Stacked log header

[COEngineeer]

Ok, usually when I use 2x header i just put them right next to each others. But what if you are building a log home and use bigger beam? I have a header that is about 8 ft long. I want to use 10x8 stacked on top of each other. How do you connect the 2? Do I need to worry about shear flow? I know the 2 can handle the moment but I am afraid if I connect them together I will have failure at connection.

 

[DaveAtkins]

You only need to design for shear flow if you are trying to make a composite section out of the two logs. If the strength and stiffness of the two individual logs, added together, is sufficient, then you need not make them into a composite section.

DaveAtkins

 

[RockEngineer]

If you do need the combined section properties calculate the combined section and do VO/I to determine shear flow. For an 8 ft long header just use the maximum shear and the minimum area. If you are bolting the logs together with a vertical bolt, the minimum areas are where the bolt hole is taken out. I do the same on log homes when I use double logs for a header or girder. It's just a little harder to calculate the exact properties so using the maximum enclosed rectangle inside the log is very conservative but simplifies the calculations. NDS-97 allows you to use a rectangle of the same crossectional area as the log which is a little less conservative. I'm not sure if there were changes in that in NDS 2005.