To: "'seaint(--nospam--at)seaint.org'" <seaint(--nospam--at)seaint.org>
Subject: RE: Anchor in Bending
From: "Satish J. Matani" <SatishM(--nospam--at)mcnengineers.com>
Date: Tue, 28 Mar 2000 13:25:49 -0800
Cc: "Lanny J. Flynn (E-mail)" <flynn(--nospam--at)aiscmail.com>, "'SpragueHO(--nospam--at)bv.com'" <SpragueHO(--nospam--at)bv.com>
thing that would have to be added is the interaction of shear and tension on the
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 subject.