From: Roger Turk <73527.1356(--nospam--at)compuserve.com>
Date: Tue, 29 Jun 1999 12:26:06 -0400
These appear to be Armco Deep High Strength Shortspan joists.
20DH8 Capacity 280#/ft based on strength (38' span)
Capacity 145#/ft based on deflection L/360
20DH9 Capacity 372#/ft based on strength (36' span)
Capacity 197#/ft based on deflection L/360
I can fax you the pages from Armco's booklet if you would like.
A. Roger Turk, P.E.(Structural)
Ed Fasula wrote:
>>I'm looking at a '72 built school for re-roof, they intend to remove the
existing built-up roofing system and replace it with a new ballasted
membrane roofing system.
In order to check the capacity of the steel joists, I looked into the
50-Year Steel Joist Digest by the SJI. Unfortunately, the joists shown on
the original building plans are not listed. First of all, can anything be
learned from these non-standard spec numbers - second if so, what or how??
Obviously, the alternative is to analyze the joists, but the ceiling finish
would have to go.
Here are the numbers listed (they are shown clearly on the plans):
20DH8 (6'-6" o.c. & span 37'-8")
26DH9 (6'-6" o.c. & span 35'-8")