Withdrawal Resistance of Lag Screws in Wood

[Grunchy]

Hello,
What effect does "edge distance" have on lag screw withdrawal resistance in wood? I need a source as well, just let me know your source and I'll look it up!

I found in "Standard Handbook of Fastening and Joining" a chart that was reproduced from AF&PA source, wherein a withdrawal strength was related to lag screw diameter and wood specific gravity. Well I know that it also depends on the thread penetration, but I wonder if it matters what the "edge distance" is.

Or maybe it is enough if I specify a minimum "edge distance", such as 4 diameters or 1.5 diameters. For instance, in the same book under lateral loading, if the direction of loading is parallel to the grain the min. edge distance is 1.5 diameters, if the loading is perpendicular to the grain the min. edge distance is 4 diameters.

-= Any Help Is Appreciated =-

Thank you,
"Grunchy" P.E.

 

[boo1]

Go to Forest Products Laboratory. 1999. Wood handbook:

http://www.fpl.fs.fed.us/documnts/FPLGTR/fplgtr113/Ch07.pdf

or AWC General Dowel Equations for Calculating Lateral Connection Values:Technical Report 12:

http://www.awc.org/pdf/tr12.pdf

 

[Taro]

See also ANSI/AF&PA NDS Section 9.4.

For lag screws in withdrawal (no lateral load):
Min. edge dist. = 1.5D
Min. end dist. = 4D
Min. spacing = 4D

 

[Grunchy]

Much obliged, "boo1" and "Taro"!
The linked resources are indispensible, thank you kindly!