Pole Barns - Revisited AGAIN

[Beltzington]

Since I will be using my tractor I'll try and squeeze this question into this forum.

When possible, I prefer not to reinvent the wheel so I am hoping someone has an answer or reference on how to determine pole size and spacing for insuring a solid structure.

My plan is to use poles to provide an elevated platform for living quarters with enclosed storage and workspace at ground level. Imaging a 24'x72' double-wide trailer sitting atop joists attached to 14-foot tall poles and you have the general idea. Obviously I don't want the thing to collapse but I also don't want it to sway in the wind.

View attachment 274426

How do I determine pole (square engineered post) size and how close do they need to be spaced? Within reason, I would prefer to over engineer this project rather then penny pinch.

Looking forward to your replies - thanks.

 

[KennyG]

I will get this started but I'm sure we will need a little more details on what you want to do. If I understand correctly, you want a 14 foot high storage/shop with a free span of 40 to 50 feet and you want to put more weight on the top of that. If that's the case, the problem isn't the poles, it's the joists to span the building. They will need to be massive to support the second floor at that span. If you can put a row of support posts down the center, it's not so bad. You can buy standard engineered joists that will span 25 feet or more and be qualified to take normal living space loads.

As far as the posts goes, that's a little easier. You will find that pole buildings usually have 6x6 posts on 8 foot centers. The reason is simple. It gives you the same amount of cross section as a 2x4 wall on 16" centers which is your standard load bearing wall configuration. Of course, the 6x6 wall will require a lot heavier top plates to take the bending forces but that's also pretty standard to use 2x10's on top of the walls.

Your design is pretty good from the standpoint of using the rafters to cross brace the structure, you're just going to have to figure out how you're going to span the outside walls.