I am modeling a building in SAP2000 software. The stiffness I have to assign in X direction is different from the one in Y direction. Does any one know how I can assign these two numbers to my building as stiffness?
AFAIK, we do not assign 'stiffness' values to the structure in a SAP2000 model, in any direction. Rather, the stifness is calculated by the software, using cross-sectional properties of structural members applicable in the relevant direction (X or Y), from trial sizes of these member used in the software model.
A good structural engineer is often a blessing for others.