Journal articles: 'Offshore foundation'

1

Schneider, James A., and Marc Senders. "Foundation Design: A Comparison of Oil and Gas Platforms with Offshore Wind Turbines." Marine Technology Society Journal 44, no. 1 (January 1, 2010): 32–51. http://dx.doi.org/10.4031/mtsj.44.1.5.

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AbstractThe offshore oil and gas (O&G) industry has over 70 years of experience developing innovative structures and foundation concepts for engineering in the marine environment. The evolution of these structures has strongly been influenced by water depth as well as soil conditions in the area of initial developments. As the offshore wind industry expands from the glacial soil deposits of the North and Baltic Seas, experience from the O&G industry can be used to aid a smooth transition to new areas. This paper presents an introduction to issues that influence how design and construction experience from the O&G industry can be used to aid foundation design for offshore wind energy converters. A history of the evolution of foundation and substructure concepts in the Gulf of Mexico and North Sea is presented, followed by a discussion of soil behavior and the influence of regional geology on these developments. Mechanisms that influence the resistance of shallow and deep foundations for fixed and floating offshore structures are outlined so that areas of empiricism within offshore design codes can be identified and properly modified for application to offshore wind turbine foundations. It is concluded that there are distinct differences between offshore O&G and offshore wind turbine foundations, and application of continued research into foundation behavior is necessary for rational, reliable, and cost-effective design.

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Ding, Hongyan, Yanjian Peng, Puyang Zhang, Hanbo Zhai, and Nan Jia. "Model Tests on the Penetration Resistance of Bucket Foundations for Offshore Wind Turbines in Sand." Journal of Marine Science and Engineering 8, no. 5 (May 22, 2020): 368. http://dx.doi.org/10.3390/jmse8050368.

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Driven by the rapid development of offshore wind farms, bucket foundations have come to constitute a very promising form of foundation for offshore wind turbines, mainly owing to their efficient construction. However, the penetration resistance of the suction penetration of a bucket foundation, when calculated inaccurately, may lead to installation failure of the foundation. In this study, model tests were performed on the suction penetration of a mono-bucket mono-compartment foundation and a mono-bucket multi-compartment foundation in saturated fine marine sand, aiming to compare their penetration resistances and critical suctions, and the development of a soil plug in the two models was analyzed. The results will provide a design reference for the penetration construction of bucket foundations for offshore wind turbines.

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Yang, Ray-Yeng, Hsin-Hung Chen, Hwung-Hweng Hwung, Wen-Pin Jiang, and Nian-Tzu Wu. "EXPERIMENTAL STUDY ON THE LOADING AND SCOUR OF THE JACKET TYPE OFFSHORE WIND TURBINE FOUNDATION." Coastal Engineering Proceedings 1, no. 32 (January 21, 2011): 25. http://dx.doi.org/10.9753/icce.v32.structures.25.

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A 1:36 scale model tests were carried out in the Medium Wave Flume (MWF) and Near-shore Wave Basin (NSWB) at the Tainan Hydraulics Laboratory (THL) with the jacket type offshore wind turbine foundation located in the test area. The loading of typhoon wave with current on the jacket type offshore wind turbine foundation was investigated in the MWF with fixed bed experiment. Meanwhile, the scour around the jacket type offshore wind turbine foundation exposed to wave and current was conducted in the NSWB with the moveable bed experiment. Two locations (water depth 12m and 16m) of the foundations are separately simulated in this study. Based on the analysis from the former NSWB experimental results, the suitable scour protection of a four-layer work around the foundation is also proposed to the impact of scour. Finally, a four-layer scour protection is tested and found to be effective in preventing scour around jacket type foundation of offshore wind turbines at water depth 12m and 16m.

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4

Mei, Bi Xiang. "Study Finite Element Analysis of Monopile Foundation Based on Mechanical Mechanics and Properties of Steel Structure for Offshore Wind Turbines." Advanced Materials Research 743 (August 2013): 114–17. http://dx.doi.org/10.4028/www.scientific.net/amr.743.114.

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Statistical data shows that monopile foundation accounts for more than 65% of all foundations for offshore wind turbines,so it is of great engineering value to perform the research on the design and analysis of the monopile foundation. By its application environments and structure features,based on a design example of monopile foundation for a offshore wind farm,the paper performs the following sequence of works including the establishment of finite element model for monopile foundation, the calculation of foundation bearing capacity and deformation, modal analysis and fatigue analysis, etc.The paper gives the related design results, which is used for reference for designers.

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5

Esteban, M., José-Santos López-Gutiérrez, and Vicente Negro. "Gravity-Based Foundations in the Offshore Wind Sector." Journal of Marine Science and Engineering 7, no. 3 (March 12, 2019): 64. http://dx.doi.org/10.3390/jmse7030064.

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In recent years, the offshore wind industry has seen an important boost that is expected to continue in the coming years. In order for the offshore wind industry to achieve adequate development, it is essential to solve some existing uncertainties, some of which relate to foundations. These foundations are important for this type of project. As foundations represent approximately 35% of the total cost of an offshore wind project, it is essential that they receive special attention. There are different types of foundations that are used in the offshore wind industry. The most common types are steel monopiles, gravity-based structures (GBS), tripods, and jackets. However, there are some other types, such as suction caissons, tripiles, etc. For high water depths, the alternative to the previously mentioned foundations is the use of floating supports. Some offshore wind installations currently in operation have GBS-type foundations (also known as GBF: Gravity-based foundation). Although this typology has not been widely used until now, there is research that has highlighted its advantages over other types of foundation for both small and large water depth sites. There are no doubts over the importance of GBS. In fact, the offshore wind industry is trying to introduce improvements so as to turn GBF into a competitive foundation alternative, suitable for the widest ranges of water depth. The present article deals with GBS foundations. The article begins with the current state of the field, including not only the concepts of GBS constructed so far, but also other concepts that are in a less mature state of development. Furthermore, we also present a classification of this type of structure based on the GBS of offshore wind facilities that are currently in operation, as well as some reflections on future GBS alternatives.

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Pan, Xiaodong, Ben He, Zonghao Yuan, Shiwu Xu, Danting Xu, Zhenqiang Jiang, Li Shi, and Honglei Sun. "Effect of Reinforced Bucket on Bearing Capacity and Natural Frequency of Offshore Wind Turbines Using Pile–Bucket Foundation." Advances in Civil Engineering 2022 (April 9, 2022): 1–17. http://dx.doi.org/10.1155/2022/9569102.

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Large-diameter monopiles have been widely used for constructing offshore wind turbines. The bearing capacity of a monopile foundation is a significant research problem. In this study, a new type of foundation, known as the pile–bucket foundation, was investigated to improve the bearing capacity of monopiles. A finite element software was used for establishing several numerical models of monopile and pile–bucket foundations to analyze the reinforcement afforded by the bucket attached to the monopile foundation. Furthermore, considering that offshore wind turbines are prone to resonance under the excitation of wind and wave loads, the natural frequencies of the monopile and pile–bucket foundations were determined and compared using both analytical and numerical methods. The results show that compared to the monopile foundation, the pile–bucket foundation has a significantly higher bearing capacity, mainly for large bucket diameters. The natural frequencies of the pile–bucket foundations are slightly higher than those of the monopile foundations. The addition of the bucket can effectively improve the natural frequency without changing the diameter of the monopile and thus saving the foundation cost.

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7

Houlsby, G. T. "Interactions in offshore foundation design." Géotechnique 66, no. 10 (October 2016): 791–825. http://dx.doi.org/10.1680/jgeot.15.rl.001.

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8

Haldar, A. K., D. V. Reddy, and M. Arockiasamy. "Foundation shakedown of offshore platforms." Computers and Geotechnics 10, no. 3 (January 1990): 231–45. http://dx.doi.org/10.1016/0266-352x(90)90037-v.

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9

Vølund, Per. "Concrete is the Future for Offshore Foundations." Wind Engineering 29, no. 6 (December 2005): 531–63. http://dx.doi.org/10.1260/030952405776234571.

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This paper compares the costs of using concrete foundations against steel monopile foundations for offshore wind turbines, and argues that concrete foundations will be cheaper. Most offshore windfarms have steel monopile foundations, but in Denmark concrete gravity foundations have been used with success. Two projects have tendered for steel monopiles and for concrete foundations and have implemented the concrete foundations that proved cheaper. No project has tendered for both foundation concepts and chosen steel monopiles. Nysted Offshore Windfarm with concrete foundations has the cheapest foundations of any offshore windfarm so far. A conceptual foundation study carried out for the London Array West Offshore Windfarm indicates that the same method and very low-cost foundations as for Nysted can be used. Optimised design of light-weight concrete constructions is the key to low-cost installation. Cheap manufacture can be carried out near the site or at even lower cost in Eastern Europa from where it can be shipped at little extra cost. The main construction of steel monopile foundations will become twice as costly as of concrete gravity foundations, and though installation is more costly for the gravity foundations it seems most likely that tendering between steel monopile and concrete gravity for London Array West will prove concrete considerably cheaper. It is argued that these considerations are to a wide extent generally valid, and also for very large turbines in deeper water. Concrete foundations will in 2006 be installed at Lillegrunden Offshore Windfarm in Sweden, and at Belgian Thornton Bank in 2006–7. So indications are strong that concrete is the future for offshore foundations.

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10

Lavanya, C., and Nandyala Darga Kumar. "Foundation Types for Land and Offshore Sustainable Wind Energy Turbine Towers." E3S Web of Conferences 184 (2020): 01094. http://dx.doi.org/10.1051/e3sconf/202018401094.

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Wind energy is the renewable sources of energy and it is used to generate electricity. The wind farms can be constructed on land and offshore where higher wind speeds are prevailing. Most offshore wind farms employ fixed-foundation wind turbines in relatively shallow water. In deep waters floating wind turbines have gained popularity and are recent development. This paper discusses the various types of foundations which are in practice for use in wind turbine towers installed on land and offshore. The applicability of foundations based on depth of seabed and distance of wind farm from the shore are discussed. Also, discussed the improvement methods of weak or soft soils for the foundations of wind turbine towers.

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11

Bhattacharya, Subhamoy, Domenico Lombardi, Sadra Amani, Muhammad Aleem, Ganga Prakhya, Sondipon Adhikari, Abdullahi Aliyu, et al. "Physical Modelling of Offshore Wind Turbine Foundations for TRL (Technology Readiness Level) Studies." Journal of Marine Science and Engineering 9, no. 6 (May 29, 2021): 589. http://dx.doi.org/10.3390/jmse9060589.

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Offshore wind turbines are a complex, dynamically sensitive structure due to their irregular mass and stiffness distribution, and complexity of the loading conditions they need to withstand. There are other challenges in particular locations such as typhoons, hurricanes, earthquakes, sea-bed currents, and tsunami. Because offshore wind turbines have stringent Serviceability Limit State (SLS) requirements and need to be installed in variable and often complex ground conditions, their foundation design is challenging. Foundation design must be robust due to the enormous cost of retrofitting in a challenging environment should any problem occur during the design lifetime. Traditionally, engineers use conventional types of foundation systems, such as shallow gravity-based foundations (GBF), suction caissons, or slender piles or monopiles, based on prior experience with designing such foundations for the oil and gas industry. For offshore wind turbines, however, new types of foundations are being considered for which neither prior experience nor guidelines exist. One of the major challenges is to develop a method to de-risk the life cycle of offshore wind turbines in diverse metocean and geological conditions. The paper, therefore, has the following aims: (a) provide an overview of the complexities and the common SLS performance requirements for offshore wind turbine; (b) discuss the use of physical modelling for verification and validation of innovative design concepts, taking into account all possible angles to de-risk the project; and (c) provide examples of applications in scaled model tests.

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12

Zografou, Dimitra, Susan Gourvenec, and Conleth O’Loughlin. "Vertical cyclic loading response of shallow skirted foundation in soft normally consolidated clay." Canadian Geotechnical Journal 56, no. 4 (April 2019): 473–83. http://dx.doi.org/10.1139/cgj-2018-0179.

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Skirted foundations are a potential foundation solution for a range of offshore structures, including hydrocarbon and renewable energy platforms and subsea structures. Offshore foundations can be subject to cyclic loading from environmental, installation, and operational events affecting the geotechnical response. A series of centrifuge tests have been performed on a shallow skirted foundation on normally consolidated kaolin clay under a range of vertical cyclic load sequences to investigate the effect of tensile or compressive average stress, the magnitude of the applied stress, and the effect of cyclic loading of low magnitude followed by consolidation on the foundation response. Results are presented as vertical foundation displacements normalized by the foundation geometry and interpreted within the traditional shear-strain contour approach. The findings indicate that the average, rather than maximum, vertical stress defines the foundation vertical displacement response and failure mode, a threshold stress exists below which a steady state is maintained even at a high number of cycles, and geotechnical resistance increases as a result of low-level cyclic loading followed by consolidation.

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13

Wang, Na, Da Chen, and Ying Di Liao. "Study on Foundation Structure for Comprehensive Power Generation of Offshore Renewable Energy." Advanced Materials Research 594-597 (November 2012): 121–25. http://dx.doi.org/10.4028/www.scientific.net/amr.594-597.121.

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The offshore renewable energy includes offshore wind, wave and tidal current energy. The power generation system of offshore renewable energy uses single form in recent year. It has caused low power efficiency, big power fluctuation and high cost of the foundation structure which will seriously hamper the development of offshore renewable energy. Firstly, a summary about the common form of foundation structure was made. Then basing on the different characteristics of a single energy power generation foundation structure, two different comprehensive power generation foundation types were put forward, and the power generation devices were optimized and reasonably arranged, which are formed a system for comprehensive offshore energy power generation. In addition, the connection, the load and structural features of each comprehensive power generation foundation structure were discussed. The results provide a basis for the design of foundation structure for comprehensive power generation of offshore renewable energy.

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14

Wang, Qian, Yong Gang Tan, and Tie Suo Geng. "Caisson Foundation Design for Offshore Anchorage." Advanced Materials Research 368-373 (October 2011): 1491–94. http://dx.doi.org/10.4028/www.scientific.net/amr.368-373.1491.

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The cross-sea suspension bridge is one of the most important development branches of long-span Bridge. The anchorage construction on the sea is a key issue of cross-sea suspension bridge. This paper introduces a new kind of caisson foundation of offshore anchorage. This new design may reduce the construction cost and speed the process of working. In this paper the structural features and the construction gist are detailed.

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15

Niebuhr, Nils, Daniel Siegel, René von der Hellen, and Christian Hamm. "Offshore Foundation nach dem Verfahren ELiSE." Bautechnik 90, no. 12 (December 2013): 772–76. http://dx.doi.org/10.1002/bate.201300092.

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16

Athanasia, Arapogianni, and Anne Benedicte Genachte. "Deep Offshore and New Foundation Concepts." Energy Procedia 35 (2013): 198–209. http://dx.doi.org/10.1016/j.egypro.2013.07.173.

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17

Magray, Adil Ahmad, Amanpreet Tangri, Zehra Khan, and Naiyara Khan. "Foundation engineering for offshore gravity structures." IOP Conference Series: Earth and Environmental Science 889, no. 1 (November 1, 2021): 012053. http://dx.doi.org/10.1088/1755-1315/889/1/012053.

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Abstract Gravity based structures are in play from early times. Numerous structures are being installed around the globe. These structures had shown a rigid face towards the harsh conditions/situation in the offshore environment. The key factors for sustainability are geotechnical design and the sub soil survey. These structures are used for collection, transport and also for temporary storage of crude gas and oil. These structures serve as a bridge between the much need fuel and the modern world. The installation of GBS involves major wings of modern engineering i.e. Mechanical, Structural, architecture and Geotechnical engineering because these structures are a great challenge as considering the harsh and hard off shore conditions. These structures are having a much importance apart from its features i.e. from the point of economy, as the oil prices are touching the heights, it influences construction of GBS. Now a days most of the multinational companies are focusing towards the construction of offshore GBS, as well as paying much attention on research work off these structures because to make huge profit. In this paper an effort has been made to understand the different aspects which are related to GBS i.e. pre-construction operations, soil investigation, construction, installment and some of the safety aspects as considering it one of the most focused topics now and in future.

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Shang, J. Q., E. Mohamedelhassan, and M. Ismail. "Electrochemical cementation of offshore calcareous soil." Canadian Geotechnical Journal 41, no. 5 (September 1, 2004): 877–93. http://dx.doi.org/10.1139/t04-030.

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The electrochemical stabilization processes are studied in a calcareous soil recovered from the Western Australia coast and on the interface of calcareous soil and steel foundation. A series of experiments are performed to study the effects of two chemical agents used in electrochemical stabilization tests. The strengthening effects of electro kinetics and electrochemical treatments on the calcareous soil are investigated first. Significant increases in the undrained shear strength and effective cohesion are obtained after all tests, and the most significant improvement is found after the electrochemical treatment using a 15% CaCl2 solution as the stabilization agent. Subsequently, an electrochemical test is carried out on the calcareous soil with an embedded steel plate to simulate a part of a caisson foundation, using CaCl2 as the stabilization agent. In this test, the practical considerations for later large-scale tests and ultimately for field implementation are taken into account in the design, including factors such as the attachment of electrodes to the foundation, injection of the stabilization agent via perforated pipe electrodes, and distributions of voltage and electrical current in the soil. The result of this test reveals a 700% increase in the steel plate axial load capacity after 7 days of treatment with an applied voltage of 4 V. The main features of the approach are that it generates virtually no disturbance to the soil and the treatment is targeted at the soilstructure interface. With further development, the electrochemical treatment may be applied in offshore engineering for stabilization of foundations installed in weak calcareous soils.Key words: calcareous soil, offshore foundations, soil improvement, chemical stabilization, electrokinetics.

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Ye, Hailin, Dawei Yu, Jianhong Ye, and Zhiwen Yang. "Numerical Analysis of Dynamics of Jack-Up Offshore Platform and Its Seabed Foundation under Ocean Wave." Applied Sciences 12, no. 7 (March 24, 2022): 3299. http://dx.doi.org/10.3390/app12073299.

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Jack-up offshore platform is a type of important marine structure, which is mainly used for satellite launch, oil exploitation, and other engineering tasks in the offshore area. The offshore platform is bound to be subjected to wave loading in the course of use. Whether it can withstand the wave impact is an important engineering problem. To solve this engineering problem, the self-developed fluid–structure–foundation interaction coupling model OlaFlow-ABAQUS is used to explore the dynamic response characteristics of a jack-up offshore platform and its seabed foundation under three conventional wave conditions (wave height is 3, 5, and 7 m, respectively) in a coupled way. The numerical results show that only a small amplitude of periodic sloshing occurs for the jack-up offshore platform under the three conventional wave conditions. The maximum sloshing amplitude is up to 8 cm, and there is no visible residual displacement. It is indicated that there is no plastic deformation zone in the seabed foundation near the pile legs of the jack-up platform. It can thus be concluded that the jack-up platform has excellent stability under conventional wave conditions. Under conventional wave loading, momentary liquefaction occurs in the seabed foundation around the pile legs of the platform, and the maximum liquefaction depth is about 1 m. This study indicates that the coupling model OlaFlow-ABAQUS for the fluid–structure–foundation interaction is feasible, and has some advantages to study the dynamic response and to evaluate the stability of large-scale marine structures and their seabed foundations under ocean waves.

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20

Iwicki, Piotr, and Jarosław Przewłócki. "Short Review and 3-D FEM Analysis of Basic Types of Foundation for Offshore Wind Turbines." Polish Maritime Research 27, no. 3 (September 1, 2020): 31–39. http://dx.doi.org/10.2478/pomr-2020-0044.

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AbstractSome problems of the foundations of offshore wind turbines are considered in this paper. A short review is presented on the two basic types of foundations, i.e. monopiles and gravity foundations, including their basic features and applications as well as general design considerations. Also, some issues regarding analysis are discussed, including geotechnical problems and modelling techniques. A numerical model of offshores turbine and some preliminary computations are presented. Finite element analysis was carried out for wind turbines supported on both gravity and monopile foundations. The wind turbine tower, blades (simplified model), gravity foundation and part of the surrounding soil are included in the model. The turbine was loaded by wind and loads induced by waves, inertia and gravity. Both non-linear static and dynamic analysis of the wind turbine was performed. The displacements and stresses under the tower foundations were calculated and a comparison analysis carried out.

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Zhu, Bin, Kai Wen, Tao Li, Lujun Wang, and Deqiong Kong. "Experimental study on lateral pile–soil interaction of offshore tetrapod piled jacket foundations in sand." Canadian Geotechnical Journal 56, no. 11 (November 2019): 1680–89. http://dx.doi.org/10.1139/cgj-2018-0292.

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Recently, tetrapod piled jacket (TPJ) foundations have shown considerable promise in offshore developments, due to the increases in power capacity and water depth for offshore wind turbines. This paper presents a set of centrifuge tests to look into the lateral loading behaviour of TPJ foundations in sand, with the overall load–displacement responses of the foundation as well as the soil resistance and internal forces on or within individual piles being examined carefully. Test results show that the back-row piles are more likely to be pulled out when the TPJ foundation is loaded laterally along the diagonal direction compared to when loaded along the orthogonal direction. The lateral soil resistance per unit length on the back-row pile(s) is approximately 60% of that on the front-row one(s) in the orthogonal loading case, and only about 40% in the diagonal loading case. Moreover, although the TPJ foundation is in its form a special case of pile groups, it is highlighted in the present study that the former case exhibits distinct loading behaviour from the latter case due to the typically large overturning moment encountered by the foundations for offshore wind turbines. Finally, the p-multipliers of the piles are demonstrated to be dependent on pile deflections, but independent on soil depths, and as a result, a modified pm model is proposed to provide guidance for the design of TPJ foundations in sand.

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Shen, Zhao Wei, Xiao Hong Wang, and Wei Liang Jin. "Reliability of Pile Foundation of Offshore Jacket Platforms Subjected to Seismic Action." Advanced Materials Research 919-921 (April 2014): 1047–51. http://dx.doi.org/10.4028/www.scientific.net/amr.919-921.1047.

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Pile foundation of offshore platform is very important. Earthquake is devastating and unpredictable.It is important to assess the reliability of pile foundation of offshore jacket platforms subjected to seismic action. This paper presents the approach to calibrate of reliability of pile foundation subjected to seismic action. The combination of loads are mainly investigated. The reliability of pile foundation of of QK18-1 in Bohai Bay related to 25-year reference period is3.37, which is close to the conclusion of some existing researches. The results could provide significant reference for the design of offshore jacket platforms.

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Basack, Sudip. "Analysis and Design of Offshore Pile Foundation." Advanced Materials Research 891-892 (March 2014): 17–23. http://dx.doi.org/10.4028/www.scientific.net/amr.891-892.17.

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The ocean environment necessitates the pile foundation supporting the offshore structures to be designed against cyclic load, moments and torques initiated by a combined action of waves, wind, tides, currents, etc. Such a complex loading condition induces progressive degradation in the pile-soil interactive performance introducing significant reduction in bearing capacity with increased settlement and displacements. The Author has carried out extensive experimental (laboratory model tests) and theoretical investigations (boundary element analysis) to study the salient features of this degradation and developed a design methodology for offshore pile foundation. The works conducted and the major conclusions drawn are highlighted in this paper.

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Haldar, A. K., D. V. Reddy, and M. Arockiasamy. "Foundation shakedown of offshore platforms. Technical note." International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts 28, no. 6 (November 1991): A386. http://dx.doi.org/10.1016/0148-9062(91)91567-b.

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Abdelkader, Ahmed, and M. Hesham El Naggar. "Hybrid Foundation System for Offshore Wind Turbine." Geotechnical and Geological Engineering 36, no. 5 (April 6, 2018): 2921–37. http://dx.doi.org/10.1007/s10706-018-0513-z.

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Cui, Lin, Dong-Sheng Jeng, and Junwei Liu. "Seabed foundation stability around offshore detached breakwaters." Applied Ocean Research 111 (June 2021): 102672. http://dx.doi.org/10.1016/j.apor.2021.102672.

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Yin, Qingguo, Xiaochun Zhang, Xiaobo Jiang, Haiwei Li, Ling Yang, Xiaoyan Wang, Yuezhou Dong, and Yan Zhu. "Structural analysis of pile-foundation offshore platform." IOP Conference Series: Earth and Environmental Science 769, no. 3 (May 1, 2021): 032047. http://dx.doi.org/10.1088/1755-1315/769/3/032047.

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Jeong, Yeong-Hoon, Seong-Won Lee, and Jae-Hyun Kim. "Centrifuge Modeling for the Evaluation of the Cyclic Behavior of Offshore Wind Turbine with Tripod Foundation." Applied Sciences 11, no. 4 (February 15, 2021): 1718. http://dx.doi.org/10.3390/app11041718.

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In this study, the cyclic responses of an offshore wind turbine with a tripod foundation installed on an actual site were evaluated in a centrifuge. To understand the behavior of the turbine at the site, the site soil conditions, environmental loads, and real offshore wind turbine structure installed at the actual site were modeled by considering the centrifuge scaling law. From a series of cyclic loading tests, the cyclic responses of the tripod foundation were evaluated in terms of temporary/permanent displacements and cyclic stiffness. Moreover, the long-term behavior of the tripod foundation was predicted from the experimental results. The test results showed that the initial stiffness of the soil–foundation system decreased as the loading amplitude increased and that the stiffness increased with the number of cycles due to soil densification. The findings revealed that the cyclic behaviors of the tripod were more affected by the load amplitude than the number of cycles. In addition, the permanent rotation increased logarithmically with the number of cycles. A simple method to predict the displacement and change in the foundation stiffness of the actual wind turbine is proposed based on the results of the model tests. The results of this study also provide key insights into the long-term cyclic behavior of tripod foundations for offshore wind turbines.

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Mana, Divya S. K., Susan Gourvenec, and Mark F. Randolph. "Experimental investigation of reverse end bearing of offshore shallow foundations." Canadian Geotechnical Journal 50, no. 10 (October 2013): 1022–33. http://dx.doi.org/10.1139/cgj-2012-0428.

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Shallow skirted foundations can mobilize uplift resistance from end bearing in the short to medium term. However, uncertainty exists over the magnitude of reverse end bearing resistance compared with resistance in compression, and how this might be affected by a gap between the external face of the foundation skirt and the adjacent soil. The study presented in this paper explores this problem through centrifuge model tests, investigating the effect of skirt embedment ratio on (i) the magnitude of reverse end bearing capacity compared with compression capacity, (ii) the uplift displacement associated with spontaneous loss of suction during uplift, and (iii) the existence of a vertical gap along the external skirt–soil interface. The results show that (i) peak uplift capacity equivalent to compression capacity can be mobilized for a fully sealed foundation with an intact skirt–soil interface, (ii) suction required for reverse end bearing can be maintained through considerable foundation displacement, even for a low skirt embedment ratio, and (iii) the presence of a vertical gap along the external skirt–soil interface causes abrupt loss of suction beneath the top plate after minimal foundation displacement, with subsequent uplift capacity being markedly reduced.

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Barari, Amin, and Lars Bo Ibsen. "VERTICAL CAPACITY OF BUCKET FOUNDATIONS IN UNDRAINED SOIL." JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT 20, no. 3 (March 10, 2014): 360–71. http://dx.doi.org/10.3846/13923730.2013.801915.

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Offshore wind turbine structures are traditionally founded on gravity concrete foundations or mono-piles. Bucket foundations were developed for the offshore oil and gas industry and are now being used in wind turbine construction. The loading in this application is characterized by a vertical load due to the slender construction combined with horizontal forces inducing a large overturning moment. Field tests on bucket foundations were performed to gain insight into the vertical load response of bucket foundations in clay soils. The field tests were accompanied by finite element numerical simulations in order to provide a better understanding of the parameters influencing bucket foundation behaviour.

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Li, Yazhou, and Li Dong. "Analysis of Factors Affecting Bearing Capacity of Large Diameter Single Piles of Offshore Wind Power under Earthquake Loads." E3S Web of Conferences 136 (2019): 04061. http://dx.doi.org/10.1051/e3sconf/201913604061.

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The offshore wind turbine single pile foundation structure is simple and easy to install, but in the earthquake environment, large horizontal displacement is easy to occur, which affects the safe operation of offshore wind turbines. For this reason, the bearing characteristics and influencing factors of large-diameter single-pile offshore wind power under earthquake load are analyzed. The Mohr-Coulomb model is used as the model. The ABAQUS is used to construct the large-scale single-pile finite element model of offshore wind power. Loads and analysis of bearing characteristics and influencing factors of large-diameter single-pile offshore wind power under seismic loading. It is found that the increase of pile foundation depth will significantly reduce the horizontal displacement at the top of single pile. After increasing to a certain extent, it has no significant effect on the development of horizontal deformation of large diameter single pile; with the increase of pile diameter and wall thickness, The deformation of large diameter single pile foundation is reduced, but the influence of the pile foundation thickness on the horizontal deformation of the large diame-ter single pile foundation is no longer significant.

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Andersson, Mathias H., and Marcus C. Öhman. "Fish and sessile assemblages associated with wind-turbine constructions in the Baltic Sea." Marine and Freshwater Research 61, no. 6 (2010): 642. http://dx.doi.org/10.1071/mf09117.

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Offshore wind farms are being built at a high rate around the world to meet the demand for renewable energy. We studied fish and sessile communities on and around offshore wind-turbine foundations in the southern Baltic Sea, 7 years after construction, using visual census techniques to determine how fish, sessile-invertebrate and algal communities are affected by the introduction of such structures. Fish assemblages were dominated by two-spotted gobies (Gobiusculus flavescens) that were found in large shoals in close association with the vertical surface. At the seabed, close to the foundation, the black goby (Gobius niger) was recorded in large numbers. The most obvious difference in fish densities was found between wind-power foundations extending through the entire water column and the surrounding open waters. Fouling assemblages on the vertical foundation surfaces and at the seabed just below differed from those at the seabed further away by having higher coverage of blue mussel (Mytilus edulis) and less algal growth. The results from the present study suggest that the introduction of offshore wind turbines in marine waters could have a positive effect on fish numbers and the presence of sessile invertebrates.

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Zhao, Yuan Lin, Zhi Wen Zhu, and Shi Deng. "Structural Analysis of Conical Bottom-Supported Offshore Wind Turbine Foundation." Applied Mechanics and Materials 117-119 (October 2011): 726–29. http://dx.doi.org/10.4028/www.scientific.net/amm.117-119.726.

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In this paper, a kind of conical bottom-supported offshore wind turbine foundation was developed. The finite element model was built in SESAM and the structure was analyzed in operating condition and survival condition. The result shows that both the bearing platform and the conical bottom can satisfy the requirement of displacement and strength. The new kind of platform can be applied in shallow sea and offshore, easy to tow, and has low cost, which is helpful to offshore wind power exploitation.

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Mei, Bi Xiang. "Study on Mechanical Mechanics with Technical Points in Foundation Design of Offshore Wind Turbines." Advanced Materials Research 703 (June 2013): 186–89. http://dx.doi.org/10.4028/www.scientific.net/amr.703.186.

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By its application environments and structure features,the five key technology issues in foundation design of offshore wind turbines including structure mechanical mechanics analysis,foundation type selection,pile design,wave force calculation,structure fatigue analysis are discussed in this paper.The corresponding technical resolution and research methods are also provided.It is aimed to provide a useful reference for the foundation design of offshore wind turbines.

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Micic, S., J. Q. Shang, and K. Y. Lo. "Improvement of the load-carrying capacity of offshore skirted foundations by electrokinetics." Canadian Geotechnical Journal 40, no. 5 (October 1, 2003): 949–63. http://dx.doi.org/10.1139/t03-045.

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Originating from the problem facing offshore foundation engineering, the present study is focused on using electrokinetics to enhance the load-carrying capacity of skirted foundations embedded in soft marine deposits. An experimental study was carried out in a model tank having dimensions of 150 cm × 75 cm × 70 cm. The experiments were conducted on the Welland River sediment mixed with a high salinity solution that simulates the composition of seawater. A steel cylinder of 320 mm in diameter was embedded in the sediment to represent a skirted foundation. Electrodes were installed around the steel cylinder, and a voltage of 5.2 V was applied over 28 days with polarity reversal. The load-carrying capacity of the steel cylinder and the undrained shear strength of the adjacent soil were measured after the electrokinetic treatment. The effect of electrokinetics is evaluated by comparing a series of test results performed on the untreated and treated soil. The load-carrying capacity of the steel cylinder and the undrained shear strength of the adjacent soil increased up to three times after treatment. The study also shows that electrokinetics can regain and further enhance the load carrying capacity of the embedded skirted foundation model after failure. With further development, the technology has the potential to be applied in offshore engineering practice to increase the load-carrying capacity of skirted foundations installed in soft clayey sediments.Key words: electrokinetics, skirted foundations, soft marine clay, load-carrying capacity, soil improvement.

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Sánchez, Sergio, José-Santos López-Gutiérrez, Vicente Negro, and M. Dolores Esteban. "Foundations in Offshore Wind Farms: Evolution, Characteristics and Range of Use. Analysis of Main Dimensional Parameters in Monopile Foundations." Journal of Marine Science and Engineering 7, no. 12 (December 2, 2019): 441. http://dx.doi.org/10.3390/jmse7120441.

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Renewable energies are the future, and offshore wind is undoubtedly one of the renewable energy sources for the future. Foundations of offshore wind turbines are essential for its right development. There are several types: monopiles, gravity-based structures, jackets, tripods, floating support, etc., being the first ones that are most used up to now. This manuscript begins with a review of the offshore wind power installed around the world and the exposition of the different types of foundations in the industry. For that, a database has been created, and all the data are being processed to be exposed in clear graphic summarizing the current use of the different foundation types, considering mainly distance to the coast and water depth. Later, the paper includes an analysis of the evolution and parameters of the design of monopiles, including wind turbine and monopile characteristics. Some monomials are considered in this specific analysis and also the soil type. So, a general view of the current state of monopile foundations is achieved, based on a database with the offshore wind farms in operation.

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Wang, Guilan, Yi Gan, Conghuan Le, Ruiyang Yan, and Xueyang Hu. "Bearing Characteristics of Tripod Bucket Jacket Foundation for Offshore Wind Turbines in Sand under Monotonic Loads." Journal of Marine Science and Engineering 10, no. 2 (February 1, 2022): 199. http://dx.doi.org/10.3390/jmse10020199.

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Tripod bucket jacket foundation is an alternative foundation solution for deep-sea wind farms. This paper analyzes and compares the bearing characteristics of two tripod bucket jacket foundations with different height-diameter ratios, the tripod suction pile jacket foundation (TSPJF) and tripod bucket jacket foundation (TBJF), under different monotonic loads. The bearing modes of the two foundations under the vertical loads are different. The ultimate vertical load is mainly borne by the inside frictional resistance for the TSPJF, while it is mainly borne by the lid resistance for the TBJF. The foundations will take place translation and rotation under horizontal load. Under the positive x-axis loading, the vertical resistance of the TSPJF and TBJF is mainly composed of the soil resistance on the 1# bucket lid, the inside and outside frictional resistance. Under the negative x-axis loading condition, the vertical resistance is mainly composed of the inside and outside frictional resistance of buckets. The ultimate moment capacities of the TSPJF and TBJF in loading of the single bucket in compression is significantly larger than that in loading of the single bucket in tension. The failure mode of the TSPJF and TBJF in loading of the single bucket in tension is the pull-out failure of the bucket in tension.

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Raktate, Tushar, and Rohan choudhary. "Design of Monopile Foundation for Offshore Wind Turbine." E3S Web of Conferences 170 (2020): 01024. http://dx.doi.org/10.1051/e3sconf/202017001024.

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Offshore wind turbines are currently considered as a reliable source of renewable energy. Pre-feasibility study includs calculation of preliminary dimensions of the offshore wind turbine structure used to be perform for preliminary costing to achieve at the commercial capacity of project. The main objective of study is to perform preliminary configuration for commercial viability and approximate size of the foundation pile structure. Design nomograms and equations are derived for preliminary design of monopile founded wind turbines situated at offshore of Gujarat. Parametric studies are carried out on various configurations of hollow monopile by changing water depths and properties of soil. A nonlinear static analysis of substructure is carried out considering aerodynamic and hydrodynamic forces for various structural and soil parameters. The design of sub structure wind turbine is based on API (American petroleum institute) standards. An example problem involving the design of foundations for The proposed area is located 23-40 km seaward side from the Pipavav port at Gulf of Khambhat off Gujarat coast. The site is easily accessible from the Pipavav and Jaffrabad Port, is taken to demonstrate the proposed calculation procedure. The data used for the calculations are obtained from publicly available sources.

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Zhang, Zhaohui, Peng Guan, Jinlong Xu, Benzhang Wang, Hui Li, and Yongkang Dong. "Horizontal Loading Performance of Offshore Wind Turbine Pile Foundation Based on DPP-BOTDA." Applied Sciences 10, no. 2 (January 9, 2020): 492. http://dx.doi.org/10.3390/app10020492.

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Offshore wind power is becoming attractive in the wind-power field. With the rapid development of wind-power technology, high-power wind turbines have been implemented in practice. However, the increase in the length of the wind turbine blade causes the pile foundation to withstand a prone overturning moment. For overcoming the problems of traditional sensing technology and meeting the monitoring requirements of pile foundations, a 20 cm spatial resolution differential pulse pair Brillouin optical time-domain analysis (DPP-BOTDA) technique is used to measure a 69 m long offshore wind turbine pile under horizontal loading. From the distributed strain data collected in the test, the maximum stress location of the long pile under the horizontal load can be obtained. By analyzing the load and maximum strain (F-εmax) curve, the horizontal bearing capacity of the pile foundation can exceed 900 kN, which is the maximum horizontal load of the design. The distributed displacement calculation method based on distributed strain data is proposed, according to the force characteristics of steel pipe piles. By comparing the calculated displacement data with the measured data by the dial indicators, the mean absolute percentage error (MAPE) value is only 0.03548. Results show that the 20 cm spatial resolution DPP-BOTDA technology is very suitable for the bearing capacity test of offshore wind turbine steel pipe pile foundations.

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Kim, Dong-Ho, Won-Yil Jang, Seong-Yun Kim, Sung-Ryul Shin, Jong-Se Lim, and Ji-Ho Yoon. "Numerical Analysis on Offshore Wind Power System Foundation." Journal of the Korean Society of Marine Engineering 33, no. 2 (March 31, 2009): 355–61. http://dx.doi.org/10.5916/jkosme.2009.33.2.355.

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Vieira, Mário, Luís Reis, Diogo Vasconcelos, and Diogo Dias. "Structural Evaluation of the DeepCWind Offshore Wind Foundation." Frattura ed Integrità Strutturale 14, no. 51 (October 14, 2019): 24–44. http://dx.doi.org/10.3221/igf-esis.51.03.

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Malek, Aziz M., Amr S. Azzouz, Mohsen M. Baligh, and John T. Germaine. "Behavior of Foundation Clays Supporting Compliant Offshore Structures." Journal of Geotechnical Engineering 115, no. 5 (May 1989): 615–36. http://dx.doi.org/10.1061/(asce)0733-9410(1989)115:5(615).

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Naggar, Mohamed H. El, and Milos Novak. "Influence of Foundation Nonlinearity on Offshore Towers Response." Journal of Geotechnical Engineering 122, no. 9 (September 1996): 717–24. http://dx.doi.org/10.1061/(asce)0733-9410(1996)122:9(717).

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Zhang, Jianhua, Issa Fowai, and Ke Sun. "A GLANCE AT OFFSHORE WIND TURBINE FOUNDATION STRUCTURES." Brodogradnja 67, no. 2 (June 17, 2016): 101–13. http://dx.doi.org/10.21278/brod67207.

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Zhao, Jie, Gao Jie Yun, and Gui Xuan Wang. "Offshore Sea Airport Revetment Structure Foundation Liquefaction Analysis." Applied Mechanics and Materials 353-356 (August 2013): 2171–76. http://dx.doi.org/10.4028/www.scientific.net/amm.353-356.2171.

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This Earthquake liquefaction analysis of total stress method is often used, but the total stress method does not consider the variation of pore water pressure and the process of development of the liquefaction over time. Using two perspectives which the total stress method and effective stress dynamic analysis given liquefied range of offshore airport foundation under the earthquake , and giving recommendations for ground treatment methods.

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Roddier, Dominique, Christian Cermelli, Alexia Aubault, and Alla Weinstein. "WindFloat: A floating foundation for offshore wind turbines." Journal of Renewable and Sustainable Energy 2, no. 3 (May 2010): 033104. http://dx.doi.org/10.1063/1.3435339.

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Tao, Shiqi, Ximei Yao, Bojing Liu, Xiaoqing Zhang, and Yaowu Wang. "Research of lightning transient potential on the jacket foundation offshore wind turbines." E3S Web of Conferences 95 (2019): 02006. http://dx.doi.org/10.1051/e3sconf/20199502006.

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Offshore wind turbines are often struck by lightning due to their tall structures and the harsh marine environment. The high transient potential from lightning strike can cause serious damage for the devices of offshore turbines. For analysing the effect of transient potential, a complete transient circuit model is established and an efficient algorithm is also presented to evaluate the circuit parameters of blade, tower, and jacket foundation. On the basis of the circuit model, the transient potential at the different locations of the offshore wind turbine can be carried out during direct lightning strike by PSCAD. Finally, the circuit model is used by a numerical example of an actual Chinese-built offshore wind turbine.

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Yan, Chaojun, Haijun Wang, Yaohua Guo, Zhen Wang, and Xiao Liu. "Laboratory Study of Integrated Wet-Towing of a Triple-Bucket Jacket Foundation for Far-Offshore Applications." Journal of Marine Science and Engineering 9, no. 11 (October 20, 2021): 1152. http://dx.doi.org/10.3390/jmse9111152.

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As a form of clean and low-carbon green energy, offshore wind power occupies an important position in the global energy structure. With the rapid development of the wind power industry, wind power projects gradually develop from offshore to far-offshore sea areas. The multi-bucket jacket foundation is a considerable foundation type for far off-shore projects, but high installation costs involving ship transportation with parted components and field installation has significantly hindered its wide application. In this study, based on a 6.7-MW triple-bucket jacket foundation (TBJF) project of a deep-sea wind farm in China, a new integrated wet-towing method of “jacket + triple-bucket foundation” composite structure was proposed, which is suitable for far long-distance transportation of far-offshore applications. The static-model test of both self-stability and wet-towing stability was conducted. Based on the test and the numerical results, the natural period of the foundation for different draft depths in hydrostatic water and the stability for different eccentric loads were first evaluated. Then, the effects of different wet-towing modes and sea conditions on the stability of the TBJF were investigated. Finally, the optimal wet-towing mode and applicable sea conditions for the TBJF structure were proposed.

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Yun, Gijae, and M. Fraser Bransby. "The horizontal-moment capacity of embedded foundations in undrained soil." Canadian Geotechnical Journal 44, no. 4 (April 1, 2007): 409–24. http://dx.doi.org/10.1139/t06-126.

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The bearing capacity of embedded foundations subject to combined horizontal and moment loading in undrained soils is of interest particularly to the offshore geotechnical engineer. These loadings can be experienced by monopod foundations and offshore manifolds and often take the form of a horizontal load applied at a lever arm height above the foundation base. Previous design methods using the failure envelope approach have suggested that peak moment capacity of a foundation is mobilized with positive horizontal loads, but that peak horizontal load is mobilized with no additional moment loading. This paper reports numerical work specifically investigating the effects of the embedment ratio on the horizontal-moment foundation capacity under no vertical load in both uniform strength and "normally consolidated" undrained soil. It is shown that the embedment ratio significantly affects the eccentricity of the M–H failure envelope so that the shape varies when normalized by the pure moment (M0) and pure horizontal load (H0) capacity. The reasons for the eccentricity of the failure envelopes are understood by investigating soil deformation mechanisms calculated during FE analysis and by accompanying upper bound plasticity analysis. This mechanistic understanding is used to suggest load reference point translations that ease curve-fitting of the complex failure envelopes for use in design.Key words: bearing capacity, foundations, numerical modelling and analysis, plasticity.

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Zhou, Li, Shifeng Ding, Ming Song, Junliang Gao, and Wei Shi. "A Simulation of Non-Simultaneous Ice Crushing Force for Wind Turbine Towers with Large Slopes." Energies 12, no. 13 (July 7, 2019): 2608. http://dx.doi.org/10.3390/en12132608.

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When the offshore wind energy industry attempts to develop in cold regions, ice load becomes the main technological challenge for offshore wind turbine foundation design. Dynamic ice loads acting on wind turbine foundations should be calculated in a reasonable way. The scope of this study is to present a numerical model that considers the non-simultaneous ice crushing failure acting on the vertical structure of a wind turbine’s foundation. The local ice crushing force at the contact surface between the ice sheet and structure is calculated. The boundary of the ice sheet is updated at each time step based on the indentation length of the ice sheet according to its structure. Ice loads are validated against two model tests with three different structure models developed by other researchers. The time series of the ice forces derived from the simulation and model tests are compared. The proposed numerical model can capture the main trends of ice–wind turbine foundation interaction. The simulation results agree well with measured data from the model tests in terms of maximum ice force, which is a key factor for wind turbine design. The proposed model will be helpful for assisting the initial design of wind turbine foundations in cold regions.

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Journal articles on the topic 'Offshore foundation'

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