DESIGN AND NONLINEAR PUSHOVER ANALYSIS OF A FOUR-LEGGED JACKET TYPE OFFSHORE PLATFORM IN MAKASSAR STRAIT

• Main Author: Putra Perdana, Tegar
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/84992
• Institution: Institut Teknologi Bandung

In order to extend the service life of an offshore platform, a feasibility study needs to be carried out to determine the strength and safety of the structure. In this final assignment, a nonlinear pushover analysis will be carried out on a four-foot wellhead platform belonging to PT Pertamina Hulu East Kalimantan which has been operating since 1983 in Makassar Strait. This platform still has a productive reservoir today. A feasibility study was carried out in order to requalify the platform. In-service conditions of the platform has been fulfilled. To ensure the maximum capacity of the platform, a nonlinear pushover analysis is carried out. This analysis will provide how the structure will response once it reaches its elastic capacity, that is, when it begins to behave nonlinearly and undergo plastic deformation. The ductility capability and Reserve Strength Ratio (RSR) of an existing offshore platform can be determined through nonlinear pushover analysis. This analysis will be carried out in two conditions, using an elastic-perfectly plastic material approach in structural analysis software and an elastic-nonlinear plastic material approach in finite element analysis software. The pushover analysis obtained the smallest RSR value at 4.78 due to loading in the 135° direction. These conditions were used as a reference for nonlinear pushover analysis and an RSR value of 6.13 was obtained. The cause of structural collapse occurs in piles that experience plasticity so that the displacement value becomes large, causing collapse.