Reaction Forces, Shear Force and Bending Moment diagrams.

Reaction Forces
Applicable conditions of equilibrium.

Sum of the Forces Up = sum of the Forces Down

Sum of the Moments clockwise= Sum of the Moments anticlockwise
(take moments about one of the unknown reaction forces)

Shear Force Diagrams

Start and finish at zero.
Are measured in KN.
Show a sudden change for a concentrated load.
Show a gradual change for a Uniformly Distributed Force (UDL)
The place where the Shear Force crosses the origin will be the position of maximum bending on the beam.

Bending Moment Diagrams

Start and finish at zero.
Are measured in kNm.
Show a straight line for a concentrated load.
Show a curve for a UDL.
The value of the Bending Moment can be found by calculating the area under the Shear Force.
Always get a value for the place that the SF diagram passes through the origin.

A lot to remember but practice makes perfect!