Need a book? Engineering books recommendations...

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

Re: Twisting of rebar

[Subject Prev][Subject Next][Thread Prev][Thread Next]


If you have the room, you could cut the bars leaving a short vertical straight portion then use a rebar coupler with a new L bar pointing is the right direction.

Thomas Hunt, S.E.

"Steve Gordin" <sgordin(--nospam--at)>
11/06/2008 08:07 AM
Please respond to seaint
Re: Twisting of rebar

Heating the rebars degrees may lower the strength of concrete (at 600 degrees - about 40%; at 1000 degrees - up to 80%). Besides, it is very hard to control the temperature (especially this time of the year) in the field.
It appears that permanent twisting of a 12" long #5 rebar can be achieved elastically - say (for the sake of argument) even to the shear stress of Fy - to a total angle of about 6 degrees.  After that, the deformations are plastic, so even if the rebar will survive the 90-degree twisting, it cannot be really relied upon.  Additionally, any considerable twisting will affect the concrete around the rebar, especially, close to the "fixity" surface.
Neither of your options appears quite acceptable; you may want to consider cutting the rebars altogether and epoxying a whole new set of reinforcement.  Even in a high wind area a concrete roof should not develop too much of net uplift.
A final crazy thought - why can't you leave the rebars as they are?
 V. Steve Gordin, SE
Irvine CA    

----- Original Message -----
From: Dickey, David
To: seaint(--nospam--at)
Sent: Thursday, November 06, 2008 07:25
Subject: Twisting of rebar

Is there an ACI document that specifies the amount that a bar can be

Hooked bars extend out of the top of a load-bearing 12" concrete wall.
The concrete roof slab has not been placed yet.  The hooks are intended
to be perpendicular to the wall, but have been placed parallel.  I
recommended that the bars be heated to 1350-1400F, straightened, and
then bent in the correct direction.  The contractor would prefer to
grasp the bar at the point where it protrudes from the concrete and
twist the bar 90 degrees.  The bar extends approx. 12" above the level
of the concrete, so 90 degrees of twisting in a #5 bar would be
occurring over a 12" length.  

I am entertaining this proposal because another case of heating and
bending bars on this job (without my approval) turned out to be a


David Dickey, P.E.
Lexington, KY

******* ****** ******* ******** ******* ******* ******* ***
*   Read list FAQ at:
*   This email was sent to you via Structural Engineers
*   Association of Southern California (SEAOSC) server. To
*   subscribe (no fee) or UnSubscribe, please go to:
*   Questions to
seaint-ad(--nospam--at) Remember, any email you
*   send to the list is public domain and may be re-posted
*   without your permission. Make sure you visit our web
*   site at:
******* ****** ****** ****** ******* ****** ****** ********

The information transmitted is intended only for the person 
or entity to which it is addressed and may contain 
proprietary, business-confidential and/or privileged material.  
If you are not the intended recipient of this message you are 
hereby notified that any use, review, retransmission, dissemination, 
distribution, reproduction or any action taken in reliance upon 
this message is prohibited. If you received this in error, please 
contact the sender and delete the material from any computer.  

Any views expressed in this message are those of the individual 
sender and may not necessarily reflect the views of the company.