Assessment Of Causes And Effects Of Variation Orders On Oromia Road Construction Enterprise Projects In The Case Of Jimma Zone

Abstract

One of the most common challenges of road construction projects is low performance in terms of time and cost. One of the contributing factors to this low performance among others is variation; because variation can affect project cost and schedules. The main objective of the study was to assess the major causes and effects of variation orders on Oromia road construction Enterprise projects in Jimma Zone. Purposive sampling technique was used to select respondents and collect data. A desk study and questionnaire survey in addition to literature review were carried out to achieve the study objectives. The research work mainly consists of literature review, questionnaires survey, and case study. Based on the literature review a total of 23 potential causes and 11possible effects of variation orders were identified. Questionnaires were distributed to the clients, consultants and contractors who are engaged in Oromia Roads Construction Enterprise projects and 83% of questionnaire were received from respondents. The collected data were analyzed via using RII and Microsoft excels software. The results of the case study indicated that the varied cost in two projects were above 30% and the total extension of time claimed in Begge-Ketta and Chira-Afalo-Chariko projects were 76% and 81.86% respectively. The causes and effects of variation orders were ranked based on the value of RII. The most significant causes based on the case study and questionnaire surveys in Jimma Zone gravel roads constructed by Oromia Roads Construction Enterprise were identified and ranked: Conflict between contract documents (0.635), poor estimation while design (under estimation) (0.621), change in design including addition and omission (0.596), right of way problems (0.595), lack of materials (0.584) and delay due to adverse weather conditions (0.441). The study also investigated; delay in project completion time (0.819), increase in project cost (0.811), dispute among parties (0.77) and decrease in productivity (0.734) as a major effects. Owners are recommended to determine the project schedule by experts and not to change the original drawings and choose a consultant that is special to the nature of the project. In addition Contractors are recommended to make a site visit before tender pricing and secure the site and Consultants are recommended to spend adequate time on design detailing and documentation