For earthquake resistant building there are many factors are taken into consideration among them shape and proportion of buildings are important. All the following points are taken as reference from NBC code.
Shape:
For earthquake resistant, building having symmetrical in plan and elevation is considered as best. Building with reentrant corners like U, L, V, H and shape in plan suffer more damage during earthquake.
To be considered when floor diaphragms are rigid in their own plan in relation to vertical structural elements that resists the lateral forces. Torsional irregularity to be considered to exist when the maximum storey drift, computed with design eccentricity, at one end of structures transverse to an axis is more than 1.2 times the average of the storey drifts at the two ends of structure.
