(A ModelSmart(2d) Resource)
Use a unit test load (one unit - 1 pound) to find the probable failure load.
Step #1 - Apply a load of 1 pound to the structure.
Step #2 - Use ModelSmart to analyze the structure.
Step #3 - Locate the member(s) with the highest efficiency ratio. In this case ".26".
Step #4 - Divide the max. efficiency ratio by the actual efficiency ratio.
1/.26 = 3.8
Step #5 - Multiply by the test load.
Probable Failure Load = 3.8 x 1 =3.8 pounds.
The math is based on a linear relationship known as "Similar Triangles" (see below).
ModelSmart finds the probable failure load automatically when you select "Loads|Calculate Maximum" from the menu before analyzing.
In order for this process to work the structure must be capable of supporting the test load.