As required by Codes, the earthquake calculation is made automatically in every 4 cases by shifting the storey masses by 5%.
In accordance with Codes, the horizontal earthquake loads are calculated automatically by shifting (+) and (-) 5%.
In modeling accidental torsion, any of the static and dynamic methods that comply with the regulation can be used for analysis. Method selection is controlled by users.
International Design Codes
ASCE 7-16 : Application of Accidental Torsion
TSC 2018 : Additional Eccentricity Modelling
Horizontal earthquake loads affecting the floor mass center or nodes is shifted by +5% and -5% of the floor dimension perpendicular to the earthquake direction considered, and earthquake calculation is also made for these cases.
Accidental torsion is a building-code requirement for both regular and irregular structures, since uneven distribution of live-load mass during lateral loading and variation between computed and actual values of structural properties.