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Active Contributor

Join Date: Dec 2008
Posts: 14

# Anchor Bolt Embedment Length

12/12/2008 5:13 PM

I have looked through the ACI 318 Manual and cannot find anything on calculating embedment lengths for anchor bolts. Is this something found in the AISC manual? The ACI Manual does discuss development lengths, however these formulas appear to be relating beam or footing stress (moments) and not load transfer from steel columns to concrete footings. Can someone point me in the right direction.

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Guru

Join Date: Mar 2007
Location: City of Light
Posts: 3961
#1

### Re: Anchor Bolt Embedment Length

12/13/2008 4:58 PM

There are guide lines in the cat of Hilti.

Thecomputationis usually done considering a shear along a conical surface. Angle about 2 x 45°. The force sould be also smaller as te bolt resistance computed for the equivalent section of the thread with safety coefficient depending on application.

Those informations are only to be taken as "informations" for the final dimensions use approuved codes.

Anonymous Poster
#2

### Re: Anchor Bolt Embedment Length

12/13/2008 11:04 PM

The embedment length of an anchor bolt (rod) is found in ACI 318 Appendix D. The antire Appendix D is devoted to anchor bolts including several modes of failure. The equations are based on strength design and may appear to be quite labor intensive. However, after designing a few, the formula's are not so bad ...

Active Contributor

Join Date: Dec 2008
Posts: 14
#5

### Re: Anchor Bolt Embedment Length

12/15/2008 9:09 AM

I have discovered the problem. I am looking at an old AIC (89') and appendix D doesn't cover anchor bolts. Thanks for the help everyone.

Commentator

Join Date: Sep 2008
Posts: 81
#3

### Re: Anchor Bolt Embedment Length

12/14/2008 12:40 AM

Hi DuneRider,

I once had an anchor bolt problem to solve in which a elevator tower was attached to an existing chimney. We used 3/4 in dia parabolts, which was a new anchor device in 1971. The bolts were rated in tension per concrte strength and bolt shear.

I was concerned about variable shear and tension loads by attached structure moving due to wind loads. I devised a lever device which had a bearing bar at the ends and the anchor bolt was set in the middle such that the bearing plate was bowed and the bolt under constant tension (to the limit of the tensile capacity with 3x safety factor considered).

Well, it worked for thirty plus years, and then the chimney was brought to the ground as the smelter was obsolete.

DRS

Member

Join Date: Nov 2008
Posts: 5
#4

### Re: Anchor Bolt Embedment Length

12/14/2008 7:54 AM

You may refer "BASE PLATE AND ANCHOR ROD DESIGN" by AISC. There are many solved examples which may guide you to solve your problem.

Anonymous Poster
#6

### Re: Anchor Bolt Embedment Length

12/15/2008 9:48 AM

In ACI 318 Appendix D you can calculate the capacity of an anchor bolt. But I don't think there is a development length. Epoxy anchors have some minimum embendments.

Anonymous Poster
#7

### Re: Anchor Bolt Embedment Length

03/26/2009 8:27 AM

Maybe PCI Design Handbook can help. Try Chapter 6 - Design of Connections

specifically eq. 6.12.2.2.