One of the most important structures composed of circular hollow sections is a steel jacket platform, used to extract oil and gas in offshore drilling, which therefore has to struggle with a harsh and complicated environment. This environment exposes the steel jacket platform to high-cyclic loading, leading to fatal damage in its joint which is known as fatigue damage. Investigating this phenomenon and also preventing or at least decreasing the damage of this failure mode has attracted a lot of research in the past decades. Based on Eurocode and CIDECT, the stress range is an important parameter for determining the fatigue strength of fully stress relieved connections. On the other hand, in recent years a new kind of strengthening technique using un-bonded CFRP laminates has been developed that can reduce the mean stress and it doesn’t suffer from adhesive failure of the adhesive layer. In this paper, this kind of strengthening is proposed for fatigue strengthening of fully stress relieved tubular X-joints. Using FE modeling the effect of such a strengthening scheme is also investigated.

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