CHIKA OKEKE examines the major causes of structural defects and writes on the strategies to avert building collapse.
The building and construction industry has been in existence since the advent of human civilisation over 3000 years ago.
Though different building patterns had emerged overtime, it gradually phased out with the advancement and introduction of technologies in the built environment.
This led to a change in the building pattern, from horizontal development to vertical development such as high rise buildings and sky scrappers especially in highly populated areas.
This exposed the sub-sector to series of age-long problems such as land grabbing, delay in obtaining governor’s consent, use of substandard building materials, difficulties in obtaining building approvals and among others.
The problems which increased overtime led to rampant cases of structural defects and eventual collapse of such buildings especially in urban areas.
It however posed serious challenges to engineers especially with the spate of collapse experienced across the country, that had resulted to loss of lives and valuables.
Investigation by LEADERSHIP revealed that over 325 persons had died as a result of building collapse in Nigeria in the last 13 years due to non-compliance of building plans and over-bearing shipment of substandard building materials into Nigeria mostly from China.
Further findings indicated that the engagement of inexperienced and untrained personnel in construction works, use of substandard materials, lack of proper supervision, inspection and monitoring of construction works were the major causes of building collapse.
Others are illegal conversion of building uses, alterations and addition to existing structure without due consultation with the professionals, interference of clients on building works as well as corruption and greed among stakeholders in the built environment.
Worried by the menace, the Nigerian Institution of Civil Engineers (NICE) organised a workshop/training on ‘Building Collapse Prevention Strategies and General Site Safety’.
The workshop which drew participants across the states was intended to increase participation and awareness by strategically positioning engineers and allied professionals to reduce the spate of building collapse.
The chairman of NICE, Abuja chapter, Engr. Dominic Onuh Akuboh said that the mistakes of a medical doctor could be buried but the mistakes of engineers could lead to massive loss of lives, properties, investments and livelihood.
He disclosed that building collapse prevention is a collective responsibility of all professionals within the built sector even as he pleaded with the regulatory and professional bodies as well as the entire stakeholders in the built environment to collaborate towards phasing-out building collapse in the country.
Akuboh called on engineers to maintain high ethical standards and due diligence while discharging their duties, adding that there is a need to modify the building sites given the earth tremor that occured in Abuja last year.
He emphasised that NICE had drawn the attention of department of development control and the Council for the Regulation of Engineering in Nigeria (COREN) about a partial collapse in Kubwa adding that the association is yet to receive feedback on the issue.
The chairman listed causes of building collapse as improper concreting, heavy downpour, pre-mature removal of form work for roof slab/concrete decking, use of sub-standard materials in building, gas explosion, illegal addition of floors and clients penchant for cheap labour.
Lending his voice, the lead facilitator of the training, Engr. Kanno Ukoabasi regretted that development control department would issue building approval without considering the carrying capacity of such structure.
He pointed out that the frequencies of building collapse and the magnitude of the losses in terms of lives and properties are a reflection of the abuse of the building profession, saying that such menace has reached an embarrassing proportion.
To phase out building collapse, he suggested that proper planning, supervision and monitoring of construction activities should be enforced by construction regulatory bodies to ensure that all buildings are constructed according to design, specifications and planning regulations.
Ukoabasi noted that one of the major areas of concern in the building industry is poor workmanship, which he said led to construction defects.
According to him, “If the workers are careless or don’t follow the construction procedures, the building may suffer defects because quality work begins with the conscious effort of the civil engineer to execute the specifications of the contract”.
The expert noted that negligence could lead to expensive repairs or failure, unskilled workman, unsuitable equipment, poor materials and lack of project management.
He cited examples of poor workmanship as poor concrete mix; compaction and lack of curing; poor fixing of reinforcement; poor installation of plumbing/electrical fittings and among others.
Ukoabasi said that qualified civil engineers should supervise the execution of building and ensure strict adherence to contract specifications.
He recommended that soil investigation, material test and Environmental Impact Assessment(EIA) must be made compulsory for all residential, institutional, industrial and commercial buildings.
Ukoabasi however disclosed that the Standard Organization of Nigeria (SON) should be vigilant to ensure that building materials imported into the country conformed to standard requirements.
To curb the menace of building collapse, he challenged stakeholders in the building and construction industry to join forces with the regulatory and professional bodies to tackle the problems headlong.
In his contribution, the chairman, Nigerian Society of Engineers (NSE), Bwari branch, Engr. Dauda Musa stated that any building that failed integrity test would be marked for demolition.
He said, “Demolition of buildings are carried out for a number of reasons which include public safety in terms of protection of lives and properties, protection of the environment, enforcement of the master plan of a city or town as well as strict adherence to government policy or regulations.
Musa maintained that if any building to be demolished contained traces of hazardous materials such as radioactive contamination, petroleum or chemicals, that it would first be removed by a specialist before the demolition.
Speaking on best practice for controlled demolition of buildings, he pointed out that the issue of demolition is multidisciplinary as it required the input of architects, engineers and surveyors.
He identified problems associated with demolition as waste disposal challenges, environmental consideration such as pollution/dusty air, water and noise likewise cost, ground vibration and avoidable site accidents.
Musa enjoined regulatory bodies to improve on the current demolition practices in Nigeria as more high-rise buildings emerges, noting that demolition exercise must be carefully planned and executed in the overall interest of public safety and in accordance with best practices.
The expert said there is a need to conduct risk and environmental assessment on the effect of demolition especially when handling implosion on the effected neighbourhood.
He revealed that professionals not conversant with demolition projects should seek training in order to equip themselves with the modern trends in demolition rather than making assumptions.