Browsing by Author "Chigwiye, G"

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    Development of parametric project cost and time estimation models for Irrigation Construction projects: a case study of the National Irrigation Commission of Tanzania.
    (University of Dar es salaam, 2019) Chigwiye, G
    Development of parametric project cost and time estimation models for Irrigation Construction projects: a case study of the National Irrigation Commission of Tanzania. Gregory Chigwiye Master of Science (Construction Management) University of Dar es salaam, College of Engineering and Technology, 2019. Cost and time overruns is a common phenomenon in irrigation construction projects in Tanzania especially to projects undertaken through government funding through NIRC as implementing agency on behalf of Government of Tanzania (GoT). This dissertation on “Development of parametric project cost and Time Estimation Models for Irrigation Construction projects: a case study of the National Irrigation commission of Tanzania (NIRC)” aimed at filling the gap where by NIRC and other developing partner in irrigation sector will have a clue to what extent cost and time overruns affect irrigation construction projects. Factors affecting cost and time overruns in irrigation construction projects were identified, ranked and prioritized on how each influences the performance of the projects during construction stage. Thirdly eight respondents who are 95% of the total respondents ranked the identified factors based on the selected projects. Association was checked between factors affecting both cost and time overruns in irrigation construction projects. Results found that, the spearman’s coefficient of correlation rs , was calculated to be 0.96. This concluded that there is high degree of association between factors influencing time and cost overruns. With the use of data from 38 projects implemented by NIRC between 2013 and 2018, cost and time parametric model were established. Cost estimation parametric model (CEPM) was developed from top 20% of the highly ranked factors contributing to cost overrun. The top 20% highly ranked factors contributing to cost overrun were inaccurate quality estimates Iqe, increase in scope of the project Isp, inadequate contractor’s capacity Ice, inadequate planning and scheduling by contractors Ipse, unforeseen ground conditions Uge and c which is the Original cost estimate multiply by 10-6. From these independent variables, the model equation was given by C=-16.21+1.07c +14.24 Iqe -11.75Isp-4.88ICC+083IPSC-1.70Uge in Tanzania. Time estimation parametric Model (TEPM) was developed from top 20% of the highly ramked factors contributing to time overrum. The top 20% ranked factors influencing time overruns were inadequate contractor’s capacity Ice, inadequate planning and scheduling by contractor Ipse, inaccurate quality estimate Iqe, increase in scope of the project Isp, adverse weather condition Awe and the original time estimate, t(in days). From these independent variables, the developed model equation TEPM given by T (in days) = -8788+1.03t+9.17ICC-20.21 Ipsc +26.53 Iqe +16.12Isp +62.33Awe.