I need to build a metal shed about 10' high and 6x6 in floor space which must be able to withstand 175 MPH winds.
How can I make sure that the shed and its anchors can hold up under those conditions?
I can think of two options that should work...
A steel shipping container should be more than strong enough to meet hurricane ratings, and come in just about any size.
This company sells anchors that it claims should withstand strong winds & hurricanes, though they "have not been scientifically tested." They're basically big triangles of metal or long screws driven into the ground:
A dome constructed of rebar, foam & concrete/shotcrete. They're very very resistant to winds (probably tornadoes too), and the weight combined with a cement slab & footing should make sure the whole thing won't blow away, ever. See Wikipedia or Inhabitat.com
Alibaba has a larger one, with images too:
For more conventional construction, if your neighbourhood/city has hurricane requirements then they must have guidelines on how to meet them, especially for usually DIY-friendly sheds. Check with them first.
I'm not an expert about coastal or island wind zones (mostly just the normal tornado/high wind stuff), but I can tell you that having a continuous load path and paying attention to uplift are important.
Having a continuous load path means that you transfer all vertical and lateral loads from the wood structure down to the foundation, usually by using hangers and/or fasteners to make the connections. This means that fastener & hanger manufacturers should have many of the resources you're looking for.
The main idea is to make sure that no matter what the wind does (push/pull/twists/racks) to the wood structure, that the structure will be able to use the foundation to resist those forces.
It's easy to overbuild your shed using a metal connector at every point, and that is what Simpson wants you to do. You would need an engineer to tell you which of these steps don't need a metal connector and where nails would be sufficient based on your specific location and exposure category: