1.0 Introduction
1.1 Background of the Study
The complexity of the construction industry due to different stakeholders' involvement makes it differ from other industries. This complexity leads to unwanted situations like variations with their associated effects. And presently, it is almost becoming a rare thing for a construction project not to have variation. Most contracts these days must make provisions for possible variations given the nature of road construction project (Finsen et al., 1999). (Uff, 2005) further pointed out that a clause permitting variation of works is an essential feature of any construction contract because without it the contractor is not bound to execute additional work or to make omissions or changes.
In line with these, the nature and approach to the conception, planning and subsequent actualization of construction projects are dynamic, complex, sophisticated and capital intensive in recent times. In consequence, these projects are subjected to adequate appraisals by the sponsors on the basis of political, social, projects relatives' benefits, externalities, etcetera, with a view of ascertaining the values of money (Onwusoye, 2005). The certification for the realization of this objection through various techniques and other implied factors by the potential owner of the projects leads to the eventual take off of a construction project.
Therefore, design variation need to be critically addressed as this continue to be a frequent problem that gets worse often in construction project. Though of recent, it is a common phenomenon for design variation to occur on construction project. But under normal circumstance, it is possible for a complex set of drawings and specification to be available for preparation of fully described and accurate bill of quantities for tendering purposes. These would deplete further charges as a result of design changes during the construction stage.
According to the J.C.T. 80, design variation in road construction refers to a change in the works initiated by the engineers, consultants, employer or other factors as the case may be which involves the alteration of any kind or standard of materials to be used in the work. A design change is regarded as any change in the design or construction of a project after the contract is awarded and signed, and such changes are related not only to matters in accordance with the provision of the contract but also changes to the work conditions. Akinsola et al (1997) also noted that these changes as any additions, omission or adjustment to the contract price or contract time, and it occurs regularly on construction projects.
Park (2002) defined design variation as a change to the work state, processes or methods that differ from the original construction plan or specification and usually resulted from different in work quality and condition, scope changes or uncertainties that make construction dynamic and unstable. Affirmed that design variations are inevitable on major construction projects particularly on road construction where the project is complex, the ground conditions variables or the employer desire to incorporate the latest technology into the project. And the more design changes on a project, the greater effect which become time consuming and costly in construction projects (Mohamed, 2001). It is therefore of greater concern regarding the adverse effects of the design changes in both public and private construction in Akwa Ibom State.
According to Arian and Pheng (2005), design variation on road construction project resulted into a substantial increment in amount of funding budgeted for the work, hence caused the inability to complete and handover the work as agreed initially at the commencement of the work. As a result of this, it is extremely noticeable that time and cost overrun occurs due to variation in many construction projects especially road construction. Similarly, variation order which contains a set of instructions that allows changes or modifications to be made to as earlier agreement in terms of volume or nature of task to be carried out, (O'Brien, 1998). These changes are however occur after the award of the initial contract or after work might have commenced at the construction sites. The changes may be due to various reasons such as the modification of original design and scope, schedule, costs and methods.
Variation from the original project design is seen as the major causes of project failure, though project monitoring and control could cause corrective actions to bring deviation during construction but failed to take cognizance of identifying and analyzing the root cause of such variation (Ubani, Nwanchukwu and Nwukonkwo, 2010). The performance objectives defect due to variation of many completed and ongoing road projects resulted in employer's dissatisfaction, project time extension and cost overrun, low quality and substandard outputs, project conflicting between the contractors and employers arising from variation in contract sum. And the unusual thing about it is the extent of such differences as well as the frequency occurrence. The causes and cost implication of variation needs to be assessed and analysed at the onset of the project, and it is on this background that the study was carried out.
1.2 Statement of the Problem
All road construction projects undergo various degrees of design variations throughout the project life cycle. Changes in construction projects are inevitable particularly when the actual work commences to correct or modify original design or scope of work (Alnuaimi et al., 2010). The research study by Naoum (1997) highlighted the lack of time and effective communication, lack of integration, uncertainty, a changing environment and increasing project complexity as the drivers of design changes.
According to a study by Ogunlana, Promkuntong and Jearkjirm (2000), construction owners are the major causes of design variations due to changing plans in line with the changing economic climate to meet customer demands or for making marketing reasons. Design variation need to be constantly monitored to avoid escalation (Olawale and Sun, 2010).
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