To: "Satish J. Matani" <SatishM(--nospam--at)mcnengineers.com>
Subject: RE: Anchor in Bending
From: "Sprague, Harold O." <SpragueHO(--nospam--at)bv.com>
Date: Tue, 28 Mar 2000 15:59:19 -0600
I agree. That is why I also referred to AISC Design Guide 3. The example
there uses a plate washer (with std. 1/16" oversize hole) welded to the base
plate to transfer shear from the base plate to the anchor bolt. I also
agree that you can't transfer very much shear through the anchor bolts.
> -----Original Message-----
> From: Satish J. Matani [SMTP:SatishM(--nospam--at)mcnengineers.com]
> Sent: Tuesday, March 28, 2000 3:26 PM
> To: 'seaint(--nospam--at)seaint.org'
> Cc: Lanny J. Flynn (E-mail); 'SpragueHO(--nospam--at)bv.com'
> Subject: RE: Anchor in Bending
> Harold Sprague
> >>The only thing that would have to be added is the interaction of shear
> and tension on the bolt.<<
> Example 5 that you refer shows base plate. Industry standard is to
> provide oversize hole in base plate and also grout under the base plate.
> This will introduce bending in the bolts. Bending of bolt is is totally
> ignored in this document except in Section A6.1.3 which states that when
> grout pads exists, reduce steel strength by 20%. There is no commentary
> provided for this section. The seminar that I attended lately, it was
> mentioned that this was done to account for bending in bolt. However,
> there is no justification given to arbitrarily reducing strength by 20%.
> There is no limit on the size of the grout pad, i.e., 1" or 1-1/2" or 2"
> or whatever. Assuming a typical job with 2" base plate and 1-1/2" grout,
> there will be 3-1/2" eccentricity on the bolt.
> Except for minor shear, bolts are useless to transfer shear in base plate
> situation and thus the example and the document should be used with
> caution for real use except for welded studs to the plate. You may want
> to refer to Practical Design and Detailing of Steel Column Base Plates,
> AISC Steel Tips, July 1999, Section 4.4 for further discussion on this