Breakwaters day 1 - introduction

BREAKWATERSBREAKWATERS
ByBy
J.W. van der Meer, PhD. CEJ.W. van der Meer, PhD. CE
J.C. van der Lem MSc. CEJ.C. van der Lem MSc. CE
ROYAL HASKONING

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

33
BreakwatersBreakwaters
February 2011February 2011
SUBJECTS
• Rubble mound breakwaters (J.W. van der Meer)
• Vertical wall breakwaters (J.C. van der Lem)
• Berm breakwaters (J.W. van der Meer)
• Submerged breakwaters (J.W. van der Meer)

44
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

55
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

66
DAY 1 - INTRODUCTION
• Information (readers)
• Functions
• Types
• Problem definition
• Design methods (intro)

77
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.

88
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)

99
Gijon (Spain)IJmuiden (Netherlands)Kamaishi (Japan)Marsaxlokk (Malta)Ras Laffan (Qatar)
Vertical Wall Breakwaters -Vertical Wall Breakwaters - FunctionsFunctions
FUNCTIONS
• Wave protection in
port/channel
• Protection from siltation,
currents
• Tsunami protection
• Berthing facilities
• Access/transport facility

1010
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)

1111
TYPES (continued)
• Vertical composite
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)

1212
TYPES (continued)
• Horizontal composite
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)

1313
TYPES (continued)
• Block type
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)

1414
TYPES (continued)
• Piled breakwater with
concrete wall
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)

1515
TYPES (continued)
• Sloping top
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)

1616
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)

1717
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)

1818
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)

1919
• TYPES (continued)
• “Combi-caisson”
Sloping top
Semi-circular/perforated
Perforated front wall
Perforated rear wall

2020
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

2121
Functional requirements
• Access
• Quay facilities
• Overtopping
• Transmission

2222
Requirements: acces (pedestrians, supply traffic)
Piraeus (Greece)

2323
Requirements: acces (harbour workers, traffic, oil piping)
Marsaxlokk (Malta)

2424
Requirements: acces (harbour workers, traffic, LNG piping)
Ras Laffan (Qatar)

2525
Requirements: acces (harbour workers, traffic, conveyors)
Porto Torres (Sicily, Italy)

2626
Requirements: quay facilities (access, warehouses, sheds)
Constantza Port (Romania)

2727
Requirements: quay facilities (access, warehouses, sheds)
Durres Port (Albania)

2828
Requirement: limit overtopping and transmission
Marina do Lugar de Baixo (Madeira, Portugal)

2929
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
≤

3030
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<

3131
Failure modes (local)
Instability of mound Erosion of seabed Partial
Instability
U
Erosion Scour
F H
f W U−( )⋅
SF
≤

3232
Example overall failure: Mutsu Ogawara Port, East Breakwater (Japan)

3333
Example local failure: Catania Breakwater (Sicily, Italy)

3434
Vertical Wall Breakwaters -Vertical Wall Breakwaters - Design methods (intro)Design methods (intro)
Impression of hydraulic forces (field)

3535
Hydraulic Forces (laboratory)

3636
Hydraulic Forces (laboratory)
iCam optical sensor (Deltaflume Deltares)

3737
• 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)

3838
• 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)

3939
• 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)

4040
• 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

4141
Hydraulic Forces
• Differentiate between non-breaking and breaking waves
• Identification of types of horizontal loading by means of the
PROVERBS parameter map (distribute)

4242
PROVERBS Definition of geometric parameters
hs
d h1
Bb
hr
hb
1:m
Beq
dc
Bc
hc hf
Rc
αα
Lhs
Hs Hb

4343
• PROVERBS parameter map (also PIANC WG 28)
Beq = Bb + 0.5∙m ∙ hb

4444
Vertical Wall Breakwaters -Vertical Wall Breakwaters - Design methodsDesign methods
• PROVERBS parameter map
Beq = Bb + 0.5∙m ∙ hb

4545
Beq = Bb + 0.5∙m ∙ hb

4646
Beq = Bb + 0.5∙m ∙ hb

4747
Beq = Bb + 0.5∙m ∙ hb

4848
Example: Sakata Detached Breakwater (Japan)

4949
Hs
hs
0.65=
hb
hs
0.541=
Hs 5.85m=hb 4.87m=hs 9m=
hb ELberm ELbottom−:=Height of berm:
Hs 0.65 hs⋅:=Design wave height
hs ELwater ELbottom−:=Design depth
ELberm 3.63− m⋅:=Berm elevation
ELwater 0.5 m⋅:=Design water level
ELbottom 8.5− m⋅:=Bottom elevation

5050
Beq = Bb + 0.5∙m ∙ hb

5151
What in case of low mound?
Hs
hs
0.65=
hb
hs
0.208=
Hs 5.85m=hb 1.87m=hs 9m=
hb ELberm ELbottom−:=Height of berm:
Hs 0.65 hs⋅:=Design wave height
hs ELwater ELbottom−:=Design depth
ELberm 6.63− m⋅:=Berm elevation
ELwater 0.5 m⋅:=Design water level
ELbottom 8.5− m⋅:=Bottom elevation

5252
• PROVERBS parameter map
Beq = Bb + 0.5∙m ∙ hb

5353
Hydraulic Forces: evaluation of wave breaking
Sainflou Goda PROVERBSGoda (extended)

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

Breakwaters day 1 - introduction

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