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Ben Hong Lau

Ben Hong Lau

PhD Research Student

Schofield Centre
High Cross
Madingley Road

Cambridge , Cambridgeshire CB3 0EL
Office Phone: +44 (0)1223 768041

Biography:

Carried out my undergraduate degree in Canada at the University of British Columbia and worked for 1.5 years in Malaysia as a geotechnical engineer at G&P Geotechnics Sdn Bhd doing projects involving piled rafts, shallow foundations, retaining walls, landfill design, and construction monitoring.  Now I am studying the behaviour of monopiles under cyclic loading in clay in collaboration with DONG Energy, KW Ltd, Sir Robert McAlpine and RES. 

 

Offshore wind farms are gaining popularity in the UK due to the current need for greener energy sources, security of energy supply and to the public's reluctance to have wind farms on-shore.  Offshore wind farms often contain hundreds of turbines supported at heights of 30m to 50m.  The preferred foundations for these tall structures are large diameter monopiles due to their ease of construction in shallow to medium water depths.  In coastal waters around the UK, it is common for these monopiles to pass through shallow layers of soft, poorly consolidated marine clays before entering into stiffer clay/sand strata. 

The completed structure is subjected to a large number of cyclic, lateral and moment loads (due to both wind and wave loading) in addition to axial loads.  This type of cyclic loading is quite different from other forms of cyclic loading such as earthquake loading in terms of frequency, amplitude, and number of cycles. 

In addition, it is anticipated that each of these foundations will see many millions of cycles of loading during their design life.  One of the biggest concerns with the design of monopiles is their behaviour under very large numbers of cycles of lateral and moment loads.  The current design methods rely heavily on available stiffness degradation curves for clays that were primarily derived for earthquake loading on relatively small diameter piles with relatively small numbers of cycles of loading.  Extrapolation of this stiffness deterioration to large diameter piles with large numbers of cycles represents a key risk factor in assessing the performance of offshore wind turbines.  Further research is therefore required.

The aims of this project are to model, both experimentally and analytically, the behaviour of monopile wind foundations subject to cyclic loading.  The objectives are:

  1.  To conduct centrifuge model tests on monopile offshore wind farm foundations including in-flight installation and combined axial and lateral loading tests using a new 2-D actuator
  2. To obtain centrifuge data on the performance of the monopile foundations under axial and lateral loading, including large number of cycles of lateral and moment loading.
  3. To develop miniature statnamic testing equipment for the in-flight measurement of the stiffness and dynamic response of the soil foundation system.
  4. To develop miniature seismic CPT equipment for the in-flight characterisation of layered soils.
  5. To develop p-y and cyclic degradation curves to allow simple analysis of the resistance of monopiles to large numbers of loading cycles.
  6. To understand the long term performance of wind farm foundations when subjected to a large number of loading cycles.
  7. To optimise and improve the current design of offshore foundations in the UK by developing appropriate design guidelines.
  8. To develop a large database of centrifuge test data and to make it freely available after the end of the project to the numerical modelling community

Research themes

Offshore Wind Farms:

Departments and Institutes

Department of Engineering: