BUILDING COLLAPSES IN NIGERIA

BUILDING COLLAPSES IN NIGERIA: CAUSES AND SOLUTIONS BY USMAN TASIU ABDURRAHMAN DEPARTMENT OF CIVIL ENGINEERING KANO UNIVERSITY OF SCIENCE AND TECHNOLOGY, WUDIL JUNE, 2011 INTRODUCTION A building, once properly constructed is expected to be in use for a very long time. Although every society has its own problems and Nigeria is not an exception yet the very recent challenges of buildings collapsing in various locations have been giving the various arms of government and the people of Nigeria sleepless nights in view of the enormous loss of huge investments in housing, properties and human life. The major challenge on the issue of building collapse is that individuals differ radically from one another on the professional to blame as the major cause of the collapse of a building. This study reviews current challenges in the building industry in relation to collapse of buildings, loss of lives and properties. Findings from the three prominent groups were varied. First, building experts blamed building collapses on the use of low quality building materials coupled with employment of incompetent artisans and weak supervision of workmen on site. Second, public opinion revealed that the blames of building collapse were due to non-compliance with specifications/standards, use of substandard building materials and equipments and the employment of incompetent contractors. Third, opinion of the academia on remote causes of building collapse showed that the route causes are mainly the non-enforcement of existing laws and endemic poor work ethics of Nigerians at large. It can be recommended that the press should lay more emphasis on educating the public at large on the dangers of the collapse of a building and less on public emotions. In addition, government should, on one hand, embark on proactive steps by mustering enough political will to allow the Town Planning Authorities to perform their functions unfettered and on the other hand, provide the legal framework that can improve and ensure smoother, less time-consuming and less burdensome ways to conduct business in the functioning of law courts. Collapse of buildings is not new to Nigeria, neither is it only peculiar to Nigeria, however that will not stop us from taking critical look at the situation and finding a solution to it. Collapse of building though can happen to any kind of building but the casualty of multistorey buildings can be so terrible. Multistorey buildings are either built because of social status, there are places you get to and all what you see are very high building so you don’t want yours to be unnoticeable among them. Commercial viability of a location also make more people to build storey structures in an area because more people will jostle for space to exhibit or get contact with their customers or client. Area accessibility, some locations are routes to a lot of places so high vehicular and human traffic is usually associated with such places, hence more commercial activities. CAUSES TO BUILDING COLLAPSES IN NIGERIA Main contributors to building failures are the owners of the buildings themselves, Architects, Engineers, Contractors, Town planners and Government, because of the unethical practices perpetuated by them. Other reasons why buildings collapse in Nigeria are:  Underestimate of wind loads during the design  Poor supervision at the stage of construction  Uncontrolled specification of the materials as well as the elements of the structure  Abuse of the standard construction process  Availability of low construction materials in the market Below are the problems in category through which they contribute in the structural collapses. Thus: (1) The first problem is boycotting the professionals - This issue has been overflogged both in print media and electronic media but the same problem still persists. There is also a problem of eggheads professionals that believes they know all and are not ready to take advice from a colleague. There are known cases like that, which has turned awry, the big buildings that are collapsing in Lagos business district, were handled by professionals. (2) Contractors cutting corners - Contractors trying to make gains at the expense and lives of the users of the building are another problem that has to be tackled. There should be a check from policy makers to make sure specification is thoroughly followed by contractors. (3) Human activities on building - As insignificant human weight may seem to be, the moving up and down of the live loads and dead load contributes overtime in no small measure in wearing down the building. It will take long time though, but houses also expires, and in the case of the types of buildings we have in Nigeria, there lifespan is shorter than others in civilised world. (4) Inadequate foundation - This is the most important part of a building; unfortunately a lot of people are not giving adequate monitoring to this and is causing more problem. A registered Structural Engineer is very important to you if you are planning on building a strong and solid multistorey building. (5)Aging Building – Many do not know that buildings also have their life span most of the building in Lagos Mainland have spent 25 years and above, despite that they are of shallow foundation and very low quality materials are used for them. As you lay your bed, so you’ll lie on it. If you had used low quality material thereby thinking you’ll cut cost, then also be expecting to park out of that building very soon. Below are the ways through which the above listed personnel contribute in the building failures (Collapses) in Nigeria CLIENT They have been blamed as contributors to building failures in the following ways:  Delayed payments of completed works (Ayininuola & Olalusi, 2004)  Construction of buildings using quacks (Ayininuola & Olalusi, 2004)  Controlled work variation/construction changes  Working without approval  Erecting structures on an unapproved land  Unauthorized addition of extra floors on existing buildings without ddue consultations with design Engineers  Altering the building purpose or live loading without Engineers’ approval  Use of sand with impurities (Clay, Silt, e.t.c) in concrete  Use of hand-moulded or hand compacted un-vibrated sand-crete blocks of low compressive strength recommended by quacks  Poor maintenance culture for completed buildings ARCHITECTS  Undertaking building construction all alone without consulting the Engineers  Not involving Engineers at all stages of design, construction and supervision of building erection TOWNPLANNERS  By not ensuring that building designs conform to the laid down specifications/regulations before and after approval  Inability to enforce regulations and by-laws on plan registration of buildings ENGINEERS  Use of too many foreign codes of practice which often do not reflect the local conditions  Use of materials prone to failure  Monetary gains  Allowing of poor or inadequate workmanship  Providing inadequate supervision of construction work GOVERNMENT  No stable policy guidelines on building approval throughout the country  No properly trained personnel for structural drawings approval in town planning offices  No monitoring personnel in town planning responsible for ensuring that plans approved are the ones executed on site  Nonexistent and/or lack of enforcement of building regulations and by-laws and construction health and safety regulations CONSTRUCTION MATERIALS Quality of the Blocks used: The quality of material used is a factor in building failure. Take for instance the 9-inch hollow blocks used for the construction of external walls of residential buildings; these blocks support the weight of the "decking" and other floors above it in conjunction with "pillars". Since the strength of the blocks depend on the ratio of cement to sand used for molding them, the right proportions must be used for molding the blocks to ensure that they are strong and durable. The so-called "ready-made" blocks sold by some block industries do not measure up to expectation. Some of these block industries mass-produce the blocks and in a greedy bid to get the most number of blocks per bag of cement, they use more sand than necessary resulting in very weak blocks. This writer witnessed cases of 9-inch blocks bought from block industries crumble while bricklayers were trying to pick them up! Now tell me, if a 9 inch block crumbles as it is being picked up, how would that block carry the weight of the "decking"? The only reason we do not have even more cases of buildings crumbling as a result of weak blocks, is because of the presence of columns "pillars" which are the primary load bearing components in buildings. Quality of concrete used: The other building material component that is sometimes bastardized at the peril of the building itself, is concrete. Concrete is used for construction of foundation footings, lintels, "decking", "German floor", beams and columns. Concrete is made up of sand, cement and stone and when iron bars (rods) are added, it is called reinforced concrete. The strength of reinforced concrete depends on the proportion of cement, sand, stone and iron rod in it. After the design of a building by an architect, the structural designer calculates the amount of weight the building will carry - this is called structural analysis. The engineer then determines the size of beams and pillars that will help carry that weight. He also determines the number and sizes of rods that will be put into the beams and pillars to strengthen them for carrying the weight. What I have just described is the ideal situation, which is not always what happens resulting in structure failures. Problem arises when proper structural analyses is not performed or better yet, when no analysis is performed. The result is that the contractor resorts to trial and error method of construction: he may not use the needed number and sizes of iron rods or may fail to construct adequate numbers and sizes of pillars. Some contractors even fail to use the correct mix design for the concrete, the list goes on. All these errors aggregate to make a building susceptible to failure. Poor compaction and consolidation of foundation soil : The other important reason a building could collapse is lack of adequate compaction of the soil inside the foundation before placing hard-core and pouring the "German floor". If the soil is not properly compacted before the German floor is cast, as construction progresses, settlement occurs causing cracks on the walls and German floor that invariably lead to structural failure. Weak soil: Also, because of their geologic make up, some layers of soil are just not strong enough to carry the weight of a building. This is mainly applicable to the top layer of the soil on most parcels of land. If this factor is neglected and the building is constructed on the soil anyway, differential settlement of the building starts and leads to cracking of the walls and decking. In some cases, the building just continues to sink and this can be seen in many parts of Lagos, in particular. If a soil investigation reveals the presence of weak soil on the upper layers of a parcel of land, the structural designer rectifies this by calling for a deeper than normal foundation. This means digging until strong soil is encountered before laying the building foundation.   SOLUTIONS TO BUILDING COLLAPSES IN NIGERIA Below are some of the proactive steps that could help in prospering solutions to the failures: Always insist on structural analysis after the architect has designed your building before construction starts. Structural analysis and design determine the weight that would be exerted on the building and specify the correct number and sizes of columns and beams needed to help carry that weight. The correct location of the columns and beams and the sizes and quantity of iron rods needed, are also specified. Make sure that the blocks you use come from reputable sources that use the correct mixture of cement and sand for molding them. Blocks with too much sand have the tendency to crumble at the slightest movement and could never support the weight of a building for long. Insist that the building foundation is properly back-filled and consolidated before the German floor is cast. This will prevent secondary settlement and cracking of walls. Your representative must keep an eye on the mixing of the concrete to ensure that the correct proportions of materials are used. For example, if the plans specify a concrete mixture of 1:2:4, it means that 1 part of cement to 2 parts of sand to 4 parts of stones should be used in the mixture. Make sure that the contractor sticks to it otherwise you would end up with concrete not strong enough to do the job. Also, ensure that the specified sizes and numbers of iron bars are used. Building collapses can also be remedied in Nigeria through the following ways: 1. Attracting suitable talents into the structural Engineering profession from the grassroots (Primary school level) by using the opportunity provided by the 9year Universal Basic Education Curriculum which has an inbuilt proposal to teach science, technology, mathematics and computer studies at the primary school level. 2. Strengthening of Post-UME screening to eliminate completely the admission of academically weak students into the universities who were hitherto admitted through corrupted Jamb examinations. 3. Increasing the number and quality of practicing structural Engineers by ensuring the survival of the B.Eng programme in structural Engineering at the University of Bennin, which is the only such programme in Nigeria. In addition, such programme should be encouraged in Nigerian Universities where applicable. 4. Immediate implementation of COREN SITSIE programme, which is proposed to enhance the On-the-Job training and experience of new entrants into the structural Engineering profession. REFERENCES  Collapse of buildings in Nigeria and the way forward: a journal presented at the annual conference & AGM of the Nigerian Institute of structural Engineers (2007)  www.buildingcontractorsecrets.com  www.ccsenet.org  www.cricketdiane.wordpress.com  www.nigeriavillagesquare.com  www.nigeriaworld.com  www.w3.org