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RE: Rebar splices in tension zones

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Erico: makes a good coupler (Lenton Coupler) that is unfortunately not ICBO
approved for A706 in seismic frames (ie type 2 connection) although that
shouldn't be a problem for basic beams.  Erico uses a special machine to
thread the reinforcing.

Dayton Richmond: The Barlock system (which doesn't require special
equipment) is a standard that has been around for a very long time. The
length and diameter of the coupler are substantial and special detailing may
be required. A new coupler produced by Dayton is the Bar XL system which is
still going through the ICBO process but has been approved by CALTRANS for
use as a type B coupler.  They are amazingly small but again require
specialized threading equipment.


Nick Blackburn

-----Original Message-----
From: Daryl Richardson [mailto:h.d.richardson(--nospam--at)]
Sent: Tuesday, February 05, 2002 8:22 AM
To: seaint(--nospam--at)
Subject: Re: Rebar splices in tension zones


	I'm interested in these couplers.  Other than Dywidag system couplers
(which utilize the thread like pattern of the Dywidag reinforcing
deformations) I've never seen these used.  Some references on the net
would be appreciated.

	Thanks in advance.


				H. Daryl Richardson

Nicholas Blackburn wrote:
> If you have to use laps in tension zones be very conservative, the concern
> is spalling concrete reducing the actual length of splice possibly leading
> to failure.  Adding some extra lap would not be unreasonable.  Another
> option is to encase the laps in closely spaced ties, 4"oc.  A third
> alternative would be to use couplers, type B.  There are several on the
> market that are quite small in length and diameter.  Longer laps and close
> spaced ties is probably the cheapest solution.  You should consider
> staggering the laps so that not all bars are lapping in the same place
> could excuse the use of closely spaced ties.
> Nicholas Blackburn
> -----Original Message-----
> From: John Holliday [mailto:john.holliday(--nospam--at)]
> Sent: Tuesday, February 05, 2002 1:56 AM
> To: seaint(--nospam--at)
> Subject: Rebar splices in tension zones
> ACI 318 recommends that rebar splices be located away from tension zones.
> am working on a large industrial facility in Mexico where the maximum bar
> length available is 12m. This is a concrete beam and slab building over
> feet tall x 180 feet long  with some extremely large loads, located in an
> intermediate seismic region. If I try to keep all my bar splices out of
> tension zones (specifically in the 180 ft. long beams), it results in a
> of cutting and wastage of reinforcement (because of the 12m maximum length
> of bar). I am therefore considering placing the full 12m length bars and
> splicing at every 12m with no cutting, resulting in some splices in high
> tension regions. These splices will be per the code for tension splices
> however I am a little worried about locating these splices in the tension
> zones based on the recommendation in the ACI to try and avoid such
> In this example what would good practice dictate in locating these
> Thanks in advance for all help.
> John Holliday P.E.

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