Effects of various stiffeners on offshore steel jacket strength

摘要

Due to a long period of exposure to severe environment and corrosion caused by impact from berthing and mooring, offshore structures can be corroded and weakened. Replacing of the entire damaged or corroded members would implicate great cost and technical difficulty. In the study, the effect of various stiffeners on weakened sections of steel a jacket is investigated numerically. The stress of surrounding members is checked with a stiffener attached to compare with the allowable strength of the structure. In the analysis, specific diagonal and K-braces are assumed to be weakened and stiffeners at various locations are applied to obtain the required strength of surrounding members. An offshore jacket which is being installed in the South China Sea in Vietnam is used as a model for the study. The environmental extreme loading conditions of that particular area are applied. The K-brace and diagonal brace members are investigated to find the optimum stiffener position and size by a FEM program. The results show that stiffeners can he effectively applied to improve the strength of surrounding members.