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[SAFE|safe:Home] version 12 allows importing of [spectrum load cases|kb:Response-spectrum analysis] from [ETABS|etabs:Home]. The export response spectrum cases option in ETABS will only be available after you run the analysis.

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h1. Load patterns

The [load patterns|kb:Load pattern] relevant to response spectrum imported into SAFE will be:

* *SPECXECC* \- These are static loads resulting from spectrum eccentricity only. One for each spectrum case will be imported. Even if no eccentricity has been specified in ETABS, this load pattern will still be imported; however, in this case values will be zero.
* *MODAL 1, 2, ..., i, ... n* \- These are the load vectors for every mode and n is the number of modes in ETABS model.

h1. Load cases

The [load cases|kb:Load case] relevant to Response spectrum imported into SAFE will be:

* *SPECXECC* \- Linear static case result of spectrum eccentricity, one for each spectrum case.
* *MODAL* \- Load type case Modal, this is a load vector of modal loads.
* *SPECX* \- Response spectrum case, one for each spectrum case imported.

h1. Other comments

Please notice that when using default [load combinations|kb:Load combination], spectrum cases will be combined assuming "QUAKE" type load, also when observing forces on elements, combinations involving spectrum cases will be defined as envelope type resulting in maximum and minimum values. Static load cases from spectrum eccentricity will be imported and flagged as "OTHER" load type, and need to be added manually to other load combinations as required.

For uplift foundation analysis, it is not possible to convert combinations involving spectrum cases to nonlinear uplift cases, due to the fact that response spectrum analysis only applies to linear analysis. You could use Response Spectrum story forces to apply as user defined lateral load case in your ETABS model and export the lateral loads results to SAFE for foundation design. Please notice this is not required for design.