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RE: UBC '97 Sec 1633.2.4 Deformation compatibility

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Thanks for the clarification Mike.  

I should have checked the Blue Book & UBC as well.

Steve Hiner, SE
Folsom, CA 

-----Original Message-----
From: Mike Valley [mailto:mtv(--nospam--at)skilling.com]
Sent: Thursday, May 25, 2000 11:44 AM
To: seaint(--nospam--at)seaint.org
Subject: RE: UBC '97 Sec 1633.2.4 Deformation compatibility


To reiterate, 1997 UBC Section 1633.2.4 does NOT give you a CHOICE for
the deformation.  It says, "Expected deformations shall be determined
as THE GREATER OF ... delta_M... or the deformation induced by a story
drift of 0.0025 times the story height."

The second condition (0.0025) is NOT a typo of 0.025.  Instead it
serves as a minimum deformation capacity compatibility checks for very
stiff systems.

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Michael Valley, P.E., S.E.                   E-mail: mtv(--nospam--at)skilling.com
Skilling Ward Magnusson Barkshire Inc.              Tel:(206)292-1200
1301 Fifth Ave, #3200,  Seattle  WA 98101-2699      Fax:        -1201

-----Original Message-----
From: Steve Hiner [mailto:shiner(--nospam--at)folsom.ca.us]
Sent: Thursday, May 25, 2000 10:11 AM
To: 'seaint(--nospam--at)seaint.org'
Subject: RE: UBC '97 Sec 1633.2.4 Deformation compatibility


Per UBC 1630.10.2, DeltaM shall not exceed 0.025 times the story
height for
structures with T < 0.7 seconds ...

UBC 1633.2.4 gives you the choice to either use the expected
deformation
based on your "calculated" DeltaM, or the expected deformation
assuming that
DeltaM is equal to the maximum allowed value of 0.025 times the story
height.

Steve Hiner, SE
Folsom, CA

ps - I appear to have a misprint in my 1998 "California" Building Code
for
Section 1633.2.4 (p. 2-19) where the 1st paragraph, 2nd sentence reads
'...
0.0025 ...' rather than '... 0.025 ..."


-----Original Message-----
From: Attila Beres [mailto:Attila.Beres(--nospam--at)Englekirk.com]
Sent: Wednesday, May 24, 2000 5:26 PM
To: Seaint Listserver posting
Subject: UBC '97 Sec 1633.2.4 Deformation compatibilty


If I am reading this right, this check asks for using the interstory
deformation value to be considered as the greater of :

1. DeltaM, as calculated in accordance to Sec 1630.9.2 (0.7*R*DeltaS)

2. 0.025*story height.

When would the first condition govern? The inelastic story drift
ratios are
limited to max. 0.025.

Am I missing something, or the first condition is redundant?
......................................................................
.....
Attila Beres