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ACI Shear Anchorage Question

ACI Shear Anchorage Question

ACI Shear Anchorage Question

I have an application where I need to use a shear key on a base-plate to transfer the shear from a steel column to a mat foundation.  Uplift = 91 kips, shear = 33.6 kips.  I have used the AISC Design guide in the past but I was told to check out the ACI anchorage section as they have a design procedure for a shear key.  I was looking at my ACI-02 and I guess I am blind because I can't seem to see it in there.  Does anyone know where this procedure is, or maybe if its in the ACI-05 and not the 02?  Thanks for your help.

RE: ACI Shear Anchorage Question

ACI Anchorage section is Appendix D - but I don't know if it has shear key design in it.

RE: ACI Shear Anchorage Question

Thanks JAE,  I know all about Appendix D and there is not anything about shear key design in there.  I guess I meant is there anything in another section that I am missing or maybe in the new ACI-05 code.

RE: ACI Shear Anchorage Question

AISC has a Design Guide #1 for Base Plates.I think you can download the pdf for free. It specifically designs for Shear Lugs or Keys welded on the bottom of the Plate. Good Luck

RE: ACI Shear Anchorage Question

ACI 349-01 section B.11.2 describes breifly how to design for a shear lug bearing toward a free edge.

The design shear strength is 4 phi sqrt f'c acting upon the projected effective area.  Phi=0.85

The old ACI 349-85 explains the method more clearly as it similar to the the old method of determining anchor bolt pullout. The reprint is still available from ACI for about $15.00, however the anchor bolt design method has been replaced by the CCD method described in Appendix D of ACI 318-02
The old method is also explained fairly clearly in AISC desing guide #7 and is available as a free download for AISC members.

Regards to all,


RE: ACI Shear Anchorage Question

Thanks to everyone for there replies.  I went back to the AISC method as I had used before.  It turns out that since the columns are sitting directly on the mat foundation, the engineer who is stamping the design wanted me to put some rebar around the shear tab to ensure confinment of the concrete.  It turned out what he was wanting me to look at was chapter 21 and its discussion of concrete confinement and not shear tab design.  Thanks for the help though guys.

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