Blr. Ojambati T. S (uyi)

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.

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

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

(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.

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

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.

- 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.

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 Authority’s 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

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

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.

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

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,

adequate construction supervision must be available especially to solve problems that may not have been foreseen during design.

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

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.

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

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

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

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,

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. Designer’s 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

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

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.