Experimental and numerical study on collapse of aged jacket platforms caused by corrosion or fatigue cracking

• Investigating the ultimate strength of the jackets with crack and corrosion damage by experiments.
• Performing the finite element analysis for the damaged jacket structures, which is validated by the experiment results.
• Finding the failure mode of the jackets with crack and corrosion.

This paper presents experimental and numerical study on the collapse of aged steel jackets, caused by corrosion or fatigue crack. The test models were manufactured in accordance with a scale ratio of a prototype jacket. Corrosion and crack damages calculated by some empirical equations were subjected to the model. The collapse experiments were performed for the intact, corroded and cracked jacket model. Damaged versus intact model comparison indicates that the crack and corrosion damage will degenerate the ultimate loads of structure significantly, and they will induce the different failure modes of the damaged jackets with intact one. The two damaged jackets are both failed by the crack tearing of the leg. Nonlinear finite element method was applied for experimental results validation. Numerical and experimental results are proven to be in a good agreement.