Proceedings of the Thirty-second (2022) International Ocean and Polar Engineering Conference
Shanghai, China, June 5–10, 2022
Copyright © 2022 by the International Society of Offshore and Polar Engineers (ISOPE)
ISBN 978-1-880653-81-4; ISSN 1098-6189

www.isope.org

A Consistent, Rigorous, and Super-Fast Suction Caisson Design Approach
Hendrik Sturm
Det Norske Veritas (DNV), Oslo, Norway
Nallathamby Sivasithamparam & Jingdong Liu
Norwegian Geotechnical Institute (NGI), Oslo, Norway
Ben He & Gao Peng
PowerChina Huadong Engineering Corporation Ltd., Hangzhou, Chinasite and soil conditions can be assessed in a very short time frame. Thisenables the designer to focus on the design basis and identify key
uncertainties which matter, i.e., risks, and not being time-constrained by
performing the calculations. The core of the implementation is a Finite
Element (FE) solver, presented by Sivasithamparam & Jostad (2020),
which is used for both foundation capacity, serviceability, and soilfoundation stiffness for ULS and FLS. By means of an optimisation
routine, which also considers the installation feasibility, SBDT identifies
an optimised foundation geometry and can in addition automaticallyestablish the input parameters to other design disciplines, including
structural design and integrated load analysis.

ABSTRACTThis article presents a framework for a consistent, rigorous, and superfast suction caisson design. By considering cyclic loading effects andimplementing all relevant geotechnical design tasks in a semi-automatic
design tool, a wide range of different site and soil conditions can beassessed in a very short time frame. This enables the designer to focus
on the design basis and identify key uncertainties and risks. The core of
the implementation is a super-fast finite element solver, used for bothfoundation capacity, serviceability, and soil-foundation stiffness. Bymeans of an optimisation routine, which also considers the installation
feasibility, the program identifies an optimised foundation geometry andautomatically establishes the input parameters to other design
disciplines, including structural design and integrated load analysis.

The streamlined and automated workflow speeds up the entire designand development process and contributes to a safe and timely transition
to the increased use of renewable energy sources.

KEY WORDS: Suction caissons, offshore wind, renewable energy,

DESIGN TASKS

geotechnical foundation design, cyclic load effects, installation,capacity, serviceability, soil-foundation stiffness.

The geotechnical design of suction caissons for the foundation of bottom
fixed Offshore Wind Turbines (OWT) comprises a series of design tasks
discussed in Sturm (2017), which are illustrated on Figure 1 andpresented in detail in the following subsections.

INTRODUCTION
The ambitious targets set by many countries around the world to increase
the amount of energy generated from renewable sources require thedevelopment and construction of large number of new power plants. Thisincludes offshore wind power, which has seen massive growth in recentyears and is expected to grow even faster in the coming years (DNV,2021). To achieve these goals, all supply chain processes must be
accelerated and streamlined without compromising reliability andproject risk. This concerns all disciplines, including the geotechnical andstructural design.

Workflow
Geotechnical foundation design for OWTs is interdisciplinary; the resultof the foundation design will affect the input which was used to size thefoundation. This applies to all foundation concepts, including suction
caissons. The size and properties of the foundation element will affectthe soil-foundation-stiffness, which in return will affect the load
response of the structure as well as the structural design. As a result of
this interdependency, the (geotechnical) foundation design is in general
an iterative process, where the foundation dimensions are continuously
updated throughout the development of an offshore wind farm project,
starting with the concept and feasibility study, continuing with the preFEED and FEED, and finalizing with the detailed design. Within eachThis article presents a framework for a consistent, rigorous, and superfast suction caisson design, based on the workflow proposed by Sturm(2017). By considering cyclic loading effects and implementing all
relevant geotechnical design tasks in a semi-automatic design tool,
denoted Suction Bucket Design Tool (SBDT), a wide range of different

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