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Re: MBS Base Plate Grouting

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The anchor bolts are designed for tension and shear only (I believe).  If a grout space is added then there is additional bending taking place between the two plates. We normally avoid making a gap and leave it to the contractor to provide level concrete bearing surfaces. With 10 A.bolts and a 100' clear span there is a subtantial kick at the bases. In the past I have cast in a double steel angle assembly that connected the tie rods across the building with the cast-in place anchor bolts.
Dave Handy, P.Eng. 
----- Original Message -----
Sent: Monday, June 20, 2005 3:32 PM
Subject: MBS Base Plate Grouting

I am designing a foundation for a MBS with 100 foot clear span and column bases that are deeper than what I am accustomed to seeing - 8" x 2'-3, with (2) rows of 5 anchor bolts.  I seldom see grouting beneath the base plates of ordinary MBS, but then I have seldom seen base plates this deep with so many anchor bolts, which are nevertheless considered to be "pinned" per the design report.
I am considering specifying a 1/4" steel plate as a stay-in-place template at the surface of the pilaster, but can't decide about the need or lack of need of grout on top of the template.  Before I impose the cost of grouting the column bases on the project, I would appreciate some other opinions.  I have even considered the use of rubber bearing pads to accommodate imperfect alignment if no grout is used.
Thank you,
Mark D. Anderson PE