Types of bridges | What are the different types of bridges
Types of bridges:
Different types of bridges include girder or beam bridge, cantilever bridge, arch bridge, truss bridge, suspension bridge, and cable-stay bridge. These are Are introduced as follows.
1. Girder (Beam) Bridge:
This is one of the simplest types of bridges. Beam bridges (Fig. 9.19) are horizontal beams supported by substructure units (piers and abutments) at each end and can be supported simply when the beams are connected in a single span or are continuous when the beams are connected through two or more ranges.
Beam bridges can range from small wooden beams to large steel boxes. The vertical force on the bridge is the shear and additional load on the beam, which transfers its length to the substructures on either side. They are usually made of steel, concrete, or wood.
2. The Arch Bridge:
This type of bridge is characterized by arch-shaped beams; It can be single or multiple arch bridges (Figure 9.20). The distribution of the load is transferred from the arch to the abutment and pier; Most of the load is transferred to the pier.
The arch bridges are built in hilly areas where the span is relatively small and the location of the piers and abutments is strong enough.
3. The truss bridge:
Truss bridges are one of the oldest bridges. The truss bridge is a bridge whose overload is supervised by the truss. The truss is a structure of connected elements that form triangular units (Figure 9.21).
Connected elements (steel or wood) may be subject to stress in response to impulse, contraction or sometimes dynamic loads. This type of bridge is more economical because it uses materials efficiently.
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4. Cantilever Bridge:
This type of bridge is characterized by a narrow concave platform resting on piers (Figure 9.22). The bridge is built using cantilevers – the horizontal beams are supported on only one end. Most cantilever bridges use a pair of continuous spans that extend from opposite sides of the supporting piers to meet in the middle of the bridge crossing stream.
Cantilever bridges are built using more same materials as beam bridges. In this bridge, all the load is transferred to the piers. Such bridges are built in an area where the basement within the width of the stream is stronger than the location of the abutment area.
5. Suspension Bridge:
These are bridges suspended by cables. The bridge is characterized by an inverted arch in the shape of cables (Figure 9.23). In modern bridges, cables hang from towers attached to caissons.
The load is transferred from the abutments to the towers via cables. Hanging spots are built in areas where streams of sand are weak, which can hold abutments. The Laxman Jhoola Suspension Bridge in Rishikesh (Uttarakhand) is an example.
6. Cable-Stayed Bridge:
Cable-bearing bridges, such as suspension bridges, are held by cables. However, in a cable-stay bridge, less cable is required and the towers holding the cables are proportionately taller.
The bridge has many cables and towers other than abutments (Figure 9.24). The load is transferred from the deck to the piers via cables. These types of bridges are built in a soft rocky area on the banks of streams. Example: New Yamuna Bridge, Allahabad (UP).