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2. What is Breakwater?
Breakwater is a structure that protects the area within it from wave
attack.
What’s the Need of Breakwater?
To provide shelter from waves.
Through this shelter, to manipulate the littoral/sand transport conditions and
thereby to trap some sand entrance inside the Anchorage Area.

3.  Availability of materials of construction.
 Depth of water at site of construction.
 Nature of natural foundations.
 Equipment available for construction.
 Funds and time available for construction.

4. Rubble mound breakwaters (Conventional Type)
Vertical wall/front breakwaters ( Widely Used)
Reef breakwaters
Rarely used
(Based on the Materials
Piled breakwaters Available on Nearby Site)

5. Objectives :-
 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 ie, on basis of material
usage

6. FUNCTIONS
 Wave protection in port/channel
 Protection from siltation,
currents
 Tsunami protection
 Berthing facilities
 Access/transport facility
Ras Gijon (Malta)
Laffan (Qatar)
Marsaxlokk (Spain)
IJmuiden (Netherlands)
Kamaishi (Japan)

7. TYPES
(breakwaters with vertical and inclined
concrete walls)
 Conventional type
The caisson is placed on a relatively
thin stone bedding.
Advantage of this type is the minimum
use of natural rock (in case scarce)
Mutsu-Ogawara (Japan)
Wave walls are generally placed on
shore connected caissons (reduce
overtopping)

8. TYPES (continued)
 Vertical composite type
The caisson is placed on a high rubble
foundation.
This type is economic in deep waters,
but requires substantial volumes of
Algeciras (Spain) (small size) rock fill for foundation

9. TYPES (continued)
 Horizontal composite type
The front slope of the caisson is covered by
armour units
Gela (Sicily, Italy)
This type is used in shallow water. The mound
reduces wave reflection, wave impact and wave
overtopping
Repair of displaced vertical breakwaters
Used when a (deep) quay is required at the
inside of rubble mound breakwater

10. TYPES (continued)
 Block type
Alderney (Guernsey, UK)
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

11. TYPES (continued)
 Piled breakwater with concrete
wall
Piled breakwaters consist of an
Manfredonia New Port (Italy)
inclined or vertical 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.

12. 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
Napels (Italy)
vertical wall with equal level.

13. TYPES (continued)
 Perforated front wall
The front wall is perforated by holes
or slots with a wave chamber behind.
Dieppe (France)
Due to the dissipation of energy both
the wave forces on the caisson and the
wave reflection are reduced

14. TYPES (continued)
 Semi-circular caisson
Well suited for shallow water
situations with intensive wave breaking
Miyazaki Port (Japan)
Due to the dissipation of energy both
the wave forces on the caisson and the
wave reflection are reduced

15. TYPES (continued)
 Dual cylindrical caisson
Outer permeable and inner
impermeable cylinder.
Low reflection and low permeable
Nagashima Port (Japan)
Centre chamber and lower ring
chamber fills with sand

16.  TYPES (continued)
 “Combi-caisson”
Sloping top
Semi-circular/perforated
Perforated front wall
Perforated rear wall

17. What is needed?
 Proper understanding of functional requirements
 Proper understanding of loads and resistance
 Insight in failure modes
 Understanding of breaking/non-breaking waves

18. Functional requirements
Access
Quay facilities
Overtopping
Transmission

19. Requirements: acces (pedestrians, supply traffic)
Piraeus (Greece)

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

21. Requirements: acces (harbour workers, traffic, Liquefied
Natural Gas (LNG) piping)
Ras Laffan (Qatar)

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

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

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

25. Requirement: limit overtopping and transmission
of water
Marina do Lugar de Baixo (Madeira, Portugal)

26. Vertical Wall Breakwaters - Loads and
resistance
Loads and resistance
Loads: Resistance:
 Hydraulic loads  Friction (mostly)
 Weight  Soil bearing capacity

27. Vertical Wall Breakwaters - Loads and
resistance
Failure modes (overall)
Hydraulic failure
Sliding Overturning
U

28. Vertical Wall Breakwaters - Loads and
resistance
Failure modes (local)
Instability of mound Erosion of seabed Partial
Instability
Erosion Scour
U

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

30. Example local failure: Catania Breakwater (Sicily, Italy)

31. Advantages:- Disadvantages:-
Easy to repair. Construction cost is high.
Protects the shore. Can be easily displaced by waves.
Functions after minor damage. Don’t absorb all energy due to the gaps
Don’t disturb the shoreline. between breakwater.
Aesthetically seems to be bad.

32. Protection of the Ports or Harbors from the Natural Calamities such as
Tsunami is essential. But exact prediction of Natural Calamities is not
possible, but some extent of it can be prevented by Breakwater
Construction.
Protection of the Ports or Harbors from the Siltation & Wave Action is
done by providing a economical & suitable type of Breakwaters.
Instead of using Armor Blocks the Sand Bags may be used to Protect or
Safe Guard the Shores to some extent . Shore Protection in Quatar

33. Indian Standard Code of practice for planning and design of ports and
harbours part 4 general design considerations [Third Revision of IS 4651 (Part
4)].
PIANC; Breakwaters with Vertical and Inclined Concrete Walls, Report WG 28,
2003.
US Army Corp of Engineers. 1985. Shore Protection Manual. Washington,
D.C., US Army Corp of Engineers.