The document discusses various topics related to bridges including their purpose, importance, components, classifications, loadings, aesthetics, materials used such as steel and reinforced concrete, types of bridges like suspension bridges, causes of bridge failures, maintenance, and some landmark bridges in India. Bridges are structures built to provide passage over physical obstacles without closing the gap below and have been developing in sophistication since early human civilization. They are important for connecting difficult terrains, aiding trade and transportation, and reducing travel time.

1. BRIDGES
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2. Bridge is a structure built to span physical obstacles such as
a body of water, valley, or road, for the purpose of providing
passage over the obstacle without closing the gap below.
Bridge building is not a new science. The sophistication in
bridge building technology has been developing since the
human civilization.
Figure 1: a) Simplest bridge
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b) The Pamban Bridge
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3. IMPORTANCE OF BRIDGES
 Connects Difficult Terrains
 Easy Trade and Transportation of Goods
 Reduces Travelling Time
 Military use
 Political and Economic importance
 Less Emission due to displacement
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4. COMPONENTS OF A BRIDGE
Figure 2:
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5. CLASSIFICATION OF BRIDGES
According
to the
flexibility of
superstruct
ure
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According
to the
position
of bridge
floor
According
to the interspan
relations
According to
the form or
type of
superstructure
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6. LOADING ON BRIDGES
 Dead Load
 Live Load
 Buoyancy Pressure
 Centrifugal force
 Earth Pressure
 Seismic load
 Water pressure
 Wind load
 Thermal forces
Figure 3: Live Load
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8. AESTHETICS OF BRIDGES
 External appearance
 Internal view
 Sequential View
GUIDELINES:
1) Beauty and Stability
2) Bridge and Environment
Integration
3) Material Choice
4)Moderate Lightings
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Figure 4: Aesthetics of a bridge
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9. STEEL BRIDGE
 Steel is largely used in construction of bridge for short
as well as long spans.
 Steel has been recognized as economic option for a
range of bridges; for long span bridges, railway
bridges, footbridges, and medium span highway
bridges.
 The world’s first cast iron bridge was built at Telford, in
1779, by Abraham Darby .
 Steel bridges now have a proven life span extending to
well over 100 years.
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10. Classification of steel bridges
Steel bridges are classified according to:
 the type of traffic carried
 the type of main structural system
 the position of the carriage way relative to the main
structural system
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Figure 5: Steel Bridge
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11. REINFORCED CONCRETE BRIDGE
 RCC bridges are the earliest form of bridges. They are
easy to construct.
 Arches are preferable where Bending moment is more
and they are easy to design.
Site Selection for RCC Bridge
1) Straight reach of the stream
2) Good foundation
3) Well defined firm banks
4) Minimum width of crossing
5) Approaches
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Figure 6: RCC Bridge
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12. Its not always possible to provide straight deck, when
horizontal curves are to be provided the following design
speed is to be considered:
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13. SUSPENSION BRIDGE
 A suspension bridge is a type of bridge in which the
deck (the load-bearing portion) is hung below
suspension cables on vertical suspenders.
 First Suspension bridge was built in 1433, in
eastern Bhutan by Thangtong Gyalpo.
 Suspension bridge is generally preferred when the
span is more than 200 m for roadway or 300 m for light
traffic like motors.
There are two types of suspension bridge:
 Un-stiffened deck type suspension bridge
 Stiffing girder type suspension bridge
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14. Components of a suspension bridge
Figure 7: Components of a suspension Bridge
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15. Comparison of RCC, Steel & Suspension bridges:
Suspension Bridge
Steel Bridge
RCC Bridge
Steel Cables, concrete
or steel deck used as
construction materials.
Steel frames and
concrete deck.
Reinforced cement
concrete
Better to withstand
earthquake movements
than heavier and more
rigid bridges.
Steel can fully meet the
structural requirement
with even small
sections.
Arches are preferred
where more bending
moments occur.
Maintenance cost is
Maintenance against
Their cost of
high as the cables needs the rusting of steel has maintenance is very
to be changed
to be done regularly
small.
which increases the cost
of maintenance
Installation takes time.
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Quick Installation.
Takes longest time for
installation.
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16. BRIDGE FAILURE
 When a bridge collapses , many lives are put at risk.
 Bridge collapse is one of the most dangerous types of
structural failure that can occur.
Causes of Bridge failure
1. Earthquake
2. Fire
3. Boat impact
4. Flood
5. Construction accidents
6. Manufacturing defects
7. Design defects
Figure 8: Bridge Failure
8. Poor maintenance
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17. MAINTENANCE OF BRIDGES
1. The bearings of girders should be coated with oil
from time to time.
2. The floor system of approaches and bridges
should be properly maintained.
3. The entire drainage system should be inspected
for its proper functioning.
4. The movement of foundations, if any, should be
carefully inspected and all attempts should be
made to stop such further movement.
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18. LANDMARK BRIDGES OF INDIA
1) The Bandra–Worli Sea Link
Official name: Rajiv Gandhi Sea Link
Carries: 8 lanes of traffic
Design: Cable-stayed
Length: 5.6 km
Width: 40 m
Opened: 30 June 2009
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19. 2) The Howrah Bridge
Official name: Rabindra Setu
Carries: 8 lanes of road
Design: Cantilever
Length: 705 m
Width: 21.6 m
Opened: 3 Feb 1943
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20. 3) The Saraighat Bridge
Official Name: Saraighat
Carries: Rail cum Road
Design: Truss
Material: Steel
Length: 1.49 km
Width: 7.31 m
Opened: 7 June 1963
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21. CONCLUSION
 Bridges connect destinations. Bridges are assets to
mankind and have to last for generations as the
construction of bridge influences the whole
ecosystem and the change is permanent. So proper
planning to adapt the bridge into the natural
ecosystem has to be done. The scope of Bridge
Engineering is ever booming and technology used
in bridge building is also getting sophisticated.
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22. BIBLIOGRAPHY
 S. Ponnuswamy (Guest faculty IIT Madras )., “Bridge Engineering” Tata
McGrwaw-Hill. 2nd Edition, 2008
 Prof. S.R Satish Kumar and Prof. A.R Santha Kumar (IIT Madras)., “ Design of
steel structure Journal” , 2006.
 S.C Rangwala and K.S Rangwala., “ Bridge Engineering” Charotar Publishing
House. 14th Edition ,2012.
 B.L Gupta and Amit Gupta., “Road, Railways, Bridges, Tunnels & Harbour Dock
Engineering” Standard Publishers.7th Edition, 2009.
 S. Ramamrutham., “Design of RCC Structures”., Dhanpat Rai Publishing, 14th
Edition ,1989-1999
 S.S. Bavikatti., “Structure Analysis”., Vikas Publishing House. 14th Edition, 2011.
 Madan Mohan Das, Bhargab Mohan Das and Mimi Das Saikia., “Structure
Analysis”., PHI Publication. 1st Edition, 2011.

Internet surfing
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www.wikipedia.com
www.pbs.org
www.design-technology.org
www.britannica.com
www.steelconstruction.info
www.tatasteelconstruction.com
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