Components of Bridge and its Function

In our lives, we often use bridge in our daily transportation. But, have you ever stopped in a while and wonder what does the bridge is composed of?

BRIDGE DEFINED:

BRIDGE by definition, is a structure that is built over a railroad, river (or any water channel), or road so that people or vehicles can cross from one side to the other.

The components of a bridge is broke down into two, namely the SUBSTRUCTURE and the SUPERSTRUCTURE. The Substructure is anything that is below the bearing of the bridge. This is composed of Foundation (pile/spread footing), Pier (Column), Abutment & Wing Wall. The primary purpose of the Substructure is to support the superstructure components of the bridge. On the other hand, Superstructure components are any structure that is above the bearing of the bridge. It is basically consists of Beams/Girders, Arch/Cables, Parapet wall/Handrail & Flooring or Deck slab.

To fully understand all these components, here are the definition of each terms:

A. SUBSTRUCTURE

1. Foundation – the foundation of a bridge is usually composed of piles and pile cap. These elements make up the initial foundation and is usually constructed to give support to the bridge. The piles help to create a smooth transition that allows the internal forces to flow evenly between the bridge and the ground.

2. Pier (Column) – this part of the bridge is used to transfer the loads from the superstructure onto the foundation. It is constructed above the foundation and is usually rises above a body of water.

3. Abutment – it is a structure that is constructed at either end of the bridge and is connected to the embankment (sometimes retaining wall).

4. Wing Wall – it is the part of the bridge that also acts as one of the earth retaining structure. It is usually located adjacent to the abutments and can be constructed either attached or independent to the abutment.

B. SUPERSTRUCTURE

1. Beam / Girder – beam, also referred to as beams, gives support to the deck by preventing its bending. These can be a single or multiple span and is dependent on the length of the bridge.

2. Arch / Cable – this component gives additional strength to the bridge. It also helps control the safety and load bearing ability of the bridge.

3. Parapet Wall / Handrail / Railings – this part of the bridge is built to serve as a safety component which prevents the vehicles or the pedestrians from falling off the bridge.

4. Flooring / Deck Slab – this structure gets the direct traffic load from the road users. It is made from either concrete or bituminous and sometimes from metal.

5. Bearing - are structural members capable of transferring loads from the deck (superstructure) to the substructure.

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