Determinant Factors Affecting Schedule and Cost Overruns on Water/Sewerage Construction Projects: The Case of AAWSA

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Addis Ababa University


The water supply and sewerage construction projects in Addis Ababa city recurrently faced several problems which lead to schedule and cost overruns. The objective of this study was to assess the determinant Factors affecting schedule and cost overruns on water supply and Sewerage construction projects in Addis Ababa City. This research used a descriptive survey design and a combination of both quantitative and qualitative data collections methods to collect primary data as well as secondary data. The research data were collected from primary and secondary sources using structured questionnaires administered to Site Engineers, project managers, consultants, contractors, procurement officers, budget/finance officers, project planning, monitoring and controlling officers, and Internal Auditors. The data collected through a structured questionnaire were analyzed with SPSS version 20.0 software and the Relative Importance Index (RII). Documentary evidence was also reviewed by the researcher for the extent of cost and schedule overruns case analysis. The study has finally pointed out the most important determinant factors that affect schedule delays on water supply and sewerage construction projects in the city as perceived by the three parties (client, consultants, and contractors) are bureaucracy in Government agencies, Government tendering system of choosing the lowest bidder, late delivery of materials, escalation of local material prices, ineffective project planning and scheduling, insufficient estimation of original contract duration, design errors made by designers, slowness in decision making, delay in site delivery, and unexpected surface & subsurface conditions. The findings from the survey result also showed that the top ten determinant factors affecting cost overruns on water supply and sewerage construction projects in Addis Ababa are design change, price escalation of labor and materials, quantity underestimation, contractual claims, such as an extension of time with cost claims, poor Contract management, omissions and errors in the bills of quantities, additional work orders/extra items at owner’s request, inadequate project preparation, monitoring, planning, and implementation, scope changes, and wastage/poor financial control on site. Further, the main conclusion was that almost the majority of the water supply and sewerage construction projects in Addis Ababa city experienced extraordinary schedule delay and cost overruns to varying degrees due to the above-mentioned determinant factors. The average rate of schedule overrun is between 7.69% and 1208.89% of the original duration, and the average rate of cost overrun is between 0.72% and 8.11% of the original contract value. The projects were predominantly affected by the three key project players (client, contractor, and consultant). It is therefore, recommended, among other things, that all relevant appropriate measures shall be put in place by the responsible parties (client, contractors, and consultants) to minimize schedule and cost overruns by implementing the general project cost and schedule management practices, functions, procedures, tools, relevant techniques and using latest technology products from the beginning of the project initiation up to the final closure process



Schedule delay, Cost overruns, water supply & Sewerage construction projects