Design Response Spectrum

S_a = k_E･k_r･ψ･β･g

where: 

k_E : seismicity coefficient depending on Seismic (see Table 2,and Fig.1)

k_r : building importance coefficient (see Table 3)

ψ : structural coefficient (see Table 4)

β : dynamic coefficient, the value of which are dependent on the free vibration period (see Fig.2);

g : gravity acceleration

      (for soil category Ⅰ)

      (for soil category Ⅱ)

      (for soil category Ⅲ)

 where:

           T₁:Fundamental period of free vibration, which can be empirically determined by Table 5.

Soil conditions are classified into three categories: I, II, III, which shall be determined based on the:

1. Seismic microzoning studies, or 

2. respective engineering geological studies (see Table 1)