4. Most easy designing and construction
Deflect waves ,loose rubbles absorb
energy
Advantages
Disadvantages
1. Can be under cut by high wave energy environment
2. Not efficient in long term
3. Prone to expensive damage
Vertical type
5. Advantage
1. Prevent overtopping the w
2. low reflected waves and much
3. reduced turbulence
Disadvantage
1.More complex design process.
2.can scour material at the base of the wall causing them to
become undermined
Round type
6. Advantages
1.Current designs use porous designs of rock, concrete armour.
2.Slope and loose material ensure maximum dissipation of wave
energy.
3.Lower cost option
Disadvantages
1.Less durable.
2.Shorter life expectancy.
3.Cannot withstand or protect from high-energy conditions effectively
Mound type
7. Functions
Primary functions
Accessory function
• Retaining soil and
surcharge loads behind
wall .
• Protection of shoreline
from wave loads
• Protect frontline beaches
from storm surges,
shoreline erosion and
wave overtopping.
• Habitate for a variety of
fauna
8. Design consideration
• Direct wave force action
• Uplift force imposed by wave action
• Wave overtopping
• Storm surge
• Toe scour
9. • The uplift force imposed by wave action is
an important factor that is frequently
neglected by design professionals .
• Leads to instability and undermines the
longevity of the Sea Wall structure
13. Sea Wall Systems
• System A: Gravity Wall
• System B: L-Shaped Wall with Buttresses
• System C: L-Shaped Wall with Buttresses
Supported by Piles
• System D: Diaphragm Wall System with
Horizontally Spun Wall
• System E: Soldier Pile System with Horizontally
Spun Wall and Tie Back Anchors (Modified
Bulkhead Approach)
14. System A: Gravity Wall
• It is extremely costly to build, especially when wall height
dictates significant development of the wall base
• Requires consideration of significant wave generated
uplift force
• Relies heavily upon the weight of the wall when that
weight significantly decreases due to buoyancy effect
15. continue
• Requires a very stiff base that can prevent
wall settlement, tilting or heavy toe scour
that affects wall integrity and stability.
• Unviable option when bedrock elevation or
elevation of other suitable base
significantly varies along the wall length.
16. System B: L-Shaped Wall with
Buttresses
• More economical than a Gravity Wall and easier to
construct.
• Buttress of the wall serves as a stiffening element for the
wall itself, and allows some force redistribution in the
wall based upon the stiffness of the tapered buttress
element
• Same design stability issues as a Gravity
Wall:Significant wave generated uplift force.
17. Continue
• Heavy reliance on soil surcharge on the
hill of the wall at the time when that weight
significantly decreases due to buoyancy.
• Requirement for very stiff base and
possibility of heavy scour that can affect
wall stability
18. System C: L-Shaped Wall with
Buttresses Supported by Piles
• A type of wall, a modification of System B, that has a
significant advantage over System B.
• Does not rely, or relies much less, on the gravity of the
hill surcharge.
• Less susceptible to distress due to scour problem.
• Stability of the wall depends upon the pile capacity to
resist uplift and the effect of horizontal load.
20. System D: Diaphragm Wall System
with Horizontally Spun Wall
• Easy to construct
• Lower cost of construction and more flexibility of the
system, as compared to the same features of
traditional designs.
• Wall stability is not dependent on the gravity load of
backfill.
• Wall stability is independent of gravity of the
surcharge.
21. Continue
• Low effect of soil scour in front of the wall on wall system
distress. Easy maintenance.
• Lack of uplift pressure on the wall base or heel, as the
Diaphragm system does not have a heel.
• Horizontally spun continuous wall supported by Deep
Beam Diaphragms. Wall Diaphragm provides support for
loads applied in both directions
22.
23.
24. System E: Soldier Pile System with
Horizontally Spun Wall and Tie Back
Anchors (Modified Bulkhead Approach
• easy to construct.
• The front of is similar to the front wall of the D system
• Design philosophy is not same
31. Continue
• Lack of uplift pressure on the wall base.
• Stiffness of the soil anchors and stiffness of
specially modified backfill allows for the design
of the retaining wall as a continuously spun
horizontally slab.
32. • Wall stability is not dependent on the gravity
load of backfill.
• Low effect of soil scour in front of the wall on
wall system distress.
• Easy maintenance.
• Lower cost of construction and higher
adaptability
33. Advantage of system D and E
• The erosion of the soil around the front pile can be easily
remedied
• Use of flowable fly ash fill that can easily restore eroded
soil around the pile to a preexisting or better condition.
• Erosion is almost never critical and does not require
urgent attention and can be restored during normal
beach nourishment operations.
35. Conclusion
• Control coastal erosion .
• Long term – hard stabilization
• Maintenance is needed
• Cost –effective approach is
recommended
• Unintentional harm to unprotected near
by shores
36. Reference cited
• Vitaly B. Feygin ,Sea Wall Systems Structural Engineering
magazine USA.
• Yoshimi goda , Random seas and design of maritime
structures ; 3rd edition
• www.channelcoast.org
