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DEPARTMENT OF ENGINEERING SCIENCE
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Dr Byron Byrne Oxford University British Geotechnical Association Institution of Civil Engineers Wednesday 9th November 2011
Blades: high strength
composites
Aerodynamics of blades
Forces from
waves and current
Dynamics of tower
Foundation design
Generator
Gearbox
Control of blade pitch
Electrical connections
to shore
November 11, 2011
Page 2
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Water depth Average wind speed
November 11, 2011 Helical Piles for Offshore
Wind Turbines Page 3
Source: DTI Renewable Energy Atlas
Offshore sites
Round 1 - 2001
~ 1 GW
Round 2 - 2003
~ 7 GW
Round 3 - 2010
~ 32 GW
UK Wind Overview
Figures are rated maximum power and not average delivered power
Total UK installed generating capacity is approximately 91GW
November 11, 2011
Page 5
Source: RenewableUK (bwea.com)
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Status Onshore
Number
Onshore
Power (GW)
Offshore
Number
Offshore
Power (GW)
Operational 296 4.2 14 1.5
Construction 32 1.5 6 2.0
Consent 232 3.6 5 1.6
Planning 314 7.3 4 2.0
Total 874 16.6 29 7.1
96.8% 70% 3.2% 30%
Offshore Wind Challenges
RenewableUK indicates plans for about 42GW of wind power to be installed, though no time scale indicated
Government announcements : 33GW by 2020
6600 5MW turbines
Over 800 turbines per year to 2020! *Replacement rate about 300 turbines per year indefinitely*
Nearly 500 turbines installed and operating since 2000
Total investment in region of 80bn to 100bn Many (tens of) thousands of jobs in the supply chain
November 11, 2011
Page 6
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Cost Makeup
4% Development and consent 33% Turbine 15% Electrical 22% Support structure 26% Production, integration and installation
Source: Carbon Trust
Foundations and installation part of the last two categories Opportunity to reduce costs by using alternative foundation
concepts and installation processes as well as by improving design approaches
Costs are of the order say 3m to 3.5m per MW installed
Source UK ERC report Sept 2010
November 11, 2011
Page 7
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Geotechnical Issues
A full range of geotechnical conditions can be found at the various sites - mobile sand banks, dense sand, stiff clays, layered materials, soft clays, rocky strata, boulder clay
Can be considerable variability over a site (turbines are typically spaced more than 500m apart)
A site investigation is important early in the design process and may involve CPTs, Boreholes, vane tests, geophysical surveys
There may also be element testing using samples obtained from the site
November 11, 2011
Page 8
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
200MN
25MN
90m to 1
20m
90m
to
120m
1MN to 2MN
3MN to 8MN
~6MN
November 11, 2011
Page 9
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Loads on an Offshore Turbine Foundation
(b)(a)
V
H
V
H
V
H
M
H2H1
V2
V1
November 11, 2011
Page 10
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Foundation stiffness
The main excitation frequencies
are 1P (the rotational
frequency) and 3P (the blade-
passing frequency)
These must be avoided
The flexibility of the foundation
reduces the natural frequency
k
EI
m
L
k
L
EI
Lm
fn 23
3
1
2
1
November 11, 2011
Page 11
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Stiff-Stiff Response
November 11, 2011
Page 12
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
frequency
DAF
1P 3P
1.0
frequency
DAF
1P 3P
1.0
Soft-Stiff Response
November 11, 2011
Page 13
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
frequency
DAF
1P 3P
1.0
Effect of Foundation
November 11, 2011
Page 14
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
frequency
DAF
1P 3P
1.0
Range of Excitation Frequencies
November 11, 2011
Page 15
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Options for Foundations
November 11, 2011
Page 16
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Gravity Base Mono-Pile Mono-Caisson Multi-Pile Multi-Caisson
Size and Location of Developments
Wa
ter
de
pth
(m
)
Turbine power (MW)
2 3 4 5
10
20
30
40
Most past
developments
Most future
developments?
Multiple
footings?
Monopods
November 11, 2011
Page 17
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Other Designs / Possibilities
November 11, 2011
Page 18
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
TLP Spar
Experimental Work
Most of the work presented is based on small scale model tests in the laboratory
High quality sophisticated work carried out
Designed to build up a framework of response
Careful consideration has been given to scaling of the results
Density of sands, strength of clays
Dimensional analysis has yielded dimensionless groups
relevant to each of the problems explored
November 11, 2011
Page 19
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
CURRENT DESIGNS PILE FOUNDATIONS
November 11, 2011
Page 20
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Mono-Pile Foundations
A wind turbine monopile is at least 4m diameter and of the order of 25m long
Driving is at the limits of offshore oil-and-gas experience which typically involves smaller diameter (~2m) and longer piles (~100m)
Large diameter drilling is suitable in certain materials
Options:
drive
drill and grout
composite e.g. drive-drill-drive
November 11, 2011
Page 21
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Mono-Pile Multi-Pile
L
D
L
D
s
Mono-Pile Foundations
Average ~89
hours per pile
at North Hoyle
November 11, 2011
Page 22
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Source http://www.rwe.com/web/cms/en/312104/rwe-innogy/sites/wind-offshore/in-operation/north-hoyle/construction-diary/wind-turbine-foundations/
Walney Wind Farm
November 11, 2011
Page 23
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Photos from Dong Energy: Christian LeBlanc Thilsted and Dan Kallehave
Pile Design Issues Wind Turbine
Stiffness is a key design criterion in addition to capacity.
Various offshore design approaches are based on much more flexible piles and are more concerned with lateral capacity than stiffness.
Typical offshore pile say L/D ~ 30 50 or more whilst wind-farm pile L/D ~ 4 - 8.
Are the usual design approaches still appropriate?
Performance under cyclic loading is important but there is very limited guidance for designers (if any at all)
Accumulated rotations? Stiffness response?
November 11, 2011
Page 24
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
November 11, 2011
Page 25
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Structural
configuration
L
D
H
e
D
L
V
Idealisation of
applied forces
H
M = He
V
D
d
L - d
Soil
reactions
00.2
0.4
0.6
0.8
1
1.2
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6
No
rma
lis
ed
Mo
me
nt
Normalised Horizontal Load
Static Tests
November 11, 2011
Page 26
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Cyclic loading
November 11, 2011
Page 27
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
M
0
MR
Real Loading Idealised Loading
Cyclic loading
November 11, 2011
Page 28
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
One Way Cycling Two Way
Cycling
M
0
MR
Min = 0Min < Max
Min = Max
November 11, 2011
Page 29
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Motor
Reaction Frame
Mass
Mass
Mass
Testing Equipment
November 11, 2011
Page 30
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Example Cyclic Loading Results
November 11, 2011
Page 31
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
-0.02
0
0.02
0.04
0.06
0.08
0.1
0.12
0 0.002 0.004 0.006 0.008 0.01 0.012
No
rma
lis
ed
Mo
me
nt
Normalised Rotation
Cycle 0 - 10 Cycle 1500 - 1510 Cycle 9050 - 9060
Definitions
Rotation
Min
Max
Moment
0 N
(N)
Normalised Accumulated Rotation
(N)
0
November 11, 2011
Page 32
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
0.01
0.1
1
10
1 10 100 1000 10000 100000
No
rma
lis
ed
Ac
cu
mu
late
d R
ota
tio
n
Number of Cycles
Test Results Accumulated Rotation
November 11, 2011
Page 33
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Analysis of Results
November 11, 2011
Page 34
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
0
1
2
3
4
5
-1 -0.5 0 0.5 1
Monotonic
Loading
One Way
Loading
Two Way
Loading
(N)
0
= f1 x f2 x Na
f2
Cyclic loading
November 11, 2011
Page 35
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
M
0
MR
Real Loading Idealised Loading
Cyclic loading
November 11, 2011
Page 36
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
M
0
MR
Idealised Loading
Real Loading1 + 2 + 3 =
00.0005
0.001
0.0015
0.002
0.0025
0.003
0 500 1000 1500 2000 2500 3000 3500
Ro
tati
on
(R
ad
ian
s)
Number of Cycles
Min
Max
Theory
Load A
Load B
Load C
Experiment Theory Comparison
November 11, 2011
Page 37
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
100
150
200
250
300
350
400
450
500
1 10 100 1000 10000 100000
No
rma
lis
ed
Sti
ffn
es
s
Cycle Number
Test Results Stiffness
November 11, 2011
Page 38
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Observations Mono-Pile Foundations
Framework for calculating accumulated rotation Change in stiffness could mean a change in structural natural
frequency serious factor in the fatigue design Scaling
Larger scale field tests or centrifuge tests
Actual field measurements from installed mono-piles
Larger number of cycles
Current tests only up to 100,000 cycles (i.e. around 7 to 10 days)
Do we need tests in the region of 100m cycles?
Effect of change in load direction
Loading is unlikely to be uni-directional
Is this more onerous?
Frequency effects / Excess pore water pressures
November 11, 2011
Page 39
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
**IMPORTANT** Field Monitoring
Data needed from installed piles!
Verify design calculations
Guidance for future designs
Database for the industry?
November 11, 2011
Page 40
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Data and photos from Dong Energy: Christian LeBlanc Thilsted and Dan Kallehave
Measured Strains
November 11, 2011
Page 41
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Data and photos from Dong Energy: Christian LeBlanc Thilsted and Dan Kallehave
0 5 10 15 20 25
Time [s]
Multi-Pile Foundations
Much more like typical oil and gas pile design
except
Any cyclic degradation of the axial response must be well understood
Mono-Pile Multi-Pile
L
D
L
D
s
November 11, 2011
Page 42
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Current designs Alpha Ventus
Bard Offshore 1
Beatrice
November 11, 2011
Page 43
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
FUTURE DESIGNS? SUCTION CAISSONS
November 11, 2011
Page 44
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Suction Caissons
Flow
Pressure differential
W
Flow
Source: Houlsby, G.T., Ibsen, L.B. and Byrne, B.W (2005) "Suction caissons for wind turbines",
Invited Theme Lecture, Proc. International Symposium on Frontiers in Offshore Geotechnics, Perth,
Australia, 19-21 September, Taylor and Francis, pp 75-94, ISBN 0415 39063 X
November 11, 2011
Page 45
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Caisson Foundations
Design Issues
Suction installation
Combined Loading (mono-caisson)
Vertical Loading (multi-caisson)
Research
Laboratory testing
Field scale testing
Theoretical investigations
Numerical modelling
Focus here is on work at Oxford
Mono-Caisson Multi-Caisson
L
Ds
L
D
November 11, 2011
Page 46
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Installation
Theoretical calculations for design (ICE Proceedings)
Separate calculations for sand and for clay
Self weight calculation and suction installation
In sand seepage gradients are important.
Beneficial reduction of the end bearing resistance
Penetration possible in very dense sand
Guidance on the limiting aspect ratios for both cases
More recent work on installation in layered soils
November 11, 2011
Page 47
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
0200
400
600
800
1000
1200
1400
0 5 10 15 20 25 30 35
Dis
pla
ce
me
nt (m
m)
Suction (kPa)
Field Installation - 3m diameter
November 11, 2011
Page 48
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Statoils Sleipner T (14m diameter)
0
1
2
3
4
5
6
0 20 40 60 80 100
Dep
th h
(m)
Required suction s (kPa)
Predicted suction
Range of measured suction
November 11, 2011
Page 49
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
COMBINED LOADING MONO-CAISSON STRUCTURE
November 11, 2011
Page 50
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Mobile met mast (Denmark, 2009) Source: LeBlanc, C. (2009). Design of offshore wind turbine support structures; selected
topics in the field of geotechnical engineering. PhD Thesis, Aalborg University.
November 11, 2011
Page 51
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
*Breaking News Oct 2011* Dogger Bank Met Masts
November 11, 2011
Page 52
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Source: Forewind website
Experimental equipment
November 11, 2011
Page 53
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Moment Loading at Low Vertical Load
-100
-80
-60
-40
-20
0
20
40
60
80
100
-2 -1.5 -1 -0.5 0 0.5 1 1.5 2
Rotational Displacement, 2R (mm)
Mo
me
nt
Lo
ad
, M
/2R
(N
)
November 11, 2011
Page 54
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Conventional approach:
effective area and inclination factors
November 11, 2011
Page 55
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
M
V
H
B
Q
B
e
V, M, H Q, e,
Source: G.T. Houlsby and R. Butterfield Gotechnique Lecture 2001
Q
B
e
Q
B
e
B' = B - 2e
Hardening Plasticity Models
The plasticity model requires
A yield surface to define
allowable load combinations
Hardening rule to define yield
surface expansion
Flow rules to define plastic
movements at yield
Elasticity expressions to define
pre-yield movements
M
V
H
2R
November 11, 2011
Page 56
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Source: G.T. Houlsby and R. Butterfield Gotechnique Lecture 2001
Moment Loading at Low Vertical Load
-100
-80
-60
-40
-20
0
20
40
60
80
100
-2 -1.5 -1 -0.5 0 0.5 1 1.5 2
Rotational Displacement, 2R (mm)
Mo
me
nt
Lo
ad
, M
/2R
(N
)
November 11, 2011
Page 57
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
00.05
0.1
0.15
0.2
0.25
-0.3 -0.2 -0.1 0 0.1 0.2 0.3
Dim
en
sio
nle
ss
Mo
me
nt,
M/(
'D4)
Dimensionless Vertical Load, V/( 'D3)
Range of potential designs for
monopod structures
Yield Points and Design Curves 1 (Sand)
November 11, 2011
Page 58
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
-0.35
-0.25
-0.15
-0.05
0.05
0.15
0.25
0.35
-0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5
No
n-D
ime
nsio
nal M
om
en
t, M
/(D
4)
No
n-D
ime
nsio
nal I
nc
rem
en
tal R
ota
tio
n,
Non-Dimensional Horizontal Load, H/ D3
Non-Dimensional Incremental Horizontal Displacement, u/D
Range of potential monopod designs
Yield Points and Design Curves 2 (Sand)
November 11, 2011
Page 59
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
-100
-80
-60
-40
-20
0
20
40
60
80
100
-1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1
Mo
me
nt
Lo
ad
, M
/2R
(N)
Rotational Displacement, 2R (mm)
Comparison of Theory to Experiment
November 11, 2011
Page 60
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Field Testing
Bothkennar
(clay)
Luce Bay
(sand)
November 11, 2011
Page 61
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Field Testing at Bothkennar
November 11, 2011
Page 62
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Moment loading
4000 4000 6000
30001500
H
H
HB
CC
A
RR
W
V
A
B
C
V
LL
L
L L LL
42
00
November 11, 2011
Page 63
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Moment tests at small and large rotations
Small
Large
November 11, 2011
Page 64
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
-30
-20
-10
0
10
20
30
-0.00005 -0.000025 0 0.000025 0.00005
Mo
men
t (k
Nm
)
Rotation (radians)
-600
-500
-400
-300
-200
-100
0
100
200
300
400
500
-0.03 -0.02 -0.01 0 0.01 0.02 0.03
Mo
men
t (k
Nm
)
Rotation (Radians)
02
4
6
8
10
12
14
16
0.00001 0.0001 0.001 0.01 0.1
G (
MP
a)
(radians)
Analysis of Results (Clay)
November 11, 2011
Page 65
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Moment Test Results (Clay)
November 11, 2011
Page 66
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
VERTICAL LOADING MULTI-CAISSON STRUCTURE
November 11, 2011
Page 67
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Multiple caissons: Draupner E platform Source: Andersen, K.H., Jostad, H.P. and Dyvik, R. (2008) "Penetration resistance of offshore skirted foundations
and anchors in dense sand", Proc ASCE Journal of Geotechnical and Geoenvironmental Engineering, Vol 134, No 1,
pp 106 - 116.
November 11, 2011
Page 68
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Tripod or tetrapod?
Tower
Tower
Tower
(a) (b) (c)
November 11, 2011
Page 69
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Vertical Loading Tests (in a Pressure Vessel)
November 11, 2011
Page 70
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
-400
-200
0
200
400
600
800
1000
1200
1400
200 210 220 230 240 250 260 270
Ve
rtic
al s
tre
ss (
kP
a)
Displacement (mm)
Cyclic Vertical Loading (Sand)
November 11, 2011
Page 71
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Vertical Loading Tests (Sand)
Com
pre
ssio
n
Tension
November 11, 2011
Page 72
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
-450
-400
-350
-300
-250
-200
-150
-100
-50
0
150 160 170 180 190 200 210
Ve
rtic
al s
tre
ss
(k
Pa
)
Displacement (mm)
Direction of movement
SLOW
FAST
FAST + PRESSURE
Capacity on tensile loading (Sand)
November 11, 2011
Page 73
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Observations Caisson Foundations
Significant body of work available for development of designs
Both mono-caisson and multi-caisson structures can make contributions to offshore wind
Suitable to a range of soil conditions
but not all
Initial structures must be monitored
To enable a better understanding of the foundation performance
To understand the limitations
To reduce conservatism
November 11, 2011
Page 74
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Concluding Comments
Mono-piles will continue to be used in the short-term
Better understanding of long term cyclic loading needed
Better understanding of stiffness of response also needed?
Suction caissons could be used for offshore wind turbines
A new technology will help to drive down costs
No pile-driving noise to worry about!
Field monitoring of structures and foundations is essential
Instrumentation relatively inexpensive
Valuable information will lead to better design guidance
and more confidence in new and improved designs
November 11, 2011
Page 75
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Acknowledgements
The co-authors of the various papers covered in this lecture
Prof Guy Houlsby (Oxford University)
Dr Christian LeBlanc Thilsted (Dong Energy)
Dr Richard Kelly (Coffey Geotechnics, Australia)
John Huxtable (formerly Fugro, now at Doosan)
Dr Chris Martin collaborated on the shallow foundation work A number of Colleagues at Oxford and elsewhere
Sponsors included EPSRC, DTI, Royal Society Industry participants for the caisson work included SLP
Engineering, Fugro, Garrad Hassan, GE Wind, NEG Micon, Shell Renewables, HR Wallingford.
Dong Energy for information and photos related to Walney
November 11, 2011
Page 76
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Gotechnique Papers
1. Response of stiff piles to random two-way lateral loading.
Gotechnique 60 9:715-721.
2. Response of stiff piles to long term cyclic loading.
Gotechnique 60 2: 79-90.
3. Transient vertical loading of model suction caissons in a pressure chamber.
Gotechnique 56 10: 665-675.
4. A comparison of field and laboratory caisson tests in sand and clay.
Gotechnique 56 9: 617-626.
5. Field trials of suction caissons in sand for offshore wind turbine foundations.
Gotechnique 56 1: 3-10.
6. Field trials of suction caissons in clay for offshore wind turbine foundations.
Gotechnique 55 4: 287-296. Contact byron.byrne@eng.ox.ac.uk for further information.
November 11, 2011
Page 77
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Blyth Scroby Sands
Barrow
North Hoyle
November 11, 2011
Page 78
Dr Byron Byrne
Gotechnique Lecture 2011
Foundation Design for Offshore Wind Turbines
Walney
Source Various websites
Recommended