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Seismic Load Effects

Seismic Load Effects

Seismic Load Effects

(OP)
In the Seismic Load Effects equation (ASCE 7-02 eq. 9.5.2.7-1)

E = rho Q(sub E) + .2 S(sub DS) D

From a number crunching standpoint, for a steel frame building (standard AISC double angle connections for typical beam to column connections) with X-bracing located symmetrically around the perimeter of the structure,  can the HORIZONTAL component of the Seismic force (rho Q(sub E))generate a vertical load in an interior column which supports only gravity loads and is not part of any of the braced frames?
 
I would think NO.

All of the examples that I have access to however, calculate a vertical load from the horizontal seismic force but they always utilize moment frames in the example.

Any thoughts would be appreciated.

RE: Seismic Load Effects

JD2,
I'm with you.  It shouldn't give you a vertical component if it's not vertically braced.  I could be wrong.  Wouldn't be the first time.
Chip

RE: Seismic Load Effects

There is a vertical component that is generated in moment frame columns due to horizontal only loads, whether it is from seismic or wind. For gravity only (pin-pin) columns, the simple (theoretical) answer is that you should not get a vertical force from horizontal only loads.

It is not a code issue but an analysis one.

RE: Seismic Load Effects

I would agree - the horizontal part of E shouldn't create any vertical reaction in pinned, gravity only connections.  But I'm just curious as to why you are asking.  

Because you are seeing vertical reactions in the moment frame examples?  Not sure why you posted the question.

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