The ice resistance of self-centering jacket offshore platform with concrete filled double-skin legs: Experimental study and numerical analysis

Abstract

Ice loading is the main controlling design load for offshore platforms in Bohai Bay. The ice-induced vibration of offshore platform can be monitored every winter. Both the freezing and drifting sea ice can damage an offshore platform causing structural damage, discomfort for workers, gas leakage and other problems. Two platform designs were studied aiming to reduce ice-induced vibration. One design is the offshore platform with concrete filled double-skin legs (JOP-CFDSL). The other design is the self-centering offshore platform with concrete filled double-skin legs (SRJOP-CFDSL). Both platforms were tested in laboratory experiments, and the data were used to prepare numerical simulations. The results showed that the ice-induced vibration of the two novel jacket platforms are all reduced under push loads, and the SRJOP-CFDSL have better control effect. The replacement of jacket offshore platform's steel circle hollow section legs with concrete filled double-skin legs can effectively improve the structural stiffness. And prestressed tendons were found to improve the platform's performance even further, helping it to reset after lateral impact. It should be noted that the prestressed tendon as an important bearing member, must do some anti-icing protection. Thus, the influence of ice force on the prestressed tendon isn't considered in this paper.