Have you ever seen this joist?
Have you ever seen this joist?
(OP)
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!
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!






RE: Have you ever seen this joist?
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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RE: Have you ever seen this joist?
Mike McCann, PE, SE (WA)
RE: Have you ever seen this joist?
RE: Have you ever seen this joist?
RE: Have you ever seen this joist?
When I use a W12 x 26, no has to pay me to explain what it is.
RE: Have you ever seen this joist?
Mike McCann, PE, SE (WA)
RE: Have you ever seen this joist?
RE: Have you ever seen this joist?
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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RE: Have you ever seen this joist?
RE: Have you ever seen this joist?
RE: Have you ever seen this joist?
I made that same mistake once looking at the bar joist tag(never again!)
RE: Have you ever seen this joist?
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RE: Have you ever seen this joist?
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!
RE: Have you ever seen this joist?
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."
RE: Have you ever seen this 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.
RE: Have you ever seen this joist?
RE: Have you ever seen this joist?
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?
RE: Have you ever seen this joist?
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RE: Have you ever seen this joist?