The metal foundations of offshore wind turbines are highly sensitive to the fatigue phenomenon. To date, current methods of fatigue design proposed in the regulations are an obstacle to the structural optimization and to the consideration of hazards. In this context, we propose an incremental two scales model of damage in order to follow the time evolution of the damage parameter. This time notion is important to the update of the model parameters using records from the Structural Health Monitoring. In this article, we focus on updating the parameters of the damage model using experimental data and the method of Bayesian updating based on an MCMC algorithm.