] [Thread] [Date] [Author]

["Don Carr" <dcarr(--nospam--at)nahbrc.org>]

------- Forwarded Message Follows -------
From:          Self <NAHB/CAR1>
To:            "Paul Feather" <pfeather(--nospam--at)san.rr.com>
Subject:       Re: OSB vs Plywood
Reply-to:      dcarr(--nospam--at)nahbrc.org
Date:          Fri, 23 Apr 1999 08:33:52 -500

Is it standard engineering practice to adjust the design for the worst
way that things could be built in the field if the builder in the
field doesn't pay attention to the design? Is it also standard code
development process to ver require certain header sizes, beam sizes,
or nailing schedules to similarly compensate for perceived field
practice? How many other professions are compensating for the
perceived field practices? How many layers of redundancy does this add
to the cost and the strength of the design? What is the final factor
of safety if a builder in the field makes even a reasonable effort to
follow the code and the engineers or the architects guidance? Is this
appropriate?  Is this why builders perceive engineers to occasionally
"overdesign"?
 Don Carr


 Paul Feather wrote:

> FWIW  The use of "sinkers" is typical on every job site I visit, 
> whether you are using plywood or OSB.  I routinely design for 75% of
> the UBC table values on all of my projects to account for the
> difference.
> 
> Sometimes it is easier to simply adjust the design for the way
> things are built....
> 
> Paul Feather PE
> San Diego, Ca

> Roger Davis wrote:
> >
> >If the contractor is using a nail gun, over-driving should not be your only
> >concern.  Commonly used pneumatic nails have only 73% of the shear
> >resistance of "common" nails.  If they use staples instead of nails, the
> >orientation of the staple is important also.  For more information you can
> >visit the Structural Engineering Consultants of British Columbia web site
Donald L. Carr
dcarr(--nospam--at)nahbrc.org
NAHB Research Center, Inc.
400 Prince Georges Blvd.
Upper Marlboro, MD 20774
301-249-4000 x575
http://www.nahbrc.org