Response Spectrum Wizard : Eurocode 8 (2004)

The Eurocode 8 : 2004 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 ($a_{gR}$)

The parameter agR is used to characterise the seismicity of the site.

Importance factor ($γ_1$)

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 ($ξ$)

The spectrum values to use depend on the level of damping in the structure as expressed in the damping ratio. Elastic spectra only.

Behaviour ($q$, $q_d$)

A behaviour factor is defined which adjusts the level of the spectral values. A separate value, qd, can be applied to scale the displacements. If qd is not specified the value is q is used instead. Design Spectra only.

Lower Bound Limit ($β$)

A lower bound factor sets a minimum level below which the spectrum cannot fall. Design Spectra only.