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RE: Transferring Anchor Bolt Forces to Concrete

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Design the vertical rebar adjacent to the anchor rod for the tensile loads.
If the bar is too big to bend, provide Lenton Terminators on the top end of
the rebar.  

Design the anchor rod per Strength Design of Anchorage to Concrete, PCA for
the applied loads using a headed anchor rod.  

Design the length of the anchor rod long enough to where the projected
failure cone intersects the rebar low enough to fully develop the vertical

Provide sufficient confinement reinforcing to resist side-face blow out.  

Don't even consider smooth bar bond.  It is too variable which is why the
last appearance of smooth bar was in ACI 318-63.  I have seen an iron worker
back out an unheaded anchor rod with a 4 ft embedment by hand with a spud

Harold Sprague

> -----Original Message-----
> From:	Jim Persing [SMTP:jpersing(--nospam--at)]
> Sent:	Thursday, June 08, 2000 7:53 PM
> Subject:	Transferring Anchor Bolt Forces to Concrete
> I have a client who wants to use a 30" diameter CIP Pile (with no pile
> cap)
> to support a column with a moment connected base plate.  There are four 1
> 1/2" diameter anchor bolts which each have a 75 k factored load (UBC
> Section
> 1923).  I normally would use a footing with enough edge distance to
> develop
> a shear cone for the anchor bolts but since these bolts are only 3 3/4
> inches from the sides of the pile a "cone" type development of the anchor
> bolt does not seem to be an option.
> Does anybody have any ideas how to transfer the loads to the reinforcing
> in
> the pile?  I think development lengths for smooth bars have been removed
> from the code.  I see footings occasionally which have 30" to 48" long
> anchor bolts but I'm not sure how the tension force transfer is justified.
> Any help/suggestions would be appreciated.
> Jim Persing