Monday, June 27, 2011

Another collapse in Montreal


This is an important lesson in seismic capacity.  If a building is in settlement distress, or buildings are collapsing on their own, then the seismic capacity is zero.  A normal building shows no distress, and can stand up to heavy live loads, and strong winds.  This is inherent seismic capacity.

I always put things in terms of peak ground velocity (PGV), which is something the Clueless Swiss should use, and might have prevented the general shirt-losing.  Thus, the seismic capacity of Montreal buildings is 0 cm/s, and the seismic capacity (non-damage) of sound buildings is about 50 cm/s.  On top of this, you must take into account that soil can amplify PGV by a factor of 10 to 100 (again, don't tell the Swiss!).

Modern soft-story, transfer-slab condos tilt at 30 cm/s.   If you are in one of these on soft soil, then get the insurance while you still can.  When Montreal gets hit, it will be worse than NZ, and I'm sure the Clueless Swiss will pull out of earthquake insurance all together.

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