Concept on positioning of Columns

1.

Symmetry : Since there is an absolute symmetry in the plan shown ,the mass is distributed evenly .It will tend to reduce the horizontal displacements in both X and Y directions and also in orthogonal horizontal directions.

Redundancy : In the diagram shown , in the border /periphery of the plan it is seen that some columns are missing. This will lead to uneven distribution of earthquake action effect in non linear range acroos the plan.

Bidirectional stiffness : The building plan will not be able to resist horizontal seismic action in shorter direction ie, Y axis , And the resistance and stiffness in Y axis is shorter compare to X axis.

Ductility : The building will not be able to resist elastic earthquake forces in shorter direction , Y direction , hence may lead to inelastic response.

2.

A building is said to be torsionaly irregular when the maximum horizontal displacements of any floor in the direction of the lateral force at one end of the floor is more than 1.5 times its minimum horizontal displacement at the far end of the same floor in that direction.
In such a case the building configuration must be revised.
Out of the many possible irregularities in building structures, the final structural design should, in absolute terms, avoid the two most dangerous irregular
situations
1) Soft storeys
2) Extremely flexible Structure in torsion
Both cases correspond to extremely irregular stiffness distributions: the former regarding the distribution in height/elevation with a very weak story and the
latter regarding the distribution in plan, with the concentration of the stiffness at the center or at a corner

3.

1. There is no proper provision of redundancy in the vertical direction.
2. Improper distribution of symmetry (or non-uniformity)
3. Provision of the weak storey on left hand bay
4. Improper placements of masonry infill wall