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Up Topic Welding Industry / Technical Discussions / Weldable rebar
- - By albcwi Date 05-09-2005 21:48
I have been in the industry for better than 15 years and still see on drawings the statement "weldable rebar". My experience is that all rebar is weldable to AWS D1.4 code. Ineed to educate some Engineers on this fact and was wondering if anyone could provide some resources to use to educate these Engineers.

Thanks
Parent - - By DGXL (***) Date 05-09-2005 22:17
albcwi:
I guess your not a special inspector. All ASTM A 706 is considered "weldable rebar" by many civil/structural engineers. This is in several test questions on the ICC Special Inspector examination for SS&W inspectors. Many local building depts. also refer to this material spec as ...
Parent - By swnorris (****) Date 05-10-2005 10:29
A couple points of interest regarding A706: The carbon equivalent is controlled so as to not exceed 0.55%, so under normal conditions, no preheat is required for commonly used bar sizes (up to #6). Typically, embedded attachments are designed so that they must develop the full tensile capacity of the rebar, so, a minimum weld is required. The weld of the rebar to the base metal must consequently be welded to develop at least the same strength. In lap joints, the minimum lap length required to develop the rebar is as follows: #3 = 2", #4 = 2 1/2", # 5 = 3", #6 = 3 1/2", # 7 = 4 1/2", # 8 = 5". The minimum (flare bevel) weld (E) = 5/32 db. For butt joints, the minimum fillet weld to rebar diameter required to develop the rebar is as follows: #3 = 1/4", #4 = 5/16", #5 = 3/8", #6 = 7/16", #7 - 1/2", #8 = 9/16".
Parent - - By albcwi Date 05-10-2005 19:51
Can you direct me to the code or engineering document where the term is specified. I have not been able to track this document down. I understand that due to the low carbon content that A706 bar is considered "weldable", but according to D1.4 all bar can be considered weldable. I am looking for supporting documentation for this information.
Parent - - By DGXL (***) Date 05-10-2005 20:45
albcwi,
All rebar specifications listed within the D1.4-98 are weldable, and that is why they are listed within the code.

However, not all rebar is weldable! I'm not going to go through my ASTM stds. and type every one that is not, but there are quite a few that cannot be welded as noted in the standards.

Get your hands on a copy of ASTM Volume 01.04 or the ASTM Referenced Standards from the ICC and see for your self.

R= "regular" bars
W= "weldable" bars
Parent - - By albcwi Date 05-11-2005 17:23
I have a copy of the 2000 IBC ASTM Referenced Standards sitting in front of me. I have been through the Standards and have found that all of the references for bar and wire are represented in D1.4.

According to the Standards for A706 and A615 there are two designators for these bars: W or S to designate that they meet the criteria for both bars. The W represents that both bars meet a dual criteria rather than being weldable. Since this designator can be on both A706 and A615 according to your statement these bars are interchangeable, but according to the Code there are very different criteria for the welding of these bars. Also according to several different manufacturers here is the list of letters that are used for designation and what they stand for:
S= for billet steel (A615M
(rail icon)= rail steel (A616M)
(rail icon) R= for rail steel (A616M)
(axle icon)= axle steel (A617)
W= low alloy steel (A706M)

These are all recognized by D1.4 for being weldable to the code with proper preheat and/or postheat. It also states in 1.3.2 that any bar can be welded with Engineering approval based on the chemical composition and its CE% value as long as it's weldability is qualified with a procedure in accordance with the code.
Parent - - By DGXL (***) Date 05-11-2005 18:18
Hi albcwi:
I used to be an L.A City Deputy Building Inspector. Believe it or not when you go to sit the exam, they will fail your answer if you quote the standards as you did in your last post.

If you don't say the "w" is for "weldable", you fail the question and possibly the exam. My friend had to re-sit the exam again (and more $$) because he disagreed (argued) with the exam dudes over the W on A 706 bars. We all had to study the bar icons, but they don't always apply to some individuals, you have to interpret as they do - I guess. (The Emperors New Clothes?) This is yet another reason I do not perform Deputy work any more...

Also, not all rebar produced is listed in the Standards for the IBC, only those with APPROVED or prequalifed applications. There are many rebar specifications that are not specified as weldable.

The R and W noted above are common designations to simplify the identification scheme, again, I guess. Maybe your better off not being a Special Inspector. Life is much easier.
Parent - - By albcwi Date 05-11-2005 19:11
Hey DGXL,

I am not trying to be a pain, as I have a couple of special inspector certs., not the SS&W, but plan to have this in the future as well.

It seems that real world and code world do not always agree from experience. We should try as field inspectors to clarify some of these descrepancies.

I am not working as a field inspector at this time, I am in a fabrication shop, so I have the ability to change some of the information that is put on our prints, to help the field inspectors to perform their job easier is the object of this excercise. Also to try to educate the engineers in my small part of the world.
Parent - By DGXL (***) Date 05-12-2005 02:08
alb:
I always prefer a shop to field work myself, when I did special/deputy inspection.

You'll find building officials have their own mind set, and then there's all the beurocracy to get past. Not all are lost though, I know several local officals who are quite sharp. The problem is many of the experienced people are due for retirement soon, some already have.

Most BO's who are worth their mud will get to know you, your experience and your abilities to work with contractors. Believe it or not some deputies get a cert. and they think their Buford Pusser, unreal. You have to be able to deal with the contractors and the public and be able to interface with the plan check or EOR. Or the deputy simply is good at passing exams, but knows not what he/she does. Even worse as this makes us all look bad. Extensive post on this in the archive threads.

BTW, Los Angeles is one of the last places in the country where you can perform work as an independent bulding inspector (a contractor to all you work for). Everywhere else you have to work for a lab w/an engineer. And we had to fight for that right back in the 90's. As far as: "We should try as field inspectors to clarify some of these descrepancies", I put in countless hours of my time for the local chapter of the Structural Engineers Ass. & I will be doing another presentation for them in one month on Welding Documentation and Welding Processes. Second one this year, and about my 8th total on various welding related topics. A good portion of L.A. Cities new moment frame QA Standard Plan is my blood, sweat and tears (my presentation will coincide with the new QA plan). All at no charge for my time.


Based upon your posts here and some of your replies to others, if you decide to hit the streets, you will do well. Good Luck, wear a harness and watch out for the penetrations in the decking.
Parent - - By ctacker (****) Date 10-21-2007 18:52
i too have been under the impression "W" means weldable, i seen a company go under for using the wrong rebar, 6 months of work shot down for using non weldable rebar!
Parent - - By darren (***) Date 10-22-2007 04:52
as a bozo on the dark end of the light stick i still don't have a definitive answer to which bar is weldable. ive always thought w meant weldable. im getting a little older so i realize what ive always thought doesn't add up a pinch of sh*t on some days.

done my share of deck welding/structural and had any where from a guy that never inspected anything on the site just signed the papers to having another inspector who measured the deck welds with a set of vernier calipers, to and this is one of my favorites, hanging off of a 30+ foot extension ladder welding around the corner on a column  in the rain and hearing a whirring noise , i looked up to find an inspector in a brand new genie man lift right behind me intently watching me weld while under an umbrella, i asked if maybe he thought it was a little ironic that he was comfortable to just watch and i was hanging like a drunk squirrel actually doing the weld. the whole concept eluded him entirely.
darren
Parent - - By aevald (*****) Date 10-22-2007 05:40
Hello darren, you're not the only one who has dark spots. I too "had" been of the opinion that the "W" stood for weldable and any others weren't considered to be so. After reading a bit more of this string I am believing that this isn't necessarily the case. I can see that I better back up a bit and read all of this more closely so that I can fully grasp the information that it contains. Slightly off track a bit, but not too long ago I understood that some rebar had been specified to only meet the D1.1 code if it was stick welded with E7018, any others out there to shed a bit of light on this? I say this because I have seen many shops weld rebar with both FCAW-G and SMAW E7018. I had also hear that this had changed. Just curious. Best regards, Allan
Parent - - By Tommyjoking (****) Date 10-22-2007 06:44
interesting thread....cause I always thought rebar welded like sh*t...stick it together thats it...I never worked a job where I had to tack up a whole floor or anything...it was always tied.   I did work a freeway job for a HUGE contractor once welding wire baskets/reinforcement...they were recycling the concrete....very well set up company out of I think S.C.        I know the baskets were weldable because the provided paper on them.   But many times I have been asked to weld up the odd rebar thingy...and more often then not it welded like crap....this post just made it clear...I was more then likely welding the wrong kind together.
Parent - - By 803056 (*****) Date 10-27-2007 12:59
The range of chemistry and mechanical properties for rebar is very wide and liberal to say the least.

One of my best cold chisels is made from a piece of rebar.

Weldable or not, there are certain precautions that need to be observed when welding rebar. My best advice to anyone welding reinforcing bar is make sure you have the CMTR for the darn stuff that you are welding and work out the carbon equivalency to determine the proper preheat and match the filler metal strength to the tensile strength of the bar. Check the sulfur and phosphorus content to verify it is below 0.04%.

As for SMAW, FCAW, GMAW, you will need to use low hydrogen practices in all cases. Both SMAW with properly stored low hydrogen electrodes with matching tensile strength and GMAW spray mode with a matching filler metal fit the bill. However, not all FCAW electrodes meet the low hydrogen requirements and the storage conditions to maintain low hydrogen characteristics are not usually observed, so the process has earned a bad reputation.

Best regards - Al
Parent - - By ctacker (****) Date 10-27-2007 16:52
make sure it aint radioactive too, I remember we had a truck load of the stuff about 25 yrs ago from mexico i think it was!
anyone remember that!
Parent - By 803056 (*****) Date 10-27-2007 21:51
Great memory! Yes, I remember it. Seems like it was detected at a nuke under construction.

Al
Parent - By Duke (***) Date 10-28-2007 03:17
Welding in the rain... thats a good one.  When the drops fall of the front of my hard hat, its a rainout, as far as welding goes.
Up Topic Welding Industry / Technical Discussions / Weldable rebar

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