Seismosoft | Earthquake Engineering Solutions

Dear colleague

Would you please inform me what is your reference for calculating modal excitation factor for rotational degrees of freedom? and if you have simple example I appreciate if you share it.

Best Regards

Dear ag110,
The modal excitation factor is calculated through the type Ln=(Ön)T*M, where M is the mass and (Ön)T the traspose vector of the mode shape. You may find examples in any good textbook on Structural Dynamics.

thanks for your reply
but my problem is calculating modal excitation factor for rotational degrees of freedom when lumped mass is used in the model.