Leena Pauline A.
Sindhana Roy J.
Any part of a body of
water and the manmade
surrounding it, that
sufficiently shelters a
vessel from wind, waves
and currents, enabling
safe anchorage or the
discharge and loading of
cargo and passengers is
Model of tuticorin harbour
function of breakwaters is to absorb or
throw back as completely as possible, the
energy content of maximum sea waves
assailing the coast.
mould - Small rocks or rubble
Outer covering - Large boulders
are built with an
aim in achieving the
minimum initial capital
coat, without incuring
DOCKS AND QUAYS:
principal operation to
which harbour works are
dedicated is „transfer of goods
from one transportation to
another(eg. From ships to
The station point of the vessels is called “Berth”
docks, wharves and quays are the
most important assets of a port. Ships
must lie afloat in complete shelter
within the reach of mechanical devices
for discharging their cargoes.
areas of firm, dry
land, immediately alongside
the ship is required.
It is essential that the
engineers must find a way to
support this land and any
superimposed loading it may
solution initially favoured and
indeed predominant for many
years was that of the simple
gravity retaining wall, capable of
holding land and water apart.
In olden days many projects were
carried out in open excavation
usind temporary cofferdams to
keep out the water.
unfavourable or unstable soils,
accidents caused by collapse
of excavation were not known.
In modern practice, no project
is initiated without extensive
exploration of the soil
monitoring of the soil
conditions during construction is
The material composing the wall
today is almost universally palin
or reinforced concrete.
In olden days heavy
ashlar(natural rock) masonry was
civil engineering structures are
impose upon or supported by
It is a two way interaction – Soilstructure interaction(SSI).
The SSI effect is reasonable for
light structures in relatively stiff
soil like low rise buildings and
simple rigid retaining walls.
is prominent for heavy
structures resting on soft soils.
Retaining structure is a prime
example of SSI
In all discussions about the
development trajectory of
India, maximum attention is
paid to infrastucture deficiency.
focus is on transport
and power – twin engines of
growth across all sectors of
Retaining structures are
engineered to retain soil or
rock from an area, building or
prevent the downslope
movement or erosion and provide
support for vertical or near vertical
They are made of masonry-stone,
brick, concrete, vinyl, steel or
Segmental retaining walls have
gained favour over poured-inpeace concrete walls or treatedtimber walls.
TYPES OF RETAINING STRUCTURES:
WALL TYPE: It
holds the earth mainly due to
its own weight and usually
made from heavy materials
It will topple relatively easily as
the internal leverage of the
earth pressure is very high.
piles, this wall is fixed by soil
on both sides of its lower
length and typically consists of
steel sheet piles that are
driven into the ground to
If the piles themselves resist
the bending forces, this wall
can take high loads.
: It is shaped like an
inverted T and is typically
made from a thin stem of steelreinforced, cast in place
The pressures from the
retained soils or rock are
carried through the stem to the
structural footing(bottom of the
T) are transferred to the soils
: This wall keeps
itself from toppling by having
cables driven into the soil or
rock, fixed by expanding
anchors and mechanically
This can be combined with
other types of walls.
RETAINING STRUCTURES FOR WATER
RESOURCES AND IRRIGATION:
is an agricultural land and
therefore Indian economy depends
upon agriculture to a vast extent.
45 million hectares of agricultural
land is to be irrigated.
This is to be achieved by devising
efficient storage and distribution
innovations are brought to play.
is to design the projects
for multipurpose usage, to get
the maximum benefit from the
same water resource.
USES - WATER RETAINING STRUCTURES:
dams, barrages, tunnels, surge
houses, regulators, aqueduct, chan
nels etc. – retaining structures for
hydropower projects and irrigation
In addition to the above 2 major
uses, they also help in flood
mitigation by creating reservoirs.
column, usually of
timber, steel or reinforced
concrete, driven into the
ground to carry a vertical
load is termed as a ‘pile’.
NEED FOR PILING:
high cost, difficulties and
possible dangers of providing
dock and quary walls have
always encouraged a search for
alternative solutions, that
would eliminate the need for
operations on or below the sea
The earliest and
alternative method is piling.
The piles can be driven from
floating craft and the deck and
super structure added thereto
working wholly above water.
With a reasonable planning of the
work, this operation can usually be
done without particular difficulty.
be conveniently assumed
that the sea bed is of a
amendable to penetration by
piles to a sufficient depth to
secure the lateral stability of the
Hard rock is not
suitable, although some of the
rocks can be pierced by steel
may be of timber, reinforced
concrete or steel.
Timber is a popular choice if
there is a large scale natural
Lateral stiffness and stability can
be achieved by using a sufficiently
close spacing of the piles in both
directions and adequate rigid
bracing between the tops.
jetties have a
considerable advantage in the
comparitive ease with
which, repairs to accident
damage or deterioration can be
Its chief drawback is the lack of
durability, particularly in the
area between wind and water.
concrete piled piers and
jetties, soundly constructed, exhibit
There are examples of construction in
which the piles are connected together
by casting a reinforced concrete slab
around the heads, its underside just
below lowest water level.
Attachment to the piles for bracing and
similar purposes tends to be more
complicated than in the case of timber.
CLASSIFICATION OF PILES:
may be classified on the
Based on materials and
on function or use
CLASSIFICATION BASED ON FUNCTION:
Based on the function or the use, piles may
be classified as:
i)End bearing piles
viii)Tension or uplift piles
BORED CAST IN-SITU
The process of
construction of a
bored cast in-situ pile consists of
a) Drilling of hole
b) Stabilization of hole
c) Placement of reinforcement
soil, that is dry or moist and
does not require
stabilization, drilling with an auger
is effective. A casing is installed in
soils requiring side support during
In very soft soils, where the drill
tool cannot operate ahead of the
casing, the casing may be pushed
into the soil and a grab is used to
remove the soil from inside the
the hole is stabilized with
continuous slurry circulation. That also
carries away the soil drilled using a
chisel type percussion tool. This
technique is referred to as the direct
mud circulation technique of drilling.
The Bentonite slurry travels through the
drill stem to the base of the hole and
moves up carrying the soil cuttings
loosened by the up-down motion of the
is recirculated after allowing
the soil cutting to settle in a pond. The
slurry density of 10.5 to 12kN/m³
ensures stability of the hole.
Concreting is carried by a technique
called tremie concreting that was
developed for underwater operations.
The concrete is sent down a tremie pipe
to gradually displace the Bentonite
slurry from the hole.
operation requires care
Two factors are important during
First, the concrete should fall through
the tremie pipe as though it were a solid
mass to displace the Bentonite slurry.
Second, the base of the tremie pipe rust
remain embedded to sufficient length in
the concrete to prevent the Bentonite
slurry from re-entering the pipe.