ABSTRACT
The foundations of offshore constructions, like e.g. wind turbines, are normally attached to the sea bed by huge steel piles. Due to the high hammer energies that are needed to drive the piles into the soil, a considerable amount of noise is emitted into the water column. Subsequently, many countries have introduced legal restrictions for the underwater noise to protect marine wildlife. Reliable and accurate prediction models to enable a prognosis of the noise levels prior to construction are therefore necessary to assess the noise emission and configure possible mitigation measures. Numerical prediction models have proven to be especially capable for this task, as they allow for a detailed consideration of the applied hammer technology, the pile geometry, possible noise mitigation measures as well as the specific propagation conditions in both water column and soil. This contribution explains the general setup of state-of-the-art numerical prediction models and illustrates the possibilities to consider innovative technologies, like e.g. optimized hammer procedures, new mitigation measures, or novel pile designs. Furthermore, also the necessary input data for a reliable prognosis is addressed. Examples comparing predicted and measured noise levels are used to demonstrate the capability and additional value of numerical prediction models for offshore pile driving noise problems.
