Influence of Low-Permeability Layers on the Installation and the Response to Vertical Cyclic Loading of Suction Caissons

In soft marine clays, suction caissons provide a foundation system for tidal current turbines that further promote the sustainable nature of the system by allowing for their removal at the end of the structure’s design life. When configured as a multipod, the moment loads resulting from the horizontal flow of water will be transferred to the suction caissons as compression–uplift loads on opposing foundation legs. The behavior of a suction caisson in soft clay was investigated at aspect ratios of 1 and 2 under monotonic and cyclic vertical loading applicable to multipod-supported tidal current turbine design. Installation and solely monotonic vertical load tests indicated lower back-calculated adhesion factor, α, values and higher back-calculated bearing capacity factor, Nc, values than design standards recommend. The capacity and stiffness response of the foundation after undergoing cyclic loading was found to be largely dependent on the magnitude of displacement the foundation underwent during cyclic loading. Additionally, a threshold of elastic foundation response was observed during cyclic loading defined by a cyclic displacement amplitude. These results indicate serviceability constraints will be critical in the design of suction caisson foundations for tidal current turbine applications.

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Uplift Capacity of Suction Caissons under Sustained and Cyclic Loading in Soft Clay

Journal of Geotechnical and Geoenvironmental Engineering ◽

10.1061/(asce)1090-0241(2007)133:11(1352) ◽

2007 ◽

Vol 133 (11) ◽

pp. 1352-1363 ◽

Cited By ~ 41

Author(s):

W. Chen ◽

M. F. Randolph

Keyword(s):

Cyclic Loading ◽

Soft Clay ◽

Uplift Capacity ◽

Suction Caissons

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The response of suction caissons to long-term lateral cyclic loading in single-layer and layered seabeds

Géotechnique ◽

10.1680/jgeot.17.p.129 ◽

2018 ◽

Vol 68 (8) ◽

pp. 729-741 ◽

Cited By ~ 12

Author(s):

F. Y. Zhu ◽

C. D. O'Loughlin ◽

B. Bienen ◽

M. J. Cassidy ◽

N. Morgan

Keyword(s):

Cyclic Loading ◽

Single Layer ◽

Suction Caissons

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Comparative study of the effective parameters on residual stress relaxation in welded aluminum plates under cyclic loading

Mechanics & Industry ◽

10.1051/meca/2020061 ◽

2020 ◽

Vol 21 (5) ◽

pp. 505

Author(s):

Yousef Ghaderi Dehkordi ◽

Ali Pourkamali Anaraki ◽

Amir Reza Shahani

Keyword(s):

Residual Stress ◽

Cyclic Loading ◽

Stress Relaxation ◽

Stress Amplitude ◽

Cyclic Plasticity ◽

Mean Stress ◽

Effective Parameters ◽

Perfect Plasticity ◽

Residual Stress Relaxation ◽

Aluminum Plates

The prediction of residual stress relaxation is essential to assess the safety of welded components. This paper aims to study the influence of various effective parameters on residual stress relaxation under cyclic loading. In this regard, a 3D finite element modeling is performed to determine the residual stress in welded aluminum plates. The accuracy of this analysis is verified through experiment. To study the plasticity effect on stress relaxation, two plasticity models are implemented: perfect plasticity and combined isotropic-kinematic hardening. Hence, cyclic plasticity characterization of the material is specified by low cycle fatigue tests. It is found that the perfect plasticity leads to greater stress relaxation. In order to propose an accurate model to compute the residual stress relaxation, the Taguchi L18 array with four 3-level factors and one 6-level is employed. Using statistical analysis, the order of factors based on their effect on stress relaxation is determined as mean stress, stress amplitude, initial residual stress, and number of cycles. In addition, the stress relaxation increases with an increase in mean stress and stress amplitude.

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