B6349 - FOUNDATIONS AND ANCHORS

Learning outcomes

The course provides students with the ability to apply the concepts of soil mechanics and geotechnical engineering to the modelling and design of the foundations of bottom-fixed and floating offshore structures. Particular emphasis is given to the foundations and anchors that support and moor offshore wind turbines.

Course contents

The course builds on student's previous knowledge of soil mechanics and addresses the geotechnical engineering aspects of the design of offshore structures with application to oil and gas and wind turbine developments. The course is organised in three modules as follows.

Introduction. Short history of offshore developments in Italy and worldwide. Overview of offshore structure and foundation types. Features of the offshore environment: met-ocean data, sediments and hydrodynamic regimes.

Behaviour of a soil element. Summary of fundamentals: compression and shear. Cyclic loading: essential features, laboratory modelling of cyclic loading, cyclic resistance curves, failure and deformations under cyclic loading.

Site investigation. Overview on investigation systems. Sampling. Penetration tests: cone (CPT), T-bar and ball penetrometers: equipment, procedures and data interpretation.

Design of piles. Overview. Essential features of driven steel piles: plugging, friction fatigue. Resistance to driving. Axial and lateral capacity of driven piles in clay and sand. Axial and lateral response of driven piles: load-transfer curves in clay and sand.

Design of shallow foundations. Overview. Shallow foundations types. Features of installation methods. Classical bearing capacity theory: uniaxial and general loading conditions. Interaction diagrams. Shallow foundations load-displacement response under general loading conditions.

Design of anchor foundations. Overview. Anchor and mooring types. Installation features. Estimate of anchors capacity under combined loading.

Design principles according to American Petroleum Institute (API), International Standard Organisation (ISO) and Det Norske Veritas (DNV).

Readings/Bibliography

Mark Randolph and Susan Gourvenec, Offshore geotechnical engineering, Spon, 2011

Subhamoy Bhattacharya, Design of foundations for offshore wind turbines, Wiley, 2017

Teaching methods

Lectures are organised as follows.

Theory: through slides, videos and at the board;

Worked examples: direct application of theory, typically at the board, with students active involvment.

Assessment methods

The assessment is a written exam, open books and concerns solving some worked examples.

Teaching tools

The course makes mostly use of slides.

Office hours

See the website of Laura Govoni