Lag Screw Shear Values, 1991 NDS vs. 2005 NDS
Lag Screw Shear Values, 1991 NDS vs. 2005 NDS
(OP)
Looking through table 9.3A of 1991 NDS, I am finding lag shear values that are significantly higher than the equivalent table, 11J from 2005 NDS. The 1991 values seem to range somewhere between 20% and 100% higher than the 2005 values. A similar issue occurs with tables 9.3B and 11k, respectively, and perhaps others as well.
I imagine there is a fairly simple explanation for this discrepancy, but I am not sure what it is. Can someone help me out?
Thank you,
Isaac
I imagine there is a fairly simple explanation for this discrepancy, but I am not sure what it is. Can someone help me out?
Thank you,
Isaac






RE: Lag Screw Shear Values, 1991 NDS vs. 2005 NDS
RE: Lag Screw Shear Values, 1991 NDS vs. 2005 NDS
RE: Lag Screw Shear Values, 1991 NDS vs. 2005 NDS
In this case both tables seem to have the same title and are allowable values. So I'm not sure if your suggestion is the case.
RE: Lag Screw Shear Values, 1991 NDS vs. 2005 NDS
I don't have either of those NDS eds. on hand, but take a look at how many times over those years the lumber grades have changed, mostly lowered. Allowable stressed in every direction have gone down, grading rules have changed, our design methods for bolts, etc. have changed, as have all of the multiplying factors for load duration, stresses, materials, etc. It's getting tougher and tougher to pinpoint what causes some of these changes. You would probably have to go directly to NDS code committee member, and I suspect some of them couldn't tell you exactly. It's all an enigma wrapped in a riddle shrouded in a mystery. Let us know when you find out.
RE: Lag Screw Shear Values, 1991 NDS vs. 2005 NDS
RE: Lag Screw Shear Values, 1991 NDS vs. 2005 NDS
RE: Lag Screw Shear Values, 1991 NDS vs. 2005 NDS
I suspect if one were to go through the numbers and all the adjustment factors for two separate specifications, the results would be relatively similar in most cases.
RE: Lag Screw Shear Values, 1991 NDS vs. 2005 NDS
RE: Lag Screw Shear Values, 1991 NDS vs. 2005 NDS
RE: Lag Screw Shear Values, 1991 NDS vs. 2005 NDS
I have (hopefully) attached a link to information from AWC regarding the changes in the 2001 NDS.
RE: Lag Screw Shear Values, 1991 NDS vs. 2005 NDS
RE: Lag Screw Shear Values, 1991 NDS vs. 2005 NDS
RE: Lag Screw Shear Values, 1991 NDS vs. 2005 NDS
Thanks for all the help.