Concept on positioning of Columns
1.ANS:-
Symmertry
- It is observed that the distribution of mass,stiffness is 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 a 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 non linear range across the plan.
- The energy dissipation across the structure is very low which results in 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) is less when compared to longer direction (X-axis).
Ductility
- The building may not be able resist the elastic earthquake forces in shorter direction (Y-axis).So it may result in inelastic Response.
- The reduction in design force in the shorter direction (Y-axis) is to be compensated by Ductility.
2.ANS:-
Soft storey irregularity
- Stiff and strong upper floor due to masonary fill
- The column in one storey is longer than the above
- Some provisions to avoid the irregulrities
- The building is torsionally irregular.So the building framing must be revised.
- The mass irregulrity is avoided by providing light weight concrete/ Low weight masonary or by providing structure with more wood materials.
- The structure should be built in a well symmmetric manner.
- The columns which are provided on the structure should be of same size and height through out the building.
- The weight of the building from ground floor should decrease towards top.
3.ANS:-
- 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.