Bar Joist Identification 1

[hdn32]

I am trying to determine the capacity of existing roof joists for new HVAC units.

I found the identification tags, which read "06-8656 NJ 12" "20-B7".
Here are measurements that I took:
The joist depth is 20 inches.
Bearing depth is 2 1/2 inches.
Top & bottom chords are cold-formed steel and parallel.
Web membs are 3/4" in diameter.
There are two rows of horizontal bridging.
The building was built after 1963.

I could not come up with any spec or load carrying capacities by looking up the SJI's "75 year Steel Joist Manual".

Thank you for any help to determine joist spec or capacity.

 

[mrengineer]

http://www.steeljoist.org/investigation/

 

[BigInch]

That needs to be evaluated in terms of your local area and the dead load existing now, the future live loads, snow, ice, etc. prevalent in your area that these roof truses must resist in combination with the new dead loads you want to add. I don't think its appropriate to do on the internet, so my sincere tip is to look under Engineers, Registered, Structural in your local Yellow Pages.



Going the Big Inch!

http://virtualpipeline.spaces.msn.com

 

[hdn32]

To mrengineer: Thank for the link to the SJI web site. I am waiting for response from SJI.

To BigInch: Thank for your time.

 

[BigInch]

Cheers


Going the Big Inch!

http://virtualpipeline.spaces.msn.com

 

[JAE]

hdn32, the designation on the tag is probably an in-house project number and joist mark used by the joist manufacturer. Usually, we try to contact joist mfrs from around our area to find the source of the joists and they then use the number to look up the size for us.

 

[hdn32]

Thank you JAE.