ABSTRACT
The strength of a bolt subject to tension has been determined by theory and test to be accurately predicted by the product of the ultimate strength of the bolt material (Fu) times the stress area of the threaded part of the bolt (As.). Because different dimensional properties of the bolt (body area, tensile stress area, area at root of the threads) are the critical geometrical parameters for the failure modes for different types of loading, the pertinent geometrical property has been used in the theoretically correct formula for each failure mode. Then, for convenience of the user, the resulting formula is multiplied by the ratio of the theoretically correct dimensional parameter divided by the full body area, and also multiplied by the body area to provide formulas for all failure modes in terms of the single dimensional property Ag. This procedure provides a sufficiently accurate formula but avoids the pitfall of inadvertently using the wrong area for a given case. The following formula is used to express the strength of a bolt subject to tension.
