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vertical seismic loads on released frames

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Rantamental

Structural
Feb 17, 2016
12
Hi guys
As you know we have to dedicate vertical effect of seismic loads on elements equal to 0.2DL in LRFD method in both directions.
My question is if we want to design and analyze an element with pinned connections like a composite beam in a composite steel deck, should we consider this load effect or no? and what about designing the pined connection ? and what about the slab of composite deck ?
Thanks for your Help [thanks]
 
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Yes, the load combinations that include the vertical seismic load effect need to be considered for all members. For members that aren't part of the lateral system, they typically won't control over the maximum dead plus live load combinations. If you are designing a steel beam collector with pinned end connections, you need to consider the combined shear and axial loads on the connections resulting from the seismic load combinations.
 
And the vertical seismic load is 0.2*SDS*DL, not 0.2DL.

DaveAtkins
 
Thanks for your answers
Yes sure, we have to combine dead and 0.2*sds*dead
In service life of a pinned member we consider dead+live to calculate deflection of beam, but in design of that beam i think we have to include effect of vertical seismic loads and design it with this combination
Dead+0.2sds*dead+live, i think in real world and when an earthquake occures, it will absorb this loads
Am i true?
 
I don't believe the vertical seismic load is to be applied in the lower Seismic Design Categories if you are using ASCE 7.

When it is required, it should be applied regardless of the end fixity of the member
 
You get a reduction factor on all transient loads when they act in combination.

DaveAtkins
 
The seismic needs to be real high and the dead load needs to be pretty high compared to the live load for (1.2 +0.2SDS)D + L to be greater than 1.2D + 1.6L.
 
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