DETERMINATION OF ENVIRONMENTAL LOAD FACTORS OF JAVA AND NATUNA SEA FOR UNBRACED MONOPOD USING RELIABILITY ANALYSIS METHOD

• Main Author: Devi Adani, Larasati
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/43543
• Institution: Institut Teknologi Bandung

The process of oil and gas field exploration activities requires infrastructure in the form of offshore platform structures. This structure needs to be designed optimally using applicable design standards in order to be able to withstand the equipment and environment loads later. Commonly used standards are published by the American Petroleum Institute (API), which adapts water conditions in the Gulf of Mexico. The condition of the waters in the Gulf of Mexico is relatively more extreme than in Indonesia, so it needs a review of the application of environmental burden factors in Indonesia. Case studies were carried out for unbraced monopod structures located in the Java Sea and Natuna Sea by reviewing the value of the Collapse Base Shear and Reliability Index (?). The structure is modeled using the API RP 2A WSD and the API RP 2A LRFD standards under operating and storm conditions, assumed to be un-manned. Collapse analysis using static pushover produces a minimum RSR value of all case study structures meeting the minimum criteria of 0.8. The reliability analysis process uses the First Order Reliability Method II (FORM II) method. The structural reliability index (?) value is very small, far from the target reliability index value issued by DNV of 3.71. However this did not occur in structures designed in the Java Sea under operating conditions, where the structural reliability index (?) value reached 4.39. The environmental load factor value obtained was 6.31 for storm conditions in the Java Sea. Whereas in the Natuna Sea the environmental load factor was chosen at 5.61 for operating conditions and 7.15 for storm conditions.