2. CONSTRUCTION AND DESIGN
OF BRIDGE
Study of construction of components of bridge on
the MAHI river near VASAD.
3. CONTENT
SITE LOCATION
SITE DETAIL
BASIC TERMS OF BRIDGE
BORE LOG DETAIL
STANDARD PENETRARION TEST(SPT)
PLATE LOAD TEST
FOUNDATION
GROUP ACTION OF PILES
SUB-STRUCTURE
4. SITE LOCATION :
This is the site of work at chainage of 93+263 to 93+827 which is part
of NH-8, 6 lane project from ahemdabad to vadodara.
5. SITE DETAIL :
We are doing study of construction and design of discontinuous T-type
and major bridge on the MAHI river at chainage of 93+263 to 93+827 as
a part of 6 lane project of NH-8 from ahemdabad to vadodara.
This project is taken by IRB infrastructure devlopmer LTD and
constructed by VMC (Vijay mistry company).
It’s a DBFOT (design build finance operate transfer) type project.It is
the busiest national high-way of INDIA.
Width of the bridge is 17 m and total length of the bridge is 564.00 m
which consist 17 piers and 16 spans, Length of each span is 33.5 m,
Proposed road level is 32.600 m it’s measured from sea level. HFL (high
flood level) and LFL(low flood level) of bridge is simultaneously
27.990m to 7.800m.
6. An important first step in understanding the principles and processes of
bridge construction is learning basic bridge terminology.
Although bridges vary widely in material and design, there are many
components those are common to all bridges.
In general, these components may be classified either as parts of a bridge
superstructure or as parts of a bridge substructure.
7. BASIC TERMS OF
BRIDGE
Foundation :
1.Piles
Sub-structure :
1.Pile cap
2.Pier
3.Pier cap
Super-structure :
1.RCC girder
2.Deck
3.Crash barrier
8. BORE LOG DETAIL
Information on subsurface condition obtained from the boring operation is
usually presented in the form of a boring record , commonly known as bore
log .
A continuous record of the various strata identify at various depths of the
boring is presented .
Description or classification of the various type of soil and rocks encountered ,
and data regarding ground water level are presented in a pictorial manner on
the log .
Our bore log detail is shown in figure
11. The standard penetration test (SPT) is an in-situ dynamic penetration test
designed to provide information on the geotechnical engineering properties of soil.
The main purpose of the test is to provide an indication of the relative density
of granular deposits, such as sands and gravels from which it is virtually impossible
to obtain undisturbed samples.
The great merit of the test, and the main reason for its widespread use is that it is
simple and inexpensive.
If the samples are found to be unacceptably disturbed, it may be necessary to use a
different method for measuring strength like the plate test.
The test is useful for determining :
Relative density of soil
The angle of shearing resistance of cohesion less soil
Unconfined compressive strength of cohesive soil
13. Plate load test is a field test to determine the ultimate bearing capacity of soil ,
and the probable settlement under a given loading.
The test essentially consists in loading a rigid plate at the foundation level , and
determining the settlement corresponding to each load increment.
The loading to the test plate may be applied with the help of hydraulic jack. The
reaction of the hydraulic jack may be borne by either of the following two
method:
Gravity loading plateform method
Reaction trust method
14. Gravity loading plateform
method :
• In case of gravity loading plateform
method ,a plateform is constructed
over a vertical column resting on the
test plate , and the loading is done with
the help of sand bags , stones or
concrete blocks .
• In our case for loading , concrete blocks
are used.
15. FOUNDATION :
Pile foundation is carried out in this
bridge.
For the design of piles , there are two
test piles on the site , one is near p3
and second is near p16.
On the basis of tests , bore log detail
and loading condition friction pile are
used in foundation of bridge.
Friction pile :
when loose soil extends to
a great depth, piles are driven up to
such a depth that frictional resistance
at the sides of the piles equals the load
coming on the piles.
16. These friction piles are used when hard stratum is not available at shallow
depth.
Total friction resistance can be increased in following ways :
By increasing the length of pile.
By increasing the diameter of pile.
By making the surface of the pile rough.
By placing the pile closely.
Diameter of each pile is 12oo-mm and depth of pile is approx 31.00m.
There are 17 piers and 2 abutments , and foundation of all these piers and
abutments are done.
18. A pile is not used singularly beneath a column or a wall , because it is
extremely difficult to drive the pile absolutely vertical and to place the
foundation exactly over its centre line.
If eccentric loading results , the pile may fail structurally because of
bending stresses.
In actual practice structural loads are supported by several piles acting as
a group.
A minimum no of three pile is used under a column in a triangular
pattern , even if the load does not warrant the use of three piles.
19. When a no of piles required are
more than three , the piles are so
arranged that they are symmetrical
with respect to the load .pile under a
wall are arranged on either side of
centre line of the wall in a staggered
formation .
There are groups of 6, 8 & 9 piles
which are used in different piers as
per requirement and highest group
of piles of 12 and 20 which are used
in
A1
and
A2
abutments
simultaneously.
20. SUB-STRUCTURE
PILE CAP :
The pile tops are connected together to
the pile cap which help the pile group
act as an integral unit .
The loads are usually transferred to the
pile group through a reinforced concrete
slab or beam called the pile cap .
The pile cap may either stand clearly
above the ground level or may rest on
the soil , partially or fully buried below
ground level .
In our case pile cap is above the ground
level .
21. PIER :
• A pier is a raised structure for bridge , typically supported by widely spread
piles .
• In this bridge solid type of pier are used .
Solid pier
• In case of solid pier the piers consist of masonry or cement concrete of solid
section throghout the entire length of pier .
• The length of pier is kept parallel to direction of flow .
22. • This type of construction is popular because of the following reasons :o It can be used for any type of super structure of the bridge .
o It provides excellent resistance to the action floating bodies .
• The end of solid pier may be rectangular , but they may be given any
suitable shape to make the entry and passage of water easy and smooth .
• There are two ends of solid pier
I.
II.
Cut water
Ease water
23. CUT WATER
• The end of pier on upstream side is
known as cut water . The cut waters
are usually in triangular in shape .
EASE WATER
• The end of pier on downstream side is
known as ease water . The ease water
are usually semi circualr or they may
consist of two parabolic arcs .
• The function of cut water and ease
water is to minimise the eddying
effect of current and to reduce the
horizontal pressure due to current of
water.
