How is the eccentricity computed in case of flexible diaphragm, in dynamic analysis?
Moment due to accidental eccentricity in the calculation of response spectrum loads could be included while defining the Response spectrum Load case
From the main menu select Load > Load Type > Dynamic Load > RS load case
In case of flexible floor diaphragm, the accidental torsion in response spectrum analysis is determined as follows. Accidental torsion is considered for each individual masses, instead of total masses. Accidental torsion is calculated by the product of inertia force and accidental eccentricity at each masses and applied as a static load case. For a given earthquake, the program selects the absolute maximum accidental torsion among four cases of eccentricities by each masses.
Note1: Using this functionality, we can check the analysis results from the auto-generated load case (Es: Dynamic load case name), which reflects the accidental eccentric moments.
Note 2: The magnitudes of the applied accidental torsional moments can be checked in the main menu select Model > Result > Tables > Result tables > Story > Story shear (Response spectrum analysis)
Note 3: This function becomes activated only when Model > Building > Story Data is defined.