B1 (Weak Story) Irregularity occurs when the effective cutting area in a story is less than the value specified in the regulation when compared to an upper story. The variables in the cutting area are shearwall, column and walls (nci). Effective cutting areas are automatically calculated according to the load-bearing system and wall-wall loads entered in the program, and the values ​​are printed in the general report of the earthquake regulation.

Also, the cutting areas can be changed in the Story Parameters dialog, Irregularities tab.