2. J.C. (Cock) van der Lem M.Sc.
Sr. Port Engineer
Maritime Advisory Group Rotterdam
Haskoning Nederland B.V.
a company of Royal Haskoning
George Hintzenweg 85
P.O.Box 8520
3009 AM Rotterdam
The Netherlands
tel. +31-(0)10-4433666
direct +31-(0)10-4433722
mobile +31-(0)6-15006372
fax. +31-(0)10-4433688
e-mail: C.vanderLem@RoyalHaskoning.com
www.royalhaskoning.com
Contact detailsContact details
4. 44
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Vertical Wall BreakwatersVertical Wall Breakwaters
Objectives (end of the course)
• To be able to make an assessment of hydraulic
loads against caisson breakwater
• To be able to make a preliminary design of a
caisson breakwater (length, width, height)
• To be able to compare caisson breakwater against
rubble mound breakwater
5. 55
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CONTENTS
• Day 1 – Introduction, set the problem
• Day 2 – PROVERBS parameter map (exercise) &
design methods (functional requirements)
• Day 3 – Design methods (static analysis)
• Day 4 – Design methods (dynamic analysis)
• Day 5 – Worked example
7. 77
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Readers
In lecture notes/distributed:
• Y. Goda, Ch. 4 Design of Vertical Breakwaters
(from: Random Seas and Design of Maritime Structures.
1985)
• S. Takahashi, Design of Vertical Breakwaters
(Short Coarse, ICCE, 1996)
• PIANC; Breakwaters with Vertical and Inclined Concrete
Walls, Report WG 28, 2003
• G. Cuomo: Wave impacts on vertical sea walls & caisson
breakwaters. PIANC On Course Magazine 127 van Mei
2007.
8. 88
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Readers (continued)
Separate:
• PowerPoint presentations (el. platform)
• PIANC WG 28 sub-group reports (el.
platform)
• Overtopping manual:
www.overtopping-manual.com
Additional reading:Additional reading:
• Oumeraci, H. et. al.; Probabilistic Design
Tools for Vertical Breakwaters
(PROVERBS), February 2001
(ISBN 09 5809 248 8 / 249 6)
• Coastal Engineering Manual
• The Rock Manual
• Breakwat (Deltares formerly WL|Delft Hydraulics)
10. 1010
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TYPES
(breakwaters with vertical and
inclined concrete walls)
• Conventional
Vertical Wall Breakwaters -Vertical Wall Breakwaters - TypesTypes
The caisson is placed on a
relatively thin stone bedding.
Advantage of this type is the
minimum use of natural rock (in
case scarse)
Wave walls are generally placed on
shore connected caissons (reduce
overtopping)Mutsu-Ogawara (Japan)
11. 1111
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TYPES (continued)
• Vertical composite
Vertical Wall Breakwaters -Vertical Wall Breakwaters - TypesTypes
The caisson is placed on a high
rubble foundation.
This type is economic in deep
waters, but requires substantial
volumes of (small size) rock fill
Algeciras (Spain)
12. 1212
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TYPES (continued)
• Horizontal composite
Vertical Wall Breakwaters -Vertical Wall Breakwaters - TypesTypes
The front slope of the caisson is covered
by armour units
This type is used in shallow water. The
mound reduces wave reflection, wave
impact and wave overtopping
Repair of displaced vertical breakwaters
(day 2)
Used when a (deep) quay is required at the
inside of rubble mound breakwater
Gela (Sicily, Italy)
13. 1313
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TYPES (continued)
• Block type
Vertical Wall Breakwaters -Vertical Wall Breakwaters - TypesTypes
This type of breakwater needs to
be placed on rock sea beds or on
very strong soils due to very high
foundation loads and sensitivity to
differential settlements
Alderney (Guernsey, UK)
14. 1414
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TYPES (continued)
• Piled breakwater with
concrete wall
Vertical Wall Breakwaters -Vertical Wall Breakwaters - TypesTypes
Piled breakwaters consist of an
inclined or curtain wall mounted
on pile work.
The type is applicable in less
severe wave climates on site with
weak and soft subsoils with very
thick layers.
Manfredonia New Port (Italy)
15. 1515
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TYPES (continued)
• Sloping top
Vertical Wall Breakwaters -Vertical Wall Breakwaters - TypesTypes
The upper part of the front slope
above still water level is given a
slope to reduce wave forces and
improve the direction of the wave
forces on the sloping front.
Overtopping is larger than for a
vertical wall with equal level.Napels (Italy)
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Vertical Wall Breakwaters -Vertical Wall Breakwaters - TypesTypes
TYPES (continued)
• Perforated front wall
The front wall is perforated by
holes or slots with a wave chamber
behind.
Due to the dissipation of energy
both the wave forces on the
caisson and the wave reflection are
reducedDieppe (France)
17. 1717
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Vertical Wall Breakwaters -Vertical Wall Breakwaters - TypesTypes
TYPES (continued)
• Semi-circular caisson
Well suited for shallow water
situations with intensive wave
breaking
Due to the dissipation of energy
both the wave forces on the
caisson and the wave reflection are
reducedMiyazaki Port (Japan)
18. 1818
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Vertical Wall Breakwaters -Vertical Wall Breakwaters - TypesTypes
TYPES (continued)
• Dual cylindrical caisson
Outer permeable and inner
impermeable cylinder.
Low reflection and low permeable
Centre chamber and lower ring
chamber filles with sand
Nagashima Port (Japan)
20. 2020
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Vertical Wall Breakwaters -Vertical Wall Breakwaters - Problem definitionProblem definition
What is needed?
• Proper understanding of functional requirements
• Proper understanding of loads and resistance
• Insight in failure modes
• Understanding of breaking/non-breaking waves
29. 2929
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Vertical Wall Breakwaters -Vertical Wall Breakwaters - Loads and resistanceLoads and resistance
Loads and resistance
Loads:
• Hydraulic loads
• Weight
Resistance:
• Friction (mostly)
• Soil bearing capacity
FH
W
U
FH
W
U
F H
f W U−( )⋅
SF
≤ M F H( )
W t⋅ M u−
SF
≤
30. 3030
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Vertical Wall Breakwaters -Vertical Wall Breakwaters - Loads and resistanceLoads and resistance
Failure modes (overall)
Hydraulic failure Geotechnical
failure
Sliding Overturning Slip
FH
W
U
FH
W
U
FH
W
U
Planar
slip
Circular slip
Earthquake loading:
LIQUEFACTION
F H
f W U−( )⋅
SF
≤ M F H( )
W t⋅ M u−
SF
≤ τ τ max<
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Vertical Wall Breakwaters -Vertical Wall Breakwaters - Loads and resistanceLoads and resistance
Failure modes (local)
Instability of mound Erosion of seabed Partial
Instability
U
Erosion Scour
F H
f W U−( )⋅
SF
≤
37. 3737
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Vertical Wall Breakwaters -Vertical Wall Breakwaters - Design methods (intro)Design methods (intro)
• Aerated impact
• The wave breaks before reaching the wall
• Air pocket entrapped in the water not on
the wall
• Pressure varies gradually in time in phase
with wave elevation
iCam optical sensor (Deltaflume Deltares)
38. 3838
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Vertical Wall Breakwaters -Vertical Wall Breakwaters - Design methods (intro)Design methods (intro)
• Air pocket impact
• The wave breaks closer to the wall
• A large air pocket is entrapped against
the wall
• Large peak force by crest hitting wall
• Followed by small force oscillations
• Duration of the pressure peak: O(0.01 s)
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Vertical Wall Breakwaters -Vertical Wall Breakwaters - Design methods (intro)Design methods (intro)
• Flip through impact
• Forward moving wave crest and rising
wave trough converge at same impact
point
• No air pocket entrapped against the wall
• Large peak force by crest hitting wall
accelating into vertical jet
• Very short duration of impacts O(0.01 s)
40. 4040
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Vertical Wall Breakwaters -Vertical Wall Breakwaters - Design methods (intro)Design methods (intro)
• Slosh impact
• Rising wave trough arrives at
convergence point way before forward
moving crest
• No air pocket entrapped against the wall
• Small forces with long durations
41. 4141
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Vertical Wall Breakwaters -Vertical Wall Breakwaters - Design methods (intro)Design methods (intro)
Hydraulic Forces
• Differentiate between non-breaking and breaking waves
• Identification of types of horizontal loading by means of the
PROVERBS parameter map (distribute)
54. BREAKWATERSBREAKWATERS
To be continued…..To be continued…..
((distribute PIANC WG 28 cases and PROVERBS mapdistribute PIANC WG 28 cases and PROVERBS map))
Homework: read the PIANC WG 28 caseHomework: read the PIANC WG 28 case
Next course: bring PIANC case, Proverbs map & calculatorNext course: bring PIANC case, Proverbs map & calculator
Notas del editor
North Eastern port of Japan, facing the Pacific Ocean Construction started in 1983 Length of some 1800 m Partially completed by beginning 1991, but also part under construction In February 1991 high waves struck breakwater during winter depression (968 mbar), i.e. not by a typhoon. Damage at three locations along the breakwater H s = 6.9 to 7.6 m H max = 12.1 to 13.2 m T1/3 = 13 s Method: Goda γ sliding = 1.35 – 2.16 γ overturning = 2.60 – 4.54 Damage (finished section) Caissons displaced (some up to 6 m) Caisson walls broken Wave dissipating blocks scattered and inside caisson! Scour Damage (part under construction): 17 caissons displaced some up to 5 m Measured waves: H s = 9.94 m, T 1/3 = 13.4 s. Cause of damage: Waves beyond design wave Scattering of wave dissipating blocks
North Western part of Japan, facing the Japan Sea Construction in 1972/1973 Length of some 1800 m In winter 1973/1974 sliding occurred. Damage at three locations along the breakwater H s = 5.9 m H max = 8.1 m T1/3 = 10.5 s Method: Hiroi γ sliding = some sections ≤1. γ overturning = ≥ 1.3 Damage (finished section) Caissons displaced (some up to 6 m) Caisson walls broken Wave dissipating blocks scattered and inside caisson! Scour Damage (part under construction): 17 caissons displaced some up to 5 m Measured waves: H s = 4.3 to 5.8 m, T 1/3 = 13.4 s. Cause of damage: Insufficient knowledge of impacting breaking waves
