How to combine nonlinear combinations with seismicity

Seismic calculation is always a linear calculation. But users can combine the seismic load cases with a nonlinear combination.

Using this feature, the user will have the nonlinear behavior of the structure for the static forces combined with the linear seismic calculation.  The idea is to add the results of a nonlinear combination to the results of a linear combination.

To activate this the following steps should be done:

1. Create all needed load cases including the seismic load cases.

2. Activate the nonlinearity functionality and add all needed nonlinearities to the structure

3. Create a nonlinear combination containing the required load cases without the seismic load cases because as stated before seismic calculation is linear calculation only.

4. Create a linear combination containing your seismic load cases only

5. In the “Nonlinear combination” tab choose the nonlinear combination that you want to combine the results with:

6. Run the BATCH Analysis

Remark: Using this procedure the combination should be defined manually meaning SCIA will not calculate the coefficient automatically for each load case.