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Coastal Engineering: Theory and Practice
8.8 Marine Piled Structures
For most of the marine structures, a strong base of the structure can be
achieved by only pile foundation. Piling secures the foundation of structures
as it delivers the essential support required for any kind of marine structure to be built. Piling is the procedure of setting deep foundations into the
ground, usually using wood, steel or concrète. Reinforced Cernent Concrète
(RCC) marine piles are basically elongated cantilever slender piles installed
in loose soil/clay and/or rocky bed. The fixity depth i.e. the effective depth
below the sea bed or dredge level should be approximated based on the
site and load condition in order to begin the construction. In general, the
marine piles are considered to be as fixed end cantilever members and the
depth of fixity is calculated as per équivalent length producing equal deflection. Provisions of Indian Standard code of Practice of Piles (IS 2911) are
generally followed. On the other hand, the fixity depth can be established
by using the modulus of sub-grade reaction and applying spring support
to the pile member of the jetty or wharf structure. The pile capacity is
usually designed by considering the soil capacity, and the structural design
is carried over based on the shear and moment forces. It is to be renowned
that in most practical cases the percentage of reinforcement is ruled by serviceability criteria of crack width, which is as per the provision of IS or BS
codes. In general, marine piles are heavily reinforced. In the case of steel
piles, a similar method is practiced however, the crack width considération
will be neglected as it is not required in steel piles. Steel piles can take large
deflections and especially for mooring and breasting dolphins piles it helps
in design.
Piling is also a cost-effective way of construction for marine structures
like jetties, berthing structures and pipe trestles. Fenders in front of the
berth either connected or unconnected to the berth usually protect and
reduces the berthing forces imposed by the ships and in turn protects the
pile rows. During berthing, the impact induces agreat impact force whereas,
the résistance offered by the vertical pile to latéral loading is trivial. Hence
the deck should be designed to support by a combination of vertical and
raking piles. The piles in the berthing head of a cargo jetty are required
to carry the following loadings: Latéral loads from berthing forces, Latéral loads from the pull of mooring ropes, Latéral loads from wave forces
on the piles, Current drag on the piles and moored ships, Latéral loads
from wind forces on the berthing head, moored ships, stacked cargo, and
cargo handling facilities, Compressive loads from the dead weight of the
Coastal Engineering: Theory and Practice
8.8 Marine Piled Structures
For most of the marine structures, a strong base of the structure can be
achieved by only pile foundation. Piling secures the foundation of structures
as it delivers the essential support required for any kind of marine structure to be built. Piling is the procedure of setting deep foundations into the
ground, usually using wood, steel or concrète. Reinforced Cernent Concrète
(RCC) marine piles are basically elongated cantilever slender piles installed
in loose soil/clay and/or rocky bed. The fixity depth i.e. the effective depth
below the sea bed or dredge level should be approximated based on the
site and load condition in order to begin the construction. In general, the
marine piles are considered to be as fixed end cantilever members and the
depth of fixity is calculated as per équivalent length producing equal deflection. Provisions of Indian Standard code of Practice of Piles (IS 2911) are
generally followed. On the other hand, the fixity depth can be established
by using the modulus of sub-grade reaction and applying spring support
to the pile member of the jetty or wharf structure. The pile capacity is
usually designed by considering the soil capacity, and the structural design
is carried over based on the shear and moment forces. It is to be renowned
that in most practical cases the percentage of reinforcement is ruled by serviceability criteria of crack width, which is as per the provision of IS or BS
codes. In general, marine piles are heavily reinforced. In the case of steel
piles, a similar method is practiced however, the crack width considération
will be neglected as it is not required in steel piles. Steel piles can take large
deflections and especially for mooring and breasting dolphins piles it helps
in design.
Piling is also a cost-effective way of construction for marine structures
like jetties, berthing structures and pipe trestles. Fenders in front of the
berth either connected or unconnected to the berth usually protect and
reduces the berthing forces imposed by the ships and in turn protects the
pile rows. During berthing, the impact induces agreat impact force whereas,
the résistance offered by the vertical pile to latéral loading is trivial. Hence
the deck should be designed to support by a combination of vertical and
raking piles. The piles in the berthing head of a cargo jetty are required
to carry the following loadings: Latéral loads from berthing forces, Latéral loads from the pull of mooring ropes, Latéral loads from wave forces
on the piles, Current drag on the piles and moored ships, Latéral loads
from wind forces on the berthing head, moored ships, stacked cargo, and
cargo handling facilities, Compressive loads from the dead weight of the