where: 

Z : Seismic zone coefficient (see Table 1,and Fig.1)

I : Structure importance coefficient (see Table 2)

R : Response modification coefficient for structural systems (see Table 3)

W : Total seismic dead load

C : Numerical coefficient given by the relation

                  where:

                   S : Site coefficient for soil characteristics (see Table 4)

                   T : Fundamental period of vibration of the structure for the direction under
                        consideration

                                   where:

                                   C_v = 0.083 for steel moment resisting frames

                                         = 0.073 for reinforced concrete moment resisting frames,
                                            and eccentric braced steel frames

                                         = 0.049 for all other structural systems

                                   h_n = Height in meters above the base to level n

                                   Alternatirely, value of C_v for buildings with concrete or masonry shear walls may be taken
                                   as . The value of A_c shall be obtained by.

                                                   where:

                                                   A_c : Combined effective area of shear walls in the first story of structure.

                                                   A_e : Effective holizontal cross-sectional area of shear walls in the first story of
                                                          the structure

                                                   D_e : Length of a shear wall element in the first story in the direction parallel to the
                                                          applied forces

                                                   The value of  D_e / h_n shall not exceed 0.9.