I’m trying to determine what the shear and moment diagrams of a bolt in single shear look like. Before anyone says it, I know that it’s rare that a bolt will ever fail first in bending, and this is something that typically isn’t even checked for.

Anyway, I’ve assumed that the bolt is essentially a beam cantilevered at one end and guided at the other (guided end only allows vertical translation, no rotation). I’ve applied a distributed load acting downward over half the bolt length, and a distributed load acting upward over the other half. I found a website that uses these assumptions as well, and even provides a shear diagram (I’ve arrived at the same conclusion). Does the moment diagram I’ve drawn make sense?


Website (see figure 4.2.4)

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1 Answer 1


The moment diagram for the shear diagram you have assumed is correct assuming the graph of the moment at any point is the area of the shear diagram up to that point.

These typical average shear diagrams are used by codes such as AISC specifications J3.-, provided one uses the criteria therein.

However, if you really want to investigate the hypothetical moment failure then neither the shear diagram nor the moment diagram you assumed is correct.

In real situation there will be deformations both in the bolt and in the shear plates depending on the relative hardness and toughness of the two materials, the bolt usually harder, that will significantly change the distribution of shear and moment on both the bolt and the plates.


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