Now that Robot 2013 has AS1170.4 Earthquake analysis built in I have started using it.
I was previously using modal + spectral and defining the response spectrum.
I am aware from previous questions that for spectral you need to define spectra, run the model check base shear then re-run with scaled base shear. The AS1170 automatic seismic should be doing these things for me.
From the previous post
Please explain the difference between using "seismic" and "spectral" in terms of the analysis method that Robot employs. Is one more accurate than the other or are they both the same. Is one non linear and one linear?
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These are the same (linear) types of response spectra dynamic analysis. The difference is that in the spectral analysis you define a spectrum yourself whereas in the seismic one it is given by the selected seismic code.
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In Rafals post (link in original post) he mentions to use modal +spectral as an alternative to seismic when encountering problems with non linear member types.
So why does he mention this, if it is actually just the same anyway?
I think he meant (non-linear) THA analysis. Starting from v.2013 for non-linear models you can also use the static force procedure.