Breakwaters day 1 - introduction
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Transcript of 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 85P.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: [email protected]
www.royalhaskoning.com
Contact detailsContact details
33BreakwatersBreakwatersFebruary 2011February 2011
BREAKWATERSBREAKWATERS
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)
44BreakwatersBreakwatersFebruary 2011February 2011
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
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Vertical Wall BreakwatersVertical Wall Breakwaters
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
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Vertical Wall BreakwatersVertical Wall Breakwaters
DAY 1 - INTRODUCTION
• Information (readers)
• Functions
• Types
• Problem definition
• Design methods (intro)
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Vertical Wall BreakwatersVertical Wall Breakwaters
ReadersIn 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.
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Vertical Wall BreakwatersVertical Wall Breakwaters
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)
99BreakwatersBreakwatersFebruary 2011February 2011
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
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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)
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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)
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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 unitsThis type is used in shallow water. The mound reduces wave reflection, wave impact and wave overtoppingRepair of displaced vertical breakwaters (day 2) Used when a (deep) quay is required at the inside of rubble mound breakwater
Gela (Sicily, Italy)
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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)
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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)
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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 reduced
Dieppe (France)
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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)
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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)
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Vertical Wall Breakwaters - Vertical Wall Breakwaters - TypesTypes
• TYPES (continued)
• “Combi-caisson”
Sloping top
Semi-circular/perforated
Perforated front wall
Perforated rear wall
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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
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Vertical Wall Breakwaters - Vertical Wall Breakwaters - Problem definitionProblem definition
Functional requirements
• Access
• Quay facilities
• Overtopping
• Transmission
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Vertical Wall Breakwaters - Vertical Wall Breakwaters - Problem definitionProblem definition
Requirements: acces (pedestrians, supply traffic)
Piraeus (Greece)
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Vertical Wall Breakwaters - Vertical Wall Breakwaters - Problem definitionProblem definition
Requirements: acces (harbour workers, traffic, oil piping)
Marsaxlokk (Malta)
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Vertical Wall Breakwaters - Vertical Wall Breakwaters - Problem definitionProblem definition
Requirements: acces (harbour workers, traffic, LNG piping)
Ras Laffan (Qatar)
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Vertical Wall Breakwaters - Vertical Wall Breakwaters - Problem definitionProblem definition
Requirements: acces (harbour workers, traffic, conveyors)
Porto Torres (Sicily, Italy)
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Vertical Wall Breakwaters - Vertical Wall Breakwaters - Problem definitionProblem definition
Requirements: quay facilities (access, warehouses, sheds)
Constantza Port (Romania)
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Vertical Wall Breakwaters - Vertical Wall Breakwaters - Problem definitionProblem definition
Requirements: quay facilities (access, warehouses, sheds)
Durres Port (Albania)
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Vertical Wall Breakwaters - Vertical Wall Breakwaters - Problem definitionProblem definition
Requirement: limit overtopping and transmission
Marina do Lugar de Baixo (Madeira, Portugal)
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Vertical Wall Breakwaters - Vertical Wall Breakwaters - Loads and resistanceLoads and resistance
Loads and resistanceLoads:
• Hydraulic loads• Weight
Resistance:
• Friction (mostly)• Soil bearing capacity
FH
W
U
FH
W
U
F Hf W U( )
SF M F H
W t M u
SF
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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 Hf W U( )
SF M F H
W t M u
SF 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
UErosion Scour
F Hf W U( )
SF
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Vertical Wall Breakwaters - Vertical Wall Breakwaters - Loads and resistanceLoads and resistance
Example overall failure: Mutsu Ogawara Port, East Breakwater (Japan)
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Vertical Wall Breakwaters - Vertical Wall Breakwaters - Loads and resistanceLoads and resistance
Example local failure: Catania Breakwater (Sicily, Italy)
3434BreakwatersBreakwatersFebruary 2011February 2011
Vertical Wall Breakwaters - Vertical Wall Breakwaters - Design methods (intro)Design methods (intro)
Impression of hydraulic forces (field)
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Vertical Wall Breakwaters - Vertical Wall Breakwaters - Design methods (intro)Design methods (intro)
Hydraulic Forces (laboratory)
3636BreakwatersBreakwatersFebruary 2011February 2011
Vertical Wall Breakwaters - Vertical Wall Breakwaters - Design methods (intro)Design methods (intro)
Hydraulic Forces (laboratory)
iCam optical sensor (Deltaflume Deltares)
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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)
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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)
3939BreakwatersBreakwatersFebruary 2011February 2011
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)
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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
4141BreakwatersBreakwatersFebruary 2011February 2011
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)
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PROVERBS Definition of geometric parameters
hs
d h1Bb
hrhb
1:mBeq
dc
Bc
hc hf
Rc
Vertical Wall Breakwaters - Vertical Wall Breakwaters - Design methods (intro)Design methods (intro)
αα
Lhs
Hs Hb
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Vertical Wall Breakwaters - Vertical Wall Breakwaters - Design methods (intro)Design methods (intro)
• PROVERBS parameter map (also PIANC WG 28)
Beq = Bb + 0.5∙m ∙ hb
4444BreakwatersBreakwatersFebruary 2011February 2011
Vertical Wall Breakwaters - Vertical Wall Breakwaters - Design methodsDesign methods
• PROVERBS parameter map
Beq = Bb + 0.5∙m ∙ hb
4545BreakwatersBreakwatersFebruary 2011February 2011
Vertical Wall Breakwaters - Vertical Wall Breakwaters - Design methodsDesign methods
Beq = Bb + 0.5∙m ∙ hb
4646BreakwatersBreakwatersFebruary 2011February 2011
Vertical Wall Breakwaters - Vertical Wall Breakwaters - Design methodsDesign methods
Beq = Bb + 0.5∙m ∙ hb
4747BreakwatersBreakwatersFebruary 2011February 2011
Vertical Wall Breakwaters - Vertical Wall Breakwaters - Design methodsDesign methods
Beq = Bb + 0.5∙m ∙ hb
4848BreakwatersBreakwatersFebruary 2011February 2011
Vertical Wall Breakwaters - Vertical Wall Breakwaters - Design methods (intro)Design methods (intro)
Example: Sakata Detached Breakwater (Japan)
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Vertical Wall Breakwaters - Vertical Wall Breakwaters - Design methods (intro)Design methods (intro)
Example: Sakata Detached Breakwater (Japan)
Hs
hs0.65
hb
hs0.541
Hs 5.85mhb 4.87mhs 9m
hb ELberm ELbottomHeight of berm:
Hs 0.65 hsDesign wave height
hs ELwater ELbottomDesign depth
ELberm 3.63 mBerm elevation
ELwater 0.5 mDesign water level
ELbottom 8.5 mBottom elevation
5050BreakwatersBreakwatersFebruary 2011February 2011
Vertical Wall Breakwaters - Vertical Wall Breakwaters - Design methodsDesign methods
Beq = Bb + 0.5∙m ∙ hb
5151BreakwatersBreakwatersFebruary 2011February 2011
Vertical Wall Breakwaters - Vertical Wall Breakwaters - Design methods (intro)Design methods (intro)
Example: Sakata Detached Breakwater (Japan)
What in case of low mound?
Hs
hs0.65
hb
hs0.208
Hs 5.85mhb 1.87mhs 9m
hb ELberm ELbottomHeight of berm:
Hs 0.65 hsDesign wave height
hs ELwater ELbottomDesign depth
ELberm 6.63 mBerm elevation
ELwater 0.5 mDesign water level
ELbottom 8.5 mBottom elevation
5252BreakwatersBreakwatersFebruary 2011February 2011
Vertical Wall Breakwaters - Vertical Wall Breakwaters - Design methodsDesign methods
• PROVERBS parameter map
Beq = Bb + 0.5∙m ∙ hb
5353BreakwatersBreakwatersFebruary 2011February 2011
Vertical Wall Breakwaters - Vertical Wall Breakwaters - Design methods (intro)Design methods (intro)
Hydraulic Forces: evaluation of wave breaking
Sainflou Goda PROVERBSGoda (extended)
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