The total horizontal seismic force acting on a building.

S = K･G

where:

K = the total seismic coefficient for the horizontal direction
G = the total weight of the building and its equipment

Note of K

K = K_o･K_s･K_d･K_p

where:

K_o = the coefficient of building category, (see Table 1)
K_s = the coefficient of seismic intensity, (see Table 2)
K_d = the coefficient of dynamic response, and (see Table 3 of Fig. 1)
K_p = the coefficient of ductility and damping. (see Note of K_p)

The total seismic coefficient K shall have a minimum value of 0.02.

Note of K_p

The coefficient of ductility and damping, K_p, depends on the type of structure under consideration:

1. For all modem reinforced-concrete structures, for all steel structures except those mentioned in section 2 of this article, and for all modem wooden structures, except structure s listed in section 3 of this article,
   K_p = 1.0;

2. For structures built of reinforced masonry, and for braced steel structures,
   K_p = 1.3;

3. For masonry structures, strengthened by means of vertical reinforced-concrete tie-beams’ for reinforced-concrete shear-wall structures which do not satisfy the requirements of article 68 of this Code; for very high and slender structures with low damping, such as high industrial chimneys, aerials and masts, water-towers and other structures with a fundamental natural period of free vibration of
   T ≥ 2.0 sec., K_p = 1.6;

4. For structures with a particularly flexible ground or any other storey, or with a sudden change in stiffness, as well as for ordinary masonry structures,
   K_p = 2.0.