> Many years ago an online friend from Britain was visiting Wellington
> when THE BIG ONE struck. His building remained upright, but one across the
> street of about the same height leaned over and came to rest against his.
> They all got out by way of the stairwell. I've had some harrowing
> experiences in my life, but none of them compare with that.
When a building is designed to be jiggly, it all works pretty well.
This one, our company occupies, was designed without active dampening
systems, but has a sliding base as well as a rubbery steel structure.
There is another tall one a few blocks away that has an active system
and it is really amazing how effective it is. The slab moves 90
degrees out of phase and will stop any given movement within two
cycles--or something like that. Another building has a steel column
running up the center and the rest of the building attaches to it with
hydraulic pistons. But the problem is that some of these earthquakes
don't rock-and-roll in single direction waves. It's weird when the
earth is moving east-west and all a sudden, it moves north instead.
But these buildings in midtown Anchorage are in an area where you can
sometimes see the ground ripple and houses down the block are higher
than and then lower than yours.
Our house is in one of the best locations in the entire Anchorage area
as far as ground movement is concerned. A little shake at our house
will translate into books falling off the bookshelf down in the city.
AG
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