Rebar Stirrup & Ties 4

[PE1999]

Hello Need some input on this RFI I received from a contractor. Is this a typical practice, "unities"?
Thank you.

 

[KootK]

If anything, the one piece ties are probably structurally better than the multi-piece versions. I'd still be inclined to lay eyes on the final pattern for good measure but, at first blush, I see no reason to oject.

 

[hokie66]

I'd like to see the bending machine that can make that 'unitie'.

 

[Trippelsewe]

The important thing it that the bars are adequately restrained in accordance with your relevant code. If bent differently it may not achieve that (eg if they close it without 135 degree bends).

Also no idea how that would be bent as one piece.

 

[BAretired]

I don't know where the name "unities" came from, but there are six ends, so it is three separate ties. The advantage of three separate ties is that the vertical bars are prevented from buckling at each right angle.

 

[KootK]

Reading the tea leaves on this, it wouldn't surprise me to see the proposed, unitie configuration look something like this, with or without 135 terminations. In addition to being unitie-able, it would open up the central pour lane nicely. Given that this is probably just nominal, gravity pier rebar, I doubt that anybody's getting too excited about seismic hooking, etc.

 

[SWComposites]

Request the sub send a sample “unitie” for inspection.

 

[bugbus]

I found a couple of examples on the internet, but it seems more trouble than it's worth (vs separate ties):

 

[dik]

I'm not big on concrete anymore... but don't they need to be enclosed by 135deg max angles? I can see unities being a big problem in tying the cages for the longitudinal bars...

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[JohnRwals]

It's not difficult to bend complicated shape with the automatic bending machine.
As an example,

 

[cliff234]

My rule-of-thumb has always been to stick to bar bend configurations that are shown in the ACI detailing manual. I also tell our younger engineers to imagine they are bending the bars and installing the reinforcing in the field, and ask themselves if they would be able to easily and quickly install what the are detailing. I suggest calling a local rebar fabricator and ask them this question.

 

[Aesur]

I actually had the opportunity to see something like what bugbus posted above bent, wasn't that difficult and was cool to see what their machines could do. I'm with KootK here, I suspect the final product will be better than the 3 separate ties. At least the RFI did say "can we get rid of these and just have the outer tie".

 

[hokie66]

Aesur,
I think you left out the word 'not'. If the single tie can be bent as JohnRwals showed, go for it. I haven't seen a machine that can do that.