Seismic Modelling in STAAD

Could all staad user help me on how to input data for seismic modelling of a space frame? I could not find how to input storey-wise masses and location of centre of mass which are normally required in other structural engineering program.

 

[Qshake]

As long as you can place a joint you can apply some load or mass. Do you have the manual? This information is detailed there under several locations amoung them: response spectra analysis, and joint loads, etc.

I encourage you to look at the space frame as two planar frames first to understand the dynamics of the structure in the long. and transv. directions. This may be done with staad or with simple MDOF techniques. Then put it all together to understand and predict the behavior in 3D with the subsequent torsional modes etc.

 

[Duppy]

You can try using the UBC load generator, which makes easier to set seismic loads applied to any structure by giving info such as zone factor, importance factor, soil factor and Rw factor along with the masses on each level input as joint or member weights.
Or you can calculate the seismic loads manually and apply them as joint loads