Rebar bending question
Rebar bending question
(OP)
I am looking for either a formula or a table showing the amount of "creepage" or stretch rebar has while it is being fabricated in the rebar shop.
Obviously the main things to know would be the angle of the bend, the bender pin diameter and the rebar diameter.
From memory it is not an absolute length but generally good enough for fabrication.
An example of what Im looking for is: I want a length of rebar to be 2m long with a 1m 90 degree bend. The diameter is 35mm and the bender pin size is 360mm.
How much will the rebar stretch during bending ? This amount would be deducted from the bar cutting length.
Any help appreciated
Obviously the main things to know would be the angle of the bend, the bender pin diameter and the rebar diameter.
From memory it is not an absolute length but generally good enough for fabrication.
An example of what Im looking for is: I want a length of rebar to be 2m long with a 1m 90 degree bend. The diameter is 35mm and the bender pin size is 360mm.
How much will the rebar stretch during bending ? This amount would be deducted from the bar cutting length.
Any help appreciated





RE: Rebar bending question
RE: Rebar bending question
Obviously the radius has a great effect on the amount the bar stretches and is dependant on the diameter of the mandrel used on the bender.
Its been a few years since I have had a need to know about "creepage", I used it on the Hibernia GBS in Eastern Canada and wanted to re-familiarize myself with the basics before I start a new job on monday in Australia.
The basic formula without the use of anything absolute was something simple like 1/2 of the angle plus 1/2 the rebar diameter = the amount to be deducted from the shearline cut length, therefore to get a 35mm dia bar @ 2m with a 1m 90 degree bend the cut length would be 2000+1000-45-17=2938
Like I said, its not absolute but usually within tolerances.
If anyone else can refresh my memory I'd appreciate it.
RE: Rebar bending question
http://www.electrician.com/electa1/offset.html
Try this search on “developed length of bending rebar". Lots of good leads to information.
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RE: Rebar bending question
You cannot use the pin dia because of springback (elastic recovery) but then I suppose it is not necessary to be so precise for a rebar bend.