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RE: Q: Lateral Resistance Capacity of Joist Seats

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> -----Original Message-----
> From: James Lane, P.E. [mailto:jamesalane(--nospam--at)]
> Sent: Monday, June 18, 2001 7:52 PM
> To: seaint(--nospam--at)
> Subject: Re: Q: Lateral Resistance Capacity of Joist Seats
> Call me tommorrow at work Bill. (210-490-4506) I believe I have the
> information you are looking for. Remember reading a design example on the
> subject. Probably can fax it to you. A fellow San Antonio Texan.

Thanks for the info, I have what I need now thanks to Mr. Stuart.

But your comments are well taken.

FWIW, I am coming at this from precisely the OPPOSITE direction:

Hitherto, I have ALWAYS put HSS 2.5s between the joists to dump the
diaphragm shears into the vertical elements (walls or steel framing as "drag
strut"). It simply occurred to me that where you have either a slight wind
load OR a long shearwall, you might actually be able to forego the collector
elements and rely upon the joist seat connection to transfer the load.

I mentioned that I did not have the old Vulcraft Joist Design Manual.
Matthew Stuart, it so happens, has put up a tutorial on this topic, based (I
believe) on the Vulcraft manual. It turns out that the "generic" K-series
joist seat looks to have, conservatively, a lateral capacity of about 500+

In my own example, I had a long shearwall that, even with a 110 mph basic
wind speed (three-second gust), gave me only 49 plf. A five-foot joist
spacing means I have more than twice the capacity I need to resist that,
without the expense of the collector elements.

Problem solved.

Thanks much for your input.

William L. Polhemus, Jr., P.E.
Polhemus Engineering Company
Katy, Texas
Phone 281-492-2251
Fax 281-492-8203

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