STAAD.Pro Help

Modal Damping dialog

Used to define unique damping ratios for the individual modes used in a dynamic analysis. It is used in response spectrum and time history analysis.

Opens when the Modal Damping tool is selected in the Dynamic Specifications group on the Loading ribbon tab.

Note: STAAD.Pro is also capable of calculating each mode's damping based on the frequency of the mode, the mass-proportional damping coefficient (α), and the stiffness-proportional damping coefficient (β). This input must be provided using the STAAD.Pro Editor. Refer to Calculate Damping for additional details.
Evaluate This option is to instruct STAAD.Pro to calculate the damping ratio for each mode based on the frequency of the mode and the Minimum and Maximum values entered in the respective fields.

The formula used to evaluate the damping ratio is explained in Evaluate Damping.

Explicit Provide values of damping ratio for the corresponding mode number.

Refer to Explicit Damping for additional details.