Metal building bolt inspection question

[gmyers]

Hello, we have just completed our 50x112 metal barn. I had the special inspection for the bolts. The engineer arrived and we tested the tightness of the bolts only to find to 80% were not to "code". I called the construction company who installed the building and he said the bolts were set to be "snug tight" and that the engineer was wrong.

So, I looked at the plans and they say- All bolt joints with A325 type 1 bolts are specified as snug-tightened joints in accordance with the most recent edition of the RCSC specifications. I went to look in the google machine and was unable to figure out what the most recent specs for those bolts were.

If you have any insight I would love to hear it, Thanks Greg

 

[dcg9381]

I assume the bolt up building design has a stamp. I'd take the plans/specs to the engineer that did the inspection and see if you can get an explanation of why he failed it.

 

[tominboise]

How was the tightness tested, to be found not to code? Snug tight usually means as tight as one can get it with a normal spud wrench, and all the plies of the connection have been pulled tight.

Snug tight inspections

 

[gmyers]

I assume the bolt up building design has a stamp. I'd take the plans/specs to the engineer that did the inspection and see if you can get an explanation of why he failed it.

The engineer was a great guy who went with me in the lift and helped me tighten every bolt that needed to be inspected. We spent 3.5 hours on a friday afternoon completing the task. He explained that it was not my fault and he wanted to help me. He let me know if the construction crew was here he would have left. Not all of the bolts needed to be inspected just the inner 3 bays and my carport. There are still 2 end bays and a porch bay that were not inspected. I called the construction company and asked that they come out and make sure the rest of the bolts are tightened and he said maybe in about a month or so he could fit me in.

I need to know from the knowledge of the group if I need to go scorched earth on the guy or if he is in the clear.

 

[vrinner]

Here is what my plans said and I also had to get a special inspection done. I hired a "Special Inspection" company (I had no idea that was even a thing), they did the inspection and no issues were found. As dcg9381 mentioned, have the inspector tell you specifically why they failed, have the builder come back out and correct. Should be pretty easy to resolve.

 

[gmyers]

How was the tightness tested, to be found not to code? Snug tight usually means as tight as one can get it with a normal spud wrench, and all the plies of the connection have been pulled tight.

Snug tight inspections

He used a torque wrench set to the foot pounds for a 3/4 inch and a 7/8 inch bolt. They were like 325 lbs or so. I did not set the wrench I just helped tighten the bolts. There were gaps between the plates that the engineer pointed out. Some you could just see light where others you could see threads on the bolts. Snug tight seems like an odd standard to me but I dont know what I dont know.

 

[strutaeng]

Per the RCSC specification, turn of the nut method is just assuming an ironworker cranks on the bolt with a certain length spud wrench. There are no requirements for torque wrench for that method. I've never looked at the actual specification in too much detail, but I think it just says something like enough force to bring the mating surfaces together. If I'm walking a jobsite for a site visit, I don't want to see nuts I can spin by hand for this method.

It sounds like the ironworkers/erectors didn't tighten them with a wrench?

We don't really do slip critical in this area, but we do have some project in the West Coast. I'd have to ask the other guys what they do or how the testing lab checks for those: Slip-critical (pretensioned) is very different. There's a lot more requirements for that method and different methods to tighten the nuts/bolts.

 

[WNYflyer]

If utilizing the bolt pre-tensioning method known as the "Turn-of-Nut" method the nuts must be rotated from the "snug-tight" condition by the amount indicated in table 8.2 of the structural joint specification of December 31, 2009

Below looks to be the latest edition of RCSC specification. Have no idea which edition of the code was referenced in the building code upon which your building was supposed to be designed though.
https://www.aisc.org/globalassets/aisc/publications/standards/a348-20w.pdf

 

[readhead]

Having been a steel fabricator and erector for twenty two years I can say that your inspector is wrong. Ninety percent of erection work requires bolts to be snug tight. That is, as tight as can be with a typical wrench. The only time I have encountered torque specs is on government jobs. The inspector assumed that there should be torque specs. Did he look at the plans? Did he take apart any connections to see that the Faying surfaces were clean and without primer which applies to torque specs? If he charged you get your money back because this guy had no business inspecting your bolts. The erector is not coming back because he knows there is no problem.

 

[readhead]

As mentioned by WNYflyer "turn of the nut" is a different process and wasn't even mentioned in the OP's question. Generally the only conditions that require inspections are slip critical. Inspection usually requires that 10% of the bolts be checked. Any bolted connection can be faked very easily. Turn of the nut can be marked after the nut is tight. Huck bolts can be disconnected and re tightened and no one would know. I would use indicating washers because they have a visual indication if they squirt paint or they can be easily checked with a feeler gauge. There was nothing wrong with your bolts.

 

[jack stand]

The erector built to the plans,
it would have taken very little effort or time to go another 3/4 turn and would have left him liable for problems if that was a requirement that fulfilled his responsibilities.
It is curious to me the term "snug", seems a little vague but I'm not a steelworker.
I don't think that I'd loose sleep over this but curiosity would probably have me doing exactly what you seen to be doing.
Edit: The 2 guys that posted while I was typing would close the book on this for me.

 

[WNYflyer]

As mentioned by WNYflyer "turn of the nut" is a different process and wasn't even mentioned in the OP's question. Generally the only conditions that require inspections are slip critical. Inspection usually requires that 10% of the bolts be checked. Any bolted connection can be faked very easily. Turn of the nut can be marked after the nut is tight. Huck bolts can be disconnected and re tightened and no one would know. I would use indicating washers because they have a visual indication if they squirt paint or they can be easily checked with a feeler gauge. There was nothing wrong with your bolts.

I stand corrected, I took post #5 as the general note for the OP's building. Seeing that the OP is in California there could be some special criteria that many areas may not have.

 

[gmyers]

Thank you guys very much....I feel better now. Like I said before, I just didnt know and the engineer had me spooked. I guess he was wrong. I will have another post about my windows later to ask for more advise.....stand by.

 

[brownbagg]

.

 

[Leaflessshadetree]

He used a torque wrench set to the foot pounds for a 3/4 inch and a 7/8 inch bolt. They were like 325 lbs or so. I did not set the wrench I just helped tighten the bolts. There were gaps between the plates that the engineer pointed out. Some you could just see light where others you could see threads on the bolts. Snug tight seems like an odd standard to me but I dont know what I dont know.

If there were gaps where you could see light of threads it sounds like the members were not pulled tight enough to be fully touching. Even the builders replying here mention that is critical even if a specific torque isn't.
Did tightening the bolts close those gaps? If so I'd tighten the rest.

 

[Renegade1LI]

Surprised they didn't use tension control bolts, takes all the guess work out.

 

[readhead]

This is a very simple structure and does not require any special bolting requirements. Snug-tight is the appropriate process here. Multi story buildings are erected every day using the same bolting process.

 

[rayra]

This whole thing is ludicrous. And I say that despite living in CA for 30yrs of my adult life.

 

[vrinner]

So I'm thinking that the reason for "snug tight" on building bolts is because buildings don't shake, move, rattle around for the bolt to come loose...like things in a car do. Is that the reason?

 

[readhead]

I suppose that is correct. There is also redundancy with multiple bolts in every connection.

 

[WNYflyer]

So I'm thinking that the reason for "snug tight" on building bolts is because buildings don't shake, move, rattle around for the bolt to come loose...like things in a car do. Is that the reason?

I do primarily heavy industrial work for steel and chemical plants and we typically require the primary framing members have their bolts be "pre-tensioned" at a minimum rather than "snug-tight". Those structures often want to shake rattle and roll due to supporting pumps, fans, overhead cranes, pipe and ductwork moving to due thermal movements, fatigue issues, load reversals, etc.

Regular old buildings with primarily static loading, i.e floor/roof loads, wind, seismic typically can be designed assuming "Snug-tight" bolts though there are a few circumstances where pre-tensioned bolts are still required in those type buildings.

 

[Stuart in MN]

Just so we're clear..."snug-tight" basically means as tight as they can get them? And, the engineer said they were too loose and then torqued them to 325 ft-lbs? Does that mean they in fact weren't as tight as snug-tight?

 

[brownbagg]

.

 

[mcbane]

I went to engineering school in the 1980s before tech terms like “oh my god” and “couple rattles” came out. Back then, snug tight meant tighten till there is no gap between flanges and there is enough resistance that you need a cheater bar to keep tightening. Then go 2/3 turn. Mark with a paint pen so the inspector can see you at least faked doing it right.