1.  What is a bridge.?
 Different types of bridges.
 Descriptions.
 History Working.
 Culverts
 Type of culverts
 Depiction
 References.

2.  Bridge is a structure built to span a valley,
road, river, body of water, or any other
physical obstacle.
 Designs of bridges will vary depending on the
function of the bridge and the nature of the
area where the bridge is to be constructed.

3. 700 A.D. Asia
1,304 years
ago
100 B.C. Romans
2,104 years ago
Clapper Bridge
Tree trunk
Stone
Arch design
evenly distributes
stresses
Natural concrete
made from mud
and straw
Roman Arch Bridge
History of Bridge Development
Great Stone Bridge in China
Low bridge
Shallow arch
Allows boats
and water to
pass
through

4. History of Bridge Development
Truss Bridges
Mechanics of
Design
Wood
Suspension Bridges
Use of steel in
suspending
cables
1900
1920
Prestressed
Concrete
Steel
2000

5. Compression Tension
Basic Concepts
Span - the distance between two
bridge supports, whether they are
columns, towers or the wall of a
canyon.
Compression –
Tension -
Force -
Concrete has good compressive strength, but
extremely weak tensile strength. What about steel
cables?

6. Basic Concepts
Beam - a rigid, usually horizontal, structural
element
Pier - a vertical supporting structure, such as a
pillar
Cantilever - a projecting structure supported only at one
end, like a shelf bracket or a diving board
Beam
Pier
Load - weight on a structure

7. There are six main types of bridges:
1. beam bridges
2. cantilever bridges
3. arch bridges
4. suspension bridges
5. cable-stayed bridges and
6. truss bridges

8. Consists of a horizontal beam supported at
each end by piers. The weight of the beam
pushes straight down on the piers. The farther
apart its piers, the weaker the beam becomes.
This is why beam bridges rarely span more than
250 feet.

9.  Forces
When something pushes down on the
beam, the beam bends. Its top edge is pushed
together, and its bottom edge is pulled apart.

10. Span range Short
Material Timber, iron, steel, reinforced
concrete, prestressed concrete
Movable No

12.  A cantilever bridge is a bridge built using
cantilevers: structures that project
horizontally into space, supported on only
one end.

13.  The arch has great natural strength.
Thousands of years ago, Romans built arches
out of stone. Today, most arch bridges are
made of steel or concrete, and they can span
up to 800 feet.

14. Forces
The arch is squeezed together, and this squeezing force
is carried outward along the curve to the supports at each
end. The supports, called abutments, push back on the
arch and prevent the ends of the arch from spreading
apart.
Types of Bridges
Arch Bridges

16. Suspension Bridges
This kind of bridges can span 2,000 to 7,000 feet -- way
farther than any other type of bridge! Most suspension
bridges have a truss system beneath the roadway to
resist bending and twisting.
Types of Bridges

17. Forces
In all suspension bridges, the roadway hangs from
massive steel cables, which are draped over two towers
and secured into solid concrete blocks, called
anchorages, on both ends of the bridge. The cars push
down on the roadway, but because the roadway is
suspended, the cables transfer the load into compression
in the two towers. The two towers support most of the
bridge's weight.
Types of Bridges
Suspension Bridges

20. The cable stayed bridge is newer than the
other types of bridge. Large upright steel
supports are used to transmit the load into
the ground.

22. Truss Bridge
All beams in a truss bridge are straight. Trusses are
comprised of many small beams that together can
support a large amount of weight and span great
distances.

24. •Pontoon bridges are supported by floating
pontoons with sufficient buoyancy to support
the bridge and dynamic loads.
•While pontoon bridges are usually temporary
structures, some are used for long periods of
time.
•Permanent floating bridges are useful for
traversing features lacking strong bedrock for
traditional piers.
•Such bridges can require a section that is
elevated, or can be raised or removed, to allow
ships to pass.
Types of
Bridges
Floating Bridge

27.  Hydraulically short conduit which conveys
stream flow through a roadway embankment
or past some other type of flow obstruction