🚀 go-pugleaf

In article <2i64ma$5k6@mailer.fsu.edu> jac@ds8.scri.fsu.edu (Jim Carr) writes:
>In article <2i1qrh$o7u@gap.cco.caltech.edu> 
>hough@seismo.gps.caltech.edu (Susan Hough) writes:
>>
>>  ...         During the 1992 Landers earthquake, the I-10/I-215
>>interchange recorded something like 0.1g at the base & over 1g on
>>accelerometers at the top of the structure, with no damage.  
>
>Impressive.  I heard last night that the 5/14 bridge is estimated 
>to have been deflected by 10 feet before it failed.  I think they 
>said it was a vertical deflection, and that the big problem with 
>this quake was that -- coming as it did from an unknown thrust 
>fault -- produced larger vertical stesses than anyone expected. 
>Is this accurate? 

I think we read the same A.P. story...I also read about the 10ft 
sway & have no idea how anyone is estimating that, unless it's
from the final resting position of the freeway segments.
There are also speculations about the apparently high peak
accelerations & their relation to the thrust mechanism, but
I think it's just a theory at this point.  I have heard second
hand that the peak accelerations systematically do exceed the
prediction curves for the given magnitude & various site
effects; I'm not sure by how much, though.

Sue