Seismosoft | Earthquake Engineering Solutions

I have a doubt concerning the damping, the damping factor is expressed in percentage or must be expressed in full. If for example you want a damping equal to 1% do I have to enter 1 or 0.01 in the settings? and by inserting damping proportional to the mass, is the mass parameter automatically defined by the software or should it be checked?

The damping is indeed % of critical and the parameters, whether mass or stiffness or Rayleigh damping is specified,are determined automatically in accordance with equations found in the help system. Should the user wish to over-ride the computed values, manual input is possible.

I need to determine damping of a structure out of a free-vibration test that is already conducted and the time histories of acceleration are measured. Is any of the software here capable of estimating damping from the structural response? Thanks

The software does not have this capability, but it is a fairly simple hand calculation. Use the "logarithmc decrement" method, which may be found in most any textbook on structural dynamics, or from a web search on the term.