CJP groove weld 1

[LeonhardEuler]

Hello complete newbie to any sort of welding here. I'm learning to analyze weld strength on the job and I have a question.

I have a connection detail that calls out CJP welds, but it shows a butt weld on one side and a fillet on the other. This is a beam web welded to a column flange.

My question is if a CJP weld is detailed and the parent material doesn't fail does the weld even need to be checked for strength?

 

[LeonhardEuler]

I have done a FEA model of the whole assembly and the Von Mises stresses are less than allowables at all locations. Do I still require connection calcs?

 

[canwesteng]

Not unless there is any impact or fatigue loading.

 

[dhengr]

LeonhardEuler:
Your thinking is generally right, if the parent metal is strong enough to take the loads, a CJP weld should be o.k. if done right. You might ask if that CJP weld on the beam web to the col. flg. was ever designed in the first place, or if it isn’t overkill showing the laziness of the original designer. Fillets on both sides of the web are usually adequate and save prep. time on the beam web and save welding time and consumables. Given the proper process and procedure, the proper weld joint design, matching (some slight over-matching) weld metal and a good welder and weld, the parent metal will control the design of this joint. So you might say ‘o.k. by inspection.’ But, what you have to watch out for is that all of the above are done well, and the detailing and welding don’t introduce stress raisers which defeat the whole idea of an adequate welded joint. Your detail, if I understand it correctly, assumes a one sided groove weld, with a min. land at its root. Then, it is assumed that the fillet on the other side will boil out any imperfections (crap) at the groove root area, and penetrate into good groove weld metal, to give you a full pen weld. Actually, not too bad a concept when done right. But, enough crap at the groove root, and you don’t boil it all out, you just mix it into a defect in the fillet weld. The other thing is, you’ve said nothing about the CJP (?) at the beam flanges, and how they get a full pen. weld in the whole ‘k’ area of the beam web/flg. That can be a great big stress raiser, brittle spot, hard spot, lack of much elasticity or flexibility (too stiff) to tolerate all the multi-directional welding going on right there. That region often shows cracking and defects before it is ever even loaded.

 

I'm learning to analyze weld strength on the job

Not the ideal approach.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[LeonhardEuler]

not the ideal approach

but such is life