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RE: Ev in UBC Equation 12-5/12-6

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In this recent thread, Rick pointed out that the 1997 UBC requires use of Ev
for both equations 12-5 and 12-6.  Similarly, the 2000 IBC requires
consideration of the equivalent term (0.2SdsD) in both additive and
counteractive cases (Equations 16-28 and 16-29).  The statement in the 1999
Blue Book is an anomoly that is in conflict with the 97 UBC and 2000 IBC.

This item was discussed in some detail on this listservice in early February
2000 under the thread "UBC 1630, Ev Question".  There is more discussion of
the rationale of both sides of the issue and the politics of the issue in
the various postings on this old thread.

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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: Rick.Drake(--nospam--at)fluor.com [mailto:Rick.Drake(--nospam--at)fluor.com]
> Sent: Monday, March 27, 2000 1:44 PM
> To: seaint(--nospam--at)seaint.org
> Subject: Re: Ev in UBC Equation 12-5/12-6
>
>
>
>
> The 1999 Blue Book is different than the previous six editions,
> which preceded
> the referenced UBC.  The 1999 edition is sandwiched in between
> the 1997 UBC and
> the 2000 IBC.  Provisions and commentary in the 1999 Blue Book do
> not always
> agree with the 1997 UBC.  Sometimes it supports proposals to the 2000 IBC.
> Places of Blue Book disagreement with the 1997 UBC are indicated
> by a vertical
> line in the margin.  The part of the Blue Book regarding E-sub-v
> is one of these
> areas.
>
> One argument for not applying E-sub-v to 1997 UBC "uplift"
> equation 16-5 is that
> the minus 1.0E term is overly conservative to "columns" with
> tension components
> due to lateral loads.  However persuasive this argument may be,
> the 1997 UBC
> requires that  E-sub-v (part of E as defined in Section 1632)
> must be considered
> in BOTH strength design equations 12-5 and 12-6.  Per Section
> 1632, E-sub-v need
> not be considered in allowable stress equations 12-9, 12-10, 12-11, 12-13,
> 12-16, or 12-16-1.
>
> Rick Drake, SE
> Fluor Daniel, Aliso Viejo
>
> *************************
>
>
>
>
>
>
> "Julian Chu" <julian(--nospam--at)gouvisgroup.com> on 03/27/2000 01:10:42 PM
>
> Please respond to seaint(--nospam--at)seaint.org
>
> To:   <seaint(--nospam--at)seaint.org>
> cc:
>
> Subject:  Ev in UBC Equation 12-5/12-6
>
>
>
> The 1999 SEAOC Bluebook page 9 states  that Ev applys to the UBC load
> combination 12-5 but not 12-6. The  commentary explains the
> reason for adding
> the Ev to 12-5. However, there is no  information given regarding
> the 12-6. I
> know a lot of us have been subtracting  the Ev = 0.5CaID from the
> 0.9D in the
> 12-6 which may give you a more  conservative result for uplift or
> tension force
> than the past strength design  provisions.
>
> Does anyone know the reason why Ev need not be  included in the 12-6?
>
> Thanks!
>
>
> Julian Chu
> Newport Beach, CA
>
>
>
>
>
>
>
>