[RESULTS]     What is the modified drift option in Story Drift Table? How is it calculated?

A: Modified Story Drift depends upon various factors like whether to consider P-Delta effect and other code provisions.

To set the parameters for modified story drift, from the main menu select Result > Table > Result Tables > Story > Story Drift


The computation of Modified Drift is as follows:
When “Response Modification Coefficient”
(1) Option is Selected:

Modified Drift
= ad * Story Drift * Response Modification Coefficient (RMC) *Scale Factor

where
ad = P-delta increment factor ( defined under P-Delta analysis control)
Cd = Deflection Amplification Factor
Ie = Importance factor




(2) Not Selected:

Modified Drift
= ad * Story Drift * Cd * Scale Factor / Ie