ABSTRACT
The demand for fatigue analysis of concrete structures such as offshore windfarms is currently growing considerably. Several methods for the prediction of the fatigue deterioration of structural components using continuum mechanics and numerical simulation have been developed. In most cases, these predictions are limited to the end of the initiation phase of the fatigue process. While these methods are very promising, in most cases the continuous material degradation and the associated remaining lifetime are not captured in a suitable manner. In this paper, the basic steps towards the development of an advanced method for the fatigue assessment of concrete offshore wind energy foundations are presented. A dynamically loaded circular shaft of a gravity base test foundation is examined. The foundation was designed according to Model Code 1990 and is equipped with novel acoustic emission devices, fibre optical sensors and an ultra sound monitoring system for the detection of early fatigue processes. A critical shaft cross-section of an offshore wind foundation and is used for the assessment of the planned and the residual service lifetime.
