Finite element analysis of grout-filled GFRP tube repaired corroded tubular offshore platforms

Steel tubular offshore platforms are exposed to aggressive marine conditions, which leads to inevitable corrosion and degradation of the structures after a long time of service. Repairing the corroded tubular structure is not easy, especially for the members that are beneath the sea level. The current paper aims to provide an alternative approach for the repairing of corroded steel tubular platforms, by which a novel method with grout-filled GFRP tube cladding the tubular members is proposed. The conception design of the method is introduced, and the repairing process is demonstrated in detail. Then the repairing efficiency of repaired joints and platforms with different corrosion rates is investigated with finite element analysis, which proves a satisfactory reinforcement on the strength of them. The enhanced ratio is up to 117% for the T-joint under compression, and 44% for the compression brace of the K-joint, 37% for the tension brace of the K-joint, 45% for the platform. Finite element models are developed to explore the influence of the GFRP tube thickness ratio and the cube strength of grout material on its strength and repair efficiency. Then the corresponding repair structure suggestions under each corrosion rate are put forward.