The design of large diameter monopiles (8–10 m) at intermediate to deep waters is largely driven by the fatigue limit state and mainly due to wave loads. The scope of the present paper is to assess the mitigation of wave loads on a monopile by perforation of the shell. The perforation design consists of elliptical holes in the vicinity of the splash zone. Wave loads are estimated for both regular and irregular waves through physical model tests in a wave flume. The test matrix includes waves with Keulegan–Carpenter ( $KC$ ) numbers in the range 0.25 to 10 and covers both fatigue and ultimate limit states. Load reductions in the order of 6%–20% are found for $KC$ numbers above 1.5. Significantly higher load reductions are found for $KC$ numbers less than 1.5 and thus the potential to reduce fatigue wave loads has been demonstrated.

中文翻译：

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通过单桩穿孔减轻波浪载荷

在中等水位至深水区的大直径单桩（8–10 m）的设计很大程度上受疲劳极限状态的驱动，并且主要是由于波浪载荷。本文的范围是通过壳的穿孔来评估单桩上波浪载荷的减轻。穿孔设计由飞溅区域附近的椭圆孔组成。通过波浪槽中的物理模型测试，可以估算规则和不规则波浪的波浪载荷。测试矩阵包括Keulegan–Carpenter（ $ķC$ ）数值范围为0.25到10，并且涵盖疲劳和极限极限状态。减少了大约6％–20％的负载 $ķC$ 高于1.5的数字。发现明显降低了负载 $ķC$ 数小于1.5，因此已经证明了减少疲劳波载荷的潜力。