blr. ojambati t. s (uyi)
TRANSCRIPT
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COLLAPSED OF BUILDING IN NIGERIA
CHAPTER ONE
1.1 INTRODUCTION
BACKGROUND
Buildings are constructed primarily to meet one of the human physical
needs. It provides accommodation for shelter, privacy, protection and
security for the man and his goods from the effect of weather and conducive
environment to stay warm and healthy.
Building comprises of main structural elements such as foundation,
walls, floors, doors, windows, walling and the root structure. These elements
must be adequately designed and efficiently constructed in line with relevant
building codes and standards, and in a way that provides expected conditions
compactable and appropriate for the activities to be carried out within it on
completion. It must also ensure the comfort and safety of the occupants.
The interior of the building must be well arranged in terms of shape
and size as to exclude noise, ensure adequate ventilation, natural lighting.
The material must satisfy the basic functional requirements of weather
and fire resistance, sound and thermal insulation, strength and stability,
durability and resistance to wear and tears.
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It must be able to safety carry all the superimposed loads and transmit
it to the ground.
It has been observed that following technological advancement and
increased passion for housing, it is widely reported in various electronic
print, news and media of incessant collapse of building structures all over
the country within the last two decades. This phenomenon of collapse is
becoming and creating a nightmare because of the time, energy, resources
wasted and especially the possible loss of lives. The high incidence of
building collapse calls for concern in the building industry today and also
the need to providing an immediate and lasting solution to the supervision
and construction of building from inception to completion is the campaign
the Nigerian Institute of Building in collaboration with the council of
Registered Builders of Nigeria (CORBON) is promoting today to enlighten
the public.
The Africa Newspaper of Nigeria (1999) reported that three different
buildings in various part of Lagos collapsed during a down pours, killing at
least five persons and wounded at least five others. This incidents bring to
four the number of such collapsed buildings in Lagos in four days. In all
cases reported in the past and recent times, it has been noticed that the
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phenomenon of collapsed buildings occurs during, immediately and after the
construction.
In view of the above, this research work will assess some of the
collapsed buildings in Nigeria with particular emphasis on the South
Western State of Nigeria by identifying their causes and proffering solutions
through a well design tools.
1.2 STATEMENT OF PROBLEMS
The increased reports of the high occurrence of collapsed building in
various parts of the country have been generating a renewed interest in the
building industry among the professionals. These professionals are not only
worried by the increased rate of collapse, but because of the consequent
economic losses, due to loss of lives, resources and time in addition to the
psychological effect of the horrible sight of the a fear math and resulting to
shame and disrespect it is causing to the members of the profession.
The research work will examine the causes of building collapses and
proffer solution to the problem through a well design technology
management.
1.3 AIMS AND OBJECTIVES OF THE STUDY
The research is to assess factors that causes collapse of building In
Nigeria while the research objectives are to
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(a) Identify the factors that influence the occurrence of the collapsed
building
(h) Investigate the impact of building collapses on the stakeholders.
(c) Assess the level of compliance of the National Building Code by the
Nigerian building industry.
1.4 SIGNIFICANCE OF THE STUDY
The study will provide technological assessment of the building
collapsed in Nigeria with the need to alert the stakeholders and the general
public about the losses and implication of collapse of building in order to
avoid future occurrence. Also the research work will provide information
that would assist the government in implementing the existing framework
and strategies for enforcing the National Building code in the building
process.
1.5 SCOPE OF THE STUDY
The study is expected to cover the whole country, however because of
the relatively large size of the country, it will be too expensive, as such the
scope of the research will be limited to the south western states of Nigeria
with various classes of buildings and having about the highest report of the
collapse of building structures in Nigeria References will be made to some
collapse buildings in some other states of the federation.
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The research will not cover such issues as the structural design and
detailing of building structures, which is purely a structural Engineers work.
CHAPTER TWO
2.0 LITERATURE REVIEW
2.1 BUILDING FAILURE
Jolade (1989) states that building failure should not be taken to mean
only a structural failure but is also include its non-performing with the
requirements expected of it, Failure in building can be defined as a defective
construction, integrated by other factors such as structural, functional,
material and environmental resulting in a short fall in performance occurring
at any time in the life of the product element or dwelling in which it occurs.
Common examples of building failure were listed to include such defects as
cracks in walls, deflection and overturning of beam, etc majority of these
failure arise during construction period or after while others are due to
natural phenomena
2.1.1 BUILDING COLLAPSE
This may arise as a result of failure in building, as the failure get to an
uncontrollable measure Collapse of a building may be either a partial,
progressive and total or sudden collapse. The effect of any collapse of a
building can be so detrimental as to cause loss of live, properties and waste
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of resource. A colossal waste is normally recorded as collapse of building
occurs,
According to Salau (1990), different types of building have been
known to collapse in use in contemporary history The story is now limited to
Nigeria only as Roman Point block of flat in London was known to have
collapse in the past, so also was famous Congress Hall, built by the
Americans with prestress concrete after twenty-three (23) years life span, in
the West Berlin, Germany Multi-storeyed Hotel in Madrid, Spain also
collapsed killing many of the occupants- The cause of failure of the skyline
mega apartment building in Fair Fax country, Virgina, U S.A- was
documented in the concrete international magazine of July, 1983 as due to
non-adherence to good construction practice.
There are basically three forms of collapse. These are:
- Partial Collapse:- This occurs when part of the building is .affected, i.e.
only a small fraction of the building or one side of it falls down
- Progressive Collapse:- In this type of collapse, there will be signs of
weakness noticeable either by seeing cracks which becomes widening with
time or by noticing unusual sound in the building due to structural member
gradually giving way from each other.
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- Total or Sudden Collapse:- As the name implies, it happens when the
building falls down suddenly it may not even given any sign prior to falling
down
2.3 CAUSES OF COLLAPSED OF BUILDING STRUCIURES
The major causes of collapse building structures could be traced down
to the defective structural design of the building elements with neglect of the
basic considerations of design procedures including under estimation of the
ground bearing structures. Ometar ((987) attributes the cause to a neglect of
real professionals advice whereby the owner prefer to build the house either
with half-baked professionals or the use of artisans and labour as a means of
direct labour contract. Iyagba (2000) averred that major causes of building
collapse are.
a. Absence of planning approval
b. Where approval was obtained, clients and contractors do not
adhere to the details of the approved drawings.
c. Proper soil investigation not carried out.
d. Engagement of quacks and half-baked professionals to take charge
of the construction
e. High cost of building materials prevents contractors from adhering
to the specifications in terms of quantity and quality.
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f. Inadequate staffing of the Town Planning Authority combined with
inadequate qualifications for the job of monitoring and control of
building activities
g. Town Planning Authoritys slow approval process and unnecessary
demand of certain documents in (such as Certificate of Occupancy
which are not easy to come by) respect of ownership of the land
which makes approval impossible or slow. This could also deterred
people from bringing plans for approval
h. Designers inability to effect compulsory and regular inspection
Ogunwasi (1999) however commented that in all the buildings that
have collapsed so far in this country, no professional builder has been
involved in the planning and management of the construction works.
Salau (1996), however grouped all the causes of structural failure and
collapse of building to occur under four basic stages of the building life as
in:
a. Planning stage
b. Design stage
c. Construction stage
d. Service stage
It is worthwhile to discuss how collapse can occur in each of these stages
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2.3.1 Planning Stage
This is the first stage in any building process and of course a very
important stage that must not be overlooked in order to avoid unnecessary
abortive work, defective overall scheme and escalation of design cost arid
expenses. According to Salau (1996), the service of an architect is usually
required at this stage, who will get other professionals actively involved
right from the conception and at the initial stage of formulating basic
planning. The primary consideration at this stage is function of which the
building is to be put. While the secondary consideration may include
aesthetic, sociological, legal, financial, economic, environmental or
resources consideration.
In terms of functional consideration, it should be realized that a
building plan for a particular purpose should be used for that same purpose
For example, if a building was originally planned to be used for residential,
it may not be safe for some building to he used for church congregation,
neither should a building planned to be used as office or residential be
converted to be used for the purpose of school. This of course is one of the
factors that led to the collapse of building of Saque comprehensive College,
Port Harcourt, in Rivers State Report of the findings submitted to the
Judicial Commission of enquiry by the Council of Registered Builders of
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Nigeria (CORBON). Also reported that cases of building collapse at
Idumota have been reportedly traced to some office apartment being
converted to storing automobile spare parts (Salau, 1996).
Also worthy of mentioning is the feasibility and viability studies of
the overall project work. The role of every professionals to be involved
must be defined. A quantity surveyor should be seen to be very prominent in
the areas of cost advise The method of tending arrangements, and selection
of the right contractor. Furthermore, decision should be made as to carrying
out of preliminary sub-soil site investigation. Many buildings too have also
collapsed due to non-availability of the sub-soil site investigation. Even
though many developers see this investigation as a waste of time and money,
it should be noted that properties of soil strata varies from one site to
another, It is very important to determine the geo-technical situation of the
site before commencing on any design. Many buildings failed due to
improper foundation, which is caused by non-availability of the subsoil site
investigation or non-compliance to it Foundation failures may be costly to
rectify and can involve expensive remedial works to the superstructure.
Every Naira spent on having a proper subsoil investigation carried out is
therefore a worthwhile insurance premium for the clients investment and the
professional reputation of all concerned with the project.
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2.3.2 Design Stage
This may be in form of architectural or structural design. The
Architect is required to produce very good drawing to suit the requirements
of the owner The Structural Engineer on the other hand produce structural
design concern with providing stable and robust structures for carrying
require loads and safely transmitting the vertical loads and horizontal
disturbing forces to the ground with suitable foundation.
According to Ambrose (1988), the design should address the
following basic issues,
a. The load sources and their effect
b. What the structure accomplishes in terms of its performance as a
supporting, spanning or bracing element.
c. What happens to the structure internally as it performs it various
tasks
d. What is involved in determining the necessary structural elements
and systems for specific required tasks
Makinde (1996) agreed that no matter how expert one may be,
everybody is prone to make mistake one way or the other, hence, and the
detailing of any structural design must be cross checked by the official of the
Town Planning Authority with a view to detecting any faults from the details
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and / or calculations of the Structural Engineer and get the designer to rectify
such faults. Where they arc in doubts, both parties should meet to iron the
grey areas out. Makinde (1996), stated further that where such faults are not
detected by the authority both the designers and officers of the Town
Planning Authority are to be blame if the building is built in accordance with
the design and specifications should he clearly put together as unrealistic
specifications or but it collapses in the long run. The material strength and
aggregate sizes should be clearly stated on the drawings to avoid
misinterpretation and that working drawings and specifications should be
clearly put together as unrealistic specification or unclear working drawings
can lead to collapse of the building.
2.3.3 Construction Stage
This stage is the most critical and sensitive stage in the building
process as any fault or omission can result into ultimate failure and collapse.
This is a stage when the work done in the planning stage and the design
stage explained above will be implemented. Where a building collapse as a
result of workmanship rather than design, the builder is to be blamed for it.
Akintunde (1990) stated that good design must be faithfully reproduced in
construction or fabrication and this includes good workmanship and use of
the specified quality of materials in the construction. To ensure this,
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adequate construction supervision must be available especially to solve
problems that may not have been foreseen during design.
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Reasons why collapse buildings during construction stage are as
follows:
a. Many contractors do not know the technique involved in the job
neither do they have enough idea of the materials they are using.
b. Because of lack of enough practical training especially for artisans
and craftsman, quality work within the industry are in decline.
c. Many clients are self-contractors without any training in building
technology and coupled with inadequate staffing, inexperienced and
unqualified personnel tend to all sorts of constructional problems.
d. Rushing of construction work to complete on time also affect the
quality of work on site. Example is the removal of shuttering arid
form-work before the concrete is adequately cured (before 28 days
from casting date).
e. Refusal by clients to pay design architects and engineers for
supervision during construction work can lead to a situation where (he
contractor will choose to modify the design to suit himself with a view
of making more profit
It is the responsibility of the design engineer to see that the materials
specifications as well as testing of the basic materials used are
complied with. In some cases where contractors has rushed a job
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before the engineer comes for checking, the contractor may be
required to open up for inspection.
f. In most public buildings e.g. churches, mosques, town hall, etc
committee are normally constituted by the members of the community
without any of them being a professional and construction are carried
out by the committee as a direct labour exercise.
According to Akintunde (1990) the reason outline above is typical of
the reasons behind the collapse of many buildings in Nigeria as
investigation carried out by Nigeria Institute of Structural Engineers
concerning the live storey building located on a plot adjacent to 109
Western, Avenue, Iponri Lagos State revealed that:
a. The building originally existed as a single storey block (bungalow)
b. The owner who acted as his own contractor, decided to add many
more storeys (floors to it).
c. There is evidence of a planning permit of only one additional storey
d. That the Town Planning Authority discovering the contravention,
marked it for demolition, the owner went ahead with construction at
nights until the collapse occurred during the concreting of the fourth
floor.
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e. No professionals were involved in the design, construction and
supervision of the project
2.3.4 Service Stage
This stage has to do with the building after construction especially
where the building is being occupied The question that now arise is what
purpose was the building designed for originally and what purpose is it now
being used for? If the building is not being used for the purpose for which it
was designed, there is likelihood of problems or failure occurring. Salau
(1996), stated categorically that the collapse of Idunshage Street, in Lagos
Island in 1987 was due to this fact. Therefore any building that is to be used
for any purpose order than that which it was designed must be referred to
Engineer for further consideration. The major causes of collapse of building
during the service period were attributed to misuse as well as new projects
developed around the vicinity of the building. Similar cases to this was
given to Masha and Bode Thomas areas where pumping of water in the
adjacent plot during foundation construction or using of precast piles have
seriously affected existing structures which were earlier on stable
structurally.
Another similar area where failure occurs in building during its
service life is where the building lack maintenance Adenuga (1999), stressed
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that our buildings (both public and private lack adequate maintenance care
or attention, and that they are in very poor and deplorable conditions of
structural and decorative disrepair). However, lack of maintenance of
building can lead to collapse from accidental, circumstantial, weather or
time-related defects. Leakage of water due. to bad plumbing installation or
blocking or the drains can weaken structural elements He also states that
pounding of yam with mortal and pestle on suspended floor can cause
collapse of the building. Makinde (1996) however view the maintenance
issue criticaLly by saying that the deterioration does not only affect the
services and finishes but also the structures.
2.4 COLLAPSE OF BUILDING RESULTING FROM
FOUNDATION FAILURE
Chudley (1988) define foundation as the base on which a building
rests and its purpose is to safely transfer the load of a building to a suitable
depth below the subsoil. The requirements of any good foundation is stated
in Building Regulations 4, that all foundations shall:
a. Safely sustain and transmit to the ground the combined dead and
imposed load so as not cause any settlement or other movement in any
part of the building or any of the adjoining building or work
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b. Be of such a depth or be so constructed as to avoid damage by
swelling, shrinkage or freezing of the subsoil.
c. Approved document recommends foundations to be capable of
resisting attack by deleterious materials, such as sulphates in the
subsoil.
Foundation being the part that carried the whole building becomes the
first suspect when a building collapses.
2.4 CAUSES OF FOUNDATION FAILURE
Ajayi (1988) states that foundation failures may be due to any or
combination of any of the following factors:
a. Absence of proper site investigation or wrong interpretation of the
results of such investigation.
b. Faulty design of the foundation
c. Bad workmanship in the construction of the foundation; and
d. Insufficient provision in the design construction for exceptional
natural phenomenon such as thermal and biological conditions.
rainfalls and floods greater than those hitherto recorded on the site.
2.4.1.1 Lack of Suhcoi1 Investigation
All building structures, no matter their size, shape intended purpose,
type of construction or use share a common thing. They all rest on the
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ground. Since soils at different point have different properties, subsoil
investigation therefore is a pre-requisite before the design of any foundation
is made. The parameters obtained during the site investigation are used in
developing the most appropriate, economic and safest foundation.
Conclusion can also be drawn from the result of site investigation as to
whether to use the site of to look for another one especially where the
investigation reveals an expensive foundation to be provided.
Omange (1988) states that the need to have a feeling of safe housing
and environment necessitate the carrying out of the site investigation.
However most developer used to run away from carrying out site
investigation as they claim that the cost will increase the total cost of the
building, it is only necessary for a very big project such as high rise, darns,
road project, etc. based on this fear regarding cost, Jack (1983) made it clear
that the cost of an exploration vary with the type of structure and the nature
of the soil but is to compared with the total cost of the building. The cost of
site investigation range from 0.1 to 1.0 percent of the cost of the structures
and is even lower for large jobs because the fixed charges for selling up an
exploration do not vary with the size of the job
Neglect of soil investigation may however leads to excessive
settlement as a result of over-stressing of the soil beneath the buildings,
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differential settlement, undercutting of foundations etc. are the result of
neglect of site investigation
2.4.1.2 Collapse Due to Poor Design of Foundation
Majority of the problems of building arises as a result of lack of
sufficient care in the design and construction of the various building
elements, chief among them is the foundation. Designers concerns range
from basic understanding of structural behaviours of the determination of the
construction details for a specific type of building Ilesanmi (1988) is of the
opinion that most designers, architects arid engineers sometimes fail to
appreciate and visualize possible structural behavior of various
constructional details in general use
Ajayi (1988) emphasis the need to give adequate consideration to the
use of appropriate design guides and data and that designer must ensure that
settlement is not large enough or vary relatively. It is equally good to note
that some changes normally occurs in the subsoil after the superstructure has
been erected, due to the effect of filing, excavation and groundwater
fluctuation due to weather, flooding, drainage or down water, etc
2.4.1.3 Failure of Foundation Due to Poor Workmanship
Very good design of foundation coupled with rightly placing of
substructure reduce problems in the whole building after completion as well
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as reducing future maintenance cost. It has been observed that most structure
collapsed as a result of using poor materials in the construction or by using
poor workmanship. This is usually practiced due to economic reasons. Most
contractors believe that by compromising the standard of materials and
workmanship, they will earn more money.
The major causes of damage to shallow foundations is from settlement
of poor slab due to inadequate compaction of infill or use of inappropriate
fill material To avoid settlement therefore, backfilling of excavations around
completed building should be with suitable material placed in thin layers not
exceeding 200mm thickness and compacted to a high standard (Seeley,
1980).
2.4.1.4 Failure of Foundation Due to Natural and External Influence
These include those factors that are not immediately possible to
foresee the extent of damage they are likely to cause, such as scour, seepage,
floods, extremes of temperature, biological and chemical effects, etc
2.4.1.5 Foundation Settlement and Movements
Ilesanmi (1988) lists factors responsible for foundation movement
among others to include the following:
a. Seasonal weather changes
b. Vegetation growth and removal
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c. Subsidence
d. Soil shrinkage
e. Made up ground
f. Movement resulting from eccentric loads
Consideration should not only he given to bearing capacity of the soil
on which a building is to be placed, but very importantly is the settlement,
which must not be large enough or vary relatively to an extent that could
damage the structure or impair its functions. The most important
consideration for a reclaimed land should be the magnitude of settlement,
both residual and that induced by a shallow foundation or the effects of
negative fraction forces on a piled foundation.
2.4.2.1 Soil Problems that Normally Causes Failure of Foundation
* Expenses Soils
This is due to behavior of soils as the water content increases or
reduces when the soil is dry, fine-grained soils shrink to a minimum value
resulting into vertical cracking to a considerable depth.