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RE: Dead Load or Live Load?

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Bill:

Can't disagree with you more.   

Case in Point:  Observed Silicon Valley roof of a high tech production
facility - about four mechanical units; tilt-up building, panelized roof
with mechanical units placed over columns

Approximately five years later - panic call from client - noises and
vibrations on roof of same building.  Climbed onto roof and observed now
about a hundred mechanical units - all over the place on sleepers - little
regard for support underneath.  (This didn't surprise me as I knew this
client's modulas of operandi).  One unit, which wasn't anchored down had
slid off of the sleeper beams and was causing the roof to vibrate. 

As I was already overloaded by this client with work, they had another firm
come in to correct the problems.  Required additional chord tie strapping
at the perimeter of the building and extensive vertical strengthening of
the roof.

A few years later - come's along Loma Preita.  My firm has no trashed
buildings.  I hear about a small platform beam failure on the top of this
same building.  Client had not told me about this and I learned about it
from another engineer.  I asked how many mechanical units on the platform.
Informed that there were three.  The original design was for one.   I
wasn't surprised.

Neil Moore, S.E.
neil moore and associates




At 03:47 PM 11/21/2001 -0600, you wrote:
>Okay, let's look at the other side of the argument.
>
>Say the "whackos" win and we have to depend even MORE on solar panels as
>they mothball all remaining electric plants.
>
>Now, suddenly, you as the building owner decide you need BIGGER solar
>panels. So you arrange to have 'em installed, knowing as you do that
>"engineers always design conservatively anyway." Now, your "static dead
>load" has just increased by 50%.
>
>When I was doing plant work, we considered ALL equipment, even if it was
>"fixed," to be live loads for design of buildings, etc. We knew the
>equipment was "here today, gone tomorrow," likely with something even bigger
>to take its place.
>
>So, anything that isn't part of the structure itself, or the function
>thereof, is "live load."

>William L. Polhemus, Jr. P.E.
>Polhemus Engineering Company
>Katy, TX, USA
>Phone (281) 492-2251
>FAX (281) 492-8203
>email bill(--nospam--at)polhemus.cc



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