Vertical Seismic Load Effect per ASCE 7-16 §12.4.2.2

Symbols

S_DS = Short period design spectral acceleration coefficient
S_av = Design vertical response spectral acceleration
D = Dead load
E_v = Vertical seismic load

12.4.2.2 Vertical Seismic Load Effect

The vertical seismic load effect, E_v, is determined in according to Eq. (12.4-4a) for buildings which are seismic design category A and B.

The vertical seismic load effect, E_v, is determined in according to Eq. (12.4-4b) for buildings which are seismic design category C, D, E and F.

If buildings obey the following rules, E_v, can be taken as zero.
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.