Wood stresses and rough cut lumber

[agodave]

Hi all,

I'm working on a cabin design and need to double check my self. I'm looking at using rough cut pine in the northeast since I have a neighbor that has his own saw mill. To make this simpler I'm planning on putting the building on concrete piers and along a length of 31.5 feet using 5 piers thus each beam would be 6 1/4 feet. By adding in all the new york state snow load along with the other normal loads I'm getting about 2000 lbs per foot for some of my main beams. Running through the numbers I need about a 8x10 beam for bending but for stress I need more in the range of 10x12 for the hor and shear stress. Does any one have an idea if I'm on the right page and could you suggest where I can get some data to support my numbers.

Thanks

 

[civilperson]

Assuming continuity across the pier, greatest moment is (W x L<2)/12. Thus the 2000 lb/ft load gives moment of 78,125 in-lb and the extreme fiber bending stresses are around 585 psi. If simple spans are used the stress increases by 50%, still within the capability of good quality lumber. Have your local structural engineer analyze your plans for some savings in structural costs, (sure to be worth it in peace of mind and probably a net savings as well).