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RE: Anchor in Bending

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Satish,

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.  

Regards,
Harold Sprague


> -----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
> subject.
>  
>  
> Satish