Seismic/torsional structural elements. We live in the Cascadian Subduction Zone. It's hard to determine what kind of forces to design for. When is
enough enough? If we get a 9.5, it'll probably twist. Then I'd regret not spending another $100 or 2 on more straps. If all skyscrapers were designed to take a hit from a 737, there wouldn't be any..
The friction between logs, the 12" spikes in the top plates and ceiling joists, the concrete/steel foundation with 6 4" tiedowns straps and the diagonal and corner straps, we'll face what may come. Insects and fungi will probably destroy it before tectonic plates do but who knows? Turns out there is no IBC code for this...