Damping in Response Spectrum Analysis

[DanCivil]

Dear Sirs,

we want to know how the response-spectrum curve will automatically be adjusted from the function damping value to the actual damping present in the model.

We just found an answer (see below), but our simplified calculations (S-DOF System) show a different behaviour.

Please clarify ! (FYI: we are using SAP2000 version 14.2.2)

Thank you very much

https://wiki.csiberkeley.com/display/kb/Damping+in+response+spectrum+analysis

A2 = A1 * (2.31 - 0.41 * log(D2)) / (2.31 - 0.41 * log(D1))

where:

* A1 = acceleration corresponding to damping ratio D1,
* A2 = acceleration corresponding to damping ratio D2,
* 0.0 < D1 < 1.0,
* 0.0 < D2 < 1.0,
* and log = natural log (base e).

 

[DanCivil]

This issue has been clarified.
The wiki-Page was also corrected.

Note: The damping ratio has to be entered like this:
5% = 5.0 (and not 0.05)