At first, this study quantified the cost of CO on rural road maintenance contracts. Then the study identified the causes of CO and its preventative measures in road maintenance activities. Lastly the study developed change order contingency estimating tool and schedule crashing tool in order to assist in change management system of these contracts. The main conclusions and limitations of these three phase studies are described below.
This study determined the amount of CO on road maintenance projects contracted under the Kenya Rural Road Authority (KeRRA). The analysis of 614 road-maintenance projects showed that the average percentage of CO in these projects was 13.07%. The study also indicated that there was a negative correlation between …show more content…
However, ‘Gravel patching’ was the most frequent maintenance activity. The main reason behind high frequency CO in these activities was due to unforeseen conditions during the time of the estimates and the time of the road maintenance. Normally, estimates for gravel patching and wearing course were prepared based on the current surface conditions. In the time lag between the estimate and the construction work, the surface deterioration increased which required more work to complete the task. Feedback received from regional managers indicated that such reasons as ‘under-packaging the amount of gravel during the bill of quantity (BOQ) preparation at the initial stage’ contributed to highest frequency CO in these activities. The non-parametric Kurskal-Wallis test showed that the median value of the CO percentages for the activity ‘600 mm culvert installation’ was significantly higher than that of activities ‘Heavy grading’ and ‘Heavy bush clearing.’ The reason behind the difference could be: unpredictable site conditions, requiring extra works for culvert installation. In some cases, before the culvert installation, some protection works may be required which may change during maintenance …show more content…
To address this issue, in this study, a tool was developed for the estimation of contingency cost for a road maintenance contract. The prediction of contingency is based on historical records of change orders on road maintenance activities. For each of maintenance activities in a contract, a contingency is estimated and an adjusted contingency value is provided for each activity. According to the cost weighting value of each maintenance activity, the overall contingency value for the project is
This study determined the amount of CO on road maintenance projects contracted under the Kenya Rural Road Authority (KeRRA). The analysis of 614 road-maintenance projects showed that the average percentage of CO in these projects was 13.07%. The study also indicated that there was a negative correlation between …show more content…
However, ‘Gravel patching’ was the most frequent maintenance activity. The main reason behind high frequency CO in these activities was due to unforeseen conditions during the time of the estimates and the time of the road maintenance. Normally, estimates for gravel patching and wearing course were prepared based on the current surface conditions. In the time lag between the estimate and the construction work, the surface deterioration increased which required more work to complete the task. Feedback received from regional managers indicated that such reasons as ‘under-packaging the amount of gravel during the bill of quantity (BOQ) preparation at the initial stage’ contributed to highest frequency CO in these activities. The non-parametric Kurskal-Wallis test showed that the median value of the CO percentages for the activity ‘600 mm culvert installation’ was significantly higher than that of activities ‘Heavy grading’ and ‘Heavy bush clearing.’ The reason behind the difference could be: unpredictable site conditions, requiring extra works for culvert installation. In some cases, before the culvert installation, some protection works may be required which may change during maintenance …show more content…
To address this issue, in this study, a tool was developed for the estimation of contingency cost for a road maintenance contract. The prediction of contingency is based on historical records of change orders on road maintenance activities. For each of maintenance activities in a contract, a contingency is estimated and an adjusted contingency value is provided for each activity. According to the cost weighting value of each maintenance activity, the overall contingency value for the project is