# Response Spectrum Wizard : Eurocode 8 (2003)
The Eurocode 8 : 2003 spectrum is defined by a set of parameters defined in the code.
Subsoil Class
Sites are classed depending on the subsoil as A, B, C, D or E as described in Part 1-1 Table 3.1.
Ratio of Ground Acceleration to Gravity (
The parameter agR is used to characterise the seismicity of the site.
Importance Factor (
The importance factor allow am amplification for topographical effects depending on the type of structure.
Spectrum
The spectrum can be either an elastic spectrum or a design spectrum.
Structure Damping Ratio (
The spectrum values to use depend on the level of damping in the structure as expressed in the damping ratio. Elastic spectra only.
Behaviour (
A behaviour factor is defined which adjust the level of the spectral values. Design Spectra only.