Answer:
The difference between the response spectrum with equivalent loads method and the response spectrum without equivalent loads method is the equivalent loads themselves. In the case of the response spectrum with equivalent loads method, they are generated at each FE node and recorded in a separate load case.
However, the response spectrum without equivalent loads method calculates the internal forces immediately and displays them as a result. Therefore, for a seismic analysis, we recommend using the response spectrum with equivalent loads method. There are practically no disadvantages compared to the response spectrum without equivalent loads method, and the accidental torsional effect can also be taken into account.
