"SX" Bolt Callout

[b.mccarthy]

Hello, All.

I was sent a drawing with an "SX" callout for a bolted connection. I understand that this specifies that the shear plane must pass through the grip portion of the bolt, not the thread.

Questions:

• The scenario I have is connecting 0.125 material with 0.375 material. The bolt head contacts the 0.125 piece. To satisfy the "SX" condition, must the bolt grip be long enough to just clear the shear plane (> 0.125) or must it clear both (> 0.5)?
• Where might I find the code that controls this specification/condition?

Thank you.

[swalton · Accepted solution]

Draw a Free Body Diagram of the bolt.

How do loads on the 1/8" and 3/8" materials generate shear forces on the bolt?

Where are the bolt threads compared to the shear loads?

It sounds like the bolt is in single shear, at the faying surface.  https://en.wikipedia.org/wiki/Faying_surface

See http://www.bgstructuralengineering.com/BGSCM13/BGSCM004/BGSCM00402.htm

[b.mccarthy]

Thank you for the links.

This is a pre-engineered connection in single shear. Load is applied along the horizontal weldment. The bolt is spec'd as an A325 5/8-11 SX

My task here is to develop the assembly for fabrication, and to supply fasteners that meet the SX condition. Since the shear plane cannot pass through the threaded portion of the bolt, the best choice would be a bolt with a 1/4" grip, if the combined material thickness does not apply. If total thickness does apply, the bolt length would need to increase.

Your link makes no mention of total material thickness, only the faying surfaces, so I am guessing total thickness does not apply.

Thanks.