Absolute Directional Combination Type?

[drile007]

Hi,

I'm trying to correctly assign Absolute Directional Combination in Etabs...but it seems that I'm not on the right way.
In Load Case data (Type=Response Spectrum) I defined two acceleration. Direction U1 and U2. Then I assigned Absolute Directional Combination Type...and assigned 0.3 for Scale Factor.
If I understand correctly that means 1.0*Ex + 0.3*Ey and 0.3*Ex + 1.0*Ey. But when I checked the reaction moments at column bases I got 1.0*Ex + 1.0*Ey?

Did I mess something?

Any comments are appreciated.

Thank you in advance

 

[JasonMcKee71]

Please use 0.3 as scale factor on U1 OR U2 component and both on them both.

Jason McKee
proud R&D Manager of
Cross Section Analysis & Design
Software for the structural design of cross sections
Moment Curvature Analysis
Interaction Diagrams
Reifnorcement Design etc.

 

[drile007]

Thank you JasonMcKee71,

But I don't understand you right.
I still don't know how to correctly apply Absolute Directional Combination Scale factor under Load Case Data tab in Etabs (Directional Combination Type=Absolute). What that factor means? CSI help state:
Absolute Summation option. Summation of the absolute values of the results caused by different directions of loading. Specify an ABS Scale Factor smaller than one to consider scaled sums. For example, if a value of 0.3 is specified, the program will consider the worst of 100% loading in one direction plus 30% in the other direction(s), and so on for each of the two or three loaded directions.
But that doesn't work?

Thank you