Vertical Seismic load criteria ASCE7/AISC

[AD_design]

Hello Fellow Engineers,

As per AISC we need to consider vertical seismic (EQ+Y) acceleration when spectral response acceleration parameter at short periods will be equal or exceed 0.125
So, Sds => 0.125 (First criteria)

Please let me know if any other condition will be applicable here.

 

[AD_design]

Any one has any opinion on this.

 

[abdallah hamdan]

ASCE 7-16
The vertical seismic load effect, Ev, is permitted to be taken as zero for either of the following conditions:
a. In Eqs. (12.4-1), (12.4-2), (12.4-5), and (12.4-6) for structures assigned to Seismic Design Category B.
b. In Eq. (12.4-2) where determining demands on the soil–structure interface of foundations.
E = Eh + Ev (12.4-1)
E = Eh − Ev (12.4-2)
Em = Emh − Ev (12.4-6)
Em = Emh + Ev (12.4-5)
but I know that some engineers don't take these effects for low occupancy and not near fault structures

 

[HTURKAK]

-For building type structures , the relevant clause is ( 12.4.2.2 Vertical Seismic Load Effect) and
Ev is determined with Eq. (12.4-4a) Ev =0.2XSds X D

- The vertical seismic load effect, Ev, could be taken as zero ( as abdallah hamdan pointed out )

i= for for structures assigned to Seismic Design Category B ,
ii=In Eq. ( E = Eh − Ev ) where determining demands on the soil– structure interface of foundations.

- If you look 11.9.3 , the clause is for development of Design Vertical Response Spectrum and this procedure is required to be used for nonbuilding structures according to Section 15.1.4 ( ..Tanks, vessels, hanging structures, and nonbuilding
structures incorporating horizontal cantilevers...)