DETERMINATION OF LRFD ENVIRONMENTAL LOAD FACTOR OF EIGHT-LEGGED JACKET OFFSHORE PLATFORM STRUCTURE IN JAVA SEA USING RELIABILITY ANALYSIS METHOD

• Main Author: Ramdhana, Fadhil
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/81391
• Institution: Institut Teknologi Bandung

The design of the fixed offshore platform structure refers to API RP 2A Standard or American Petroleum Institute – Recommended Practice 2A. The API RP 2A Standard has two methods, Working Stress Design (WSD) method and Load and Resistance Factor Design (LRFD) method. Currently, API RP 2A Standard – LRFD method was developed using data on an environmental load factor value of 1.35, which was derived from environmental conditions in the Gulf of Mexico. Meanwhile, this research was conducted in the waters of the Java Sea which has calmer and quieter environmental conditions compared to the environmental conditions of the Gulf of Mexico. The design of an offshore platform must fulfill two factors, safety factors and economic factors. Therefore, if this research uses Gulf of Mexico environmental condition data it will certainly produces structures that are overengineered, overdesigned and not economical. In this research, in-place analysis and pushover analysis will be carried out on the structure of an eightlegged jacket fixed offshore platform in the Java Sea. In-place analysis is carried out to determine the unity check of member tension and determine the relationship between wave height and wave base shear equation. While pushover analysis is carried out to determine the relationship between yield strength and collapse base shear equation. Reliability analysis is carried out using the First Order Reliability Methods Method II with wave base shear equation and collapse base shear equation for five environmental load factor values, LRFD 1.00, 1.10, 1.20, 1.35 and WSD 1.00. The result of the reliability analysis is the reliability index value (????). The reliability index value is used to determine the recommended value of the environmental load factor (????????). In this research, the reliability index target value used is 3.72. The reliability index value of structure designed with LRFD 1.35 method is 4.282 and designed with WSD 1.00 method is 4.349. The recommended environmental load factor value of structure is 1.04.