The document discusses different types of breakwaters used to protect coastal areas from wave attack. It describes rubble mound breakwaters, vertical-wall breakwaters, and floating breakwaters. Rubble mound breakwaters are constructed from natural rubble or stone and dissipate wave energy through breaking. Vertical-wall breakwaters use a vertical wall structure and reflect wave energy. Floating breakwaters are removable structures constructed from caissons or pontoons that are anchored but less effective against long waves. The document provides details on the characteristics, uses, advantages, and disadvantages of each type of breakwater.

1. BREAKWATERS
A structure that protects the area within it from wave
attack.

2. Breakwater
• 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. Basis in selecting a type of
breakwater.
• Availability of materials of constructions
• Depth of water at site of construction
• Nature of natural foundation
• Equipment available for construction
• Funds and time available for construction

4. Breakwater types
• Rubble Mound Breakwaters
• Vertical-Wall Breakwaters
• Floating Breakwaters

5. Rubble Mound Breakwater
• A breakwater constructed by a heterogeneous assemblage of natural
rubble or undressed stone.
• When water depths are large RBW may be uneconomical in view of huge
volume of rocks required.
• Built up to water depth of 50m.
• Not suitable when space is a problem. If the harbor side may have to be
used for berthing of ships, the RBW with its sloping faces is not suitable for
berthing.
• These type of breakwaters dissipate the incident wave energy by forcing
them to break on a slope and thus do not produce appreciable reflection.

6. STRUCTURAL COMPONENT
• Constructed by natural rubble or undressed stones.
• Comparatively safe.
• Has a broad base which helps in distributing the load on a wider area.
• Consists of central portion called core, protective cover called Armour layer and in
between is the under layer.

7. Advantages of RMBW
• Use of natural material
• Reduces material cost
• Use of small construction equipment
• Less environmental impact
• Most widely used in Indian ports
• Easy to construct
• Failure is mainly due to poor interlocking capacity
between individual blocks
• Unavailability of large size natural rocks leads to
artificial armour blocks .

8. Vertical Breakwater
• A breakwater formed by the construction in a
regular and systematic manner of a vertical wall of
masonry concrete blocks or mass concrete, with
vertical and seaward face.
• Reflect the incident waves without dissipating
much wave energy.
• Normally it is constructed in locations where the
depth of the sea is greater than twice the design
wave height.

9. Preferred to VBW for
following reasons:
• Saving in material due to smaller body width.
• Rapidity in construction.
• Non availability of large quantities of stones.
• Occupies less space.

10. Definition sketch

11. Disadvantage of VWBW
• Sea bottom has to be levelled and prepared for
placements of large blocks or caissons.
• Foundations made of fine sand may cause erosion and
settlement.
• Erosion may cause tilting or displacement of large
monoliths.
• Difficult and expensive to repair.
• Building of caissons and launching or towing them into
position require special land and water areas beside
involvement of heavy construction equipments.
• Require form work, quality concrete, skilled labour,
batching plants and floating crafts.

12. Floating Breakwater
• A removable breakwater constructed by caissons
or pontoons with valves for trimming whilst afloat
and for sinking when is position and pump
connections for refloating, moored to the sea bed.
• inexpensive, easily moved from site to site, often
very quickly fabricated.
• ineffective to long waves, must be anchored.

13. Types of Floating
Breakwaters
TYPICAL FLOATING BREAKWATERS

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

15. -Ernel Gonzaga
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