2.
A pile is a long slender foundation member, made either of
timber, structural steel or concrete which might be cast-in-
situ or driven and acts as a structural member to transfer
the load of the structure to a required depth in deep
foundations carrying a load which may be vertical or
lateral or lateral plus vertical.
What is pile…
3.
If the load is
transmitted to the soil,
the pile is called a
FRICTION PILE.
If the load is
transmitted to the soil
through the pile’s
lower tip, the pile is
called an END
BEARING PILE.
Pile…
4.
Piles can be classified on the basis of either
there use or material from which they are
made.
On the basis of use there are two major
classification…
1). Sheet Pile
2). Load Pile
Pile Types…
6. Sheet piles are used primarily to create a rigid barrier for
earth and water.
Typical uses include cutoff walls under dams, and for
coffer dams, bulkheads, and trenching.
On the basis of the material from which they are made
sheet piling can be classified as
1. Steel
2. Prestresses concrete
3. Timber
4. Composite
Pile Types…
9. Timber
a. Treated with preservative
b. Untreated
Concrete
a. Precast Prestressed
b. Cast in place with shells
c. Augured cast in place
Steel
a. H section
b. Steel pipe
Composite
a. Concrete and steel
b. Plastic with steel core
Pile Types…
10. The type size and weight of structure to be
supported.
The physical properties of soil stratum at the
site
The availability of materials for piles.
The no. of piles required.
The driving equipment.
The durability required.
Selection of piles…
12.
1) Drop
2) Single acting steam or compressed air
3) Double acting steam or compressed air
4) Differential acting steam or compressed air
5) Diesel
6) Hydraulic –Impact and drivers
7) Vibratory drivers
PILE HAMMERS…
13.
Drop hammer is a heavy metal weight that is lifted
by a hoist line, then released and allowed to fall onto
the top of pile
Because of high dynamic forces, a pile cap id
positioned between the hammer and pile head
Standard drop hammer weight:500-3000 lb
Suitable for driving piles on remote projects that
requires only a few piles and for which time of
completion is not important factor
A drop hammer can deliver 4-8 blows per minute
1. Drop Hammer…
16.
It has freely falling weight, called a “ram,” that is lifted by
steam or compressed air
When the piston reaches the top of stroke , the steam or air
pressure is released and the ram falls freely to strike the top of
the pile
These hammers rely solely on gravity acting on the striking
weight
The heavy weight strikes with low velocity due to short fall
distance (usually 3ft, limited to 4ft)
Hammers are available in sizes varying from about 7,000-
1,800,000 ft-lb of energy per blow
40-60 blows per minute
2. Single acting steam or
compressed air…
19. The striking ram(piston) is driven by compressed air
or steam both when rising and when falling.
Double acting hammer commonly delivers 95-300
blows per minutes
Lower blow counts are for the larger hammer and
higher counts for the smaller hammers
In comparison with single acting hammer, the ram of
double acting is only 10-20%, 90% of its energy is
delivered by action of air or steam.
Advantageous when driving light to medium weight
piles into soils having normal frictional resistance
3. Double acting steam
or compressed air
20.
It is modified single-acting hammer.
The air or steam pressure used to lift the ram is
not exhausted at the end of upward stroke but it
is used to accelerate the ram on the down stroke
The no. of blows per minute is comparable with
that of Double acting hammer.
Weight and equivalent free fall are comparable
with Those of single acting hammer
It has advantage of single & double- acting
hammer
4. Differential acting
steam or compressed air.
22.
It is a self contained driving unit that does not
require an external source of energy such as air
compressor or steam boiler.
It is simpler and more easily moved from one
location to another than steam hammer
Open end diesel hammer deliver 40-55 blows per
minute and closed end models operate at 75-85
blows per minute
It works well in cohesive or very dense soil layers
The hammer may not operate when driving piles
into soft grounds.
Diesel hammer…
24.
They are reported to have an efficiency of 90% or better
in delivering energy to piles
More efficient than steam, air or diesel hammers.
It operates on differential pressure of hydraulic fluid
instead of compressed air or steam.
hydraulic drop hammer:- ram is lifted by hydraulic
pressure to preset height and allowed to free fall
Double acting hydraulic hammer:- ram is lifted by
hydraulic pressure and is also driven hydraulically on
its downward stroke
6. a)Hydraulic –Impact
hammers…
25. Press in hydraulic pile drivers, which can be used for
thrusting and extracting steel H piles and steel sheet piles.
The pile driver grips the pile and then pushes the pile down
approx. 3 ft.
At the end of down stroke, the pile is released and the gripper
slides up the pile 3 ft to begin the process of another push
It develops 140 tons of pressing or extracting force
Are compact, make minimal noise and cause very little
vibration
Suited for driving pile in areas where there is restricted
overhead space
6. b)Hydraulic Drivers…
26. Effective when piles are driven into water saturated non
cohesive soils
The drivers may experience difficulty in driving piles into dry
sand or similar materials or into non cohesive soils that do not
respond to vibrations.
The vibrations are transmitted to pile because it is rigidly
connected to driver
From pile the vibrations are transmitted to adjacent soil.
The agitation of the soil materially reduces skin friction between
the soil and pile
It is powered either electrically or hydraulically, therefore a
generator or hydraulic power pack is needed
7. Vibratory drivers…
27.
All hose connections including air hammer hoses and steam
lines, that lead to the hammer must be securely attached.
Hydraulic hammer hoses can be under high pressure and
heat, so you must always protect these lines.
Hanging or swinging pile driver leads must have fixed
ladders for access.
Workers can not stay on the leads or ladders when piles are
being driven.
All workers must wear hearing protection during pile
driving operation.
Pile Driving safety…
