Whether you're putting together a set of bleachers or a playground set for a local park, it's likely that you'll be installing angle irons as part of the process. Manufactured with acute, right and obtuse angles, these pieces of iron guard against forces pulling in a variety of directions. For example, in bleachers, angle irons hold seat backs in place when spectators sit down on benches and lean back. Angle irons vary in strength, because their applications vary as far as applied force. When purchasing angle irons, you'll need to know that the ones you have will handle the force they will receive.
Measure the dimensions of your angle iron with a tape measure. You'll need to know the width and depth of the bar, as well as the combined lengths of both sides. Measure the force that is working against the angle iron. Multiply that force by 3, and then multiply that product by the combined length.
Multiply the depth by itself, then multiply that product by twice the iron's width.
Take the answer you calculated in the first step and divide it by the result from the second step. The quotient will be your angle iron's strength against forces trying to pull the iron apart.
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