Fatigue life prediction on jacket leg structure subjected to axial and wave loads

Abstract

Fixed jacket platform is an offshore structure consists of many elements such as leg and braces. Both legs and braces play an important role to support the structure from internal and external loads like structure its self and wave loads. Especially for jacket leg, the deck load is distributed to all jacket leg to support deck structure. Besides, jacket leg also resists wave loads in horizontal direction. Due to the axial load caused by deck and horizontal load caused by wave, these loads act periodically on jacket leg. Therefore, the analysis of fatigue life to jacket leg should be performed for structural design. The present study focuses on fatigue life prediction on jacket leg under axial and wave load. The numerical method is conducted to analyze fatigue life on jacket leg. It is found that the fatigue life due to axial and wave loads are 185 and 108 years, respectively.