What is the Difference Between Beam and Girder

Beams and girders are two horizontal structural member made either of timber, concrete or steel that act as a primary structural system in buildings, bridges and many heavy structures. Both the members are subjected to flexural loads and generally they are terms that are used interchangeably but possess certain distinguishing factors.

Also Read: What is the Difference Between a Beam and a Joist?

Understanding the important difference between beam and girder is a necessary skill for any engineer, contractor or builder in construction industry.

In a brief, girders are main horizontal supports of a structure that is used to support smaller beams. This means, all the girders are beams, but all the beams are not girders. 

Wooden Beams
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PARAMETER	BEAMS	GIRDERS
DEFINITION	Beams are horizontal members that are designed element of building structure.	Girders are larger types of beams that carry smaller beams
SIZE	In a structure, if there are smaller beams that are supported by larger beams, especially in bridges, the larger beams are called as girders. The smaller beams are called as beams.	Beams can be girders. But girders cannot be beam. If there is only a single type of beam that act as major horizontal member, it is called as a girder. A girder cannot be supported by beams.
LOADS	It is used to carry distributed loads from the parallel walls or tributary areas of the floor system or roof system.	It acts as a major horizontal support of a structure. It carries major concentrated loads such as columns or beam reactions.
APPLICATION	Construction of residential projects like buildings, and tall structures.	Construction of commercial structures like bridges and flyovers.
FABRICATION OR CONSTRUCTION	Beams are mainly of smaller cross-section which can be either cast in site or fabricated. This do not require consideration of additional requirements.	The fabrication of girder requires consideration of factors like erection, stability , plate sizing etc. Image Credits: www.countymaterials.com
TYPES	Beams cane be simply supported, fixed or cantilever beam	Girders are mainly I-Beam, or Box Girders which is mainly used in bridge construction.

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