RISK ANALYSIS OF COST OVERRUN IN DAM CONSTRUCTION PROJECT DUE TO CHANGE ORDER

• Main Author: Sella Fajar, Sandy
• Format: Theses
• Language: Indonesia
• Subjects: Teknik sipil
• Online Access: https://digilib.itb.ac.id/gdl/view/48131
• Institution: Institut Teknologi Bandung

Risks and uncertainties can be a factor in the failure of construction projects to achieve their stated goals. There are seven risk events that often occur in construction projects, one of them is the provision of additional or less work, which is called a change order. Based on preliminary data collection for 30 reservoir works carried out by the Ministry of PUPR, obtained 93% of work that has changed the contract value through contract addendum for 9% - 9,7%. Based on that information, this research is specifically to know cost overrun on dam works project which is larger and more complex than reservoir works. This study aims to obtain risk factors that occur in the dam project that cause change orders from the point of view of the owner, so that it can be a description to take a decision and minimize these risk factor that affect to cost project. The method used in this study is a qualitative method using a questionnaire to obtain probability and impact values based on respondents ratings. The determination of the questionnaire is based on a literature study on risk factors in dam construction work that has been clarified by the owner. Based on the results of the quantitative method, risk factors obtained at the design stage that have an impact on document quality and have the greatest severity index value, namely the insistence of stakeholders to accelerate work, conditions on the field are not in accordance with the scope stated in the ToR and the desire of the Owner to provide review and comments to the design. While at the construction stage, there are risk factors, namely environmental conditions that are not as expected, the occurrence of unexpected things such as natural disasters and design changes during construction. Then, the next step is looking for cost overruns percentage in dam construction through a second questionnaire to respondents. Quantitative method used to obtain the percentage of costs based on the assessment of respondents in several dam works. From these data using @risk program will be made a distribution for every work items on dam project. Determination of the distribution uses a triangular distribution to easily understanding of the cost overruns parameters with three values, namely the minimum value, most likely value and the maximum value. The next analysis is using a montecarlo simulation based on the results of the parameters that have been obtained by adding up each cost overrun of work items so we get a PDF curve and tornado diagram as a form to understand the work items that are most sensitive to the total cost overruns. Based on the simulation results, the total cost overruns for the Sadawarna Dam work was 4.09% of the total initial contract of Rp 1.8 trillion and based on sensitivity analysis using tornado diagrams, it is found that the most influential work items to increase costs are land acquisition work and main dam work. At the stage of land acquisition, the factor that has the biggest contribution in increasing costs is the change in government policies or regulations that affect the project and unexpected inflation or price fluctuations. While risk factors for maindam work are detailed design that do not correspond to field conditions and design changes during construction. The final results of this study found there are 13 risk factors at the design stage which have an impact on the quality of design documents and 29 risk factors at the construction stage which are the source of increased costs through change orders.