The 15/32" is scant ½" sheathing. The #8 drywall screws are ABSOLUTELY not structural fasteners!!!! Drywall screws are hardened to very high levels which makes them VERY brittle. This does not allow the fastener to bend slightly, under load, and redirect/distribute/share load with the neighboring fasteners in the group. Framing nails are soft enough to do this, as are steel WOOD SCREWS. Drywall screws and deck screws (Galvanized drywall screws) are NOT structural fasteners. The bugle heads of drywall/deck screws also allow the screw to be tightened flush with the surface of the panel. This will also allow the fastener to be pulled UNDER the surface of the panel, thereby reducing the fastener's capcaity. Drywall screws are intended to hold up drywall. They do that, and that alone, very well. Do not even use them to fasten kitchen cabinets to the wall!!
I hope I didn't get too excited about this, but drywall screws are NOT the wonder fastener that contractors would like us all to believe.
The design capacities of the 10d nail vs. the #8 screw can be found in the NDS or in the code books.
Mike Perakis, P.E.
>>> michael.bryson(--nospam--at)englekirk.com 03/21/01 05:19PM >>>
Does 15/32" Floor Span Sheathing w/ #8 drywall screws @ 4" sound like a
reasonable replacement for 3/4" Struct I w/ 10d@6" ?
----- Original Message -----
Cc: <inctbuh(--nospam--at)lehigh.edu>; <cd(--nospam--at)cmdg.com>; <fgeorge(--nospam--at)acec.org>;
<sjaeger(--nospam--at)nspe.org>; <NSPE(--nospam--at)aol.com>; <nwebster(--nospam--at)asce.org>; <jhowell(--nospam--at)asce.org>;
Sent: Monday, March 19, 2001 4:28 PM
Subject: Chicago SKYSCRAPER Cladding Problems
> Attention SEAINT members:
> I don't know how much your local media is covering the following
> structural/architectural engineering story, but we have a major problem
> here in Chicago with a 70 year old skyscraper.
> The terra cotta cladding is in serious disrepair and coming off the
> It your are interested in this story PLEASE visit the SEAOI website
> We have provided "LINKS" to the stories that have been appearing in the
> Chicago newspaper (Chicago Tribune).
> Bob Johnson