Girder
Girder
A girder is a large and deep type of beam that is used in construction. It is typically capable of longer spans and taking greater loads than a normal beam, and is often used as a main horizontal structural support for smaller beams, such as in bridge construction. It is the main horizontal support of a structure which supports smaller beams. Girders often have an I-beam cross section composed of two load-bearing flanges separated by a stabilizing web, but may also have a box shape, Z shape, or other forms. Girders are commonly used to build bridges.
Small steel girders are rolled into shape. Larger girders (1 m/3-foot-deep or more) are made as plate girders, welded or bolted together from separate pieces of steel plate. A plate girder is typically an I-beam cross-section made up of separate structural steel plates which are welded, bolted or riveted together to form the deeper vertical web and narrower horizontal flanges of the beam.
