Log wall strength
Log wall strength
(OP)
How do I calculate the bearing capacity of a stacked log wall?
While the main run of a typical log wall is probably not a problem I am concered about concentrated loads from beams or dormer trusses coming down on a short section of a stacked log wall which has no bracing walls attached to it.
Should I just calculate the slenderness based on the log contact area and screw the logs together with lag screws to handle my worst calculated moment?
Because the logs shrink the lag screws could loosen but perhaps this is negligable on the length of a lag screw.
While the main run of a typical log wall is probably not a problem I am concered about concentrated loads from beams or dormer trusses coming down on a short section of a stacked log wall which has no bracing walls attached to it.
Should I just calculate the slenderness based on the log contact area and screw the logs together with lag screws to handle my worst calculated moment?
Because the logs shrink the lag screws could loosen but perhaps this is negligable on the length of a lag screw.






RE: Log wall strength
Dr. Edwin J. Burke
Wood Science Laboratory
School of Forestry
University of Montana
Missoula, MT 59812
(406) 243-5157 FAX (406) 243-4845
RE: Log wall strength
RE: Log wall strength
Different companies solve (or say they did to the customer) this problem in many different ways. Some use 3/4" rebar rods or bolts drilled through the log courses to stiffen the wall. (And the buckling capacity of a 3/4" 8 foot tall rod is?...I don't think that really does much except to keep the logs from warping out of position. The key is to reduce any eccentricities from loading and make sure the logs are stacked directly on top of one another. "Rough bucks" or a tongue and groove system in the window frame is mandatory to allow log settling without crushing the window. Oly-Log or Log Hog brand screws work very well and are usually used every 2-4 feet. I wouldn't recommend using traditional lag screws. The ones mentioned have a small head and actually countersink themselves about .25 inch allowing for log shrinkage without inducing stress on other logs.
I hope this helps.
Alex
alex@alexanderstructures.com