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LRFD vs. ASD

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AF&PA plans to support both ASD and LRFD for wood for a while. the move toward
LRFD, as I understand it, is being driven by folks that develop the loads
standards, like ASCE 7. almost all the development in that area (e.g., wind,
seismic, flood loads) is on a strength basis. several of the codes are backing
those loads down to an ASD basis to keep that methodology. my experience giving
seminars indicates that less than 10% of the design community is using LRFD
(except for concrete), that's why we plan to support both.

*****************


From: FEMCCLURE(--nospam--at)aol.com
To: seaint(--nospam--at)seaint.org
Subject: Re:Lag Screws in withdrawal from end grain.

I agreee with Charles Greenlaw's September 7, 1998 discussion on the subject
matter.

The 1996 edition of Load and Resistance Factor Design, (LRFD), Manual for
Engineered Wood Construction, American Forest & Paper Association, American
Wood Council, 1111 19th Street, NW, Suite 800, Washington, DC 20036, Section
7.5.4, Resistance to lateral forces, Section 7.5.4.2, Adjusted lateral
resistance, page 32, "End Grain: The reference lateral resistance shall be
multiplied by the end grain factor, Ceg = 0.67, for lag screws inserted into
the end grain of wood." 

I believe that LRFD as well as Allowable Stress Design for the design of wood
construction will be in the 2000 International Building Code.  However, I have
heard rumors that there are those who are advocating only LRFD for the design
of wood construction in the 2000 International Building Code. Contact Shirin
Ader, IBC Secretariat for Structural Chapter 16 through 25, ader(--nospam--at)icbo.org, and
express your opinion concerning the possibility of only LRFD (not also ASD)
being in the 2000 IBC.

If you like LRFD for the design of structural steel, you will love LRFD for
the design of wood.

Frank E. McClure    FEMCCLURE(--nospam--at)aol.com  September 8, 1998