1960s era joist 3

[CUTiger1989]

Working on a job in South Carolina to determine capacities of existing joists. Most I have had to measure and search the historical SJI tables.

But, for one gymnasium we have drawings that specify a 60G22 steel joist for the roof framing. The span is approximately 101'-0". They are spaced at 8'-0" o.c. I have yet to find a table or manufacturer for the 60G22.

If any of you can point me in the right direction, it would be greatly appreciated.

 

[jerseyshore]

G's are usually joist girders.

 

[hokie66]

My first call would be to Vulcraft.

 

[jerseyshore]

Did you contact SJI also?

 

[CUTiger1989]

Thank you for the replies!

@jerseyshore
Like you, I suspected the 'G' designation meant 'girder'. However, there are no joists framing into it. So, I did contact SJI. They were stumped as well.

@hokie66
I will give Vulcraft a try.

 

[robyengIT]

Once I had from SRE attached catalogue (Haven Busch). Hope it can help

 

[CUTiger1989]

@robyengIT
Thank you for your reply.

I actually have that catalog from another school project I worked on. Unfortunately, the Haven-Busch joists have WT sections as top and bottom chords. The joist I am looking at now have double angle top and bottom chords.

 

[JAE]

This doesn't match exactly but Great Western Joists have a 60" deep joist that spans about 100 ft. and weighs about 22 plf.
See page 20 of 24 of the attached.

 

[CUTiger1989]

@JAE
Thank you for your reply.

Looking at the top/bottom chord sections for the GWS joist do match what I observed in the field. Interesting that they used hat sections for the chords. I don't believe I have ever seen that.

 

[JedClampett]

The way it was explained to me was that the joist manufacturers will guarantee capacity (230/110), section properties (12K3), etc., whatever you specify, but they'll make them out of whatever they have that day. Angles, hats, T's, etc.
It makes them a joy to work with.
True conversation:
Me; "We specified 110/220, but they want to put a AHU on there, what's the capacity?"
Joist Guy; "It's good for 110 lb./ft. live load and 220 lb. per foot total load."
Me; "Yeah, but it must have a little margin?"
Joist guy; "It's good for 110 lb./ft. live load and 220 lb. per foot total load."
Me; "I have your calculations, but they're indecipherable. How can I figure out the section properties?"
Joist guy; "It's good for 110 lb./ft. live load and 220 lb. per foot total load."

 

[jerseyshore]

Are the drawings with the notations shop drawings or design drawings? Is it possible the G is actually a different letter on an old print?

 

[CUTiger1989]

@jerseyshore
The designation is on an architectural (!) design drawings. The drawing is dated 05/15/70. I have attached a screen clip.

 

[phamENG]

Don't be too shocked that they were spec'd by the architect. Back in the 60s there were likely quite a few architects that could remember when structural engineers didn't really exist - at least not in a form that we'd recognize today. The architect did it all.

I can't make heads or tails of the designation, either. You'll probably have to use detailed field survey data to do a complete analysis of the joist.

 

[jerseyshore]

It's a little blurry, but it does look like 60G22. Are they 60 inches deep?

You'll probably just have to do a typical survey like pham said and see if SJI can find a close comparable.