Evaluating the impact of climate change on offshore structures design: A practical case study

Abstract

Climate change is a topic discussed worldwide. There is concern about how climate change will influence human activities, including offshore engineering. Climate change will alter the metocean data used for design purposes. These changes will possibly cause some impact on the structural responses of ships and offshore structures, more specifically fatigue damage accumulation and extreme responses. These possible impacts will depend on the structure life span, structure geographic location and climate change scenario assessed, among other aspects. This paper discusses the results of dynamic stochastic analyses and long-term extreme response estimates of a Steel Catenary Riser (SCR) connected to a semi-submersible platform considering future climate change scenarios for two locations: South East Brazilian Coast and North Atlantic Ocean. The long-term response is estimated by the Environmental Contour Method (ECM). Climate change is assessed by using different climate change scenarios available. The climate change scenarios considered in this work are the Representative Concentration Pathways (RCPs) RCP 4.5 and RCP 8.5 proposed and described by the Intergovernmental Panel on Climate Change (IPCC). Specifically, this work focuses at the influence of climate change on the wave parameters, significant wave height (Hs) and zero up-crossing period (Tz), and their impact on the structural responses of a SCR, for both locations aforementioned.The results obtained suggest that climate change can affect the structure response in different ways, depending on the geographic location. They show an increasing trend for the long-term structural response in the Brazilian location and a slight decreasing trend for the North Atlantic Ocean location. However, these results show high variability due to considerable uncertainties in the ocean climate forecasts, related mainly to shortcomings in global climate models.