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Re: FW: Effects

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If you have an Ev = 0.3 D then you do this

Load Combo: 1.2D + 0.5L + E

now becomes

(1.2+0.3)D +0.5L +E

=

1.5D +0.5L +E

-gm

On Thu, Feb 14, 2008 at 7:26 PM, Haan, Scott M POA <Scott.M.Haan(--nospam--at)usace.army.mil> wrote:
D is the effect on the piece and  W seismic weight is used for base shear.  I
guess it depends whether you are looking at the whole building or a part of
it whether you say D=W seismic weight.  Up here the local structural
engineers association believes that you can include .2*snow in your dead with
seismic load combinations to resist uplift if the snow is part of the seismic
weight.

If you had a finite element model and wanted the seismic effect on a member
in it you would load the building with Eh=V and Ev=.2*SDS*D and run a load
combo of 1*Eh + or -1*Ev and the seismic effect on the member is the internal
forces from this. Run your model with just dead load and the dead load effect
on the member would be the internal forces in it.

-----Original Message-----
From: ECVAl3(--nospam--at)aol.com [mailto:ECVAl3(--nospam--at)aol.com]
Sent: Thursday, February 14, 2008 6:10 PM
To: seaint(--nospam--at)seaint.org
Subject: Re: Effects

I get the load combinations idea and the effects of combining the factors but
the elements themselves are defined as "the effects of...". The procedure is
to calculate the base shear "V"  or the component force "Fp" but whether
these equate directly to QE or D is not really clear because of the
definition of these elements. (D is not defined as the "dead load" but as the
"effects of the dead load"). I'm also assuming the "D" dead load is not the
same as the "W" ((defined in section 12.7.2) and "D" is only the dead load
acting directly on that particular shear resisting element being analyzed
(eg: shear wall or frame).

Maybe I'm reading to much into this but I can't help but think what a lawyer
would do with this kind of wording. There's always an Expert Witness" lurking
around the corner that would testify that the Engineer of Record did not use
all "the effects of V or Fp" by using just V or Fp in the formulas.
S.Macie

In a message dated 2/14/2008 6:44:42 P.M. Pacific Standard Time,
Scott.M.Haan(--nospam--at)usace.army.mil writes:

       You plug the horizontal seismic load effect together with the
vertical
       seismic load effect into the load combinations.

       12.4.2.2 defines the vertical effect of seismic up or down as a
funtion of
       dead load times Sds times .2

       -----Original Message-----
       From: ECVAl3(--nospam--at)aol.com [mailto:ECVAl3(--nospam--at)aol.com]
       Sent: Thursday, February 14, 2008 4:48 PM
       To: seaint(--nospam--at)seaint.org
       Subject: Effects

       12.4.3.1 defines QE = effects of horizontal forces from V or Fp..
       12.4.2.2 defines D = effect of dead load

       Are the effects simply the V, Fp and dead load W or is there
something else
       involved?

       S.Macie



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-gm