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RE: Boggled Out By Load Combinations

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Michael -

I don't believe I ever said steel, but, even if it was steel, couldn't it be
a steel spring?

Regardless, that's off the point. Are you saying that I don't have to design
for a any force due to the relative movement ("multiplier is zero")?

I was hoping I could design for Delta_sub_s divided by 1.4, but as it turns
out, designing for Delta_sub_m divided by 1.4 is possible. I just don't feel
this is the right value to design to. After all, I don't have to design any
other member in the structure for a strength to withstand a deflection of
Delta_sub_m, just provide enough space between the structures to accommodate
this deflection.

Regards,

T. William (Bill) Allen, S.E. (CA #2607)
ALLEN DESIGNS (http://www.AllenDesigns.com)
San Juan Capistrano, CA

:-----Original Message-----
:From: Michael L. Hemstad [mailto:hemstad.ml(--nospam--at)tkda.com]
:Sent: Monday, April 12, 2004 10:57 AM
:To: seaint(--nospam--at)seaint.org
:Subject: Boggled Out By Load Combinations
:
:Bill,
:I agree with Bill Cain.  The correct multiplier is zero.  I know what
:you said.  I just can't believe AE could be that small in a steel member
:(sounds like you're talking about steel).  Besides, won't it buckle when
:the buildings move the other way?
:
:What is this mystery member, anyhow?  You've got me curious now.
:
:Mike Hemstad, P.E., S.E.
:TKDA
:St. Paul, Minnesota
:
:
:
:Bill Allen wrote, in response to Bill Cain:
:
:Bill -
:
:=20
:
:Believe it or not, I think I can accommodate the force (think: rubber =
:band - AE is very small). Allowing for the movement (sliding connection)
:in my = case would create more problems than it solves.
:
:=20
:
:Sooo.If I understand your response to the original point, you're saying
:= to take Delta_sub_s and divide by 1.4 to arrive at the ASD level =
:displacement for design of this rubber band?
:
:=20
:
:Thanks,
:
:=20
:
:T. William (Bill) Allen, S.E. (CA #2607)
:
:V/F (949) 248-8588
:
:San Juan Capistrano, CA
:
:http://www.AllenDesigns.com
:
:-----Original Message-----
:From: BCainse(--nospam--at)aol.com [mailto:BCainse(--nospam--at)aol.com]=20
:Sent: Saturday, April 10, 2004 3:20 PM
:To: seaint(--nospam--at)seaint.org
:Subject: Re: Boggled Out By Load Combinations
:
:=20
:
:Bill-
:
:The force E for ASD is 1/1.4 times the value calculated by code =
:formulas. (See CBC Section 1612.3.1 Eqns 12-9, 12-10 and 12-11)
:
:=20
:
:But, unless the L is very big and/or the AE is very small, the force for
:most calculated deflections will be huge.  Wouldn't it be better to =
:provide a sliding connection on one end?  Then the force would be quite
:small.  = But the bearing for the element will need to allow the full
:range of = movement.
:
:=20
:
:Regards,
:
:Bill Cain, SE
:
:Berkeley  CA
:
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