A bridge is structure which allows passage over an obstruction. The obstructions may be river, valley, rail route or road way etc.
Types of Bridges
Bridges are classified into so many types based on different criteria’s. They are explained below.
Types of Bridges based on Type of Super Structure
- Arch bridge
- Girder bridge
- Truss bridge
- Suspension bridge
Arch bridge is curve shaped bridge, in which horizontal thrust is developed and is restrained by the abutments at each end of the bridge. There are many types of arch bridges are there. In some cases, the arch may be under the deck slab also.
In case of Girder Bridge, the deck slab is supported by means of girders. The girder may be of rolled steel girder or plate girder or box girder. Load coming from the deck are taken by girder and transferred them to the piers and abutments.
Truss is member consisting connected elements to form triangular units. In case of truss bridge the super structure is provided with trusses. Generally, trusses are made of steel. There are several types of trusses are available.
In case of Suspension bridge, deck slab is suspended with the help of cables and suspenders. These will give good appearance. For long span bridges, this type of suspension is suitable.
Types of Bridges based on Materials
- Timber bridge
- Masonry bridge
- Steel bridge
- R.C.C bridge
- Pre stressed concrete bridge
Bridges constructed using timber are called timber bridges. These are generally constructed for short spans or as temporary bridges. They are not useful for heavy loads.
Masonry Bridge constructed by using bricks or stones. These are generally constructed for short spans and in low depth canals.
Steel bridges are constructed using steel bars or trusses or steel cables. These are more durable and bear heavy loads.
R.C.C bridges are constructed using reinforced cement concrete. These are more stable and durable. They can bear heavy loads and are widely using nowadays.
Prestressed Concrete Bridge
If concrete material is placed under compression before applying the loads, then it is called as prestressed concrete. To construct pre stressed concrete bridge, pre-stressed concrete blocks are arranged as deck slab with the help of girders. These blocks are suitable for shorter span to longer span bridges.
Types of Bridges based on Span
- Culvert bridge
- Minor bridge
- Major bridge
- Long span bridge
When the bridge span length is below 6 meters then it is called as Culvert Bridge.
If the bridge span length is in between 8 to 30 meters, then it is called minor bridge.
For major bridge, the span is generally about 30 to 120 meters.
Long Span Bridge
When the span of bridge is more than 120 meters then it is termed as long span bridge.
Types of Bridges based on Level of Crossing
- Over bridge
- Under bridge
To pass over another route (railway or highway), a bridge is constructed to allow traffic. This is called over bridge or fly over bridge.
If over bridge is not possible, an underground type bridge is constructed to pass another route. This is called under bridge.
Types of Bridges based on Function
- Foot bridge
- Highway bridge
- Rail way bridge
- Aqueduct bridge
- Road cum railway bridge
Foot Bridge is generally constructed for humans to cross the roads or rail route or any canal by foot. Vehicles are not allowed in this bridge.
High way or road Way Bridge is used for road transportation. These are constructed over rivers or another routes to allow road way traffic. Girder type bridges are used as highway bridges over rivers or canals.
Rail bridges are constructed for rail transportation. Truss type bridges are preferred for railways but how ever r.c.c bridges are also used.
Aqueduct bridges are nothing but water carrying bridges which are constructed to0 transport water from source to system.
Road cum Railway Bridge
This type of bridge is useful for both road way and railway transport. It may be of one floor or two floors. If one floor is there then, rail and road way are arranged side by side. Otherwise roadway on top deck and railway in bottom deck is preferred.
Types of Bridges based on Inter Span Relation
- Simple bridge
- Continuous bridge
- Cantilever bridge
Simple bridge is like simply supported beam type which consist two supports at its ends. For shorter spans, simple bridges are suitable.
If the bridge span is very long, then we have to build more supports in between end supports. This type of bridge is termed as continuous bridge.
Cantilever type of bridge have only supported at one end and another end is free to space. Generally, two cantilever portions are joined to make way to the vehicles or humans.
Types of Bridges based on Utility
- Temporary bridge
- Permanent bridge
During construction of dams or bridges or during floods, temporary bridges are constructed at low cost for temporary usage. These bridges are maintained at low cost. After construction of original structure temporary bridges are dismantled. Generally timber is used to construct temporary bridges.
These bridges are constructed for long term use and maintained at high level. Steel or R.C.C bridges are come under this category.
Types of Bridges based on Position of Floor
- Deck bridge
- Through bridge
- Semi-through bridge
In case of Deck Bridge, super structure or floor of bridge is positioned in between the high flood level and formation level.
In case of through bridge, Super structure of bridge is completely above the formation level.
If the super structure of bridge is partly above and partly below the formation level, then it is called as semi-through bridge.
Types of Bridges based on High Flood Level (HFL)
- Low level bridge
- High level bridge
Low Level Bridge
The super structure of bridge is generally below high flood level. So, whenever floods occurred these are submersed in water. So, these are also called as submersible bridges. These are generally constructed for unimportant routes with low cost.
High Level Bridge
High level bridge is non submersible against floods. It is well above the high flood level and constructed in important routes.