Types of pile according to their composition. Foundation Engineering

1. PRESENTED BY —
NAME : MD DILUAR HOSSAIN
ROLL : 27901322041
REG. NO. : 222790120053
SUB : FOUNDATION ENGINEERING ( CE-(PE) 601 B )
DEPT. : CE
COURSE : B tech DATE : 27-01-24
SEMESTER : 6 th
IDEAL INSTITUTE OF ENGINEERING

2. Types of Piles according to
their composition

3. Introduction
Pile foundation is a type of deep foundation. It is used where foundation work is not possible by ordinary method of
open pit excavation.
Pile foundation is one type of deep foundation. It is used where the good soil is at higher depth (10 or 15 m) or soil
having low bearing capacity. Pile is also used for tall structures. In pile foundation load coming from the super
structure is taken by pile cap and equally distributed in no. of piles. Pile transfers this load in to the soil.
Following are the situation in which a pile foundation are used:
1: The load of super structure is heavy and its distribution is uneven.
2: The top soil has poor bearing capacity.
3: Subsoil water level is high so that pumping of water from the open trenches for the shallow foundation is difficult and
uneconomical.
4: large fluctuation in subsoil water level.
5: structure is situated near river bed, where there is danger of scouring action of water.
6: the top soil is of expansive nature.

4. Function of piles
As with other types of foundations, the purpose of a pile foundations is:
to transmit a foundation load to a solid ground to resist vertical, lateral and uplift load
A structure can be founded on piles if the soil immediately beneath its base does not have adequate bearing
capacity. If the results of site investigation show that the shallow soil is unstable and weak or if the magnitude of
the estimated settlement is not acceptable a pile foundation may become considered. Further, a cost estimate may
indicate that a pile foundation may be cheaper than any other compared ground improvement costs.
In the cases of heavy constructions, it is likely that the bearing capacity of the shallow soil will not be
satisfactory, and the construction should be built on pile foundations. Piles can also be used in normal ground
conditions to resist horizontal loads. Piles are a convenient method of foundation for works over water, such as
jetties or bridge piers.

5. CLASSIFICATION BASED ON MATERIAL AND COMPOSITION:
1. CONCRETE PILES
a. Pre-cast
b. Cast-in-situ
i. Driven Piles: Cased or Uncased
ii. Bored Piles: pressure piles, under reamed piles and bored compaction piles.
2. TIMBER PILES
3. STEEL PILES
a. H-pile
b. Pipe pile
c. Steel pile
4. COMPOSITE PILES
a. Concrete and Timber
b. Concrete and Steel

6. ➢ PRE-CAST CONCRETE PILES
* The precast concrete piles are generally used for maximum design load of about 80 tonnes. They must be
reinforced to withstand handling stresses.
* They require space for casting and storage, more time to set and curing before installation and heavy machine
are required for handling purpose and driving.
* These piles require heavy pile driving machinery which is mechanically operated.
* The size of pile may vary from 30cm to 50cm in cross-sectional dimension, and upto 20m length or more in
length.
* Reinforcement may include longitudinal steel bars of 20mm to 40mm in diameter, 4 to 8 nos. with lateral tie
5 to 10mm wire spaced at 10cm c/c for top and bottom 1m length and 30cm c/c for the middle length.
* A cast steel shoe, properly secured to pile by mild steel straps, is provided at its lower end.
* Toe protect the pile and help in penetrating into hard strata during driving.

7. ➢ PROCEDURE FOR FORMING PRECAST CONCRETE PILES:
* The form work of required space is prepared. Usually metal forms are used for mass manufacture.
The inner sides of the form is coated with either soap solution so that soil does not adhere to the side.
* The reinforcement cage, as per design, is placed in the form, maintaining proper cover all around.
* Cast steel shoe is also placed, and is secured to the reinforcement with the help of mild steel straps.
* Concrete is then placed in the form and well vibrated with the help of form vibrators. Mix of concrete 1:2:4
with maximum size of aggregate equal to 19mm.
* When the pile is driven into soil it is subjected to impact stress at its head.
* Remove the form after three days. But the piles are kept in same place for 7days. The piles are then shifted
to curing tank where concrete is allowed to mature for at least 4weeks before being driven.
*Maturing period can be reduced if, raped hardening cement is used instead of normal Portland cement.

8. DISADVANTAGE OF PRECAST CONCRETE PILES:
* The piles are manufactured in the factory. Hence proper control can be exercised over the
composition and design of these piles.
* The position of reinforcement in the pile cannot be disturbed.
* Large numbers of piles are manufactured at a time in the factory or any other place, cost of
manufacturing will be less.
* These piles can be driven under water. If the soil water contain more sulphate. Thus pre-cast
concrete piles have added advantage in such circumstance. - These piles provide highly
resistant to biological and chemical action of the subsoil.
DISADVANTAGE OF PRECAST CONCRETE PILES:
* These piles are very heavy.
* They require equipment for handling and transporting purpose.
* The length of the pile is restricted since it depends upon the transport facilities.
* It is very difficult to increase the length of the pile, previously estimated on the basis of bore holes.

9. CAST-IN-SITU CONCRETE PILES:
The cast-in-situ concrete piles are generally used for maximum design load of 75 tonnes.
They are installed by pre-excavation, thus eliminating vibration due to handling stresses.
There are two types of cast-in-situ concrete piles:
(1) DRIVEN PILES (CASED OR UNCASED)
BORED PILES (PRESSURE PILES, BORED COMPACTION AND UNDER-REAMED
PILES)
(1) CASED –IN-SITU CONCRETE PILES:-
This method is practically suitable for all type of ground condition.
Shell is driven into intimate contact with the surrounding soil and remains in place to maintain driving resistance
and protect the concrete filling during the place of other adjacent piles.
Cased pile can be easily cut or extended to meet the variation in shell length.

10. ➢ FOLLOWING ARE THE COMMONE TYPE OF CASED CAST-IN-SITU CONCRETE PILES:
Raymond standard pile and step-taper pile
Mc-Artuhr cased pile
Swage pile
Western button bottom pile
1. RAYMOND PILES:
* (RAYMOND STANDARD CONCRETE PILE) is used primarily as a friction pipe. It is
uniform heavy taper of 1in30 result in short piles for equal driving resistance or higher
driving resistance for equal lengths, than piles of lesser or no taper.
* Length of piles varies from 6 to 12m. diameter of piles vary from 40 to 60cm at top and
20 to 30 at bottom
* The shell is driven into the ground with a collapsible steel core in it having the same taper.

11. * When the pile is driven to desired depth the core is mechanically collapsed and
withdrawn, leaving the shell inside the ground.
* Shell is inspected internally by using the flash or drop light.
* Shell is gradually filled with concrete up to the top.

12. (RAYMOND STEEP TAPER CONCRETE PILE)
* This type of core driven pile is used either as an end bearing pile.
Can be driven in any type of soil.
* The pile uses shell section in different length. The bottom most section is made of heavier gauge
and enclosed with flat steel.
* Joints between the sections of shell are screwed and connected.
* Shell are driven with a rigid core, rigid core provides high degree of penetration and efficiently
transmit the hammer energy to the bearing strata.
* The pile diameter increases at rate 2.5cm in each successive shell section.
* Pile can be drawn upto maximum depth of about 36m.
* The method of forming piles is same as of standard pile.

13. Mc ARTHUR CASED PILE:-
* This pile is of uniform diameter, best example on non-taper pile.
* It used extra steel casing heavy gauge in driving pile.
* Steel casing with central core is driven into ground.
* After reaching the desired depth, core is withdrawn and shell is placed in casing.
* After that concrete is placed in the shell, by gradually compacting it, and withdrawing steel
casing.
* These piles are used in place where the driving soil is very hard and it is designed to kept
water tight before filling the concrete in shell.
* There are four stages of forming these piles.
* First stage: thin shell with steel core not easily fitted over the pre casted concrete plug is first
inserted to plug such that plug gets fixed in the shell.

14. • Second stage: pipe is driven over the plug till the core reaches the plug and forms water tight joint.
* Third stage: pipe is driven upto desire depth. Driving force is applied by core on plug, Pipe is pulled
down rather than driven.
* Fourth stage: when the pipe reached to desired depth, the core is removed and the pipe is left open for
filling the concrete.
* These piles are used in place where increase in the end bearing area is needed.
* Pre casted concrete button shaped plug is fitted at end of pipe are used, as this button forms the
enlarged hole in the soil during pipe driving.
* Side friction is reduced. These piles are used upto depth of 23m, for load of about 50 tonnes.
* First stage: steel pipe having 12mm thickness and reinforced base is fitted over the concrete plug.
* Second stage: the pipe and button driven upto desired depth.
* Third stage: corrugated steel shell is inserted in the pipe, resting on button. Steel plate with a bolt hole
in it is welded on the bottom of the shell, before lowering it, so that the hole may fit over the central
bolt in button.
* Nut is tightened with the help of long wrench.
* Fourth stage: casing is removed, leaving the button in place, and the shell is filled with concrete

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