Spot welding rebar???

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What do you-all think about this:    Is it better to spot weld the joining of rebar in a concrete form,  or tie them together with wire?
Reply:If I remember the code book that I read eons ago, there is not to be any welds on the rebar in footings , piers, or floors. Only to be tied , but that's been several years back. Sent from my iPhone using Tapatalk
Reply:I don't know about code work,but rebar is strange stuff to weld,I would wire tie it.
Reply:If you care any sort of bit about what your building wire tied is what you would wantVantage 500's LN-25's, VI-400's, cobramatics, Miller migs, synch 350 LX, Powcon inverters, XMT's, 250 Ton Acurrpress 12' brake, 1/4" 10' Atlantic shear,Koikie plasma table W/ esab plasmas. marvel & hyd-mech saws, pirrana & metal muncher punches.
Reply:Tied is typical, but some structural bar is welded. You often see welded bar on large projects where lots of heavy steel bar is all interconnected. Not all bar is weldable though, you need to have rebar that is designed to be welded. AWS D 1.4 covers welding steel reinforcement.https://connect.ncdot.gov/resources/...ce%20Angle.pdfhttp://www.concreteconstruction.net/...m45-340900.pdf.No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Someone here posted what is as close to a Primer on concrete placement, thickness, WW square and rebar as I've ever seen a couple of weeks ago. I think it was one of the mods but I can't recall. Just a brilliant, informational piece for someone like me who's getting ready to lay a large home shop floor and he'd be the best to answer this. I hope he sees this post and responds. I wanted to copy it and save/use it but\ I can't find it.
Reply:I'm betting that was me Jon.http://weldingweb.com/vbb/showthread.php...oncrete-Priceshttp://weldingweb.com/vbb/showthread.php...g-a-shop-build.No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:As far as strength is concerned, it really makes no difference whether it is tied or spot/tacked welded so long as it is secure enough to prevent the rebars from losing their position while the wet concrete is being placed and worked out.If you are doing a code inspected job then you will have to follow the coded specs.  If you are doing the job for yourself and it is not a coded project, use whichever technique you want.Wire ties or welds only need to secure the rebar lattice into its proper shaping and spacing until the concrete sets and cures.Once the concrete sets and cures, the effects of wire ties or welds are moot and add no further strength to the overall concrete pour.The biggest risk with using welding instead of wire tie is the reasonable chance that welding will produce undercutting on at least one of the rebar members and that will weaken that section of rebar.
Reply:Originally Posted by walkerweldThe biggest risk with using welding instead of wire tie is the reasonable chance that welding will produce undercutting on at least one of the rebar members and that will weaken that section of rebar.
Reply:Moons ago I welded the rebar for a gov't job. The Army Corp engineer was pleased. It was against Ca. code though. Its best to tie with wire. Flat work not as particular. Structural you'll prolly never see it.Arcon Workhorse 300MSPowcon 400SMTPowcon SM400 x 2Powcon SM3001968 SA200 Redface1978 SA250 DieselMiller Super 32P FeederPre 1927 American 14" High Duty LatheK&T Milwaukee 2H Horizontal MillBryan
Reply:It was and THANKS!  Originally Posted by DSWI'm betting that was me Jon.http://weldingweb.com/vbb/showthread.php...oncrete-Priceshttp://weldingweb.com/vbb/showthread.php...g-a-shop-build
Reply:the wire lather's can't be all wrong. tied is the accepted method of joining re-bars in re-enforced concrete construction. i  worked on only one repair job where rebar was welded to the top flange of a beam in the flat position. i've read about threaded splicing connections (sleeve lock and/or flange coupler) but never saw them on any job i was on.i.u.o.e. # 15queens, ny and sunny fla
Reply:Originally Posted by docwelderthe wire lather's can't be all wrong. tied is the accepted method of joining re-bars in re-enforced concrete construction. i  worked on only one repair job where rebar was welded to the top flange of a beam in the flat position. i've read about threaded splicing connections (sleeve lock and/or flange coupler) but never saw them on any job i was on.
Reply:Get your self one of these wire feeders in the top of this picture, and have at it. A good rod hand will make a welder look foolish! Attached ImagesDon’t pay any attention to meI’m just a hobbyist!CarlDynasty 300V350-Pro w/pulseSG Spool gun1937 IdealArc-300PowerArc 200ST3 SA-200sVantage 400
Reply:From a structural engineering perspective.  I would not recommend it, unless you do the following, follow all the guidelines and restrictions in the welding code regarding what elements can and can not be welded, what electrodes are recommended to be used in combination with which grades of rebar, for instance,...forget it with A615 which is the most commonly specified rebar specification as is does not weld well.  Be ready to request permission from owner and engineer to cover cost of analysis of where you are going to spot weld and if that location is allowed for the specific design part,..e.g. beam, footing, slab, near a naturally occurring inflection point or potential crack/highest stress location, or stress reversal and fatique locations.  Plenty of discussion and code commentary to cover this, most of which involves too many considerations to merit this unless this is massively produced element where by doing the research or hiring an engineer to give you the final word on the subject and if yes,...would save you lots of money in the long run by spot welding in lieu of tying for some reason.  A properly tied rebar cage is very study provided it is handled correctly.  I've seen two story double layered steel cages for precast architectural wall being picked up in two places without failure of any reinforcing ties.  Obviously less important for massive, overly reinforced items but very critical for tall/slender walls, columns, beams, and elevated slabs and backside reinforcement in cantilever retaining walls.  Hope this helps, too much to cover really, in short.   If it's A615,....which it probably is,...don't weld it.  Ask engineer if you can replace it with A706, and then ask if you can spot weld the cage and where if any locations he would prefer you didn't.  He may not have it in his budget for a complex job to entertain your request; however, he for simpler items, with oversized reinforcing, he may say OK.  I wouldn't ever assume it's OK to spot weld rebar in general.  Have a good one.