It is my understanding that the SJI publishes LOAD TABLES that establish
performance criteria. The manufacturer may use any individual members,
within a yield strength specified, to achieve the load carrying capacity and
deflection performance prescribed by the load tables. So it is impossible
to know the joist designation without finding a tag or doing your own
analysis and testing.
My approach would be to locate a tag wired to the joist end; it will give
the manufacturer and conforming specification. If no tag is found, I'd
defer to the SJI, who I think will help for a fee.
If the owner is not willing to pay SJI, I might just give up. If there's no
way to weasel out of it, I'd analyze it as a simple truss, assuming the
worst for yield strength. My letter report would state a) the procedures
used to derive the capacity, b) that the derived capacity is to be
considered a preliminary indication of performance, and c) that load
testing is required for verification.
John P. Riley, SE
Blue Grass, Iowa
----- Original Message -----
From: Bruce Pooley <bdpooley(--nospam--at)home.com>
To: Seaint List Serve <seaint(--nospam--at)seaint.org>
Sent: Saturday, June 17, 2000 7:32 PM
Subject: Evaluation of salvaged Steel Joists
> I have a client that has salvaged some steel joists from a commercial
> structure and wants to use them in a garage structure. These joists are 18
> inches deep. The top chord is comprised of 2 angles, 3/8 inch thick with 2
> inch equal length legs. The webs are 5/8 inch steel rods and the bottom
> chord is constructed using 2 7/8 inch rods. The salvaged pieces are
> approximately 31 feet long (some are slightly longer as it appears that
> were cut by a torch). The Steel Joist Institute provided a reasonable
> that they are an 18H8 series. They estimated the joists to be from 1979
> the H series was in effect.
> Does anyone know how to evaluate the strength and stiffness of these
> What is your opinion of using these in this structure (second story floor
> 100 psf)?
> Bruce Pooley