G'day,
If you define a Response Spectra (Custom or Code) with a rotated axes do the eccentricities get similarly translated, perhaps rotated about the COM?
I seeking to confirm that I am offsetting the mass by 0.1b perpendicular to the direction of action as defined in AS1170.4 Clause 6.6.
Kind Regards,
Chris
RAM Frame - Diaphragm Masses Definition
RAM Frame - Custom Response Spectra Definition
AS1170.4 - Clause 6.6
Following this up for others, I rotated the model with the excel file provided , that was the least painful option.
communities.bentley.com/.../141903
If I wanted to check my building to AS1170.4 for an EQ at 45 degrees to global X/Y, in order to locate the 0.1b eccentricity, I would either have to do the following:1. Rotate the whole model, proceed with eccentricities now in global axes?
2. Shift the COM in the translated axes, proceed with no eccentricity as the shift is now inbuilt to the model. So 4 separate models or running the model 4 seperate times would be required to capture each +/- direction of 0.1b?
I am pretty sure the eccentricity values are always measured on the global axis X and Y, not on the rotated axis, because you can only enter one set of values per diaphragm, while the loading could be applied at various angles simultaneously.