Need a book? Engineering books recommendations...

Return to index: [Subject] [Thread] [Date] [Author]

RE: ACI 318-02 Appendix D

[Subject Prev][Subject Next][Thread Prev][Thread Next]
Title: ACI 318-02 Appendix D



Section D.4.2.1 says that “The effect of supplementary reinforcement provided to confine or restrain the concrete breakout, or both, shall be permitted to be included in the failure models.” If you then read the commentary it says you can use reinforcement oriented in the direction of load and fully anchored on either side of the failure cone to transfer the required forces. I take this to mean that you draw the failure plane from your anchor bolt and then make sure your rebar can be developed on either side of this plane. If that’s the case, then the concrete won’t break out and the load will be transferred to the reinforcement.







Matthew O. Hood, E.I.T.
Plan Review Engineer
Municipality of Anchorage

-----Original Message-----
From: Bruce Holcomb [mailto:bholcomb(--nospam--at)]
Sent: Friday, November 19, 2004 1:52 PM
To: seaint(--nospam--at)
Subject: ACI 318-02 Appendix D


I have been asked to verify an anchor bolt design based on IBC 2003 which has either the ASD table in section 1912 or the strength design approach of section 1913 which basically just references ACI 318-02 Appendix D.  I typically design anchor bolts and base plates in accordance with AISC Design Guides 1 & 7, so I need to get up to speed quickly on Appendix D of ACI 318-02. 

My main question is, how does Appendix D account for the vertical reinforcing in a concrete pedestal?

Long story short… I have a reinforced concrete pedestal on an individual column footing for a fixed-base column.  My anchor bolts are 1¼” diameter by 30” embedment, which puts the nut at the bottom of the anchor bolt below the bottom of the pedestal and in the footing.  I can draw failure planes and explain that I am using the tensile strength of the rebar to transfer the load into the footing, but I am being asked by a plan reviewer to verify by Appendix D.

I remember reading somewhere that 12*AB diameter embedment in 3000 psi concrete provides strength = anchor bolt yield.  Of course, this is for the case where the anchor bolt is not near an edge of concrete.  I think this was in an AISC publication… can anybody help me find this?


Bruce D. Holcomb, P.E., S.E.

Structural Engineer

Butler, Rosenbury & Partners

300 S. Jefferson, Suite 505

Springfield, MO 65806

ph. 417-865-6100

fax 417-865-6102

Architecture, Engineering, Interior Design, Planning & Development

Your Vision.  Our Focus.