A3 - Finding Protrusions in the Plan: The situation in which both the dimensions of the protruding parts in two vertical directions in the floor plans of the building are larger than 20% of the total plan dimensions of that floor in the same directions ( Figure 3.3 ).
TBDY Article 3.6.2.2 - In buildings with A2 and A3 type irregularities, floor slabs will be modeled with two-dimensional plate (membrane) or shell finite elements to show that they can safely transfer earthquake forces between vertical bearing system elements in their own planes (See 4.5.6.2 ).
According to Article 4.5.6.2 - 3.6.2.2 of TBDY , in buildings where there are A2 and A3 type irregularities and / or floors are not intended to operate as a rigid diaphragm , and in slab systems without reinforced concrete beams, floors will be modeled with two-dimensional finite elements.