrometer (SPT) tests.

“In fact, N values ​​are commonly falsified because not taking SPT at regular or necessary intervals has become the norm,” he said.

Furthermore, he specifies that there was no school or training center for drillers who deal with soil analysis operations on sites, hence the trial and error approach.

The former NIOB Chairman said: “These days most drillers avoid soil testing sites where extensive monitoring is in place. Drillers are always in a hurry to complete the study of the basement.

“Therefore, a geotechnical drilling that is supposed to take at least 3 or 4 days could be completed by these ignorant drillers in one or two days.

“It is pathetic that young people are not interested in hard work drilling but in immediate pecuniary gains.

The unfortunate thing, Awobodu said, was the fact that the number of experienced drillers had been depleted by old age or death, adding that the souls of the energetic and seasoned drillers had rested in peace.

According to him, some have become weakened with age, adding seasoned drillers who could take SPT and also U-4 (undisturbed samples in cohesive strata with a 4 inch/100 mm tube) at critical depth and the formation is very thin on the ground.

“Lab tests on disturbed and undisturbed soil samples are barely adequate. Sieve analysis (particle size distribution curve), rapid undrained triaxial compression test, Atterberg limit test, oedometer consolidation test and water test have become a waste of time .

“Rising prices for diesel, transportation, spare parts, bentonite, and changes in other variables do not seem to affect the price of soil testing.

“Essentially, for many years, the soil test seems to be inflation-proof and therefore the price remains stable. In those days, a driller worked with two assistants. But nowadays, a driller works with an assistant, even when taking SPT to a stratum as deep as 25 m Hand-operated rigs (hand-rigs) have replaced percussion rigs at many soil testing sites.

“Some engineers and geologists, especially young people, who do not have paid employment, colluding with unscrupulous drillers, do not hesitate to sign and seal soil analysis reports which have not been supervised by them for a nominal fee.Yet the qualified civil/structural engineers who design the buildings and the developers are unsuspecting.Under these circumstances, the survey of the subsoil has become a mere formality.

“Unlike in the past, confirmatory soil testing has become fashionable due to lack of trust, causing customers to spend double,” Awobodu said.

Further, he added that the prevalence of pile foundation failure in the future was predicted due to substandard works encouraged by the free entry and non-remediation of this sector.

To correct these anomalies in the sector, Awobodu stressed the need for all built environment professionals to work cordially together, believing that when this happens, building safety will no longer elude Nigerian society.

He commended the Ogun State Government for a recently signed Memorandum of Understanding with the Building Collapse Prevention Guild, Ogun State Chapter, saying that through this singular effort, the seemingly impossible synergy between the Built environment professionals from the public service and those from the private sector had to become realistic.

According to him, the barriers created by the mentality of defending the territory have now been dissolved in favor of a collective attack on the tendencies of building collapse.

“Kudos to the Gateway State government for not putting revenue generation ahead of building and life safety,” he said.

He pointed out that many building owners and developers tend to circumvent building regulations, hence the need for professionals in the private sector to support their colleagues in the civil service to overcome pessimism.

Awobodu said, “Building safety can be achieved through reinvigorated determination and commitment from all stakeholders.

“In a very short time, our generation will grow old and leave the stage for another. It is in the enlightened interest of professionals and society not to pass on chaos, arbitrariness and responsibilities to the next generation. We just have to work together while respecting each other’s skills so as not to endanger this generation and the following ones.