Centrifuge modelling of monopiles subjected to lateral loading

S. Darvishi Alamouti; Majid Moradi; Mohammad Reza Bahaari

doi:10.24200/SCI.2018.20222

Centrifuge modelling of monopiles subjected to lateral loading

Published on Mar 14, 2018in Scientia Iranica1.435

· DOI :10.24200/SCI.2018.20222

S. Darvishi Alamouti2

Estimated H-index: 2

(UT: University of Tehran), Majid Moradi9

Estimated H-index: 9

(UT: University of Tehran), Mohammad Reza Bahaari11

Estimated H-index: 11

(UT: University of Tehran)

Sources

Abstract

Monopiles are the most common foundation type used for fixed-bottom substructures in offshore wind installations. In an offshore environment, the predominant load is cyclic, which affects the stiffness and deformation properties of foundation systems, especially monopiles. To investigate the effect of cyclic loading on a short (rigid) steel monopile, a set of displacement-controlled ηg laboratory tests were designed. This paper presents the procedure and results of eight centrifuge tests investigating monopile behaviour when subjected to lateral monotonic and cyclic loading. The general trend of monotonic response is in good agreement with the results of similar experimental studies, however, much softer behaviour was observed compared to the equivalent Winkler model on API p-y curves. The cyclic tests focused on the stiffness and deformation properties of a soil-pile system under fatigue loading. Increases, decreases or no changes in secant stiffness were observed depending on the regime of the applied cyclic displacements which are in contradiction to current design methodology where only cyclic degradation is assumed. Influence of load cycling on cyclic bending moments along the pile shaft was discussed and found to be of minor significance

References (19)

Citations (2)

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References19

Newest

Firoozkuh Sand: Introduction of a Benchmark for Geomechanical Studies

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#1K. Farahmand (UT: University of Tehran)H-Index: 1

#2Ali Lashkari (SUTECH: Shiraz University of Technology)H-Index: 15

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Response of Static and Cyclic Laterally Loaded Rigid Piles in Sand

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An experimental investigation was made into the response of piles in sand subjected to lateral cyclic loading. Seven instrumented model piles tests were conducted. Five tests were conducted under typical magnitude and number of cyclic loading, and two were under static loading. The results were used to deduce modulus of subgrade reaction k and the profile of limiting lateral resistance force per unit length (LFP, pu profile) in light of closed-form solutions. The study demonstrates a large impac...more

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Testing of laterally loaded piles in natural sandy gravels

Nov 13, 2015·International Journal of Physical Modelling in Geotechnics1.46

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#2Željko ArbanasH-Index: 10

In this paper, the authors present the results of field tests on a single laterally loaded pile and two piles in line. Bored reinforced concrete piles with a diameter of 0·25 m and a depth of 5 m were constructed in natural sandy gravels. The lateral loading on a head of tested piles is applied using a hydraulic press with a maximum force of 500 kN. A single pile and two piles in line were incrementally loaded with a controlled head displacement of 2 mm until the ultimate capacity of the pile wa...more

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Scaling issues in centrifuge modelling of monopiles

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#1Rasmus Tofte KlinkvortH-Index: 9

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Last. Sarah M. SpringmanH-Index: 33

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This paper deals with three different and important issues for centrifuge testing on monopiles for offshore wind turbines. A series of centrifuge model tests has been conducted on cylindrical stiff model monopiles that were installed at 1g and in-flight before being loaded laterally as well as on conical model piles installed in-flight. All model tests were performed in normally consolidated dense dry sand, simulating drained conditions. The tests confirmed three important issues for centrifuge ...more

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Experimental Investigation Into Pile Diameter Effects of Laterally Loaded Mono-Piles

#1Etienne A. Alderlieste (TU Delft: Delft University of Technology)H-Index: 1

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This paper presents the results of model tests on laterally loaded mono-pile foundations in sand. The tests have been performed in a geotechnical centrifuge. The objective of the research is to quantify large diameter effects of these mono-piles on the lateral capacity and the stiffness response for cyclic lateral loading. These large diameters are out of the validity range of the commonly used design methods. For this reason prototype pile diameters up to 4.4 m with a length over diameter ratio...more

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Centrifuge modelling of mono-pile under cyclic lateral loads

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Mono-pile foundations are widely used for wind turbines at present. They are always subjected to significant cyclic lateral loads due to wind and wave actions. In order to better understand the performance of mono-piles under cyclic lateral loads, a series of cyclic lateral load tests was conducted on a stainless steel mono-pile in the centrifuge. The axial and lateral responses of a large diameter mono-pile under one-way force-controlled cyclic lateral loads are described. Accumulated permanent...more

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A new elasto-plastic spring element for cyclic loading of piles using the p-y curve concept

#1Ole HededalH-Index: 8

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Modeling the response of large diameter piles subjected to lateral loading is most often done by means of p-y-curves in combination with Winkler beam models. Traditionally the p-y curves are formulated as non-linear (elastic) relations between the lateral movement y and the soil response pressure p in terms of monotonic loading (until failure) as e.g. prescribed byAPI (2000). However, the cyclic and dynamic performance is only to a limited degree accounted for. Here the elasto-plastic framework ...more

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Cyclic shakedown of piles subjected to two-dimensional lateral loading

Jul 1, 2009·International Journal for Numerical and Analytical Methods in Geomechanics4.26

#1Nina H. Levy (WorleyParsons)H-Index: 4

#2Itai Einav (USYD: University of Sydney)H-Index: 32

Last. Tim Hull (GHD Group)H-Index: 1

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Pile foundations are frequently subjected to cyclic lateral loads. Wave and wind loads on offshore structures will be applied in different directions and times during the design life of a structure. Therefore, the magnitude and direction of these loads in conjunction with the dead loads should be considered. This paper investigates a loading scenario where a monotonic lateral load is applied to a pile, followed by two-way cycling in a direction perpendicular to the initial loading. This configur...more

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Centrifuge Modelling of Monopiles in Calcareous Sand Subjected to Cyclic Lateral Loading

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Monopiles are the most common foundation type for offshore wind turbines. These structures are subjected to millions of cyclic horizontal loads during their lifespans, mainly from waves and wind; however, there are gaps in conventional design methods for different aspects of cyclic loading. The present study examined the cyclic behaviour of monopiles in dry calcareous sand. Centrifuge tests were carried out to investigate the effect of cyclic loading on the accumulated displacement and soil-pile...more

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