To: "SEAOC Newsletter" <seaint(--nospam--at)seaint.org>
Subject: Re: Dynamic Analysis - STAAD III
From: Christopher Wright <chrisw(--nospam--at)skypoint.com>
Date: Wed, 12 Apr 00 18:36:12 -0500
>Does this limitation imply that
>the effect of mode frequencies higher than 60 cps are insignificant?
> If so,
>is that assumption valid for all structures?
No. For seismic analysis there is no significant magnification of ground
motion above 30-40 Hz (rule of thumb), but I've seen nuke plant response
spectra with magnification up around 100 Hz because of some peculiarity
in the plant. I haven't run into any, but there's no reason that some
subsystem might not have significant response above 60 Hz which could be
excited by ground motion.
Christopher Wright P.E. |"They couldn't hit an elephant from
chrisw(--nospam--at)skypoint.com | this distance" (last words of Gen.
___________________________| John Sedgwick, Spotsylvania 1864)