AWS D1.1 Structural weld details 2

[ColonelSanders83]

Hello All,

It recently came to my attention that we make Tjoint in W sections using a full pen B-U4b-GF weld on the flanges and opposing 1/4" fillet welds on the webs and flanges one jointing beam is smaller (see the attached picture).

In my reading of the code and looking at our weld procedure I have come to the conclusion that this may not be acceptable. Fistly our structural welding procedure is prequalified for the B-U4b-GF joint only and makes no mention of fillet welds. Unlike BPVC section IX wich extend butt welds to fillets D1.1 does not apear to do so. Futher more I can't find a way to justify the use of this joint design per the code rules. It seems I need full pen welds on these joints.

My questions are as follows.

1) Can I Justify the use of this joint design, and how would I go about doing so. If not, where in the code does it say so (I will get indescribable pressure to prove the case when I bring this forward to managment)

2) If I can use this joint design, how do I develop an AWS complient weld procedure for this type of joint.

I will greatly appreciate any help on this matter.



A question properly stated is a problem half solved.

Always remember, free advice is worth exactly what you pay for it!

http://www.ap-dynamics.ab.ca/

 

[connectegr]

If I understand your detail and post, I think you have two weld procedures. CJP weld of the flanges, which should provide a weld access hole (not shown) for backguoging access and welding. And fillet welds for the web/bottom flange. An SWPS is available for the B-U4b. And the fillet welds are a separate welding procedure for which a WPS is easily written. SWPS's are available for many of the weld details shown in D1.1. They can purchased from the AWS website. I don't know why, but fillet welds are not available as an SWPS. But, a CWI can write the WPS easily and it does not require physical testing for qualification.

http://www.FerrellEngineering.com

 

[ColonelSanders83]

Hello connectegr,

Right now we have one procedure (B-U4b) to do both types of welds. I beleive that we need two procedures as you state. Looking at the code requirements this doesn't seem like a big deal to put together.

We currently do not use an access hole but it seems that would be neccasary to meet the code requirements.

Thank you for your reply

A question properly stated is a problem half solved.

Always remember, free advice is worth exactly what you pay for it!

http://www.ap-dynamics.ab.ca/

 

[connectegr]

Many fabricators do not have a written WPS for fillet welds. Since the weld strength is specifically related to the weld geometry, I would think a procedure would be helpful. Especially when multiple passes are required to achieve the required size.

http://www.FerrellEngineering.com

 

[ColonelSanders83]

Hello conectegr,

Is there any way out of using weld access holes for a T joint made up with W members? If not where can I find an example of a proper W to W member connection with access holes to help solidify my case (the code is not quite as clear as I would like it to be).

A question properly stated is a problem half solved.

Always remember, free advice is worth exactly what you pay for it!

http://www.ap-dynamics.ab.ca/

 

[connectegr]

Another thought, an SWPS is selected by welding process and filler metal. And the procedure is applicable to several weld details, groove, J-Groove, U-Groove, (Joint Types), and state "FILLET WELDS: All Joints"

There are additional considerations for weld profile provided in D1.1. And there are also consideration for skewed conditions, such as Z-loss. I have written procedures for fillet welds with details for these special conditions.

BUT, technically your existing welding procedure may cover fillet welds to an extent. Just want to share as much information as possible, before you raise the warning flag.

http://www.FerrellEngineering.com

 

[connectegr]

Weld access holes are necessary in order to properly backguoge in the web area of the continuous web. For your welding procedure, B-U4b, which does not require backing, the access hole aids in minimizing shrinkage stresses, and residual stress of intersecting welds.

If the welds are not properly backguoged and repaired, discontinuities will be present in UT results. Without access at the beam web, UT will note areas of incomplete fusion.

Detail information can be found in AISC Specification for Structural Steel Buildings, J1.6

http://www.FerrellEngineering.com

 

[connectegr]

Also SEE Figure 5.2 in D1.1

http://www.FerrellEngineering.com

 

[gtaw]

AWS D1.X welding codes are intended to be used with other design codes and standards such as the AISC Steel Construction Manual. There are other considerations that have to be factored into the design that are not addressed by the AWS D1.X codes.

The welding procedure specification is typically the responsibility of the fabricator, no the design professional. Afterall, the WPS must include the welding process that is to be used. In many cases the design professional has no idea of what welding process is preferred by the fabricator.

A prequalified WPS can be developed when all the factors involved are known, i.e., welding process, base metals, filler metal, shielding gas (if required), joint details (must be prequalified groove, fillet, ploug, slot, et.), and specific techniques as found in Clause 3 of the D1.1 Structural Welding Code/Steel. Be aware that not all of the D1.X structural codes enspouse the concept of prequalified welding procedures.

You can enlist the help of a Senior Certified Welding Inspector to develop the welding procedures needed on the project. A Certified Welding Inspector may or may not have the knowledge and background to properly document or develop the welding procedure you need.

The WPS can apply to more than one joint detail or one weld type as long as it is addressed in the WPS.

My personal opinion is that a Standard Welding Procedure Specification purchased from the AWS is not specific enough to provide proper direction to the welder. I have clients that have purchased them, but then ask me to modify them to make them "usable" by the welder.

Best regards - Al

 

[connectegr]

Gtaw
I agree with your comments concerning SWPS's which can be purchased via AWS. They are not very useful in terms of welder information. However, they do represent the required information in terms of approval and qualification. I find that in most cases of steel fabrication these are clerical requirements and welder training and experience fill most of gaps. You are correct, as a designer and CWI, I rarely meet other engineers with any knowledge of the specific welding procedures.

http://www.FerrellEngineering.com

 

[gtaw]

I have always been under the impression the purpose of the WPS was to provide critical and useful information to the welder.

Many of the welding problems I encounter on a daily basis can be traced to welders not following properly written WPSs or WPSs with insufficient or incorrect information.

The belief that WPSs only serve a clerical purpose is most troubling when it is a CWI that says it. There is a critical element missing in a CWI's training and experience when the CWI misses the point and purpose of the WPS.

In a similar vein, the welder has to be trained to understand the purpose of the WPS and how to implement it properly to produce the desired results.

I have worked with numerous fabricators to reduce their rework and rejection rates. The being point is typically the WPSs and then followup training to ensure the welders and inspectors understand how to follow the WPSs. It works wonders when done properly.

A common phase I use is that a WPS that meets the code can be totally useless to the welder. The trick is to write a WPS that meets code and provides usefull information to the welder and the inspector. That is where experience as a welder is useful and it is not easily learned by reading books alone. A WPS that sits and collects dust is wasted effort and lost opportunity because it isn't serving the function for which it is intended. It is like an expensive piece of badly engineered equipment that doesn't perform its function.

Best regards - Al