Mechanism of Localized Corrosion of Steel Pipe Pile Foundation for Offshore Wind Turbines and Corrosive Action

Abstract

The wind turbine foundation serves as a permanent construction in the harsh marine corrosive environment, its anti-corrosion design is essential to the safe use of the wind turbine structure. At present, there is a significant controversy over the local corrosion mechanism (such as pitting corrosion, and crevice corrosion) and its diffusion mechanism in the academic circle. In the paper, the Faraday electrochemistry formula was used to compute the local corrosion degree of the steel pipe pile for the wind turbine and obtain the general corrosion equivalent. The local corrosion effect of the offshore steel pipe pile for the wind turbine was converted into homogeneous corrosion thickness loss of certain length, and then the ultimate strength of the offshore steel pipe pile foundation for the wind turbine was analyzed under the conditions of local corrosion. The result indicates that the maximum ultimate strength reductionof the steel pipe pile for the wind turbine induced by the local corrosion in the splash zone is 80.8% of the non-corrosive ultimate strength. The maximum ultimate strength reduction of the steel pipe pile for the wind turbine induced by the local corrosion in the continuous immersion zone is 63% of the non-corrosive ultimate strength. Once the local corrosion rate in the splash zone exceeds 10%, the ultimate strength of the steel pipe pile for the wind turbine will exhibit a negative exponential decrease. The local corrosion in the continuous immersion zone has a huge effect on its ultimate strength. There are no significant signs of the structural strength loss. The areas prone to local corrosion should be prioritized in anti-corrosion design of the steel pipe pile for the wind turbine.