Concept on positioning of Columns

1.

Ans:

Symmetry:

It is observed that the distribution of mass and stiffness across the plan has good symmetrical aspects.

This tends to reduce the horizontal displacements in both of the two horizontal displacements in both of the two Orthogonal Horizontal Directions.

It also has very good uniformity also.

Redundancy:

There are missing structural elements in the Periphery of the plan. This causes the uneven distribution of earthquake action effects in a nonlinear range across the plan.

The energy dissipation across the structure is very low which results in a non-reliable structure.

Bi-directional Stifness:

The building plan may not be able to resist the horizontal seismic actions in the shorter direction (Y-axis) and also the resistance and stiffness in the shorter direction (Y-axis) are less when compared to the longer direction (X-axis).

Ductility:

The building may not be able to resist the elastic earthquake forces in a shorter direction (Y-axis). So it may result in an inelastic Response.

The reduction in design force in the shorter direction (Y-axis) is to be compensated by Ductility.

2.

Ans:

The possible type of irregularities for the given structure is:

Soft storey irregularity:

1. Stiff and strong upper floor due to masonary fill
2. The column in one storey is longer than the above.

Some provisions to avoid the irregularities:

The building is torsionally irregular. So the building framing must be revised.

The mass irregularity is avoided by providing lightweight concrete/ Low weight masonary or by providing structures with more wood materials.

The structure should be built in a well-symmetric manner.

The columns which are provided on the structure should be of the same size and height throughout the building.

The weight of the building from the ground floor should decrease towards the top.

3.

Ans:

The structure is not symmetric.

Larger strength is provided hence low ductility.

In this building, there is no proper placement of masonry infill walls.

In this building, Redundancy in the vertical direction is not provided properly.