Bridges play an important role in the development of any country. There are various types of bridges are used in transportation engineering. The bridge must be stiff enough to resist movement. Each member of the bridge is made to withstand the load which is placed or moving upon it.
The Bridges are classified into different types according to,
The flexibility of the structure
The length of the span as culvert
Based on utility
Based on the high flood level
According to the flexibility of the structure:
1: Fixed span bridge:
Fixed bridges having no moving parts and stay in one place until they fail or demolished.
They are designed to stay where they are made to the point they are unusable or demolished.
2: Movable span bridge:
The movable bridge having consisted of move able decks and mostly often powered by electricity.
The superstructure of the bridge can be moved or lifted with the help of a suitable arrangement.
According to inter-span:
1: Simply supported:
In simply supported bridge the width of the bridge is divided into the number of the individual spans.
For each span in the simply supported bridge, the member load supported at both ends.
In these types of bridge plate and truss, girder have been used.
2: Continuous bridge:
The spans are continuous over the two or more than two supports.
In continuous, the stresses have reduced due to the negative bending moments developed at the piers and abutments.
In this type of bridge, the bending moment in the span is less than the simply supported bridge.
3: Cantilever bridge:
Cantilever bridge only supported at one end and another end is free to space.
Generally, we are joined two cantilever portion to make the way for vehicles and human.
According to superstructure:
1: Suspension Bridge:
The most expensive type of bridge and they are too strong and its span long distance such as across river.
The main element is suspension cables stretching over two towers and can be attached at each end to another deep in the ground.
The span over 500 m up to 1400 m.
Vertical smaller suspension cables are attached to main cables to support the deck below.
2: Beam Bridges:
These are the oldest and simplest type of bridge consisting of vertical piers and horizontal beam.
It is suitable for an only short span but can be used for larger crossing by adding the additional piers.
Span up to 10 to
Beam bridges are easy to built and inexpensive than other bridge types but they have a limited span.
3: Truss bridge:
It consists of an assembly of triangles and is commonly made from a series of straight steel bars.
Simply supported the span up to 30 to 375 m.
In cantilever, span up to 550 m.
Rigid arms extend from both sides of the two piers. Diagonal steel tubes are projecting from the top and bottom of each pier hold the arms in the place like a strong diving board which is also called cantilever arms.
Truss bridge is very strong and it can support heavy loads.
4: Arch bridge:
The arch bridge is looking like same a curved shape bridge.
In this bridge, the horizontal thrust is developed.
An arch bridge is restrained by the abutments at each end of the bridge.
For masonry, span up to 3 to 15 m.
Steel, span up to 519 m.
Concrete, span up to 305 m.
According to the length of the span as culvert:
1: Minor bridge:
The total span length of the bridge is greater than 6 m and less than 60 m is called minor bridge.
2: Long span bridge:
The total span length of the bridge is more than 120 m is called long span bridge.
3: Culvert bridge:
A culvert is a small bridge having a total length of 6 m or less than the 6 m between the faces of the abutment is called culvert.
According to based on utility:
1: Temporary bridge:
The temporary bridge is the low-cost bridge.
It is necessary where the construction of dams or bridges or during floods.
After the construction of the original bridge structure then temporary bridges are removed or dismantle.
2: Permanent bridge:
Permanent bridges are constructed for a long time period for use.
Permanent bridges are maintained at a high level.
According to based on high flood level:
1: Low-level bridge:
The superstructure of the low-level bridge is below the high-level flood.
When floods, these bridges are submerged in water.
These type of bridges are constructed for unimportant routes with low cost.
2: High-level bridge:
When flood high-level bridges are not submerged in water.
These type of bridges are constructed for important routes.