How to Draw Shear Diagrams
Shear diagrams are an easy way to visualize shear values along a beam or member and also reveal the maximum positive and negative shear values.
The first step will always be to simplify any and all load distributions into point loads and to solve for all exterior reactions.
Begin the shear diagram by drawing a horizontal line, this is the line for zero shear. I like to draw my shear diagrams directly below the actual member so that they line up and I designate my shear diagrams with a big V.