20-09-2013, 03:58 PM
Seminar Report On Suspension Bridge
Suspension Bridge.ppt (Size: 1.37 MB / Downloads: 249)
Bridge
A bridge is a structure built to span a valley, road, body of water, or other physical obstacle, for the purpose of providing passage over the obstacle.
Designs of bridges vary depending on the function of the bridge and the nature of the terrain where the bridge is constructed.
Types of Bridge
There are six main types of bridges:-
Arch Bridge
Beam Bridge
Cable-stayed Bridge
Cantilever Bridge
Truss Bridge
Suspension Bridge
Arch Bridge
Arch bridges are arch-shaped and have abutments at each end.
An arch bridge doesn't need additional supports or cables. In fact it’s the shape of the structure that gives it its strength.
Arch bridges are designed to be constantly under compression.
The weight of the bridge is thrust into the abutments at either side.
Usually they are made for short span range but often set end-to-end to form a large total length.
Beam Bridge
Beam bridges are the simplest kind of bridge today.
Bridges consist of one horizontal beam with 2 supports usually on either ends.
It is frequently used in pedestrian bridges and for highway overpasses & flyovers.
They are constructed for short span requirements.
The weight of the bridge and any traffic on it is directly supported by the piers.
The top side of the deck is under compression while the bottom side of the deck is under tension.
To increase the bridge’s strength designers introduce truss to the bridge’s beam.
Cable-stayed Bridge
A bridge that consists of one or more pylons with cables.
There are two major classes of cable-stayed bridges such as a harp design & a fan design.
The cable-stay design is best suited for a medium span range.
The towers form the primary load-bearing structure.
It has greater stiffness.
The cables act as both temporary & permanent supports to the bridge-deck.
The tower in a cable-stayed bridge is responsible for absorbing and dealing with the compression forces while the cables are under tension.
Cantilever Bridge
A bridge built using cantilevers, structures that project horizontally into space, supported on only one end.
For small footbridges, the cantilevers may be simple beams; however, large cantilever bridges are designed using trusses.
These are constructed for short to medium span ranges.
Cantilevers support loads by tension of the upper members & compression of the lower ones.
Suspension Bridge
Nowadays these are the pioneers in bridge technology.
Of all the bridge types in use today, the suspension bridge allows for the longest span ranging from 2,000 to 7,000 feet.
This type of bridge has cables suspended between towers & the cables support vertical suspender cables that carry the weight of the deck below. This arrangement allows the deck to be level or to arc upward for additional clearance.
The suspension cables are anchored at each end of the bridge.
They are ideal for covering busy waterways.
Conclusion
These are the pinnacles in modern days bridge technology.
Longer spans of up to 2000 ft-7000 ft is possible.
They are ideal for covering busy waterways such as Gulf, Strait, Lake, etc.
These bridges are mainly meant for light & heavy roadways rather than railways.
The main forces in a suspension bridge are tension in the main cables and compression in the pillars.