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In this article, we will discuss the flyover bridge.
A flyover is constructed over the road for the purpose of traffic management. It can be constructed over the railway or existing roadway. Nowadays, the use of these flyovers has become a common engineering term in big cities where traffic is hard to manage.
Reason for providing Flyover Bridge?
As the traffic volume on the road goes on adding due to which we don’t have any space left in both the dimensions, there is the only option left will be to go to the third dimension and that is carried out through flyover construction on the cities.
1. Types of Flyover
a. Road crossing Flyover
In this case, the main road is utilized for quick traffic movement which is made to travel at a high level by a bridge, having ramps on both the sides; and the low traffic is made to travel below. Thus the raffles pass at two levels so, there is no chance of an accident.
b. Railway crossing Flyover
At railway crossings where there is high traffic crowding in terms of the frequency of trains moving by or the traffic on the road, in both the cases the flyover should be kept along the road. Here the flyover becomes very essential to construct.
a. Classification of Flyover Bridges as Per According to Form.
1. Overpass Flyover
When the flyover is made passing through an existing roadway or railway crossing obstacles over it is known as an Overpass flyover. Overpass flyovers are mainly built to separate the railway path from the other traffic (i.e vehicle and pedestrian traffic).
2. Underpass Flyover
When the flyover is made passing through an existing roadway or railway crossing obstacles below it is known as an Underpass flyover. Generally, an underpass flyover is made for pedestrians and vehicles to move without disturbing of railway and roadway. Both of these flyovers help in the improvement of traffic management, which directly decreases the rate of accidents.
b. Classification of Flyover as Per According to Material
1. Composite Flyover
The flyover was prepared by use of two or more construction materials such types of flyovers are known as composite flyovers.
2. Steel Flyover
The flyover made use of steel as the main component on the flyover is known as steel flyover. This type of flyover is less expensive than that composite and concrete flyovers. As it is made of steel, the temperature variance can great a problem related to expansion and compression so, the steel should galvanize or painted well.
3. Concrete Flyover
The flyover made use of concrete as the main component on the flyover is known as a steel flyover.
2. Components of Fly Over
It consists of a deck slab, longitudinal girders, cross girders, deck beam, pier, and foundation. All the components present in a flyover are shown in the figure below.
3. Difference Between Flyover and Bridge
The bridge is a structure that spreads horizontally between two or more supports, whose work is to carry vertical loads. A flyover is the type of bridge constructed over the road.
| Sr.No. | Flyover | Bridge |
| 1 | The bridge stands for the structure that arranges passage over an obstacle devoid of sealing the way underneath. The necessary passage may belong to a road, a railway, pedestrians, a canal, or a pipeline. The obstacle to be passed may range from a river, a road, a railway, or a valley. | Flyover stands for a bridge that bears one road or railway line over another either including or excluding supplementary roads for making communication between the two. |
| 2 | This is utilized for connection use but it is built above roads as an overpass. | The bridge is made to connect the two different points. |
| 3 | They are made for road vehicles. | Bridges are used for dive traffic across the obstruction. They are also used to steer pipelines, wires, and other forms of transport. |
| 4 | They are made over road junctions, roads, streets, etc. | When there are any obstructions then the bridge is made, it differs in types in seas, rivers, valleys, etc. |
| 5 | It is constructed for lowering traffic jams. | The Bridge has been built for small distances & bypasses. |
| 6 | They are made over man-made structures such as roads, intersections, etc. to prevent crowding, and give a more easy way to steer over the traffic. | A bridge is made for less transportation cost and to reduce time consumption. |
| 7 | It is combined with a junction point or rich point like a station point connected. | The length of the bridge fully depends on the gap between the two points. |
| 8 | It is made in those areas where the roads are crowded. | The Bridges were mainly built over the River, Valley, etc. |
4. Advantages of Flyover Bridge
The advantages of flyover are as follows:
✔ It helps in traffic management.
✔ It saves time for people there is negligible chance of traffic jams.
✔ Improves pedestrian safety.
✔ It provides more space for emergency vehicles.
5. Disadvantages of Flyover Bridge
The disadvantages of flyover are as follows:
✔They are not as a rule suitable for built-up areas as they need a huge area.
✔ Lack of proper management in the flyover construction may cause many problems.
✔ Loss in the case of accidents is increased. The risk of accidents is decreased but in case an accident occurs then the damage will be huge. As the vehicle is at a high point, during accidents there is less chance of surviving.
✔ It is very costly to build.
✔ As the people who cannot risk their lives by relying on it are not using it. So, it’s ironic that the flyover has become a liability here instead of an or the city.
| Read Also: Factors Controlling Highway Alignment |
