Help with lag screw lateral capacity calculation
Help with lag screw lateral capacity calculation
(OP)
Anyone care to take a look through the attached calculation sheet for lateral capacity for a 1/4" diameter lag screw. I think there is an error in the calculation, but I cannot find it. In the attached calculation the controlling yield limit equation is Mode IV which is 105 lbs. However, the value listed in NDS Table 11K is 150 lbs. The online calculator at the American Wood Council website also calculates 150 lbs. Link
I thought maybe the other resources were possibly using the full shank diameter, D, whereas I have used the reduced body diameter, Dr, but I don't think that is the difference.
Can anyone spot where I have gone wrong?
I thought maybe the other resources were possibly using the full shank diameter, D, whereas I have used the reduced body diameter, Dr, but I don't think that is the difference.
Can anyone spot where I have gone wrong?






RE: Help with lag screw lateral capacity calculation
RE: Help with lag screw lateral capacity calculation
Curiously, I could not get your spreadsheet to return 107 as you did. Instead I get a marginally higher value of around 114 when I plug my values into your spreadsheet (attached). But 107 or 114 is still much closer to my calculation sheet value of 105 than the 150 in the NDS table.
RE: Help with lag screw lateral capacity calculation
RE: Help with lag screw lateral capacity calculation
RE: Help with lag screw lateral capacity calculation
Mike McCann, PE, SE (WA)
RE: Help with lag screw lateral capacity calculation
RE: Help with lag screw lateral capacity calculation
RE: Help with lag screw lateral capacity calculation