NOTE: The option to export response-spectrum load cases from ETABS into SAFE becomes available once analysis is run in ETABS. Cases may then be imported into SAFE.

Load pattern

The response-spectrum load patterns imported into SAFE include:

SPECXECC represents linear-static loads which result only from spectrum eccentricity. One will be imported per spectrum case, regardless of whether or not eccentricity is specified. If no eccentricity is specified, values will be zero.

MODAL 1, 2, ... n represents the load vectors associated with each of the n modes.

Load case

The response-spectrum load cases imported into SAFE include:

SPECXECC represents linear-static loads which result only from spectrum eccentricity. One will be imported per spectrum case, regardless of whether or not eccentricity is specified. If no eccentricity is specified, values will be zero.

MODAL represents the load vectors associated with each of the n modes.

SPECX represents the response-spectrum case. One will be imported per spectrum case.

Additional comments

When using default load combinations, spectrum cases will be combined by assuming a QUAKE load type.

Load combinations which include response-spectrum load cases will be defined with an ENVELOPE load type. Maximum and minimum values will be associated element-force results.

Static load cases from spectrum eccentricity will be imported and flagged as OTHER load type. These cases may be manually added to load combinations as necessary.

For foundation analysis and design, nonlinear uplift cases may not be converted from spectrum combinations because response-spectrum analysis is a linear formulation. As an alternative, spectrum story forces may be applied within ETABS manually as a lateral load case, then response may be exported to SAFE for foundation design.