Welding Rebar

[chuck1870]

Is there any way to weld grade 60 rebar? A contractor has cut the rebar over a column in a two way slab system. The owner wanted to put in a recess shower stall and the contractor chipped out the concrete and cut out the rebar. Then they decided they should check with an engineer. We considered using connectors to splice rebar, but there just isn't enough room since the rebar are spaced very close together and the connectors conflict with the perpendicuar bars.

 

[JStephen]

They make rebar with higher alloy content and lower carbon content that can be welded (I think it's a A706 spec), but if that isn't what's been used, it quite likely can't be welded reliably.

 

[civilperson]

If the chemical analysis is provided for the bars in question (carbon equivalent), then a welding proceedure can be furnished to conform to ANSI/AWS D1.4 Welding Code. A minimum preheat is required for bars when the chemical composition is unknown. See ACI 318, R3.5.2.

 

[JAE]

Yes, - its ASTM A706 for weldable reinforcing bars.

 

[UcfSE]

It sounds like you have an existing problem and cannot use A706 bars, unless they are already in place. A615 is not "good" enough for welding and may have cracking problems at the welds. If you cannot get a mechanical splice in there I don't know what else you can really do. I would have the contractor chip back far enough to get the mechanical splice in, and probably far enough to stagger the splices so you will have some more room.

 

[hokie66]

It just depends on the type steel you have. In the US, most Grade 60 steel is not good for welding. In Australia, most of our reinforcing is, if it is not imported.

 

[BigH]

In PRC (China) in the area I worked (and sure elsewhere too) welding of rebar was the norm even though it was only to be done if approved by the Engineer. Not sure of the equiv US grade of the steel or composition - but they welded all "normal" rebar.

 

[dancristescu]

there is a "Head" that you can thread over rebar (large diameter bars-I think) that will eliminate the need for a "bend". Unfortunately I dun't know the name of it. We used it on # 14 and #11 bars at the connection from friction pile to grade beam. It's an approved device...

 

[mrengineer]

1) Agree with civilperson response - One of the major precasters in the Denver area does this a lot - sometimes when chemical composition is known, sometimes not.

2) The device Dancristescu is referring to is the Lenton Terminator.

 

[chuck1870]

Thanks for all the responses. Looks like ACI 318 R3.5.2 may be the answer.

 

[csd72]

Chuck,

You can get mechanical splices that do not require threaded ends.

Lenton does these for smaller bars up to #6.

http://www.erico.com/products/QuickWedge.asp

You just need to have the existing bars projecting 6" past the concrete face (or cut away the concrete around it that distance).

I imagine these would be cheaper and easier to do on site than welds that may need to be pre-heated and inspected.

csd