V : horizontal seismic base shear

C_d : seismic coefficient

Seismic coefficient C_d

              C_d ≤ 0.3I  for low ductile structures

              C_d ≤ 0.2I  for medium ductile structures

              C_d ≤ 0.1I  for high ductile structures and ductile steel structures

Z : normalized maximum acceleration factor from Table 1 and Fig. 1
R_a : spectral amplification factor
K : reduction factor from Table 2
S : site coefficient from Table 3
I : importance factor from Table 4
W : total dead load of the building

Normalized maximum ground acceleration factor Z (See Table 1)

Reduction factor K (See Table 2-1, 2-2)

Spectral amplification factor R_a (See Fig. 2)

and

T : fundamental natural period  

               T = 0.073H^3/4  for concrete structures 

               T = 0.085H^3/4  for steel structures 

               T = 0.049H^3/4  for other structures 

               H : total height of the structure

Site coefficient S (See Table 3)

Importance factor I (See Table 4)