The short answer is "design for adequate uplift". The chances that a tornado
will come tearing right through is small. And you can only do so much with
regard to airborne projectiles. But the severe localized winds that occur in
the immediate vicinity of the twister CAN be handled by the structure if you
do it right.
For more information, see the following URL for the Wind Engineering
Research Center at Texas Tech:
From: Mark E. Deardorff [mailto:MarkD(--nospam--at)DandDEng.com]
Sent: Friday, March 31, 2000 10:22 AM
Subject: RE: Texas Twisters
Being from California I have never had to design for a tornado. In fact, I
was under the impression that the most design anyone ever actually does is
to pray that the tornado misses the building.
If required to endure the extreme loads a tornado can produce, how could a
light-weight flat roof ever be economically designed?