DESIGN AND PUSHOVER ANALYSIS OF EXISTING PLATFORM AS CONSIDERATION FOR SERVICE LIFE EXTENSION

• Main Author: Fadel Hidayat Marzuki, Muh
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/43109
• Institution: Institut Teknologi Bandung

Nowadays, most of the oil and gas companies are considering to reuse the existing offshore platform structure. This solution is quite strategic, because designing and constructing new platform usually requires more expensive cost. In this Final Project, an 8 (eight) legged process platform owned by PT Pertamina EP has been modeled. This platform is located in Java Sea and has existed since 1974. The feasibility study in terms of platform requalification was evaluated with SACS 11.2 software according to API RP 2A 22nd Edition. Firstly, inplace analysis has been performed. When there is overstress, a face check and local design of strengthening will be performed with Section 4.0 software. Furthermore, the structural evaluation will be continued through seismic analysis by using SLE and DLE earthquake loading. When there is a failure, the critical component will be noted and will be verified by ductility check. In addition, spectral fatigue analysis will also be conducted. If there is any connection with critical fatigue life, several inspection and repair procedures will be recommended. Moreover, there will also be performed pushover analysis to evaluate the ductility and the reserve strength ratio (RSR) of the existing offshore platform. Based on the inplace analysis results, several strengthening has been designed for the critical members. Those are member 1529-1506 (UC box = 0.73; UC plate = 0.754) and member 0846-6347 (UC box = 0.579; UC plate = 0.714). Furthermore, the seismic analysis showed that 107P pile has a UC of 1.246. Next in the fatigue analysis, it was found that there are 17 joints had a fatigue life under 130 years, so that the inspection and repairing procedure should be considered. Moreover, the pushover analysis shows that pile 107P has acceptable plasticity of 8.3% during the DLE earthquake design load. It also obtained an adequate ductility value where the smallest value obtained was 2.85 (storm pushover from the West) while for RSR the smallest value was 1.42 (DLE pushover).