scholarly journals Setup of axial bearing capacity of open ended tubular steel piles driven in sand

2020 ◽  
Vol 42 (1) ◽  
pp. 74-82
Author(s):  
Marx Ferdinand Ahlinhan ◽  
Edmond Codjo Adjovi
Keyword(s):  
Bearing Capacity ◽  
Wind Turbines ◽  
Comparative Evaluation ◽  
Lower Estimate ◽  
Case Histories ◽  
Best Estimate ◽  
Steel Piles ◽  
Upper Estimate ◽  
Offshore Foundation

AbstractThis paper focuses on the setup of axial bearing capacity of open ended tubular steel piles that are used for offshore foundation systems such as those of wind turbines. A comparative evaluation of the most commonly used models for setup prediction shows an upper estimate bound and a lower estimate bound, which correspond approximately to a setup rate of 60% increase per log cycle of time and 20% increase per log cycle of time, respectively. This finding is validated with the results of case histories reported in literature, which show that the setup values of most case histories considered lie in the best estimate zone between the upper estimate zone and the lower estimate zone. The analysis results show a minimum setup factor of approximately 1.5 for 100 days following end of driving of open-ended tubular steel pile driven in sand.

scholarly journals Bearing Capacity of the High-Rise Pile Cap Foundation for Offshore Wind Turbines

2014 ◽  
Author(s):  
Wen-Gang Qi ◽  
Jing-Kui Tian ◽  
Hong-You Zheng ◽  
Hai-Yan Wang ◽  
Jing Yang ◽  
...  
Keyword(s):  
Bearing Capacity ◽  
Wind Turbines ◽  
Offshore Wind ◽  
Offshore Wind Turbines ◽  
High Rise ◽  
Pile Cap

Limit Equilibrium Solutions to Anti-overturning Bearing Capacity of Suction Caissons in Uniform and Linearly Increasing Strength Clays

2021 ◽  
Author(s):  
Yuqi Wu ◽  
Qing Yang ◽  
Dayong Li ◽  
Yu Zhang
Keyword(s):  
Bearing Capacity ◽  
Failure Mechanism ◽  
Wind Turbines ◽  
Limit Equilibrium ◽  
Soil Surface ◽  
Equilibrium Analysis ◽  
Offshore Wind ◽  
Offshore Wind Turbines ◽  
Aspect Ratios ◽  
Suction Caissons

Suction caissons supporting offshore wind turbines are exposed to great horizontal loading above the soil surface, which may lead to overturning failure of the caisson. This paper presents a modified three-dimensional failure mechanism to analyze the anti-overturning bearing capacity of suction caissons. The modified failure mechanism is composed of meniscus-conical wedge having meniscus shape at the soil surface and scooped shape. The analytical solution to the anti-overturning bearing capacity of suction caisson is deduced in terms of the limit equilibrium method, following by a parametric study of wedge depth ratio (c) to optimize the critical failure mechanism that satisfies both the force and moment equilibriums. Thus, the methodologies are relatively easy to implement in traditional spreadsheets and the analyses tend to perform very fast. Meanwhile, the effects of gap formation at the rear side of the caisson, loading eccentricity and adhesion factor at caisson-soil interface on anti-overturning bearing capacity are investigated. Comparing with finite element limit analysis results, experimental data and existing theoretical solutions, it is proved that the presented limit equilibrium analysis can satisfactorily predict the anti-overturning bearing capacity of suction caissons with low aspect ratios for offshore wind turbines in uniform and linearly increasing strength clays.

Bearing capacity of composite bucket foundations for offshore wind turbines in silty sand

2018 ◽  
Vol 151 ◽  
pp. 1-11 ◽  
Author(s):  
Nan Jia ◽  
Puyang Zhang ◽  
Yonggang Liu ◽  
Hongyan Ding
Keyword(s):  
Bearing Capacity ◽  
Wind Turbines ◽  
Silty Sand ◽  
Offshore Wind ◽  
Offshore Wind Turbines

scholarly journals Carbon export and sequestration in the southern Benguela upwelling system: lower and upper estimates

Ocean Science ◽  
2009 ◽  
Vol 5 (4) ◽  
pp. 711-718 ◽  
Author(s):  
H. N. Waldron ◽  
P. M. S. Monteiro ◽  
N. C. Swart
Keyword(s):  
Lower Estimate ◽  
Low Frequency ◽  
Dimensional System ◽  
Carbon Export ◽  
Nepheloid Layer ◽  
Episodic Events ◽  
Upwelling System ◽  
Hypothesis Model ◽  
Benguela Upwelling ◽  
Upper Estimate

Abstract. Three independent studies of carbon export and sequestration in the southern Benguela upwelling system are presented. They were undertaken by Waldron (upwelling index), Monteiro (discrete upwelling centres – gate hypothesis model) and Swart (cross-shelf advection in bottom nelpheloid layers). The annual estimates were, 3.9×1013, 0.72×1013 and 8.6×1011 gC, respectively. The lowest estimate was derived from a consideration of low frequency lateral carbon export in the bottom nepheloid layer and was thought likely to be an under-estimate. Taking into account high frequency episodic events, intermediate nepheloid layers and along isopycnal export of DOC at surface and intermediate depths was thought likely to result in a substantial upward revision. The remaining two estimates were considered to be an upper and lower estimate of carbon export and sequestration due to factors inherent in the methodologies. The upper estimate presents a two-dimensional system, integrated alongshore; the lower estimate sums a series of upwelling centres in order to obtain a system flux. The former is therefore a uniform extrapolation along the coast while the latter omits upwelling between the upwelling centres.

3D FEM Analysis on Bearing Capacity Behaviors of the Multi-Piles Foundation for Offshore Wind Turbines

2012 ◽  
Vol 170-173 ◽  
pp. 2233-2242
Author(s):  
Xiao Wei Tang ◽  
Qi Shao ◽  
Bin Xue Liu
Keyword(s):  
Finite Element ◽  
Bearing Capacity ◽  
Wind Turbines ◽  
Wind Farm ◽  
Offshore Wind ◽  
Combined Loading ◽  
Hangzhou Bay ◽  
Offshore Wind Turbine ◽  
Offshore Wind Turbines ◽  
Finite Element Software

With the fast development of technology, offshore wind power generation is playing a major role for developing renewable sources in the whole world nowadays. According to the proposed Hangzhou Bay wind farm in China, using general-purpose finite element software, bearing capacity behaviors of the multi-piles foundation for offshore wind turbine are simulated in this paper by the 3D finite element method. The Mohr - Coulomb model is adopted as the elastic - plastic constitutive model of the soil and also the Coulomb Friction model as the pile - soil contact model. The bearing capacity behavior of multi-piles foundation for offshore wind turbines under monotonic and combined loading are discussed, also the bearing capacity behaviors by changing diameters, spaces of piles and loading directions as well.

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