Beams What is a beam Beam definition A

Beams What is a beam?

Beam - definition • A beam is a structural element that carries transverse loads • A beam is long, compared to the dimensions of its cross section • It does not carry loads in the direction along the length of the beam.

Types of beam Each type of beam is defined by how it is supported • At each support there will be REACTIONS (i. e. reactions to the applied transverse loading) • A reaction may be a vertical force (to maintain vertical equilibrium with the applied loads) • Or a reaction may be a rotational moment (to maintain rotational equilibrium of the beam)

Types of beam Name Simply Supported Cantilever Propped Cantilever Continuous Encastre Symbol Reactions

Statically determinate (and indeterminate) beams Static equilibrium gives 2 conditions for any of the beams on the last slide: • Vertical equilibrium • Rotational equilibrium • Because beams do not carry loads along their length horizontal equilibrium does not provide any information about the beam. As we only have 2 useful equilibrium conditions we can only determine the reactions for any of the beams with only 2 reactions (2 forces or 1 force + 1 moments) using the method of static equilibrium. For all other types of beams more sophisticated methods of analysis must be used (not covered in this specification).

Types of loading ‘Dead’ or ‘Self Weight’ loads (constant loads) ‘Live’ or Imposed Loads (moving loads) Point loads E. g. street furniture. E. g. Railway locomotive + train. Uniformly distributed loads E. g. Weight of the material used to construct the beam. (Often the largest load of all. ) E. g. Design loading for general road traffic or pedestrians.