Response spectrum generator according to PS92 (French standard)

Procedure to input a new PS92 seismic spectrum

  1. Expand branch Libraries of the main tree menu.
  2. Expand sub-branch Loads.
  3. Start function Seismic spectrum to open the Seismic Spectrum Manager.
  4. Click button New.
  5. In combo box Input type select option French standard.
  6. Review and, if required, adjust the spectrum parameters.
  7. Click button Code parameter to review or modify the code-defined parameters of the spectrum.
  8. Confirm the code parameters with OK.
  9. Click OK to confirm the spectrum.
  10. Close the Seismic Spectrum Manager.

Spectrum definition and code parameters

A response spectrum can be defined according to PS92 by selecting French standard as Input type.

Max frequency & Step

The values of the spectrum are generated between a maximum period of 4 seconds (=0.25 Hz) and the input maximum frequency, using the input Step value.

Code parameters

This button opens the dialogue defining the code-dependent parameters.

Site

Type of geological site (S0, S1, S2, S3)

coeff accel. ag

Value of the design acceleration expressed as a multiple of the acceleration of gravity g

An - nominal acceleration

Nominal ground acceleration

Horizontal / vertical action

Select the direction of the seismic action

Internal forces / displacements

Type of spectrum: for calculation of internal forces or displacements

Use q' instead of q?

Yes/no: modified behaviour coefficient

q - behaviour coefficient

Base value of the behaviour coefficient

Rho damping coefficient

Damping correction coefficient

Tau - topographic coefficient

Correction coefficient for topographic effects

Theoretical background

TB, TC, TD, kB, kC, kD are obtained from the table below, depending on the selected type of site.

An, ρ, τ, q are defined by the user.

For Q and kdir, see below.

Direction of the spectrum

Horizontal spectrum

Vertical spectrum

Internal forces spectrum

Use q' instead of q

Do not use q' instead of q

Displacements spectrum

Site TB [s] TC [s] TD [s]  kB Horizontal Vertical
kC kD kC kD
S0 0.15 0.30 2.67 2.5 1.12 2.99 1.12 2.99
S1 0.20 0.40 3.20 2.5 1.36 4.34 1.36 4.34
S2 0.30 0.60 3.85 2.25 1.60 6.16 1.36 4.34
S3 0.45 0.90 4.44 2.0 1.86 8.29 1.36 4.34