Inspection of Existing Weld

[StrucDesignPE]

Need to have this existing weld inspected. Any suggestions on what kind of inspection I should ask for? Just visual...or maybe UT?

The vertical plate section welded to the plate on the bottom of the wide flange was pinched between a steel beam that moved and some other parts of the structure. The vertical plate section shows signs of yielding and I want to check the weld to see if I can just replace the vertical plate with a new one. Any thoughts or suggestions are much appreciated.

 

[darthsoilsguy2]

i'm not really following what you are describing with regards to the trauma. i'm having trouble figuring out where the field weld was that made those burn stains. i don't see any burn marks or bolts for what is holding the vertical plate strap (or angle?) to the clip. it kind of looks like there was supposed to be a bolt, but instead we have slightly out of aligned holes... it looks like the clip was shop-welded because of the coating beneath the stains.

UT only could play in if the weld needed to be full-penetration by design. If it is a partial pen weld by design (fyi. fillet welds are also partial pens in this instance), the UT2 inspector will just ask what the pass/fail criteria is and you will have the ball back on your court.

a visual weld inspection will only look at surficial conditions and not provide any information on underlying defects. The coating would need to be removed to clean metal.

i suppose, if anything, there could be merit to cleaning the welds and inspecting for cracks with dye penetrant and visual.... but i'm really grasping here since i don't understand the damage, not sure how this is connected and what the other side looks like, nor do we know the weld detail designed.

maybe a few more and closer pictures would help...

 

[StrucDesignPE]

I apologize for not being more clear. The vertical plate straps are welded to the clip which is welded to the bottom of the wide flange with what was detailed as a 3/16" fillet.

In the picture above, you can see that the horizontal W24 beam has moved to the right and pushed the strap. I would like to replace the strap but do not feel comfortable with assuming the welded clip is still ok. The vertical strap goes further down to support a catwalk. I don't know why there are no bolts in the connection. Two 3/4" bolts have plenty of capacity to support the loads applied to the strap. A lot of things about the way this was constructed don't make sense or don't follow the original plan. Building is nearly 20 years old. My main concerns for the weld are that it might have ruptured or have some type of smaller separation/cracking that would reduce the capacity of the weld.

 

[TehMightyEngineer]

If I understand what failed (plate was bent/yielded) then you're probably just looking for fracture in the weld or base-metal. I'd suggest cleaning the coating off and doing a dye penetrant (or mag particle) and visual inspection. If this weld failed it's likely visible on the surface. I doubt you would get much additional benefit from UT or X-Ray.

Maine Professional and Structural Engineer.

http://www.fepc.us

 

[racookpe1978]

Yes. Remove the paint, and ask for a dye pen (PT) or mag particle test. Mag particle might work though the paint.

Test the lower weld/mount of the vertical as well. It took just as much stress.

 

[TehMightyEngineer]

Also, just for curiosity, what is this? An elevator hoistroom?

Maine Professional and Structural Engineer.

http://www.fepc.us

 

[Ron]

Agree...clean the weld and MT or PT. UT and RT would not work for this.

Keep in mind that you now have residual stress in the displaced member and the welds.

 

[StrucDesignPE]

Ok, so what should my criteria be for pass/fail? There are more welds than this one, though this is likely to be the worst. I think I will call for a visual of all welds and a dye test of a certain few, or any that don't pass the visual.

This is actually a theater, over the stage area. I can't do any welding due to fire hazards.

 

[darthsoilsguy2]

AWS D1.1 is the criteria to your last question, which includes looking for cracks. Dye is great for finding cracks and makes the best photos if you need to convince someone to fix it. There is always a way to weld and if so... sometimes the best approach is additional members instead of shoring, cutting, and working with old metal that has been heated a few times (not to mention whatever the stress was)

i would think the weld between the beam/clip could be in pretty good shape since it looks to me like the clip was on-center with the beam web and that would stiffen the system greatly ... i have a hard time imagining the weakest link not being the weld group holding the strap to the clip which also appears to have been a field weld (neither of which we have seen).

The comment i made about the EGR providing criteria was meant to apply to UT because AWS D1.1 doesn't cover PJP welds. I've just seen a lot of Egrs get caught flatfooted when they are asked that question.

 

[racookpe1978]

Pass/Fail criteria is simple.

IF it has any crack - ANY crack at all - it has already failed and is now no longer carrying any weight at all. It can carry no additional loads in the future.

It IS a current danger NOW against further movement, further stress, and eventual (or near-immediate!) complete failure from roof movement (snow loads, wind, rain, or anybody stepping on the member for repairs, painting, or maintenance.

Now, if there is no crack, then the upper base metal (the horizontal beam), the weld metal (of beam-to-vertical plate) AND the vertical plate metal, AND the weld metal (of vertical plate-to-vertical strap) AND the vertical strap metal has already yielded, not "might not" yield further under current loads. Maybe.

You're focusing too narrowly on the single weld joint you can see.

All of the welds can be done in place in the overhead. it just takes a little bit more care.