Have you ever seen this joist? 5

[Localeng]

I'm working on a project of installing a new heavy equipment on the existing roof structure. Roof structure is made of metal deck with insulation and open steel joists are supporting the deck.
Site visit found the existing steel joist is like this in the photo.
It reads 3371138-1J24, VULCRAFT 140.
I researched '75-YEAR STEEL JOIST MANUAL' and website, but I could find NO clue at all about this joist.

I contacted Vulcraft for requesting information of their old joist and I'm waiting.

Using structural analysis program to model and analyze the structural will be another option, you think?

Any good idea or comment are welcomed.
Thank you so much!

 

[JAE]

Vulcraft can help you with this. The first number is a project number for them.
The J24 is simply the joist mark and has nothing to do with the joist size.

Vulcraft should be able to look up the joist and get you a copy of the joist cut sheet which would have its size and/or load capacity.

In our area they are starting to charge for this - $200 to $400.


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[msquared48]

Boy. If they start doing that here, I guess I will not specify Vulcraft any longer.

Mike McCann, PE, SE (WA)

 

[Triangled]

same experience as JAE

 

[Paydroe22]

God forbid anyone wanting to get paid for their services.

 

[JedClampett]

Or they could mark their products with an easily translated piece number.
When I use a W12 x 26, no has to pay me to explain what it is.

 

[msquared48]

Sorry, but I have a real problem with a client paying more for a product than the original price just just because it is "special" as it were. If the client who owns the joists wants to make a change or addition (that could involve using the same product), he should not have to pay a surcharge or penalty because he needs the information that should have been supplied in the first place.

Mike McCann, PE, SE (WA)

 

[Ron]

What you have is a J-series joist, probably 24" deep. Check joist tables from about 1962 thru 1980. You should find this one.

 

[JAE]

Ron - not sure if that is correct. I've had many joist tags from buildings over the years from Vulcraft and that tag layout and numerology is pretty common that the J24 is a mark, not a size.
In fact I've got three tags in my office right now that all look like that and all the J numbers are marks from their shop drawings.

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[RobertHale]

I have to agree with JAE on this one. It is effectively the piece mark. Vulcraft in my area is pretty good about being able to produce a summary sheet with corresponding SJI designations for each mark. They haven't charged me for it yet, but they did threaten to charge me for the actual joist profile.

 

[Ron]

Sorry guys...you're probably right.....I glossed over the "Vulcraft" and was looking at a Bethlehem J-series table from the 1960's....similar designation for their joists. Too bad there's not a uniform standard for designations and tagging.

 

[XR250]

@Ron;

I made that same mistake once looking at the bar joist tag(never again!)

 

[JAE]

Ron I've always wondered why these joist manufacturer's don't just put their joist sizes on the tags - or weld them onto the chords or something. Sure would make for an easier job checking existing structures for new loads. And it seems that it would put a joist manufacturer in a better position liability-wise. If someone sets a 4000 lb. rooftop unit on a couple of joists without checking them, and the joists fail - the manufacturer could simply point to the provided joist size and suggest that the building owner had no excuse as the joist capacity was readily available.



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[Localeng]

Many thanks to all of you.

I was surprised with Vulcraft's charge for providing information of their product.
My service charge to check the capacity is not expensive, possibly cheaper than Vulcraft's charge, so my client may not want to spend money to get the information of Vulcraft's steel joist.

Fortunately, I could get access to the steel joists and measure the profile of steel joist. Its depth was 18" deep and the diagonal web members had 24" spacing.

Do you think it is possible to find the capacity of steel joist after running a structural program or hand calculation?

Thank you again!

 

[theonlynamenottaken]

@ Localeng:
There are two issues here...

1) your specific problem with this project. Getting the manufacturer to provide the joist designation and the capacity is the safe way to go. However, in the past I've been able to estimate which bar joist is in question using member self-weight. If you can get up close and get very good measurements of the bar joists components using calipers, you can then estimate the self-weight of the joist in plf. Using the old SJI tables you can then ESTIMATE which bar joist designation it is +/- one series. The problem is that to be conservative you end up choosing the bar joist series that is on the less heavy side, and often that won't provide the load capacity you may need.

2) the problem of being typically unable to identify existing bar-joists. As far as that is concerned it sounds like the solution is in our hands...

From now on anytime I specify bar joists I'm adding a note on the drawings, or in the specifications, or both, that requires:
"BAR JOIST MANUFACTURER TO PROVIDE SECURELY FASTENED, EMBOSSED METALLIC TAGS WITH THE SJI BAR JOIST DESIGNATION AT EACH END OF EACH MEMBER. THE TAG IS TO BE PHYSICALLY EMBOSSED WITH THE MEMBER TYPE, THE DEPTH AND THE SERIES (e.g. 20K5). TAGS WITH LOT INFORMATION, MANUFACTURING DATE OR OTHER MANUFACTURER'S INFORMATION SHALL BE SEPARATE AND DO NOT SATISFY THESE REQUIREMENTS."

 

[Once20036]

I've never had Vulcraft try to charge me for information, but I've also never found a situation where they still have the information on an old joist.

I once drew a Vulcraft engineer into a conversation about stamping the joist designation onto the tag. They couldn't (in my opinion) provide a very good reason as to why it wasn't done. They mentioned not wanting to stamp the capacity onto tags because an owner could mis-interpret that information and overload the joists.

Local - With existing joists like this, I typically run the calculations by hand.
Based on the age of construction, you should be able to have a good guess at the material strength.
Based on the top and bottom chord geometry - you should be able to determine allowable compression/tension.
You should also be able to check the allowable load for deflection.
I take these two numbers into the historic charts, make sure I have good alignment with a joist that was manufactured, and use those published values moving forward.

 

[hokie66]

I don't see why a product manufacturer should be held to a higher standard than a building owner. The design drawings would have shown the required joist size...but nobody bothered to keep them?? At least Vulcraft is still in business, while the opportunity to seek information from many manufacturers is not.

 

[theonlynamenottaken]

I can understand that perspective. If you lose the maintenance records for your car you can't really expect anyone to believe your memories of what maintenance work was done. However, your car can be identified without the owner's paperwork. It's like a car manufacturer making a car without any discernible manufacturer's label, model name, or tags indicating the engine size, tire pressures or GVWR... just a VIN that you have to pay to have translated.

Also, if there is no way to discern which bar joist is which how would anyone in the future know if the actual in-place bar joist matched what the design drawings called for?

 

[JAE]

Just for information - I understand that Vulcraft may be charging a bit to retrieve data due to the time involved for their staff to find the old shop dwgs in their remote warehouse and the time involved to make sure that they get the right data (internal QC). I would suppose also that the reason may also be to ensure that someone really wants/needs that data and isn't just asking and not actually using the data (i.e. checking off a box on a list somewhere).



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[SKIAK]

One of the concerns to be aware of when trying to analyze joists is the length of the weld provided at panel points and other locations, and it is not adequate to only measure one weld or assume a full length weld. Field verification of each weld would be required to ensure capacity, as I was told by a product rep. Manufacturers often specify a specific weld length at each connection to conserve materials. Sometimes welders weld the whole length and sometimes they weld exactly as shown on fabrication drawings. Not an exercise I've ever carried out, the product reps were usually able to get me the information I needed.