D1.8 States,"backing"

By jrw159

Date 10-20-2008 19:41

Richard,
I think that D1.1 clause 2.17.1 might be what you are looking for.

jrw159

By Richard Cook (**)

Date 10-20-2008 20:06

I did see that, but my take is if "welded from one side". If you remove and weld the second side would that be prohibited and would you still be able to be prequalified? My take would be yes. That section states "groove welds, made from one side only". I didn't accept that section as prohibiting the use for non steel backing in all cases. Where am I thinking wrong? That section does present itself, but I don't think all inclusive.

By jrw159

Date 10-20-2008 20:36

Richard,
I see what your getting at now. Honestly I don't see a problem with it, and I see how it could be looked at in both ways. I looked through the clause 3 and 4 as well as hit every avenue I could find through the index, and I do not see anything prohibiting it.

Good question for sure. LOL I am sure that some of the more seasoned veterans will chime in.

jrw159

By Duke

Date 10-21-2008 01:56

Here we go...

By kipman

Date 10-20-2008 20:28

John,
Woody is correct on this one. D1.1 does not require WPS qualification for the use of non-steel backing, unless the weld is to be made from one side only. For example, if I plan to use ceramic backing and then remove the ceramic and backgouge and backweld, that in and of itself does not require WPS qualification.

Woody,
I am not familiar with D1.8, but seeing as how you are looking at the commentary of it is it possible that the text you refer to is itself referring to single sided welds?
Mankenberg

By jrw159

Date 10-20-2008 20:39

Mankenberg,
Thanks for clarifying that. I would agree. :-)

I am not familiar with D1.8 and was wondering about your question as well. ???

jrw159

By Richard Cook (**)

Date 10-20-2008 20:57

AWS D1.8 is the new Seismic Provisions that AWS adopted from FEMA recommendations for structural steel buildings. Came about from the Northridge earthquake in California.

The specific section I referred does not specify in regards to one sided welding. In D1.8 it is in reference to special welder qualifications, they have to weld up a mock up of a connection that is considered demand critical in the seismic standards. They require the welder be qualified with the type backing whether back gouging or not. Using non steel backing I have always considered to be a welders qualification variable as D1.8 has made it. D1.8 refers you back to D1.1 for WPS requirements.

thanks, the head ache is about gone, trying to convince an third party inspector, when he can't even provide references for is call. All he said and has provided is "you can't do it". "Power" plays hard in the game.

By jrw159

Date 10-21-2008 00:21

Richard,
Even if you are wrong, and I am NOT saying you are, if the third party can not "show his call" then you are in the drivers seat. You have taken the steps to either confirm or negate the issue. I personaly would have a hard time holding my head high telling someone they can not do something without showing them why.

jrw159

By jwright650 (*****)

Date 10-21-2008 11:13

I interpret this the same way as kip does.....if you mess with the second side you can still call it prequalified. ie. use a non-metallic backing, then gouge out the second side and reweld....

Northridge didn't want to repeat the failures due to the one sided welds that did not have full penetration and a notch was left in place to be the stress raiser at the root.

By trapdoor (**)

Date 10-21-2008 04:30

I don't have the code in front of me right now but the last time i read through section 2 of d1.1 "2.17.1" was for cyclic tubular or something more critical than static non tubular. I think.

By swnorris (****)

Date 10-21-2008 14:06

Even though you're removing the backing and welding the second side, WPS qualification is required for non-steel backing. Welding against ceramic backing requires training and skills. The welder has to learn to control the arc differently than with steel backing. With steel backing, the weld metal is to fuse to the backing bar so the arc is directed to the front of the puddle. With non ferrous backing, the arc has to stay in the puddle or the electrical continuity will be interrupted and weld quality will suffer.

By jwright650 (*****)

Date 10-21-2008 14:48

Scott I don't follow the relevance completely....if you are taking out the root on the second side (where it meets the ceramic backing) what difference does the type of backing make?

By swnorris (****)

Date 10-21-2008 15:08

I think it's basically all the same when backgouging and welding the second side, but seems to me it's different on the first side because ceramic or copper is just a little more difficult to weld to than steel backing, particularly if the root is wider. You'd weld a wider root with a different technique when welding to ceramic or copper backing as opposed to welding to steel backing, wouldn't you? Also, if you already know up front that you're going to have to remove the backing and backgouge the second side, which prequalified joint (if any) would you use? One with a smaller root opening designed for backgouging, or a wider root opening that's designed for backing, but not designed for the backing to be removed, and then the second side gouged and welded? Seems that technically speaking, neither joint type could be used, could it?