Long-term response of offshore structures under climate change conditions

Abstract

This thesis addresses the possible effects of climate change on the long-term response of offshore structures. The work shows how climate change may influence maritime climate and therefore, metocean data used in the design of offshore structures. Thus, the design environmental loads for offshore structures should not be considered stationary in the long-term. This work, it is presented an adaptation of the traditional design procedures used to calculate the long-term response of offshore structures which takes into account the effect of climate change. The long-term response fatigue and extremes of a steel lazy wave riser (SLWR) connected to floating production storage and offloading platform (FPSO), and a singledegree-of-freedom system are evaluated for future and historical metocean scenarios. The analysis considers emission trajectories RCP4.5 and RCP8.5 and two climate models for two locations, one on the offshore southeastern Brazilian coast and another in the North Atlantic Ocean. The results show that the impact of climate change on the long-term response depends on several factors, such as the geographic location, lifespan, and dynamic characteristics of the offshore structure. However, the results show enormous variability, especially when comparing the same emission scenarios simulated with different climate models, generating considerable uncertainty in the result.