F_tot = C_s･G_cq                       (see Table 1)

where:

C_s is the seismic base shear coefficient and is determined from

C_s = α･β･γ                      (see Table 2)

and G_cq  is the equivalent permanent load and is determined from

G_cq = G_k + ψ･Q_k                      (see Table 3)

where:

G_k = the characteristic dead load
Q_k = the characteristic live load
Ψ = live load incidence factor (see Table 1)

In Eq. 3, the values of α, β and γ are determined as indicated in Section 1 to 3.

Section 1:

The coefficient α is the design bedrock acceleration ratio given by

α = α_o･I

where:

α_o = the bedrock acceleration ratio for the site and depends on the seismic zone (see Fig. 1) as given in Table 2.
I = the importance factor which depends on the classification of the structure with respect to the economic value and post-disaster use (see Table 3)

Section 2:

The coefficient β is the elastic design response factor for the site and is given by

β=β_o･S ≤ 2.5

where β_o is the elastic design response spectrum factor for bedrock foundation and standard damping of 5% as determined from

and S is the soil classification and site condition factor (see Table 4)

Section 3:

The coefficient γ is the ductility and energy absorption factor and accounts for response modification due to inelastic behaviour and/or energy-absorptive capacity of the structure and due to damping other than 5%.

The values of γ are given as function of the type of structural system (see Table 5). The values of γ for structural Types 1 and 2 in Table 5 are set on the assumption of compliance with sophisticated design, detailing and construction control requirements in accordance with the state of the art in earthquake engineering and are therefore not recommended for general application.