Height to width ratio for sound structure?

[TCJatko]

One fundamental requirement to multi-story homes is that they MUST have a proper foundation including footers and frost walls. One cannot construct more than one story on a floating slab. I'd suggest you shelve your plans until you can get proper access to the site.

 

[ishiboo]

One fundamental requirement to multi-story homes is that they MUST have a proper foundation including footers and frost walls. One cannot construct more than one story on a floating slab. I'd suggest you shelve your plans until you can get proper access to the site.

Lots of two story houses are constructed on floating slabs. Not common where I live (we all have basements), but where I work (Las Vegas) has a ton of post-tensioned slab foundations with two/three story homes. There are also 4-5 story buildings on top but I believe many/most may make use of piers under the slab.

I wouldn't hesitate to build the structure the OP is speaking of on a monolithic slab.

 

[Cord]

Believe it or not, but a building designed to code is intended to survive a direct hit from a category 1 tornado. Now, this is a really weak storm, not the monsters we see on TV. Those storms will wipe a foundation clean. "Survive" has to be qualified. This means that the building isn't a total loss. The roof stays on, the walls stay up and the occupants are safe. To achieve this there has to be a tensile load path from the rafter or trusses all the way down to the foundation. The foundation keeps the building from being lifted up.

For your building, if you sheath it with plywood, nail it well and don't have any large openings (like a door) on a corner, then you'll be fine. The plywood will act as a shear panel and keep the building from racking. If at all possible, try to get a full sheet of plywood on each corner.

This is empirical design and I'll take no responsibility for a life safety issues that may crop up.

 

[myjohndeere]

Jim Timber,

If you are still concerned about height to width ratio there is a simple calculation to determine overturning moment. overturning moment is the tendency for a structure to tip over due to wind loads in this case. some things must be know first; dimensions, weight, roof slope or peak height, roof overhangs, peak sustained wind speed for your location(I have charts for this), and terrain such as hilly, flat, wooded, ect.

If the weight of the structure alone cannot resist the overturning then anchors or deeper foundations must be used.

let me know if you are interested and i can help you out. I am a civil/structural engineer working towards professional licensure, my word, advice or calculations are not legally binding.