Understanding the Types of Bridges: A Comprehensive Guide

Concept about Bridge

Bridge is the engineering construction which helps to play an important role in connecting two points that have been separated by any kind of natural obstacles such as rivers, chasms, or valleys.

The structure of the bridges has been designed to stand with the forces of gravity, varying loads and other environmental factors thus helping to enable the safe passage for vehicles, pedestrians, trains and others. Bridges have been constructed on the basis of specific environmental conditions and functions. Bridges are essential to facilitate the transportation process as well as help to foster the connection between different communities.

Factors impacting the design of the bridges

There are different factors that influence the design of the bridges which include geographical factors, environmental factors, the demands of traffic, the load requirements, and the selection of the materials on the basis of cost, aesthetics and durability.

Geographical and environmental factors

The design of the bridges has been influenced by the location of the bridges. The condition of the soil, the seismic activity, the topography and climate conditions help to dictate the selection of the materials, the design of the foundation and the overall structural configuration of the bridge structure.

The selection of the materials

The selection of the right materials is also crucial for ensuring the longevity, safety and aesthetics of the bridge. The common materials that have been used in civil engineering projects for bridge construction are concrete, timber, steel, and composite materials. Various factors including cost, visual appeal, maintenance requirements and durability of the materials help to ensure that the bridge will meet the intended function and lifespan.

Aesthescity

There should be a balance between the functionality of the bridges with the aesthetics. In this context, the colour, lighting, architectural features and shapes need to be considered to achieve a visually pleasing structure of the bridge.

Load and traffic requirements

Different types of loads including dead loads, environmental loads and live loads must be supported by the bridges. Engineers have to analyse the traffic patterns and the types of vehicles to determine the appropriate load-bearing capacity for the bridges. The high-traffic bridges require stronger materials, wider decks and additional lanes for accommodating the excess load thus helping to ensure the safety of the bridge.

Different types of Bridges

Suspension Bridge

There are vertical towers or pylons in the suspension bridge which have been constructed from reinforced concrete or steel. This type of bridge features tall towers, a suspended roadway and strong cables.

Truss bridge

Truss bridges consist of a series of interconnected triangles. The geometric design of this type of bridge helps to provide exceptional strength to the bridge which is ideal for railway or road crossings.

Arch bridge

A curved shape, classic and enduring design is in the arch bridge which is suitable for spanning valleys and rivers.

Beam bridge

This type of bridge is the simplest type of bridge. In this type of bridge, a crossbeam is needed to cover the span which has been supported from abutments under each end. Several beams have been included in the beam bridge which helps to provide support to the deck above.

Cable-stayed bridge

In this type of bridge, deck cables have been used to connect one or more vertical columns, pylons, or towers that can be connected in a fan or harp configuration. The most common materials that have been used for the construction of cable-stayed bridges are concrete pylon, steel, steel rope, or post-tensioned concrete box girders.

Cantilever bridge

Different types of materials have been used to construct this type of bridge which include box grinders or structural steel which helps to carry rail traffic or road. This type of bridge has been built by using pillars which have been anchored to the soil.

Tied-arch bridge

This type of bridge helps to combine the strength of the arches along with the tensioned cables.

Details about Arch Bridge

In an Arch bridge, curved arch abutments at each end are present which involves transferring the weight of the bridge partially into the horizontal thrust that is held by abutments on either side. The curved design of the Arch bridge helps to convey the load forces along with the Arch curves which helps to support each end of the bridge. This support helps to bear the entire load of the bridge as well as helps to keep the arch in a precise and unmoving position.

Examples of Arch bridge

➢ Chenab Rail Bridge is located in the Reasi district of Jammu and Kashmir which helps to connect Bakkal and Kauri and it is made with steel and concrete. This arch bridge lies 42 km from the main town of Reasi.
➢ Godavari Arch Bridge is the longest concrete arch bridge with a length is about 2.745 km.

Advantages of Arch Bridge

➢ Arch bridge helps to provide unnatural strength which helps to allow the bridge structure to achieve a higher level of resistance towards the bending forces.
➢ The arch bridge has been constructed with stone, brick, and other natural materials which are able to stand with the compression forces.
➢ The half-circle shape of the arch bridge helps to ensure that no distortion to the structure of the bridge has occurred due to extreme pressure or load.
➢ A lot of dead weight is there on the top of each arch which helps to support the loads whenever the bridge gains weight.

To learn more, watch the following video tutorial.

Video Source: Practical Engineering

Details about Beam Bridge

The construction of the beam bridge is easy and it has been fabricated from wood beams. In civil engineering projects, beam bridges have been designed to hide valleys, water bodies, loads, or alternative natural obstacles thus helping to provide a route over the barrier. The strength of the beam bridge has been depends upon the strength of the routes and it has been multiplies by adding extra piers. In the case of the beam bridges, the distance between the adjustment piers is typically small.

Examples of Beam Bridge

➢ Manchac Swamp Bridge is located in Louisiana, USA and its span is about 36,690 m.
➢ Feiyunjiang Bridge is located in Ruian Shi, Wenzhou Shi, Zhejiang Sheng, China which is about 2,956 m.