Working Load of HS Bolt 1

[moonriver]

I have a structural drawing calling out a "3/4-inch HS bolt" and I am trying to find a safe working load. It is a galvanized bolt being used on an exterior rooftop steel structure. Does anyone have a reference for the safe working load of this fastener. I have found an A992 spec referencing HS designation, but it seems to apply to structural shapes. It calls out a minimum tensile strength of 65 kpsi and yeild of 50 to 65 kpsi. Does this standard apply to fasteners as well?

 

[14159]

A992 is only for steel shapes such as wide-flanges.

"HS bolt" means either ASTM A325 or A490 and the strengths can be found in Chapter J of your friendly AISC steel Manual.

If you're doing any steel design, you should get with more experienced folks in your firm. This is Steel 101.

DBD

 

[sunstructures]

On a typical structural drawing, "HS bolt" would refer to ASTM A325 bolts. I would expect that A490's would be specifically called out as such because of their particular fatigue requirements.

As mentioned in the other post, the AISC Steel Construction Manual, 9th edition, would have allowable stresses and loading values for A325 bolts. However, the values depend on the loading configuration and the connection type, so you may want to get some more information from the structural engineer who designed the connection. If it's designated as part of a 'slip critical' connection, don't mess with it. Leave it alone.

In the typical case, you could make some assumptions that would give you a lower boundary to check against: bearing type connection, loads applied in single shear, and bolt threads included in the shear plane. That is usually designated simply A325, or if it is spec'd, it will read A325-N on the structural drawings. For example, a 5/8" A325-N in single shear specs out at as 6800 lbs allowable.

Good luck, and get more info as needed. Make sure all expected loadings and building code required loadings are accounted for.