F_b : Base shear force for simplified modal response spectrum analysis

              W : Total weight of the building

              S_d(T)  : design spectrum normalized by the acceleration of gravity g (Fig.1)

              T₁ : fundamental period of vibration of the building

              :

：

：

：

α : ratio of the design ground acceleration to the acceleration of gravity

              q : behavior factor

                            for RC structures :

                            q₀ : basic value of the behavior factor from table 1

                            k_D : factor reflecting the ductility class from table 2

                            k_R : factor reflecting the structural regularity in elevation from table 3

                            k_W : factor reflecting the prevailing failure mode in structural systems with walls from table 4

              S, β₀, T_B, T_C & T_D : values from table 5

              k_d1 & k_d2 : values from table 6