|One more thought, according to my outdated (2001) copy of the NDS, the
adjustment factors for compression strength perpendicular to the grain
do not include the LDF. The LDF is only used to adjust the strength for
compression parallel to the grain.|
--- On Mon, 8/30/10, Joseph R. Grill <vveng(--nospam--at)cableone.net> wrote:
From: Joseph R. Grill <vveng(--nospam--at)cableone.net>
Subject: RE: Hankinson with different LDF's
Date: Monday, August 30, 2010, 7:20 PM
Appendix B of the NDS says that the stress from any combination
of loads is less than or equal to the adjusted design value modified by the
load duration factor for the shortest duration load in that combination of
That would seem to agree with using a 1.6 factor on the final Z
Joseph R. Grill, PE
Verde Valley Engineering, PLLC
From: Drew Morris [mailto:dmorris(--nospam--at)bbfm.com]
Sent: Monday, August 30, 2010 3:44 PM
Subject: Re: Hankinson with different LDF's
agree. The LDF of 0.9 applies to the force perpendicular to the grain
from the soil loading and the LDF of 1.6 applies to only the inplane shear.
On 8/30/2010 2:14 PM, David Topete wrote:
soil loading is "static." How can a 1.6 LDF increase
be justified for that loading direction? I think it's similar
to a steel beam loaded in both the strong and weak axes.
The interaction equation from the green steel manual (9th Ed.
ASD). fbx/Fbx + fby/Fby <= 1.00 Any LDF's, such as short term
loading due to wind/seismic/impact and applied left of "<=", and
not to the right of it. Just my thoughts...
On Fri, Aug 27, 2010 at 3:54 PM, Joseph R. Grill <vveng(--nospam--at)cableone.net> wrote:
But the loads are being applied at the
same time, so wouldn’t the LDF of 1.6 be used on the final Z theta after
the equation is run without adjusting Z perp and Z parl?
0.9 for "static loading" from soil... LDF = 1.6 for
wind-induced shear.... I'd applied each to each Z_perp and Z_parl
respectively... The 0.9*Z_perp will be the governing case....
Wed, Aug 25, 2010 at 2:42 PM, Joseph R. Grill <vveng(--nospam--at)cableone.net>
you have an anchor bolt in a sill plate with a top of wall restraint force from
soil loading of 200 plf perpendicular to grain and a parallel to grain load
from a shear wall of 250 plf. Are the LDF’s of .9 and 1.6 applied
before input to the Hankinson formula or is the result from the formula
multiplied by the larger LDF of 1.6? Sudden brain blockage
R. Grill, PE
Valley Engineering, PLLC
David Topete, SE
David Topete, SE