Identity of open web joists 3

[campbelltc]

Wondering if anyone can help me with identifying a joist manufacturer by the type of joist. The top and bottom chords (13 3/4" deep joist) are a T section: 2 1/4" wide x 1/4" thick flange with a 1/2" high x 3/8" wide web. The bottom chord slopes up beyond the last panel point to form the beam seat. The chords are 1/2" diameter bar with 16" between panel points. I didn't see any tags on the joists. Photo is attached. Cornerstone on the building says 1949. I believe I have access to the SJI historical data, so any help with identifying a manufacturer would be appreciated. Thanks.

 

[JAE]

Looks like maybe a Truscon joist...see attached - table 2 and Figure 20:



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[stevenspm]

You can find the catalog for the Truscon Joist at

https://archive.org/details/TrusconOpenTrussSteelJoistsForFloorConstructionNdAsPurlinsForRoof

They do seem to match your photo.

 

[campbelltc]

Thanks, guys. That was perfect.

 

[mellis2]

Hello,

I have a similar situation, and I am drawing a blank on getting good data. The style of construction matches very closely the Truscon OT joist, but my dimensions do not match any of those in the linked publications.

My joists are 19 3/4" deep, and have a panel point spacing of 22". The top and bottom chords are T shaped, 3 3/8" wide, with a 3/16" flange. The stem of the T is approximately 3/4" tall, and tapers from 0.4" to about 0.62" where it meets the flange. They have 3/4" diameter rod web members, and support about 3" of concrete.

Pictures attached. Any advice?

 

[Liam Nesson]

Hi Mellis2,

Although not for owsj (but for coalescing filters), i have in the past contacted suppliers i suspect might own the said produce and showed then the photos. Its best to call them, explain your situation and hope u get a guy whos been around for a while and can identify his own product or maybe point you in the right direction.

 

[campbelltc]

Mellis2,

I believe yours are probably Truscon Clerespan joists. They look exactly the same as the ones I encountered except for the size and panel point spacing. The load tables for Clerespan joists are in the latter pages of the link that stevenspm provided above, but I also understand that there's probably no way to positively identify what joist size they correspond to. If it was me, I'd run a hand or computer truss analysis to determine the stresses in the members and back into a load capacity after comparing the analysis to a calculation of the maximum strengths of each member. As a guide, I'd check the top and bottom chords at the center (maximum chord compression and tension), and the second round web from the end (maximum compression).

 

[mellis2]

I considered that they were perhaps Clerespan series, but they are installed on about ~26' span, and the table for 20" joists starts at 29'-0". I built a model of a single joist, and backed out an allowable live load of about 80 psf. I then applied that load to the supporting girders and that matches their capacity pretty closely.

Thanks for the suggestions.