Seismosoft | Earthquake Engineering Solutions

Hello
I have two questions:
I need to analyse a structure subjected to some Ground acceleration of 50 seconds. Seismostruct takes only half of the record. How could I extend the analysis to take the complete record file?

secondly; it is referred in the Help, (Global Response Parameters), that viscous damping is equal to the difference between the Total Internal forces (stiffness forces) and the Total Inertia forces.

My question is: I found this true in the results of the Seismostruct but it is not necessarily true for the equation of motion. What is the definition of (Total) Inertia force and (Total) Damping force for a Multiple degree of freedom (MDOF) structure?

My best regards
Mohamed

Dear Mohamed,

On the issue of long records, you might want to look into past posts in this Forum, such as http://www.seismosoft.com/forum/topic.asp?TOPIC_ID=367.

For what concerns the second question, 'total internal forces' are obtained by multiplying the stiffness matrix by the displacement vector, whilst 'total inertia forces' are obtained by multiplying the mass matrix by the acceleration vector.

Regards,

Seismosoft Support