This document provides an overview of pile construction and testing. It discusses the different types of piles, factors that influence pile spacing in a group, and methods for determining a pile's load capacity. Load tests and formulas that use static soil properties or dynamic measurements during driving are described. Causes of pile failure like improper installation, soil conditions, and excessive loads are outlined. Methods for pulling existing piles are also summarized. The document is serving as a study guide for a civil engineering technology unit on deep foundations and pile construction.

1. Construction Technology_Unit 1.6
1 SBG Department of Civil PCCoE,2020-21
Unit I (6 hours)
Pile construction- Introduction, uses, selection, types
of piles, pile spacing, group of piles, efficiency of group
of piles, pile cap and pile shoe, load tests on piles, pile
driving, pulling of piles, loads on piles, Construction
details of precast piles, pre stressed piles, steel piles
and friction piles, causes of failures of piles and
precautionary measures

2. 2
Pile Driving Formulas

3.  Load carrying capacity of pile determined by –
1. Static formula
2. Dynamic formula
3. Penetration test
4. Pile load test
3
Load carrying capacity of soil

4. 4
Load carrying capacity of soil
The static formulae are based on the assumption that
the ultimate bearing capacity Qu of a pile is the sum
of the total ultimate skin friction Qs and total ultimate
point or end bearing resistance Qb

5. 5
Load carrying capacity of soil
2. Dynamic formula:

6. 6
Load carrying capacity of soil
2. Dynamic formula:

7. 7
Load carrying capacity of soil
2. Dynamic formula:

8.  The center to center distance of successive piles is known
as pile spacing.
 It has to be carefully designed by considering the following
factors,
 Types of piles and Material of piles
 Length of piles
 Grouping of piles
 Load coming on piles
 Obstruction during pile driving
 Nature of soil through which piles are passing.
 The spacing between piles in a group can be assumed
based on the following:
1- Friction piles need higher spacing than bearing
piles.
8
Pile Spacing

9. 9
Group of Piles
 Group Pile: Load carrying of a pile group is not necessary
equal to the sum of the capacity of individual piles. If piles
are spaced closely because of stress overlap, the group
capacity will be reduced.
 Efficiency of pile group: The efficiency of a pile group is
define as the ratio of the load carrying capacity of the pile
group to the sum of the load carrying capacities of the
individual piles.

10. 10
Group of Piles

11. 11
Group of Piles
Factors of Group Efficiency:
The number, length, diameter, and spacing of the
piles
The load transfer mode (friction vs. bearing)
The sequence of installation
The soil type
The interaction, if any, between the pile cap and
the soil
The direction of the applied load

12.  To replace the damaged piles during the driving
operation.
 To reuse the existing piles when the structure above
the pile is demolished.
 To prepare the data of strata trough which piles are to
be driven by carrying out pulling tests.
 To remove the pile which are driven temporarily as in
case of a cofferdam.
12
Pulling of Pile

13.  The method for pulling of piles will depend on the
type of pile, equipment availability.
 Various method are;
Use of double acting steam hammer
Use of pile extractors
Use of tongs
Use of vibrator
Use of electricity
13
Method For Pulling of Pile

14. SBG Department of Civil PCCoE,2020-21
14
Method For Pulling of Pile
Use of pile extractors Use of vibrator

15. Causes of Pile Failures
 Pile foundation has large bearing capacity, well stability and
small differential settlement compared to other foundation
types. But pile foundations may also get damaged and fail
specially during earthquakes.
 The failure of the pile foundation may result from any of the
following causes:
1) Lack of adequate boring
2) Inaccurate soil classification
3) Soft strata under tip of pile
4) Inadequate driving formula (wrong data)
5) Improper size of hammer cause insufficient penetration, too
light or damaged if too heavy
15

16. Causes of Pile Failures
1) Misinterpretation of load
2) Damaged of encased piles
3) Buckling of piles and Breaking of piles
4) Vibration that cause lateral or vertical movement
5) Flowing strata caused by adjacent excavation
6) Tension failure of concrete pile for lack of reinforcement
7) Insect and marine borer attack on timber and corrosion
8) When pile load is greater than the design load.
9) Poor and defective workmanship while casting the pile.
10) Disintegration of concrete due to poor quality of concrete or
reactive aggregate
16

17. Causes of Pile Failures
11) Dislocation of reinforcement while casting.
12) Bearing pile laying on delicate strata.
13) Inappropriate characterization of soil.
14) Incorrect selection of pile types.
15) Inadequate reinforcement in the pile.
16) Corrosion of the timber pile because of assault by insects.
17) Buckling of the piles because of insufficient lateral support.
18) Defective techniques used while driving the pile. Collapse of
the thin shell of the piles.
19) Overweight due to earthfill
20) Inaccurate determination of the bearing capacity of the pile.
17

18. Precautionary measures to control Pile
Failures
18

19. Construction Technology_Unit 2.1
19 SBG Department of Civil PCCoE,2020-21
Unit II (6 hours)
Coffer Dams: types, selection, design features of
coffer dams and construction of single, double
wall, Sheet pile cofferdams, concrete wall movable
cofferdam, land cofferdams, soldier construction
method. Cofferdam construction by different
techniques, diaphragm wall construction, leakage
prevention, economic height.