1.5. Research questions
What are the factors responsible for continuous building collapse in Lagos state?
Does the building professional, practice with the standard building codes in Nigeria?
Does the property owner in Lagos state engage nonprofessional in their projects?
Do the building professionals in Lagos state ignore or manipulate critical areas in the construction method?
Do the buildings in Lagos obtain approval from the town planning bodies before the execution of construction works?
1.6. Study Aims and objectives
This study proposes to investigate the conditions of buildings structure in Lagos Nigeria, by critical analysis of the defects in their current state, with a view to consider the future to avoid other relative crisis and also to investigate the approach to building construction, maintainace culture and the level of compliance with the past recommendations on construction projects within the state.
The research aim would be achievable by the following objectives
To access the compliance level of building law, by building professionals in Lagos state.
To investigate the rate of professionals involve in construction works in Lagos state
To investigate the level efficiency, of building law and regulatory agencies in Lagos state
To analyze the level of building maintenance and the use of buildings design in
To analyze building sizes, shapes, materials and location of the buildings.
The end result of this analysis is predestined and anticipated to analyze and point out the major defects in buildings structure across the city, with the aim of preventing them from collapsing in future which will restore and enhance the buildings strengths in order to perform its main objectives.
1.7. Significance of study
There is a need to prevent buildings structure from collapse, these will have a positive effect to the nations built environment in various ways, the research will point out realistic states of the buildings to analyze how they were built, their current in terms of their conditions to know if their are defects which can results to a calamity in future, this research will provide data that point out the main defects in order to make building structures a safer place for people to perform their daily activities, this will also enliven the standard of dwelling in the community and its significant is positive in an extensive perspective.
Ayuba, Olagunju, Remi and Akande, Olufemi (2012) states that For regular hustle to be administered by people, not only a common structural building is indispensable and vital, but a secured structural building is required in order not to endanger lives and properties and to provide a safely wellbeing of the occupants.
It is essential to make proper measures towards the prevention of defected building structures in to avoid collapse in future and also to make sure occupants attain satisfaction, desire and comfort.
CHAPTER TWO – LITERATURE REVIEW
This chapter comprises of various issues concerning building collapse in Nigeria and some other parts or the world, this chapter focuses on in the areas or issues that might likely be responsible for building collapses in a general perspectives. These areas of focus are material selection, methods of practice by building professional and also the standard building codes.
2.2. Definition of building collapse
Structural collapse of a building structure refers to the loss of structural integrity, which is the loss of the load-carrying capability of an element or member within a building structure, or of the structure itself (Tauheed, 2007).
Structural collapse is originated when the component is stressed beyond its strength limit, thus causing fracture or excessive deformations. In a well-designed organization, a localized failure should not cause immediate or even progressive collapse of the entire building structure (Shoraka, 2003).
Collapse of buildings could be total or partial collapse of one or more of its components leading to the inability of the building to perform its principal functions of safety and stability (Ezeagu, et al., 2015).
Deformations in a well-designed organization, a localized failure (Amadi et al 2012; Ezeagu et al 2015; Oloyede et al 2010) asserts that collapse of a building structure can occur from various types of problems which are basically unique to the type of building structure or to the numerous industries and most of which can be traced to due to the lack of consideration of unexpected problems. Natural disasters, sabotage and vandalism which can overstress the building structure to the point of collapse.
Manufacturing errors is also a cause, which may be due to the improper selection of materials, in correct sizing, improper heat treating, improper comply with the design, or poor and low quality labor.
2.3. Analytical discourse of building collapse
Building failure has frequently been linked with structural defects. A building structure comprises an intricate or simple framework or vital component of a building. Therefore, Fakere, Fadaro and Fakere (2012) define structure as part of building component which gives the construction ample strength to resist the load to which the whole edifice is subjected. The structural component is that which carries load and subsequently transfer such applied load to the position of load bearing. Structural members of building also carry the imposed load on it and safely transmit such load to foundation. There are two extensive classification of the structural framework. The first is the frame structures which function include resistance of applied loads through their geometry formation. The mass structures constitute the second type of structural framework and function as load resisting structures using its mass weight (Fakere et al., 2012).
In general Olaguju, (2012) noted that buildings are liable to fail with time as a consequence of human factors. These factors can be summarized as human carelessness, design issues, ageing component, material weakness and overloading, environmental conditions, accidents, and terrorists attacks. Building failure can also be broadly divided into two categories; cosmetic failure and structural failure. Cosmetic failures arises as a result of addition or subtraction to any part of the building thus impacting the structural facade. Structural failures impact both the structural facade and building stability (Ayuba, Olagunju and Akande, 2012). The structural failure prevents the building from successfully transferring both live and dead, including its own weight safely to the foundations. This failure to transfer such imposed load to the foundation hence leads to building failure and collapse (Ukpata, 2006).
Individual structural component are designed to perform certain functions and ensure safety of life, assets and any form of collateral damage to the environment. Within an acceptable design standard, structural or any other form of failures should not occur during the projected lifespan of structures. Nevertheless the limitation in the measures taking by human and the reality of other peripheral factors that influence the wellbeing of structures, failures or collapse do happen (Ede, 2010). Ogunsemi (2002) noted that, the paramount measures that a building must satisfy are; ability of it structural member as individual structure or as structural system should be able to resist, without failure or collapse, the applied loads under the service conditions. This implies possession of adequate strength by structural member. This means materials of the structure must be satisfactory resist the stresses imposed by the loads. The shape and size of the structure must also be satisfactory enough to withstand external load and itself imposed load.
The mechanism of the structure should be able to stand firm and not buckle or deform under loading conditions. The change in size and shape of structures when subjected to stress is term âDeformationâ. This implies that the structural constituent should possess adequate stiffness to avoid any form of deformation under imposed load. Therefore the stiffness of a beam or column is a measure of its resistance to bending or buckling. A component or structure that is very strong but lacking in stiffness will highly deform that it will not be able to resist applied loads. (Ogunsemi, 2002).
Ezeagu, Udebunu and Obiorah (2015) argues that structural members of building must be compacted properly; otherwise the whole structure is understood to be unstable. Structural stability is needed to maintain shape since it is the ability of a structure to maintain under load, its primary state of stability. It can mean anything from resistance to sliding, overturning, partial or complete collapse. Any development that can change or alter the load carrying behaviour of a structure, if proper measures are not observed, it can lead to instability; a situation in which the support reaction is less than applied load. Thus to assure stability and strength, loads must be balanced by reactions, and the moments by virtue of loads must be balanced by the moments due to reactions. Any building that can neither bear nor carry the load applied upon it will demonstrate symbol of distress which may lead to failure and invariably total collapse.
Buildings are structures which serve as a place of abode for man, his belongings and diligence. Which are anticipated to be accordingly planned, designed and erected to obtain desired satisfaction from the surroundings (Ayuba et al., 2012).
The risk of building collapse in developing countries is increasing at a fatal rate, obviously intractable or exceeding uncomplicated control and this has been a source of serious concern to all stakeholders – the competent professionals in building industry, government, private developers, clients and users, as well as neighbourhood residents (Kingsley, 2010). Building collapse is very dangerous and should be refrain using all significant precautions and machineries possible (Fagbenle, 2010). Ultimately, the effect of collapse of building structures, especially at its finalization point as well as when it is immersed by occupant is devastating on human lives (Ede, 2010).
Adenuga (2012) argues that it is also crucial to safeguard the lives of people which may be jeopardized in a manisfestation of a building collapse in the time of construction. Although incidents of collapsed buildings have received professional and public criticisms, few of the cases do not make media caption broadcast, hence, the general public may not know the gravity of the situation. Adenuga also states that naturally, shelter in form of building is amongst the three basic needs of life universally acknowledge and admits as indispensable for life sustenance and survival. Nevertheless, it is the aspiration of every individual to live a life of comfort, security, physical and mental development without hints of possible mishaps of collapse or failure associated with his place of abode. It is therefore a social responsibility of the government to ensure that the wishes of the people are achieved within the limited resources and constraint.
Iyagba (2005, as cited in Olamide, 2012 ) explores that past few years in these developing countries witnessed the collapse of many buildings in various stages of completion, wherein, many lives were lost and property worth millions of money destroyed. It is worthy to note that these buildings were sick buildings.
2.4. Quality control of buildings
All buildings are prone to deterioration (i.e., wear and tear) and no structure can reasonably be expected to last forever, and thus, requires adequate design works by a qualified designer; during the construction works, a good quality control check at periodic intervals with constant and adequate maintenance resulting to prolonging their longevity ( Umeora, 2013).
This proneness of buildings to depreciation (and degradation) is traceable amongst other factors to the materials, elements as well as composite used in constructing them. They exhibit different reactions when exposed to the elements, environment, man-made conditions and the type of use they are subjected to. The geographical location and environmental conditions of the building also have significant effect on materials specification (Amadi et al., 2012).
Kingsley (2010) argues that the socioeconomic habits of users have a role to play in building collapse because it has been discovered that non-professionals design buildings and after the design by these quacks, for fear of paying appropriate fees to qualified people, they are passed on to the local planning authorities. Again, the right professionals are not appointed into the right positions in local authorities responsible for checking building designs. Kingsley further explores that the contractor owner syndrome should also be highly considered because the owner in a bid to save cost wants to build by himself using the so-called direct labour work force. The owner of the property purchases the materials by himself, buying cheap and inferior building materials without any idea of what type of materials should be bought for a particular part of a job.
Improper supervision of the project during construction also has a role to play because the involvement of competent professionals to handle the planning and design of a project does not entirely guarantee its stability. The project competently created on paper must be faithfully and accurately reproduced on the site. A building structure is said to be as good as its construction and not just its design. Every stage of the work must be supervised and managed by an appropriate qualified professional (Amadi et al., 2012)
Ajufoh, Gumau and Inusa (2014) argues that construction problems can cause building collapse due to the use of poor construction materials and low standard of workmanship into construction in an attempt to lower the overall cost of construction. It should be noted that only good materials in the hand of experienced artisans are the best ways of saving cost.
Ebehikhalu and Dawam (2014) opines that Building collapse caused by foundation problems may be due to any or a combination of bad workmanship, poor construction materials, faulty design, absence of a proper investigation of the site and insufficient provision in the design construction.
Site construction error instigates building collapse when construction is carried out with insufficient or non-existent geotechnical studies. Insufficient soil investigation before embarking on a new building work may result in structural failure and eventual collapse. Steep slopes may be subjected to creep under heavy superimposed pressure. Sulphate in clay soil is deleterious to buried concrete, iron and steel. High water table also lowers the soil bearing capacity (Amadi et al., 2012).
According to Onyemachi and Uji (2005) Design errors which include errors in concept, assessment of loading, calculation errors, improper elemental assembles, maintainability, detailing errors etc. can cause building collapse. Design errors can result in collapse but often times, failure due to design errors are easily traceable when not compounded by construction errors.
Operational errors which occur when alterations made to the structure are not taken into consideration during the design stage. This usually occurs when there is an upward change in the economic value of the building location, in such a case whereby a building might have been designed and constructed as residential might be converted into a school or supermarket requiring large free space or sometimes, more floors may be added thereby leading to overloading the existing foundation. Foundation and structural membersâ inadequacy are usually the causes of collapse in this regard (Atkinson, 1999).
Olagunju (2011) states that inadequate maintenance of a building structure may result in to building collapse in the end because much attention is not paid to maintenance of building structures. Maintenance should start from the day the excavation is dug. Maintenance should be a continuous exercise that ensures that defects are rectified as soon as they appear before further damage is done.
FagbenleandOluwunmi (2010) opines that it should be noted that architects, builders, engineers, surveyors and others in the construction should be held responsible and liable under a criminal law if it is proved that collapse of a building takes place due to their own criminal negligence. Diligent prosecution of such cases should also be advocated.
2.5. Structural deficiencies responsible for building collapse
It is however evident that the rate of building collapse globally is very alarming and has resulted in the loss of lives, properties and even with much financial investments wasted. Every building structure is expected to satisfy the functional objectives that are of safety, serviceability and economy (Fagbenle and Oluwunmi, 2010)
Oloyede, Omoogun and Akinjare (2010) asserts that there are quite a number of factors that are responsible for this incessant collapse of building in a general view which ranges from the use of substandard materials, non-enforcement of building codes, poor workmanship, greedy clients, cost of building materials and many other factors.
According to the tribunal of enquiry on building collapse constituted by the Lagos State Government on May 20th, 2013 (NAN 2013), the problem of building collapse endured because most building projects were handled by incompetent people also known as non-professionals.
Richard (2002) opines that the deterioration of reinforced concrete could occur as a result of corrosion of the reinforcement generated through carbonation and chloride ingress, cracking caused by overloading, subsidence of basic design fault and construction defects are structural causes of building collapse. The use of local building materials and approach of construction style without certain design code is another reason for building collapse (Ayininuola and Olalusi, 2004). Various researchers have conduct investigation towards the causes of building collapse with a lot of recommendations and yet the situation is getting worse in the study area. Akinpelu (2002) categorized the following as major causes of structural building collapse: environmental changes, natural and man-made imperilment; improper presentation and interpretation in the design. Collapse could also occur in the form of partial or total collapse of the building structure. This suggests a holistic approach of researching into the structural factors that may be responsible for building collapse from stakeholderâs point of view. Building collapse can be attributed to many factors. Many buildings have collapsed due to some of the following structural reasons.
2.5.1. Inadequate preliminary works
Preliminary works are operations which include site investigation and foundation. Site investigation is carried out to determine the properties of the soil strata. Building collapse is imminent where preliminary works are carried out shoddily (Adenuga, 2012). Seeley (1987, as cited in Fakere et al, 2012) assert that all potential building sites would need to be investigated to determine their suitability for buildings and the nature and extent of the preliminary work that would be needed. If the building sites are not properly investigated to determine the suitability to sustain the building and the building is erected where the site is structurally poor, it could lead to building collapse in the end. Particular attention should be given to the nature of the soil and its feasible load-bearing competence, as there may be shake, variations over the site confines. The past antiquity of the site need to be considered and investigated with particular reference to the former existence of trees, water level, borehole log, underneath soil category and refuse heap. An intent inspection should be made of the adjacent structures in order to ascertain whether failure can result due to localized conditions. Neville and Chatterton (1987) asserted that the development of soil details which correlate to the understanding of the physical properties of any particular soil type in relation to loads was truly the principal stepping stone towards a scientific approach to foundation problem and construction which are one of the structural factors that could lead to building collapse. However strong, rigid or structurally stable a building may be, its adequate performance lean entirely upon the ground which serves as it bracings. Suitable site examination prevents the issue of foundation problems because it would ensure that the most appropriate foundation is prescribed for the proposed building that is to be supported.
2.5.2. Adoption of wrong foundation
Lambe and Whitman (1979) defined foundation as the part of the structure in direct with the ground and which transmits the load of the structure to the ground which perform a vital role in the development of building structures. Onyemachi and Uji (2005) states that foundation is expected to carry all the dead, super-imposed and wind loads from a building to the soil on which the building stand upon in a specific way that settlement of the building structure is limited, so that failure of the underlying soil is prevented in order to avoid the event of building collapse. The depth of soil strata in response to the loadings from the structure has to be igeria e accurately in order to safely bear the foundation of the building. Otherwise, the structure will be prone to collapse.
2.5.3. Weak soil
Weak soil also contributes to building failures. As a result of the geologic nature of some terrains, some layers of soil are often not strong enough to carry the weight of buildings particularly the top most layer. Sunday (2006) argues that most buildings are erected without a proper soil test by the engineers. If this factor is not considered from the unset, it could lead to the uneven settlement of the building and cause caused cracks in the walls and decking. In areas with weak soil, the whole building might just sink.
2.5.4. Poor compaction and consolidation of foundation soil
Philp (2002, as cited in Ayuba et al, 2012) In the building industry, a building could result to collapse if it is deficiency of adequate and competent compaction of the soil within the foundation before placing hardcore and placing the oversite concrete slab. If the soil is properly compacted before the oversite concrete slab is cast, settlements may take place causing cracks on the wall and oversite concrete slab resulting to structural failure.
2.5.5. Improper design of walls
The wall is a very important part of the building that also provides support. Other functions are to enclose or divide space. A wall that will adequately provide support is a load-bearing wall which must provide adequate firmness and stability, weather resistance and durability. As a matter of fact, walls which also serve as support and strength to buildings must be erected in properly, perpendicular and produced of relevant quality materials. Cracks in buildings are a symbol of building failure. Failure in block-laying may lead to eventual collapse of the building structure as a whole (Oyewande, 1992).
2.5.6. Alteration and conversion in the use of a building
Alteration and conversion in the use of a building refers to the cases whereby the use of a building is adjusted or modified, other than that which it was originally design for. Ayininula and Olalusi (2004) observed that even admitting that majority of the clients inquire for approval afore the commencement of projects in most developing countries, additional alterations and amendment at the time of construction are performed without the knowledge of the authority where the approvals were sought from. For instance, a storey building planned and designed to sustain only two floors approved and constructed, if granted an additional weight without due consideration for its effect on foundation, column and slab will eventually fail and collapse as a result of structural inefficiency due to excessive loading, inappropriate remodeling, improper binding of units and unequal distribution of load on the building area.
2.6. Materials testing and inspection factors
2.6.1. Quality of concrete
Concrete is an important and versatile material that is cast with or without reinforcements to achieve the required strength needed to support building structures. Concrete is often used in the construction of foundation footings, wall and floor slabs, beams, columns, decking and lintels. It is composed of a mixture of cement, sand and stones. When metals are added to concrete it becomes reinforced concrete. Oyewande (1992) argues that the strength of reinforced concrete depends on the mixture of correct proportions of cement, sand stones and iron rods. Oyewande (1992) argues further that these constituents are especially needed for concrete required in the construction of massive structural works.
126.96.36.199. Poor concrete mix ratio
Ayuba et al (2012) states that concrete is mostly a composite of cement, sand, gravel and water in definite proportion. In order to provide support for a building, concrete is the most commonly used construction material by man. Poor materials do not usually make acceptable concrete. The cement, sand and stone should be solid, intact and should all have the types and qualities specified or adequate for the building structure. The result of poor concrete material could induce a building to collapse.
188.8.131.52. Improper concrete curing
Dan, Dan, Seongcheol and Moon (2005) explains that proper curing of concrete enhances the quality of the properties that comprises the concrete and prepare the concrete for a long term duration with high quality performance. Curing is arguably the most abused aspect of the concrete construction process. Concrete requires adequate time to cure, proper temperature and humidity. The absence of the above often results in the lack of expected characteristics needed to provide necessary durability (Akinpelu, 2002). Akinpelu (2002) argues further that the poor alignment of formworks, premature removal of formwork, improper mixing, inadequate design and improper concrete placement often leads to inconsistency and discontinuity in the surface of concrete which causes cracks and results eventually to building failure or total collapse
2.6.2. Poor quality sand crete blocks
Sand-crete blocks are made from a mixture of specified proportions of cement, sand and water. The overall strength of building structures is dependent to a great extent on the quality of blocks used for construction. High quality sand crete blocks are characterized by; strength, durability, density, efflorescence, thermal conductivity, fire resistance and dimensional changes. However, these characteristics are dependent on the type and proportioning of constituent materials, the ratio of mixing, duration of curing and mode of compaction. Constituent materials are first mixed then compacted in to molds to form pre casting units. When the molds hardened and set, they become blocks to be used for the construction of walling units (Oyewande, 1992).
The quality and size of blocks greatly determine the strength of buildings. For example the 9 inch (9â) hollow block often used for the construction of the external walls of buildings are meant to support the decking and the floors above in conjunction with the columns. Since the durability of blocks depends so much on the appropriate mixture of cement and sand, great attention should be given to mixing and molding them according to correct specifications. Due to the increasing demand for blocks in Nigeria, operators of block making industries tend to compromise the quantities of materials required for molding; adding more and more sand to increase the quantity of blocks per bag, resulting in the production of very weak blocks (Ayininula and Olausi, 2004). Most of these poorly produced blocks do not meet the standards set by the Standard Organization of Nigeria (SON). These blocks often crack or disintegrate during the process of transporting them from the molding site to the building site. The Nigerian industrial standard (NIS 87:2000) stipulates minimum requirements for producing sand crete blocks in terms of strength, dimensions and general appearance. Only blocks of good shape and size, free from holes, cracks and other flaws are fit for construction in the building industry.
2.6.3. Lack of steel test and calculation errors
In the construction of building structure, structural analysis and steel testing should be done by the structural engineer who expected to calculates and estimates the weight of the proposed building and determines the required number and sizes of iron rods needed for constructing beams and columns to support the buildingâs weight. Unfortunately in many cases, structural analysis is not carried out at all or very poorly done as contractors rely on trial on error methods to estimate the right amount of required iron rods. In other cases, contractors even fail to correct errors during the mixing of concrete resulting in building failure and even total collapse. The steel bars and reinforcements are inserted in concrete, because compressive stresses are absorbed by the concrete, while tensile stresses are catered for by the steel reinforcements. For this goal to be attained, steel rods must be placed correctly (Ayuba et al, 2012).
2.6.4. Specification writing
Ayodeji (2011) states that Specification writing is a core areas that need adequate attention before the embarkment of any construction work, one of the critical parts of negeligence in writing specification is the prevision project adopted without quality review of the area that requires improvement or modifications. Inadequacies of specification writing can bring about building failures especially when the client give a wrong information about the function or use of the building building, this may create a false calculations which will led to deformations.
The application of wrong and substandard building material specifications have been possible origin causes of building collapse in developing countries. In the construction of buildings, the materials that are basically engaged on construction sites are cement, sand, gravel, granite , woods, iron rods and sandcrete blocks. Other materials used are aluminium, glass and ceramics. Good building constructions are enhanced by materials of good and sound quality. Proper handling and storage must be given to the building materials in order to ensure that their good and sound quality is adequately preserved. Material specifications must relate exactly to the intended construction and must be of adequate standard of quality and quantity. Specifications are to prescribe what materials should be used and where there is a deviation from these stated specifications, building collapse should be expected (Fakere et al, 2012)
2.7. Management factors responsible for building collapse
2.7.1. Approval of building design
Ataev (1985, as cited in Fakere et al, 2012) states the basic requirement of any structural component of a building is that it should be strong enough to carry and withstand every possible types of loads to which it is likely to be subjected. Therefore, building design is not just the architectural design but it also includes structural, electrical and mechanical engineering designs. A poorly designed building structural will finally result to case of collapse. The final objective of structural analysis is to enable the structural engineering design to be obtained and to be able to construct a building structure, which is satisfactory in function and service, and that such designs must be approved by the approving body. This means that it must not collapse when loads are applied and the deformation must not be excessive. In addition, some clients in order to try and save cost hereby patronize quacks to do designs for them. This is very common in developing countries and such designs are grossly inadequate and usually results ultimately in building collapse.
2.7.2. Unprofessional conduct involved in the construction projects
Oyewande (1992, as cited in Ayuba et al, 2012) observes that due to the high cost of some building materials in developing countries, use of substandard materials, in appropriate approval of unproven local construction methods are employed, with lack of enforcement of building control and management, by- laws and construction health and safety management, such as placement of structural beams and columns in the building. Lack of experience on the part of the contractor and the consultant could result in poor craftsmanship and inferior standard of construction. This could develop to high running cost and in some cases it outcome to collapse of some part or the whole building. These non-professionals otherwise known as quacks have over taken up the services of architects, planners, building engineers and other allied professionals in the building industry.
2.7.3. Ineffective building supervision
Avading building collapse confined in largely on effective structural guidance and supervision of works. Hence, improper structural supervision will lead to the collapse of the building structures (Ayuba et al, 2012).
Structural supervision comprise the elaborate knowledge of workmanship and materials of the structural elements of the building, while inspection is absolutely to maintain adherence to contract documents, especially the structural drawings. The objective of the structural supervision is primarily to ensure that employerâs requirements as expressed in the contract documents as regarding the structural elements are correctly interpreted and the problems which are bound to arise are satisfactorily resolved. In the case of the building under study, there was no proper supervision for the demolition works (Fakere et al, 2012)