Simply Supported Beam

Trees on river banks often fall of their own accord and 'bridge' across streams. It is quite likely that such natural occurrences gave early man the idea to cut down a suitable tree to cross a river. The word 'beam' describes this basic bridge design and is also an old word for 'tree' - such as found in Hornbeam or Whitebeam for example.

A Simply Supported Beam is any 'beam' supported at or near each end - usually with a Pin Joint at one end and a roller or similar at the other (to allow for expansion and contraction, for example, and to ensure the Reaction at that point is always vertical).

In addition, Simply Supported Beams can be imagined to be able to rotate around either of the two supports. These conditions ensure that the beam is Statically Determinate such that all forces within it may be calculated.