X=Plan length of the building for X direction Xp =Reentrantplan length of the building for X direction Y=Plan length of the building for Y direction Yp =Reentrant plan length of the building for Y direction
Reentrant corner irregularity is defined to exist where both plan projections of the structure beyond a reentrant corner are greater than 15% of the plan dimension of the structure in the given direction.
In buildings with reentrant corner type irregularities, story slabs is modelled with two-dimensional plate (membrane) or shell finite elements to show that they are able to safely transfer earthquake forces between vertical bearing system elements in their own planes.