Response spectrum generator according to ÖNORM B4015 (Austrian standard)

Procedure to input a new ÖNORM 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 ÖNORM - Austrian 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 ÖNORM B4015 by selecting ÖNORM - Austrian 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.

coeff. accel. ag

Design ground acceleration expressed as a multiple of g

Ah - design acceleration [m/s^2]

Design ground acceleration in [m/s^2]

Eta - damping coefficient

Damping correction coefficient

k5

Behaviour coefficient

T1, T2, k1, beta manually?

No: T1, T2, k1, beta0 are pre-defined according to the selected subsoil type

Yes: T1, T2, k1, beta0 are defined manually by the user

Subsoil type

Subsoil type I, II or III; sets pre-defined values of T1, T2, k1, beta0

T1

Lower limit period of the constant acceleration portion of the spectrum, pre-defined according to the selected subsoil type or user defined

T2

Upper limit period of the constant acceleration portion of the spectrum, pre-defined according to the selected subsoil type or user defined

k1

Subsoil dependent scaling factor of the spectrum, pre-defined according to the selected subsoil type or user defined

beta0

Scaling factor of the constant acceleration portion of the spectrum (typically = 2.5)

Theoretical background

Subsoil type T1 [s] T2 [s] k1 β0
I 0.1 0.4 0.9 2.5
II 0.15 0.6 1.0 2.5
III 0.2 0.8 1.2 2.5