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Up Topic Welding Industry / Technical Discussions / A449 ANCHOR RODS - WELDING EXTENSIONS
- - By rherrera Date 05-23-2003 12:44
We have some anchor rods too short - contractor error. Per AISC Solutions Center, I received the following:

A449 bolts are Quenched & Tempered. When you weld to them you need a weld procedure that preserves the properties of the original bolts. It's kind of tricky in the field and there are no prequalified welding procedures per AWS D1.1 to do this.

Does anyone know of an acceptable procedure to do this?

Thanks
Parent - - By jwright650 (*****) Date 05-23-2003 13:55
http://aws.org/cgi-bin/mwf/topic_show.pl?id=3709

Above is a link to an earlier post concerning short anchor rods. Look this over and see if it could be of some help to you.
John Wright
Parent - - By jwright650 (*****) Date 05-23-2003 14:16
Anchor problems seem to be a common occurrance these days. We see anchor rods set with the pattern out of square, wrong elevations, completely off the column grids, wrong stick through and it seems nobody cares until the steel hits the site and problems with fit-up arises. Money spent up front doing an anchor survey sure does pay off, in my opinion. We can wash off base plates and relocate holes on columns in the shop a lot easier than if the column have been stood up and steel is in the air.
Now you 've heard all my complaining and I'll stop now that I feel better. Where are all those guys that used a string and a framing square that could get the anchor rods within a sixteenth gone to? Lasers and high tech equipment has taken over and now anchors are set several feet off the grid.
John Wright
Parent - - By DGXL (***) Date 05-23-2003 18:09
RH:
I just completed another project whcih required welding these anchors.
I already know what it says in AISC, but I have done this repair several times with satisfactory results. Kleinfelder crushed one of their pull testing fixtures trying to break my welds.

DGXL - 5, Naysayers - 0


Post a contact (I do not post my addy) if your interested in retaining my services. I have "canned" procedures for welding Q&T anchors.

John:
One of my clients subs got the anchors so far out of place recently, we had to cut off exsisting BP's and install larger ones due to the concrete dudes. They could only get 2 correct within the pattern. They help me earn a living.
Parent - By jwright650 (*****) Date 05-23-2003 18:15
I feel like it's completely out of hand. Every job we have has anchor problems. I mean every one. Some of the columns we can catch before they are shipped then the others are expensively fixed in the field.
John Wright
Parent - - By WBI (*) Date 05-23-2003 18:25
Then there's my case where a crawler ran over a 1 1/2 AB that had been laid out and verified by the surveyor. That one took a proceure to repair. Welding Q&T is not a good practice to take from a can. Every condition is a bit different. That's just my opinion. In my case the bolt had to be cut off and the concrete chipped back to get a flat face for the chisel point of the new bolt.
Parent - By DGXL (***) Date 05-23-2003 18:48
WBI:
Just an fyi, my clients build some weird sh#!, uplift is a big concern (large area canopies, tensile structures using fabric or glass as a structural element, etc.) resulting in high tensile loads on the anchors. Have also welded Q&T 4140 anchors (ASTM A 354 Gr. BD) with satisfactory results.

I love a challenge. All involved said it could not be done including the RDP. There are some humongous structures in Vegas and here in CA with my repairs. These canned procedures are not implemented without information on the specific application, approval by the RDP and building depts. I don't just sell paper.

If the concrete guys don't screw it up, the backhoe operator expedites the process of retaining my services.
Parent - - By G.S.Crisi (****) Date 05-26-2003 17:55
John Wright,
I'm one of those guys. Apart from string and square we used also a measuring tape, a spirit level to level off the anchor bolts that were close to each other and a water level made out of a hose, for the bolts that were less close. And the tolerance was one millimeter, which is less than the one sixteenth you mention.
Back in 1970 I authored an article on Hydrocarbon Processing magazine (one of the best magazines in the world devoted to oil and petrochemical industries) whose title was: "How to set anchor bolts precisely". We had developed a special template to increase the precision of the operation, and in those days this was considered very sophisticated. This is why Hydrocarbon Processing was interested in publishing it.
Giovanni s. Crisi
Parent - By jwright650 (*****) Date 05-27-2003 12:35
Giovanni,
I can appreciate those guys who didn't have the luxury of having all that high tech stuff they have today and got things set right. One would think the latest and greatest gadgets would only enhance the accuracy of the settings, but it really hasn't. I'm amazed at the pyramids and how the builders fit large stones with such tight tolerances.
Detailing used to be like a work of art, each draftsman had his/her own style and was proud of each sheet of drawings like it was art. The lettering was ledgible and line weight was precisely the right weight and their work, when fabricated, fit.
Things have changed and not all for the better. I would like for some of those guys with the primitive tools to have access and the knowledge to use these new high tech gadgets and just see how well they do.
Some things to think about,
John Wright
Parent - - By G.S.Crisi (****) Date 05-23-2003 23:03
There's a difference between Rob's problem posted a few days ago on this same site and rherrera's one.
Rob's nut is made of A563, an easily weldable steel, whereas rherrera's is made of A449, quenched and tempered.
First of all, quenched and tempered steels are difficult to weld, although not impossible.
Second, Rob's nut will melt partially when welding, and the quench and tempering will go fishing. So, the condition imposed by AISC (the weld procedure must preserve the original properties) won't be obeyed.
As the anchor bolts are already embedded into the concrete foundation, there are no means to restore the "original properties" after welding. Am I wrong?
rherrera, if I were you, I'd forget about AISC and weld the nut anyway. You have no other choice, have you?
Giovanni S. Crisi
Sao Paulo - Brazil
Parent - - By DGXL (***) Date 05-23-2003 23:14
G.S.:
A good point was made. This is the reason for the repair. The RDP's (through calculations) determination that these anchors do not require the "full strength" of the anchors in the Q&T condition. The as welded condition of the anchors we welded still exceeded the design minimum.

BTW, I have done this repair without the luxury of the dillution that occurs by welding a nut or sleeve. It was Q&T anchor to Q&T anchor. Also did a repair this year that did not require welding. All of these repairs have to get approval as I noted previously.

Enjoy the long weekend ya'll.
Parent - By jwright650 (*****) Date 05-27-2003 12:17
I mentioned a fix in another post that we had worked out with the engineer on that job and he blessed it at the time. We turned down (machined on a lathe) about half of the flats on some of those "Coupling Nuts" to where half of the nut actually fit into the hole in the base plate and allowed thread engagement with the short anchors. I guess it depends on how short your anchors are as to whether or not that would work in your condition.
Just thought it might be an alternative to welding,
John Wright
Up Topic Welding Industry / Technical Discussions / A449 ANCHOR RODS - WELDING EXTENSIONS

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