INTRODUCTION:
We are living in a country where the news of building collapse
is no longer seen as breaking news. It is happening across the nooks and cranny
of Nigeria .As soon as it happens the accusing fingers of the general public go
to the Engineers.
It is a well-known fact that the building industry
comprises The Client,Architects,Engineers [Structural,Electrical,Mechanical
Geotechnical and Environmental], Builders and Craftsmen. All these groups play major
roles in ensuring that the building projects stand the test of time.
Collapse in
Buildings could be total or partial failure of one or more components of a
building leading to the inability of the building to perform its principal
function of safety and stability
· BRIEF
HISTORY OF BUILDING COLLAPSE IN NIGERIA FROM 2013 TO 2014:
It is alarming to hear that between January 2013 and September
2014, no fewer than 27 cases of building collapse were recorded in different
parts of the country with about 173 innocent Nigerians confirmed dead and 427
others injured [Daily Trust Research.)Colossal sums of money have been lost as
a result of this various cases of collapsed buildings.
A survey of
building collapse within the period under review shows that 17 buildings
involved are residential buildings, 6 were churches while the rest are plazas
and uncompleted buildings. THE Southwest zone of the country had the highest figure;
the south east had only 6 incidents while 4 cases were recorded in south south.
Only 13 cases were recorded in Northern zoneof the
country. It is disheartening that despite the existence of the Development
Controls of various States, nobody has been tried and jailed.by competent court.
Only the Synagogue case is being handled at the law court now.The consequence
is more cases of collapsed buildings as those found culpable are escaping with
their nefarious activities.
Before I go ahead to discuss some of the root causes of
collapsed buildings in Nigeria,may I take you down the memory lane of some
latest cases in Nigeria.
The Synagogue Church buildingcollapse in Lagos .On
September 12 2014, the guest house of the Synagogue Church located at Ikotun
Lagos State collapsed killing about 115 people of various countries, and
wounding about 131 others. On 21st October 2015, a 3-storey building
located at Swamp Street Odunfa Lagos Island collapsed trapping the occupants. Plateau
State has also witnessed few cases of collapsed buildingsin recent past. About
three cases recorded earlier had no human casualty; however On Sunday 13th September
2015 an Islamic School Building –Abu-Naib School building collapsed killing 10
pupils and injuring many. TheL shaped on-storey building collapsed after heavy
down pour while lessons were in progress without any ample warning to the
occupants.
This problem of building collapse is not peculiar to Nigeria,
however our case has become so frequent that all stake holders in the built
environment need to come together to proffer lasting solution to curb this ugly
cankerworm that is gradually eating deep into the fabrics of our society and
giving us the professionals bad image in the comity of nations.
· CAUSES
OF STRUCTURAL FAILURE IN BUILDINGS:
Listed below are some of the basic causes of Structural
Failure of buildings
·
Dominance of quacks in the construction
industry
·
Government legislation
·
Design Error
·
Poor Construction Supervision
·
Conversion of Residential Buildings to
Commercial and Religious purposes.
·
Renovation of Burnt Houses/Abandoned
Structures
·
Civil Commotion, Religious
Disturbances/terrorism
·
Natural Disasters.
·
Geotechnical Investigation
·
Code of practice
·
Effect of high temperature
·
Developers Interference
·
Poor Building Materials.
·
Lack of Building Maintenance culture.
DETAILED
CAUSES OF BUILDING COLLAPSE.
1.
DOMINANCE
OF QUACKS IN THE CONSTRUCTION INDUSTRY:
The
jobs of the qualified Professionals have been hijacked by Politicians and
Contractors through award of what is purely a professional job. Most times
those who are entrusted with engineering and construction business have no
knowledge of what to do.So long as you have connection with those at the
corridors of power, you are sure of very juicy contracts. These groups execute
the job so poorly because they have no professional allegiance .As a result of
the high level of connection of these contractors to those at the corridor of power,
even those saddled with the responsibility of supervising them are incapacitated.
They end up using substandard materials in the execution of the jobs, bridge
construction procedures, resulting in building collapse.
2.
GOVERNMENT
LEGISLATION:
The
basic requirement for approval of building plans is that planning and design should be executed by persons with the current license from COREN [The Council for
the Regulation of Engineering in Nigeria.] Architects Registration Council of
Nigeria, [ARCON],the Council of Registered Planners.We have seen cases where
building plans of one-storey Buildings are approved without being certified, and
sealed by COREN Registered Engineers due to existing Government legislation.
In some cases the buildings are completed
without the building plans being submitted to the Development Control for approval.
Of late we understand that the Builders have started analyzing,designing and
certifying Structures for approval contrary to COREN decree. The result is
collapse of buildings here and there. The existing Plateau State Urban and
Regional Planning Law recommends for approval Buildings below two floors
without structural calculations.This was reviewed by stake holder’s forum of
all professionals in the built environment in Plateau State some years back.We
understand the bill has not yet been signed into law. Recall that the four
cases of collapsed buildings in Plateau State are one-storey buildings.
3.
DESIGN
ERROR:
Poor
analysis and design of building structures is a major reason for many collapsed
buildings in Nigeria.These days’ analysis and design of concrete and steel elements
are carried out by people who have no thorough knowledge of the theory behind
many assumptions. These analysis are often done with some soft wares like Orion
and without sound judgment, the results obtained are deceptive and dangerous.
The major objective of
structural analysis is to ensure that the analysis satisfy the following
· The Structure is safe under the worst system
of loading
· The deformation of the structure does not
impair the appearance, durability and performance of the structure.
· The dynamic response of the structure does
not cause alarm or discomfort to the users
· The structure must be economical and shall
not require excessive repair due to accidental over load or bad weather
condition.
· This implies that most good designs depend on
the sense of judgment based on experience of the designer. These days we
witness the garbage in garbage out syndrome associated with use of computer
applications.
4 POOR CONSTRUCTION SUPERVISION:
In most cases, analysis and design of a project may be ok
however poor construction supervision may result in a lot of mistakes during construction.
In most Federal and State Government projects, Resident Engineers are appointed
to supervise the project on regular basis to ensure that the contractor carries
out his contractual obligations well.Due to economic issues most Consultants
are made to supervise projects once a month during which problems must have
arisen that could jeopardize the durability of the structures
5. CONVERTION OF RESIDENTIAL BUILDINGS TO COMMERCIALPURPOSES:
Indiscriminate conversion of residential buildings for religious and commercial
purposes is another reason for collapse of buildings. The imposed load for residential structure is
not the same as that of classroom blocks, computer centers, churches, etc. The
past ten years have witnessed the proliferation of churches and computer
centers. Whereas the imposed loads for residential building are1.5kn/m2, church
requires imposed loads of 3km/m2according to BS6399. Hotels bars and vestibulesrequire
imposed loads up to 5kn/m2. To convert a
residential building to serve any of the above purpose is tantamount to
overloading the structures and this may lead to serviceability failure and
eventual collapse of the structure.
6. CONTINUATION
OF ADANDONED BUILDINGS:
There are
cases were buildings abandoned for very long times are rehabilitated without
proper material tests to verify the present state of the structure. Such
buildings should be verified for overall stability, strength of the structural
members, durability, fire resistance, impermeability and appearance, electrical
and mechanical installation before constructions can continue.
In some
cases, property owners increase the number of floors of their house without
considering the suitability of the existing foundation to take additional
loads.
This usually results in failure as witnessed in the
Synagogue building collapse.
7. RENOVATION OF BURNT HOUSES:
Research has shown that steel can lose
its ductility at temperature over 600c. It loses about 20% of its actual
strength. Investigations are necessary to ascertain the extent of damage to
building materials before renovation work could be carried out. This could be a
potential source of failure of the structure if ignored. {See effect of temperature on structural
properties}
8. CIVIL COMMOTION /RELIGIOUS DISTURBANCES / TERRORISM:
This is
another source of structural failure of buildings. During civil commotions and
religious disturbances such as in Kano, Bauchi, Plateau State etc. witnessed in
the country, many houses collapse due to arson and felony. Some structures were made to collapse due to
use of explosives like the Jos main market case.
In America for instance,
high jacked plane at top speed crashed into the world trade center. This
resulted to the collapse of the building. There are many tall buildings
worldwide that should be protected against such attack. In Chicago, NO 311
South Watcher, USA, the world tallest reinforced concrete building 300m high is
a case study. We have another reinforced concrete building in London, the
Canary Wharf Building 245m high. All these tower buildings need to be properly
protected against airplane attack as experienced in the world trade center.
9
NATURAL DISASTERS: LAND SLIDES AND EARTHQUAKES:
Landslides floods earthquakes etc. can cause buildings
and other engineering infrastructures to collapse.In Zaria Terrace here in Jos some
timeago, movement of the earth caused part of the road to collapse. InfarawayPhilipines,
thousands of high and low rise buildings collapsed killing thousands of people
due to ground shaking and extensive soil liquefaction. We thank God we hardly
witness these cases of earthquake in this part of the globe.
Erosion and flood has caused the collapse of many
buildings as witnessed during the 2012 floodmenace in Plateau State.Some of
these mishaps can be averted by huge investment in erosion control and flood
checks and ecological disaster fund.
10
GEOTECHNICAL [SUB SOIL]INVESTIGATIONS:
Most designs in this country
are carried out on assumption of subsoil conditions. Most clients are unwilling
to carry out the basic subsoil investigation which should guide the structural
Engineer on the choice of the foundation type to be adopted. Geotechnical
investigation is very necessary in the analysis and design of any storey-structure.Foundations
transfer and spread the loads from the structural elements like, columns, beams
walls and slab to the ground.The safe bearing capacity of the soil must not be exceeded;
otherwise excessive settlement may occur resulting in damage to the
building.Foundation failure affects the overall stability of the building,
making it liable to slide, uplift,or overturn.
11
EFFECT OF HIGH TEMPERATURE ON STRUCTURAL ELEMENTS:
Temperature fluctuation has a lot of consequences on most
construction materials like steel and concrete.Research has shown that there is
deterioration in the strength and ductility properties of reinforcing steel [both
mild and high yield steel] when exposed to high temperature.Both mild and high
yield steel show permanent strength loss when exposed to temperature above
600deg centigrade.They lose their ductility.
During the last riot in Jos many structures were set
ablaze .Most of these structures have been reconstructed without consideration
to the loss of strength and ductility of the reinforcements. The iron rods
recovered from such houses were used to construct other storey structures
subjecting the new structure to possibility of collapse.
12
THE NIGERIAN STANDARD CODE OF PRACTICE:
The Code of Practice being used for the design of
concrete and steel structures in Nigeria today is the British Standard code of
practice or the Euro code.Most Countries have domesticated the Euro codes to
reflect the reality of the situation in their countries.Maylasia, India,
Singapor etc. have domesticated the Eurocode.Nigeria the giant of Africa should
begin to think of the Nigerian Standard Code of practice that suites the
Nigerian Environment. In 1973, the Nigerian Standard Organization,member of the
International Organization for Standardization constituted a Technical
Committee with membership from Nigerian Society of Engineers,Nigerian Institute
of Building,Federal and States Ministry of works, NSO,Representatives of
Universities etc.The Committee came up with Nigerian Standard Code of Practice
which is essentially a set of minimum requirements for design of buildings.The
code should be revised to conform to the prevailing situation worldwide with
adequate integration of the Nigerian Situation and the changing nature of
engineering practice.
You may shudder to hear that some professional who have
refused to imbibe the culture of continued professional development are still
designing with CP110, CP114 in a changing world that has moved to Euro code.
The Nigerian Society of Engineers has set up Codes and
Standards Committee to draft the Nigerian Code of Practice.This is a welcome development
.As a member of the NSE Codes and Standard Committee
representing Nigerian Institution of Civil Engineers,I strongly feel that this
is a capital intensive assignment that should be properly funded by the Federal
Government and all stake holders in the built environment, considering the
anticipated benefit to the safety and durability of infrastructure in Nigeria.
13 DEVELOPERS
INTERFERENCE:
We have seen cases where developers economize materials
to the detriment of the quality of construction. Such projects often collapse,
killing innocent people who pay exorbitant rents to occupy them.
14 LACK
OF BUILDING MAINTAINANCE CULTURE:
We have poor maintenance culture in Nigeria.Most
buildings are hardly maintained even when serviceability failure starts to
manifest.Most of the buildings that collapsed in Lagos showed ample
serviceability failure signs before ultimate collapse. The occupants were asked
to relocate but could not until the buildings crumbled on them. The Lagos
building Control Agency has marked about 1104 buildings as defective /illegal
construction. Most of the occupants due to poverty and exorbitant rent in Lagos
refused to quit and as such were trapped each time this failure occurred.
15
POOR CONSTRUCTION MATERIALS:
We need to be mindful of the
type of materials we use in our construction industries.
Many of us do not know that we have different grades of
cement for building industry.[Grade 32.5mpa,42.5mpa,52.5mpa]Grade 32.5mpa
cement for instance is for plastering while 42.5mpa is used for block molding,concrete
work while 52.5mpa is for high density work like bridge construction dams embankments
retaining walls etc.Here in Nigeria anything goes.Sometimes the cement is re-bagged
thereby compromising the mixing ratio and subsequently the strength.
THE
WAY FORWARD:
1. The
collapse of buildings cannot be totally eradicated but can be minimized if
public emotions can be played down and the press can lay more emphasis on educating the publicat large
on the dangers of the collapse of buildings.
2. Use
of right materials for construction of buildings and other infrastructures.
3. Periodic
testing of building materials and concrete during construction.
4. Employment
of the right caliber of professionals and artisans in the design and
construction of buildings.
5. Ensuring
that designs are checked and cross checked by the right professionals and
sealed and approved before construction can commence.
6. Produce
the Nigerian Standard Code of practice for the analysis and design of building
and Civil engineering Structures.
7. Adopting
preventive, corrective and condition based maintenance culture in Nigeria.
8. Reporting
cases of buildings showing signs of failure to the Nigerian Society of
Engineers committee on Prevention Investigation and Failure analysis Committee.
By so doing you may be saving lives.
9. The
Architects who incidentally are usually the first point of call by most clients
have a civic duty to remind the clients about the need for structural,
electrical and mechanical engineering designs as well as geotechnical
investigation.
10. To
check the activities of erring professionals, members of staff of the Town
Planning Authority and individual housing developers, the legal framework
should be improved upon to ensure smoother, less time-consuming and less
burdensome ways to try earing professionals and quacks at the law courts.
11. To report
cases of quackery in Engineering to COREN Engineering Regulation Monitoring
Inspectorates for possible prosecution by COREN tribunal for appropriate sanction.
Once
this is put in place, those who flout the law can be promptly and heavily
sanctioned by the judiciary if the present tempo of building collapse is to be
reversed.
CONCLUSION:
Most times when a building collapses, lives are lost;it
could be you, your friends or relations. Besides, properties worth millions are
lost. We are duty bound to ensure that such failures are averted. Thank You.
ACKNOWLEGEMENT:
Daily Trust, Osun Defenders, R.E.Olagunju, S.C.Aremu, J.Ogundele.
S.A. Oloyede, C.B. Omoogun, O.A.
Akinjare,Haruna Ibrahim, Fidelis
Mac-Leva, Mustapha Suleiman
BY
About CHIEF ENGR.OKEY EZEMA FNSE FNICE
Engr Okey Ezema FNSE is a Civil/Structural Engineer based in Jos, Plateus State, Nigeria. He is the Managing Director of Zemas and Partners Nig Ltd a consulting Engineering firm based in Jos..
He is a Fellow of Nigerian Society of Engineers,Fellow Nigerian Institution of Civil Engineers and COREN Engineering Regulation Monitoring Inspector. He has successfully handled the Structural analysis and design of many projects in Nigerian.He has equally participated in the Construction of many Federal Government projects in Nigeria as Project Manager.
He has served as a member of national exco of Nigerian Institution of Civil Engineers for two consecutive terms. Engr Okey Ezema FNSE was listed on page 208 of Nigerian Role Models A Compendium of Distinguished Nigerians[PIFAC]. He can be reached at : okeyezema@yahoo.com
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