Shearing involves the application of force across a material, causing structural failure a certain point. The effects of shear failure make it look as if the material had been cut with a pair of scissors; this type of failure can be catastrophic, even if it occurs in something as simple as a wooden bridge over a stream running across your property, which we will use as an example. This means that calculating the shear force affecting the unsupported beams that support those decorative bridges can be crucial.

- Skill level:
- Moderately Challenging

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## Instructions

- 1
Determine the load. This means adding up the weight of everything that you will be supporting with the beam.

- 2
Measure the span of the beam between its end supports. For an evenly distributed load, multiply the load by the length of the span.

- 3
Divide the result by the number of end supports. If the unsupported span of a beam is 2 meters, the load is 20 Newtons, and each end of the beam is supported, the maximum shear force is expressed as the load (w) times the length of the span (t) divided by the number of supports (2): w x t / 2 = maximum shear force.

#### Tips and warnings

- "Load" means both static and live loads.