Joist Repair 2

[SteelPE]

I have a small project that is currently under construction. After the building was erected something happened and a open-web steel joist was damaged (the bottom chord of the joist was significantly kinked). Standard protocol has us go back to the joist manufacturer for a repair detail. Since the manufacturer isn't waiting around to fix joists on my project getting a suitable repair our of them took a few days. During that time the owner/contractor became inpatient and decided to hire a third party engineer to come up with a repair. A repair was given and carried out without my knowledge or approval.

I was given the sketches and the repair prepared by the third party is very similar to repair prepared by the manufacturer with a few differences the largest of which being #5 reinforcing bars (ASTM A615) being used to reinforce the bottom chord. I know that welding this type of steel is very difficult and should be avoided if necessary. Now they are looking for my approval of the repair which I have refused to give them to this point and I am thinking about having them do the repair specified by the manufacturer. Am I being too harsh on the Owner/GC? I am extremely aggravated at this point.

 

[CELinOttawa]

Your stamp, your rules.

I would likely do what I feel is technically and professionally *right* after a night's sleep. I would also tell the owner exactly that if they called.

 

[KootK]

Unless you have serious concerns about the technical merit of the fix, I'd let it go. You've every right to be miffed about not being kept informed. However:

1) I bet the fix stays as is even if you put up a fight. That's precisely the kind of fight that we generally lose.

2) If point one is true you'll just be needlessly pissing people off and making more work for yourself.

3) Joist reinforcing is mostly BS in my opinion. A worthy goal is simply to not mess things up worse. Undoing the first repair and undertaking another sounds like making things worse to me.

I'll leave it to you to decide if my advice is pragmatic or reckless. It's just what I would do when it's my stamp and my rules.

The greatest trick that bond stress ever pulled was convincing the world it didn't exist.

 

[SteelPE]

Kook,

I had similar concerns to your #3 as well. We are not talking about thick materials so you might do more damage by removing the existing reinforcing. However, I have decided to have them remove the reinforcing bars and add the proper steel rods as specified by the manufacturer. I'm growing tired of trying to work with people who only want to play by their rules.

 

[KootK]

Are your chord members hot rolled or cold formed? If hot, I'm sure you'll be fine. If cold, you may be left with a smouldering ruin of a bar joist.

The greatest trick that bond stress ever pulled was convincing the world it didn't exist.

 

[BUGGAR]

AWS has stringent rules on welding A615. Can they furnish all this documentation? Don't forget the microetch samples. And appropriate welder certifications for welding rebar. And chemical analysis or tests of sample welds using pieces of the actual rebar used? And, and.........


Bob

 

[KootK]

Crap, I didn't catch the A615 bit. I would consider that a serious technical issue. Could you leave the bars in place and weld plate to the underside of the chords? Yeesh, these goofballs really are not doing themselves any favours.

Question for any weld gurus: if you weld non-weldable steel to weldable and mess it up, will the damage be limited to the non-weldable steel? Or will the weldable steel be damaged as well?

The greatest trick that bond stress ever pulled was convincing the world it didn't exist.

 

[CELinOttawa]

The main issue is hydrogen cracking in the Heat Affected Zone (HAZ). My understanding is that this damage is limited to the steel which wasn't weldable, though a mixing of the weldment consumable material and base material can occur.

As a general rule, all steels are weldable. Some steels have limited weldability which needs to be accounted for with very careful pre and post heat treatment, sometime specialized treatments can be available, and ultimately the procurement of a matching electrode can be tough.

Note that I am *not* a weld expert, but have worked closely with several. This is the general stuff that rubbed off...

 

[jike]

I would explain to the Owner (in a letter) your concerns with welding and what repairs that you recommend. I would include an article if you can find one. Ask the Owner directly, if he would like to retain your services to do these repairs. If he says "NO", this will put the ball in his court. If you consider this a serious liability issue, send a copy to your liability underwriter and the building official. If the work is not done properly, list it as an exception in your compliance report to the building official.

Incidentally, I would not approve this either.

 

[ztengguy]

As the other engineer to write a letter taking full responsibility for the repair. Make sure he is a PE

 

[chicopee]

About posting a picture of the damaged joist as to get an idea of the magnitude of the damage.

 

[SteelPE]

Chicopee,

The concern isn't whether or not the joist as currently damaged is repairable, it has more to do with using materials that are not easily weldable..... even though the GC/owner seems to think everything that is metal can easily be welded. I would be more inclined to accept the repair if steel rods had been used vs reinforcing bars.

 

[hokie66]

Why don't you guys lobby to get all your reinforcing up to date so that it is weldable?

 

[wannabeSE]

Has the contractor submitted a valid Weld Procedure Specification (WPS) for welding the reinforcing?
Has the contractor submitted Welder's qualifications?
Have they submitted mill certs for the reinforcing?
Is special inspection required?

By the way, I would have the repair design engineer review and approve all of the above documentation before being submitted to the SEOR for approval.

Has the higher strength material been considered in the design? If the reinforcing strength is combined with joist steel strength, the joist steel will yield first.

Unless the contractor (sub) is experienced with welding A615 and has all the required documentation, it seems like a lot of trouble to use A615 in lieu of A706 and a typical grade 50 steel bar may be less trouble than either rebar options.

 

[SteelPE]

So I received communication from the owner/gc today, 5 days after I told him the repair as done in the field in unacceptable, that he going to leave the repair in place. This means that he poured the suspended slab on top of this joist after I told him not to until the repair was done. So now I have to call the building inspector this morning to let him make the decision as to whether or not the repair, as completed in the field, is acceptable. If he says everything is fine then I will follow everything up with a letter stating the situation and the BI decision.

 

[CELinOttawa]

Yup. Good call; I agree with your approach entirely.

Do make sure to CC the BI.

 

[KootK]

Would it be within the bounds of forum policy to share this thread with the owner? From his perspective, he's got one SE saying that he has to spend a bunch of money and another saying that he doesn't have to do squat. I'm not terribly surprised by his decision. Perhaps the consensus opinion developed in this thread might convince the owner that there are legitimate safety concerns in play with this.

On the other hand, maybe it would seem too sketchy to back up your professional opinions with those of strangers online. I myself am really a line cook at Chilli's.

The greatest trick that bond stress ever pulled was convincing the world it didn't exist.

 

[dcarr82775]

SteelPE,

You are doing the right thing. Why can't the 3rd party engineer provide a stamped letter taking the responsibility for his joist repair?

 

[KootK]

Now that the welding has been done, is there any inspection or non-destructive testing route that could be taken to verify that the welding is ok?

The greatest trick that bond stress ever pulled was convincing the world it didn't exist.

 

[SteelPE]

Just a follow up:

I spoke to the building inspector on 10/22 and explained my situation. He wasn't pleased and said that he was planning on shutting the project down later that day. A few days later I talked to the site and they said that the building inspector came onsite and instructed that the repair be completed as I have requested (removing the existing material and replacing with weldable material). Today, 10/28, I received a phone call saying that the building inspector has changed his mind and is going to allow the existing repair (made with ASTM A615 rebar) to remain in place. I guess he went full circle.

I am now going to write a letter explaining the situation as I understand it and CC the building official.