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Re: Bar Joists

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Here's the capacity as presented in SJI's 60-YEAR MANUAL:
Allowable stress of 30,000 psi
Nominal depth: 18"
Resisting Moment (in-lbs): 325,000
Max. End Reaction (lbs): 4500
Approx. Weight (lbs/ft): 8.0
Span in feet = 30 ft:
    LIVE LOAD per linear foot which will produce an approx. deflection of 1/360 of the span:  140 lb/ft
For deflection of 1/240 of span multiply 140 x 1.5.
"...Standard Load Tables are applicable for concentrated top chord loadings...when the sum of the equal concentrated top chord loadings does not exceed the allowable uniform loading for the joist type and span and the loads are placed at spacings not exceeding 33" along the top chord."
Your span is one foot above a line that delineates joists that are to be used for roof construction only. Shear does not govern the loads.
Let me know if you need the specification too. I can fax it to you.
Teresa Dellies, P.E.
Senior Structural Engineer
Carter :: Burgess
3001 Meacham Blve Ste 200
Fort Worth, TX 76137

>>> thill(--nospam--at) 09/15/2000 10:40:21 AM >>>
I have structural drawings dated 1978 for a project in Oklahoma.
The drawings call out a 18H5 joist on 5'-0" centers, spanning 30'-0".
Anyone know what the capacity for this joist would be?
Anyone know what the history of this lettering for steel joists?
Most recent catalogs I have, list K series joists.
I also have older information on J series joists.
What do the letters actually mean?

Todd Hill
TK Architects, Inc.
816-842-7552 ext. 233

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