The CWB and AWS welding standard specify that if there is not a size specified a grove weld shown on a drawing is to be full pen. Depending on plate thickness you might need to indicate if you are looking for 25% pen 50% or 90%. The grove angle may or may not be relevent.
You should provide the E (effective weld size) and S (depth of grove). Unless you can assure that the weld will be completed by FCAW or GMAW weld processes, you should assume that SMAW (stick) welding is used and determine the appropriate prep geometry. For most manual processes the bevel angle is 45 deg.
Note: Your plate thickness must be adequate to provide the minimum root face. It is less expensive to increase the plate thickness and use a partial pen, then to revert to CJP weld of the thinner material.
The engineer designing the connection should provide the AWS weld designation and specific information if necessary. If the engineer does not know this information, how will the detailer or welder? The short-cut is showing CJP or PJP
This is a general rule...
For example a CJP, TC-U4a, is typically a field weld with backing for flange welded moment connections. This information is very helpful to the weld inspector when verifying the welding procedure and qualifications. The specific detail, groove angle, root opening, may be a fabricator or erector preference, but should be detailed on the erection drawings for future inspection and verification of erection fit-up.
I frequently see design drawings with a bevel groove weld symbol and nothing more. This wisdom is continued on the shop drawings and erection drawing. Is the intent CJP, or PJP with ??? effective weld? You know what (ass)(u)(me)ing does for us. Do you really want the iron worker to be the first person to recognize that more information is needed. If you really need a CJP weld for strength, do you want to try and determine if an AWS procedure was used after the welding is complete.
I have seen a million welder short-cuts made with WPS in hand. But, at least they were aware that a procedure is expected.
Connect-
Actually, I'm glad to read your rambles.
What I have is a very small wideflange in tension welded to an endplate.
I want to simply use a fillet all around, but the top of the wideflange must be flush with the top of the endplate. So, I plan to call out a fillet all around except along the top where i was going to use a partial pen.
Somehow, I seem to have run into this exact situation a lot over the last few years.
...usually when i run into this, I detail out the weld on the drawing in an enlarged detail to make sure I get what I want.
I admit, like a lot of engineers, I am lacking in knowledge exact weld processes and terminology....like TC-U4a...if I see that, I have to look it up everytime
ToadJones,
You have a BTC-P4. You can convert the 2-sided fillet to a partial pen.
SEE ATTACHED - Hope this helps.
I do understand that AWS requirements and weld designations can be an additional headache. Between the engineer (EOR or connection engineer), fabricator, and erector these requirements should be clearly defined on the shop drawings and erection drawings. IMHO Just another reason the EOR should require a licensed connection engineer. Someone who understands the force/design requirements and the fabrication erection issues.
Connect-
That is what i called out "BTC-P4"
Thank you for the conversion....I really appreciate that.
why is there a need to put both the size and effective size on the weld call out?
ToadJones
Regretfully, in your case a CJP (TC-U4b, shop weld with backguoge) may be required.
If the weld strength required is greater than 5.25 k/in. the flange is not thick enough for a partial pen.
At 5.25 k/in. the (E) effective weld size is 1/4.
S = 1/4 + 1/8
min PL = S + 1/8 = 1/2
BUT, in the proper position with FCAW/GMAW (wire feed) you could use BTC-P4-GF. S = E = 1/4, and min thickness would be 3/8"
5/16 all around was not required for strength, but rather min weld size due to plate thickness and the weld all around, believe it or not, because that is what the owner will want to see.
This is not for a lot of connections....just one big bracket.
When sizing the welds, a 1/4" fillet weld on the effective tension area (like a tension base plate design) was was sufficient.
This will be made in the field by our own welders so cost is really not a concern, at all.
If you call out BTC-P4, will the welder know that the size given is the groove depth or the effective weld required? If he uses the dimension as the groove depth, you could loose 25-50% of the weld strength. And it is difficult to tell visually after welding. UT testing can determine the penetration depth. But, do you specify NDT of PJP welds?
For CJP welds most of the welding information is provided in the WPS. The strength is equal to the material strength. And there is no need to provide an effective weld size.
For PJP welds the information missing from the WPS is the effective weld size. If the welder knows the "E" he can determine the rest of the information from the WPS.
The reason I believe this information should be clearly shown on the shop drawings and erection drawings. Is that the WPS is not provided to the CNC operator or other non-welders in the shop. With some of the new CNC equipment, the beam line will prep the flanges and cut the access holes. The welder walks up to a piece ready for welding, he verifies the fit-up, cleans the surface, and starts welding.
I do understand the simplicity of CJP for the engineer. But, this a much more expensive process. Especially when joint details are repeated.
E @ 1/4" should suffice....I'll have to check my numbers.
Connect- you've been more than helpful and I dont want to waste anymore of your time.
To be quite honest, I am embarrassed to ask for some of these clarifications. I have been doing this long enough that I really should know better. But, as a design engineer doing mostly structural analysis on steel structures and foundations and only lately doing my own detailing as well, I have just recently gotten more involved in more detailed weld call-outs.
