Seismic acceleration of calculation

Seismic acceleration of calculation, ac, is defined as the product: AC = S· ρ· ab where:

AB:
Basic seismic acceleration.

Adimensional risk coefficient, function of the acceptable probability that it will be exceeded ac in the life period for which construction is projected.
It takes the value ρ=1.0 for constructions of normal importance, and ρ= 1.3 for constructions of special importance.

S:
Ground amplification coefficient.
It depends on the coefficient of the terrain, C and the dimensional coefficient of risk, ρ.