To: "'seaint(--nospam--at)seaint.org'" <seaint(--nospam--at)seaint.org>
Subject: RE: Stud bolts
From: Mark Pemberton <Markp(--nospam--at)lbdg.com>
Date: Fri, 16 Feb 2001 08:11:54 -0800
We have managed to find in the DSA Interpretations
of Regulations manual (IR 22-1) that for welded
shear connectors, 1/3 of the values given in
Table I4.a of the AISC (9th edition, ASD) must be
used for all applications other than composite action.
No explanation as to why though.
Mark Pemberton, P.E.
From: Mark Gilligan [mailto:MarkKGilligan(--nospam--at)compuserve.com]
Sent: Thursday, February 15, 2001 11:02 PM
Subject: Re: Stud bolts
Note that the code provision refered to (2205A.13) is in Chapter 22A.
This chapter only applies to public schools that are checked by DSA
(Division of the State Architect in California). This provision was
written and inserted in the Code by DSA. Does anybody know if DSA has
written a commentary that provides a technical justification for the code
My understanding is that their concern has to do with the fact that the
studs were already stressed because of dead and live loads and as a result
the capacity was not availible for lateral loads..
The concern about brittle failure does not sound right because a properly
installed stud is quite ductile. The acceptance test for headed studs is
to hit them with a big hammer till they bend over. While an occasional
stud may fail in a brittle manner we would not expect all of the studs to
fail in this manner.
If you look carefully, I think you will see that the formulae used to
the shear forces the studs need to resist for composite action are based on
the unreduced (nominal) strengths of the steel and concrete. As I
understand the composite design methodology, the per stud shear strength
tabulated in the code for comparison to this demand is an ULTIMATE value.
Because shear failure of the weld at the base of the stud can be abrupt, a
safety factor of three is appropriate and the ALLOWABLE loads are thus 1/3
of those in the tables.
Anyway. that's how I have always understood it. Some one else will
presumably speak up if I've got it wrong.
Drew A. Norman, S.E.
Drew A. Norman and Associates
----- Original Message -----
From: "Mark Pemberton" <Markp(--nospam--at)lbdg.com>
Sent: Thursday, February 15, 2001 3:21 PM
Subject: Stud bolts
> Does anyone know the reason the 1998 CBC requires
> that you use only 1/3 of the tabulated allowable shear
> for stud bolts used for any purpose other than composite
> action? This seems a bit extreme. (2205A.13 page 2-272.2)
> Mark Pemberton