Bridge is one of the most critical and beautiful structure built by the civil engineers. Any structure that is built to cross a low or unaccessible area is called a bridge. Their are also many classifications of bridge based on their length, structure type, foundation type and many more.
TYPES OF BRIDGES IN THE WORLD:
There several types of bridges in the world. They are based on general theories of the bridges and in some cases they also contain some modified theory to make the structure more stable. General tension,compression, shear,torsion and bending are main topics in bridge design. In almost all of the cases bridges are earthquake resistant and wind resistant. Some of them are made of light weight concrete.
There is a general classification of bridges:
a)Depending on the structure type:
- Beam Bridge
- Truss Bridge
- Cantilever Bridge
- Arch Bridge
- Tied Arch Bridge
- Suspension Bridge
- Cable Stayed Bridge
- Fixed or Movable Bridge
b)Bridge Classification according to material
- Steel Bridge
- Wooden Bridge
- Concrete Bridge etc.
Bridge maintenance mainly includes the regular maintenance work. It includes the maintaining of the expansion joints of the bridge,lighting repair and re-installation, electrical wiring check and installation, cleaning the transition zone, bearing maintenance, movement check and solve,pier protection,scouring protection,river bed protection etc.
RIVER BED PROTECTION AND JOINTS REPLACING:
River bed is always subjected to change in elevation. Sometimes scouring takes place and sometimes sedimentation takes place.This action is emphasized by the meandering process of the river. this is a normal phenomena of any tidy river and in any river where the current has.
When the current is high the concave part of the river get scoured and deposition takes part on the convex side. Again,when the velocity gets disturbed by the bridge pier or any other obstruction then horse shoe vortex is formed and it causes erosion around the bridge pier.In some cases the pile cap is exposed that causes serious danger to the bridge.
In this case it is needed to take immediate action either it is temporary or permanent.
In permanent measures one need to seal a big area around bridge pier so that the further erosion can not occur around bridge pier and pile cap.
The temporary action may be filling the scoured area with sand bags,then geo-bags and then placing the concrete block over the geo-bags, so that they can no remove by the high current. This measures can help the bridge to prevent further scouring and to control the extra vibrations that occurs on bridge.
In permanent protection work you can replace the damaged joints of the bridge with a new and improved one. You can also change the damaged hinge bearing of the bridge which will make the bridge more stable.