Transcript basic civil fondation by civil1st sem

UNIVERSAL COLLEGE OF ENGINERING & TECHNOLOGY
CIVIL 1ST SEMESTER
ECE(Elements of Civil Engineering) 2110004
VISHAL SHAH:- 130460106096
VIJAY S LADVA:- 130460106029
VIPUL B PRAJAPATI:- 130460106081
MAYURSINH RATHOD:- 130460106086
GUIDED BY:
Mr. PARTH JOSHI
Basic Civil Engineering-Foundation
Foundation
Foundation
• Introduction :
• A structure essentially consists of two parts, namely the super
structure which is above the plinth level and the substructure which is
below the plinth level.
• Substructure is otherwise known as the foundation and this forms the
base for any structure. Generally about 30% of the total construction
cost is spent on the foundation.
• The soil on which the foundation rests is called the “foundation soil”.
• Objectives of a foundation :
A foundation is provided for the following purposes:
• To distribute the total load coming on the structure on a larger
area.
• To support the structures.
• To give enough stability to the structures against various disturbing
forces, such as wind and rain.
• To prepare a level surface for concreting and masonry work.
Foundation…
• Types of foundation :
The two main types of foundation
are :
• Shallow foundation (spread
foundation) and
• Deep foundation
Types of Shallow foundation :
• Isolated footing (single footing,
Column footing)
• Combined footing
Types of Deep foundation :
• Pile foundation
• Pier foundation
Types of Pile foundation :
• Friction pile
• Load bearing pile
Note : Under-reamed piles is a
type of load bearing pile
Foundation…
• Shallow foundation (spread
foundation):
• Depth of foundation is less than
or equal to its width.
• Isolated footing (single footing,
column footing):
• In framed structures where
several columns are to be
constructed, isolated footings
can be adopted.
• The columns involved can be
provided with masonry or
concrete footing.
• If masonry footing is provided,
steps are given and the
foundation area is thus
increased so that the stresses
developed at the base is within
the limit.
• In case of masonry footing, the
projection of each step must be ½
brick thick and each step is made
of 1 or 2 bricks put together.
• Concrete can be moulded to any
shape and hence a concrete
footing may be a sloping one to
provide sufficient spread.
Foundation…
• Isolated footing (single footing, column footing)…
Foundation…
• Isolated footing (single footing, column footing)…
Foundation…
• Isolated footing (single footing, column footing)…
wall footing
Foundation…
• Combined footing:
• This type of footing is
adopted when the space
between two columns is so
small that the foundation for
individual columns will
overlap.
• Combined footings are
proportioned in such a way
that the centre of gravity of
the loads coincides with the
centre of gravity of the
foundation. Hence these
footings have either a
trapezoidal or a rectangular
shape.
Footing :
Footings are structural members
used to support columns and walls
and to transmit and distribute their
loads to the soil in such a way that
the load bearing capacity of the
soil is not exceeded. Also
excessive settlement, differential
settlement or rotation are
prevented and adequate safety
against overturning or sliding is
maintained.
Foundation…
• Pile :
• A slender, structural member
consisting steel or concrete or
timber.
• It is installed in the ground to
transfer the structural loads to
soils at some significant depth
below the base of the structure.
Foundation…
Pile caps are thick slabs used
to tie a group of piles together
to support and transmit column
loads to the piles.
Foundation…
• Deep foundation :
• Deep foundation consists of
pile and pier foundations.
• This consists in carrying down
through the soil a huge
masonry cylinder which may be
supported by the sides of soil
or may be supported on solid
rock (hard stratum).
• Pile foundation :
• Pile is an element of
construction used as
foundation. It may be driven in
the ground vertically or with
some inclination to transfer the
load safely.
Foundation…
• Pile foundation…
• Loads are supported in two
ways.
• If the load is supported by the
effect of friction between the
soil and the pile skin, it is called
friction pile.
• Friction piles may be made of
cast iron, cement concrete,
timber, steel, wrought iron and
composite materials.
• If the load is supported by
resting the pile on a very hard
stratum, it is called load bearing
pile.
• Load bearing piles are steel
sheet piles, concrete piles and
timber piles.
• Piles may be cast-in-situ or
precast.
• They may be cased or
uncased.
Load
Bearing
Pile
Friction Piles
Load bearing
pile
Friction Pile
TYPES OF PILES
• Concrete Piles
i) Cast-In-Situ Concrete Piles
a) Cased cast-in-situ b) Uncased cast-in-situ
ii) Precast Concrete Piles
• Steel Piles
i) H-Piles ii) Cylindrical piles iii) Tapered piles
• Timber Piles
• Composite Piles
TYPES OF PILE CONSTRUCTION
1. Displacement Piles
It cause the soil to be displaced radially as well as vertically as pile
shaft is driven or jacked into the ground.
b) Non Displacement Piles (Replacement piles)
It cause the soil to be removed and the resulting hole filled with
concrete or a pre cast concrete pile is dropped into the hole and
grouted in.
Displacement Pile Non Displacement pile
METHOD OF INSTALLATION
• Dropping Weight or Drop Hammers
- commonly used method of insertion of displacement piles
• Diesel Hammers
-Most suitable to drive pile in non cohesive granular soil
• Vibratory Hammers or vibratory method of pile driving
-very effective in driving piles through non cohesive granular soil
• Jacking Method Of Insertion
4 November 2010
Pile installation using Drop Hammer
Pile Driving Rig - temporarily support the pile that
being
driven and to support the pile hammer.
Jacking Method Of Insertion
• Jacked Piles are most commonly used in underpinning structures
• By excavating underneath a structure short lengths of pile can be
inserted and jacked into the ground using the underside of the existing
structure as a reaction.