Subject: E, allowable bending and horiz. shear for #2 hem-fir
Date: Fri, 03 Aug 2001 10:40:57 -0400
Just wanted to clarify a couple of issues:
1) wrt Hem-Fir vs. Hem-Fir(N): these are "species combinations," which means
there are various individual species that make up each combination. if you take
a look at Table 2.1 of the 1997 NDS Supplement you can see the difference
between the two. the latter includes only 2 species, the former contains 6.
Hem-Fir has species in the combination that aren't included in the Hem-Fir(N)
combination and vica-versa, so the design values are different. Hem-Fir is the
US version and Hem-Fir(N) is the Canadian version. (N) stands for North.
Here's a link to a Demo version of the NDS in PDF format. it should give you
access to Table 2.1 of the NDS Supplement.
2) wrt increased shear design values that you see listed on the WWPA site, make
sure you are aware that NDS shear provisions are being revised in the next
edition of the NDS (due out first quarter of 2002) in order to utilize new
lumber shear design values. However, until revision of the NDS has been
completed, 1997 NDS design provisions are only to be used with design values in
the 1997 NDS Supplement: Design Values for Wood Construction, or similar values.
Here's a link to a write-up about it on the AWC website:
Buddy Showalter, P.E.
From: Michael Bryson <MBryson(--nospam--at)mhpse.com>
To: "'seaint(--nospam--at)seaint.org'" <seaint(--nospam--at)seaint.org>
Subject: RE: E, allowable bending and allowable horiz. shear for #2 hem-fi
The WWPA values for Fv are twice the values that you list =150psi. I don't
know what Hem-Fir(N) means.
From: David Williams [mailto:dwilliams(--nospam--at)snydereng.com]
Sent: Thursday, August 02, 2001 9:44 AM
Subject: RE: E, allowable bending and allowable horiz. shear for #2 hem-fir
>From the 1997 NDS Table 4A Base Design Values for Visually Graded Dimension
Lumber, for No. 2 Hem-Fir, width=2"+, Fb=850 psi, Fv=75 psi and E=1,300,000.
Values are for normal load duration and dry service conditions. For Hem-Fir
(N), Fb=1000 psi, Fv=75 psi and E=1,600,00.
I don't know if this information is available on the web, perhaps others on
the list know. I have it on a CD that came with some commercial wood design
software we use.
David L. Williams, P.E.
Vice-Pres., Snyder Engineering, Inc.
409 Vandiver Drive, Bldg. 5, Ste 203
Columbia, MO 65202
From: Ken Peoples [mailto:kspeoples(--nospam--at)lvta.net]
Sent: Wednesday, August 01, 2001 4:35 PM
Subject: E, allowable bending and allowable horiz. shear for #2 hem-fir KD
I think this is an easy one, but who knows these days. I seem to recall
that the allowable bending stress of wood has been reduced in recent years
and I thought I heard it had something to do with the way forests are
managed to grow trees faster and then the growth rings are wider (I might
have this wrong). But anyway, I don't have a current NDS so what I would
like to know is: What is the current allowable bending stress (Fb),
allowable horizontal shear stress (Fv) and modulus of elasticity (E) for #2
hem-fir KD 15% (2x6's through 2x12's). Is this information available on
Thanks for your help.
Kenneth S. Peoples, P. E.
Lehigh Valley Technical Associates
1584 Weaversville Road
Northampton, PA 18067-9039
Phone: (610) 262-6345
Fax: (610) 262-8188
e-mail: <mailto:kpeoples(--nospam--at)lvta.net> kpeoples(--nospam--at)lvta.net
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