Christelle Abadie

Research Assistant

Christelle Abadie

Office: Room 10.04, Jenkin building
Phone: +44 (0)1865 2 73129
Email: Contact Search
Address: Department of Engineering Science,
Parks Road,
Oxford,
OX1 3PJ,
U.K.
College: St Catherine's College

 

 

Research interests

My research is concerned with the development of theoretical and numerical methods for the design of offshore wind turbine foundations.

In the past years, I have been working on the development of design methods to ensure stability of monopile foundations for (1) long-term cyclic loading and (2) ultimate capacity. 

(I) Cyclic lateral loading of monopile foundations in cohesionless soils

1) Laboratory floor model testing of rigid monopiles in cohesionless soils

During my doctorate, I conducted a series of experimental tests (Fig. 1) to identify the key mechanisms driving the pile response to cyclic lateral loading ([4],[5],[7], Chap. 2 and 3). The experimental tests involve a range of targeted load cases that provide new insights on the behaviour of a rigid pile to cyclic lateral loading with the aim of improving current design methodology for cyclic loading. The tests were performed with a cyclic loading rig designed in 2004 by Rovere (see picture below) and mimic a typical 2MW offshore wind turbine foundation. The model tests comprise:
- Continuous cyclic loading, up to a 100,000 cycles
- Multi-amplitude cyclic loading tests studying the evolution of the soil-pile interaction during and after storm-type load series
- Damping tests 

 

Experimental test set up
Experimental test set-up

2) Development of a constitutive model that captures cyclic loading response of monopiles:

The key mechanisms identified with the laboratory floor tests were integrated within a constitutive model, called HARM (Hyperplastic Accelerated Ratcheting Model, [1], [7], Chap. 4). This constitutive model is embedded within the hyperplasticity framework developed by Houlsby and Puzrin (2006) and captures trends such as shown in the Figures below in a simple, yet rigorous manner ([2],[3],[7], Chap. 5).  

mergedgraphs
Typical moment-rotation results from (a) continuous and (b) multi-amplitude cyclic tests

(II) Improved procedures for the design of monopiles to ultimate load (PISA2)

Since 2017, I am the lead post-doctoral research assistant on the PISA2 project at the University of Oxford. PISA2 is a joint industry project run through the Carbon Trust, with academic work group comprising Oxford University and Imperial College and industry partners headed by Orsted, and including EDF, E.ON, GE, Innogy, Iberdrola, SSE, Statoil, Van Oord and Vattenfall. The PISA2 project follows on the very successful PISA project (awarded with the BGA Fleming Award 2017).

The PISA2 project mainly aims at broadening the PISA methodology to a wider range of soils, including layered profiles. This is achieved through numerical method involving 3D FE analyses, from which soil reaction curves are extracted and used to further develop the PISA 1D modelling approach.

Publications:

Journal Papers:

[1] Houlsby, G. T., Abadie, C. N., Beuckelaers, W. J. A. P. & Byrne, B. W. (2017) A model for nonlinear hysteretic and ratcheting behaviour. International Journal of Solids and Structures, 120, 67-80. Paper

Conferences:

[2] Abadie, C. N., Byrne, B. W. & Houlsby, G. T. (2017) Modelling of monopile response to cyclic lateral loading in sand. 8th International Conference, Smarter Solutions for Future Offshore Developments (SUT OSIG). London, U.K., September 2017. Paper

[3] Abadie, C.N., Richards, I., Byrne, B.W. and Houlsby. G.T. (2016) Cyclic Loading of Monopiles for Offshore Wind Applications, SUPERGEN Wind General Assembly, Cranfiled University. United-Kingdom. poster

[4] Abadie, C. N., Byrne, B.W. & S. Levy-Paing (2015). Model pile response to multi-amplitude cyclic lateral loading in cohesionless soils. 3rd International Symposium on Frontiers in Offshore Geotechnics (ISFOG). Oslo, Norway. paper | poster

[5] Abadie, C. N. & Byrne, B.W. (2014). Cyclic loading response of monopile foundations in cohesionless soils. International Conference of Physical Modelling in Geotechnics (ICPMG). Perth, Australia. pp. 779–784.

[6] Abadie, C. (2011), Study of the long-term cyclic loading response of piled foundations for offshore wind turbines. Twelfth BGA Young Geotechnical Engineers’ Symposium, Leeds

Thesis:

[7] Abadie, C. N. (2015). Cyclic Lateral Loading of Monopile Foundations in Cohesionless Soils. DPhil Thesis, Department of Engineering Science, The University of Oxford. abstract | thesis as pdf

Academic background

After completing my undergraduate education in France (Classes Préparatoires aux Grandes Ecoles (CPGE); ENSTA ParisTech; MSc TACS, ENS Cachan), I joined the civil engineering group at the University of Oxford in 2011 for my DPhil. I graduated in 2016, and have since been continuing research within the group as a post-doctoral research assistant. 

More information on my academic and professional background can be found on my Linkedin webpage