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RE: half height steel nuts

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     I do not have a copy of the document in the office at this time but if memory serves me correctly ANSI B18.2 requires standard nuts to be designed so the strength of the threads exceeds the ultimate strength of the bolt.  Based on that the 1/2 height nut could develop 1/2 the bolt strength.  
-----Original Message-----
From: Eli Grassley [mailto:elig(--nospam--at)]
Sent: Thursday, November 17, 2005 10:14 AM
To: seaint(--nospam--at)
Subject: RE: half height steel nuts

Nels –


Thanks for the reply.  I think the word “jamb nut” is throwing off your picture of the situation though.  Forget I said that.


It’s really simple.  There is an A36 threaded rod in vertical tension, and it is supported at the top end by a nut.  Only the nut is half the height of a standard nut due to geometric constraints.  I need a coherent way of showing what the capacity of this half-height nut is.  I can’t find any equations on nut strength in the AISC code.


~~ Eli ~~


-----Original Message-----
From: Nels Roselund [mailto:njineer(--nospam--at)]
Sent: Wednesday, November 16, 2005 4:38 PM
To: seaint(--nospam--at)
Subject: RE: half height steel nuts




I’m not sure that I have your detail clearly in mind, but I’ll describe what I’ve done to join rods in tension.  


When handling 2 rods joined with a coupling not, you’ll observe that there is a little bit of looseness in the longitudinal direction.  To remove the looseness, I use jamb nuts, one tightened against each end of the coupler.  That pulls each rod toward its end of the coupler so that, before the assembly receives structural tension, the threads are already in bearing.  In that case, I would assign no load to the jamb nuts.


It’s a good idea, using half-height nuts as jamb nuts – I’ve not done that.  Are they less costly than standard nuts?


Nels Roselund, SE

South San Gabriel, CA


From: Eli Grassley [mailto:elig(--nospam--at)]
Sent: Wednesday, November 16, 2005 11:15 AM
To: seaint(--nospam--at)
Subject: half height steel nuts


Listers –

I am trying to research design capacities for some half-height “jamb nuts” for use with connecting some A36 threaded rods in tension.  I would assume that you could conservatively take 1/2 the allowable tensile strength in the threaded rod as the half-height nut capacity (because obviously a standard height nut can develop the full rod capacity).

Can anyone point to a text resource that might give me some nut capacity formulas or, really just something to back up my simple argument.

thank you



Eli S. Grassley, PE

PSM Engineers