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RE: 97 UBC 1633.2.4 Deformation compatibility - is that a typo?

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Mark - Right On. I thought 0.025H was wrong until I read the design example
in the ICBO Seismic Design Guide. It is 0.025H (0.025 x H(ft) x 12(in/ft))
for period T less than 0.7 seconds and 0.020H for T<=0.7. This is a
tremendous deflection - over 3.6" for a 12' story.
What I don't understand is why. It was my understanding that the past codes
set story drift at 0.005H (L/240) which is about 0.72" for a 12' story

If the code is correct then how in heck will a diaphragm of plywood ever
calculate a flexible if the diaphragm deflection based on 2.5 times the
blocked diaphragm calculates in the code is still less than 0.005H?


-----Original Message-----
From: Swingle, Mark [mailto:Mark.Swingle(--nospam--at)]
Sent: Monday, November 15, 1999 4:08 PM
To: 'seaint(--nospam--at)'
Cc: 'mswingle(--nospam--at)'
Subject: 97 UBC 1633.2.4 Deformation compatibilty - is that a typo?

The first paragraph of the above section (97 UBC 1633.2.4 - Deformation
compatibilty) appears to have a typo.

Reference is made to a drift (deltaM) of 0.0025 times the story height.

Shouldn't that be 0.025?

Mark Swingle, SE
Oakland, CA