Design of Monopile Foundations for Offshore Wind Energy Converters

Lesny, Kerstin; Hinz, Peter

doi:10.1061/41021(335)64

Cited by 18 publications

(7 citation statements)

References 9 publications

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“…The number of loading cycles was 5000 with three different frequencies (0.07, 0.14, and 0.28 Hz) for all experiments. The loading frequencies adopted in this research were in the range of 0.05-0.3 Hz, which typically occur during the lifetime of offshore structures [6]. It is worth mentioning that the frequency of cyclic loading of soils is classified between 0 to 1 Hz [39].…”

Section: Test Program and Proceduresmentioning

confidence: 99%

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Experimental study on the lateral cyclic response of the piles in sand

Keshavarz

Bazaz

2022

Scientia Iranica

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The established foundation type for most offshore wind turbines is monopile. Due to waves and wind, the monopile of such structures experiences cyclic loading that causes the rearrangement of the soil grains around the pile, altering the damping ratio and stiffness of the soil-pile system. In this study, the impact of changing the loading frequency and soil density on the horizontal displacement, stiffness, and damping ratio on piles under cyclic lateral load has been evaluated. A series of experimental tests have been carried out by applying one-way cyclic lateral loading with three frequencies on PVC piles with different length-to-diameter (L/B) ratios in loose and dense sand. The horizontal displacement, stiffness, and damping ratio values were obtained for each test. Also, the constant coefficients of equations proposed by other researchers (to determine deformation, stiffness, and damping ratios) were evaluated.The results are presented that the change of loading frequency has a considerable influence on the absolute values of displacement, stiffness, and damping ratio, however, it has a negligible effect on constant coefficients.

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Section: Test Program and Proceduresmentioning

confidence: 99%

“…In contrast, mechanical degradation results from soil yield occurring along the pile or by gaps developing between the soil and pile [5]. Figure 1 depicts the three states of soil behavior subject to cyclic loading concluded from experimental and numerical research, including progressive failure, stabilization, and shakedown [6,7].…”

Section: Introductionmentioning

confidence: 99%

Experimental study on the lateral cyclic response of the piles in sand

Keshavarz

Bazaz

2022

Scientia Iranica

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“…Relative vertical displacement is defined as the vertical displacement normalized by anchor width, expressed as a percentage. According to Lesny and Hinz (2009), soils in contact with cyclically loaded monopole foundations exhibit three stages of behavior: (1) shake down, (2) stabilization, and (3) progressive failure. Fig.…”

Section: Anchor Response To Cyclic Loadingmentioning

confidence: 99%

Three-Dimensional Simulations of Plate Anchor Pullout in Granular Materials

Evans

Zhang

2019

Int. J. Geomech.

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Plate anchors are embedded into the ocean floor to provide holding capacity for offshore structures. Anchor holding capacity is a function of both the anchor and soil properties. Although plate anchors have been widely studied experimentally and numerically, there is still no universally agreed-upon design approach, indicating that the problem physics remain elusive. In this work, discrete-element method (DEM) simulations were used to investigate the behavior of plate anchors during pullout in an effort to elucidate some of the microscale physical processes that influence overall system behavior. Macroscale assembly response was compared to published experimental results and empirical solutions. The influence of embedment ratio, anchor roughness, soil density, and anchor size on holding capacity was investigated, and system-scale results reasonably agreed with previously published work. Thus, observations of the simulated contact force network and particle velocity during uplift were used to provide insight into anchor failure mechanisms. Finally, the model was used to briefly explore the response of a cyclically loaded plate anchor embedded in a granular assembly.

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“…In one of the tests, however, due to excessive vertical displacement of the pile it was only possible to carry out 350 cycles. The loading frequency in offshore conditions can vary during the lifetime of a pile and is typically in the range of 0•05-0•2 Hz (Lesny and Hinz, 2009). Since the main objective of this research was to find monopiles' response under changing load direction, the loading frequency remained constant throughout the investigation.…”

Section: Applied Load Pattern and Loading Directionmentioning

confidence: 99%