1. Beams
What is a beam?

2. 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.

3. 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)

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

5. 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).

6. 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.