Accidental Torsion per ASCE 7-16 ยง12.8.4.2
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.
