Interaction effect is defined by users.

Moment-resisting frames that are enclosed or adjoined by elements that are more rigid and not considered to be part of the seismic force-resisting system should be designed that any failure of these frames ahould not effect the vertical load and seismic force resisting capability of the frame. The design should satisfy these rigid elements on the structural system at structural deformations corresponding to the design story drift (Δ) as determined in Section 12.8.6.

The interaction requirements are intended to prevent unexpected failures in members of moment resisting frames. When masonry infill is fitted without any seperation with reinforced concrete columns, hinges are occured at the top of the column and at the top of the masonry as ıt has seen figure C12.7-1. By reason of the masonry is much stiffer than the columns.