Conceptual design of a building with columns and shear walls

Q1

Aim:- To distinguish between the three alternatives of providing shear walls with respect to technical aspects like lateral stiffness and torsion etc

technical aspects	shear wall arrangement (a)	shear wall arrangement (b)	shear wall arrangement (c)
restraint to shrinkage	as we can see in the image all the corners are fully restrained	in this case, corners are left free but the structure is restrained along the edges	the structure is restrained non uniformly so we can conclude that there will be less possibility of cracks
lateral stiffness	less lateral stiffness along both X-direction and y-direction	since the shear walls are provided uniformly and symmetrically comparatively there will be higher stiffness along both directions	in this case, shear walls are provided non uniformly so there will be non-uniform lateral stiffness
torsion with respect to the vertical axis	since the structure is restrained along corners there will be high resistance to torsion	edge walls provide good resistance	irregular walls may not resist the torsional effects
static eccentricity	shear walls are placed structurally symmetric	shear walls are placed structurally symmetric	shear walls are placed structurally unsymmetric so this arrangement of the shear wall will have static eccentricity
redundancy	uniform placement of lateral load supports in both the axes	uniform placement of lateral load supports in both the axes	concentrated lateral load supports in both the axes
architectural constraints	in this case, walls are provided at the corners so it will be accepted architecturally	walls are provided along the edges which obstruct access to the building	walls are provided along the edges which obstruct access to the building
foundation systems	due to the geometry of the shear walls, the layout of the foundation is difficult	since the walls are provided symmetrically along the edges the foundation design is easy	since the walls are concentrated the design of the foundation is critical

Q2

• diversion of lateral forces

in the structural plan shown we can observe that the beams and columns are not connected concentrically

B3 is resting on B9 and B7 is testing on B4, this will result in the diversion of loads when the structure is subjected to lateral loads

• eccentricity

since the center of mass of the structure and centroid of the frame are not coinciding the structure may be subjected to torsional moments and when the lateral loads have applied the structure could not resist the loads and lead to the failure of the structure

• size of beam-column

we can observe that the size of the column is 25 x 25 and that of the beam is 25 x 50 which is deeper than the column section and the beam will have higher inertia compared to the column which will lead to the formation of a strong beam- weak column mechanism and results in the failure of the columns first

ALTERNATIVE OPTION OF FRAMING

• to avoid the collapse of columns first, more reinforcement should be provided in the columns
• the beams should be connected directly to the column and should not rest on other beams

Q3

• FLOOR PLAN

the floor plan of the building is not uniform and symmetric so a special lateral load resisting system should be accommodated to resist the additional torsional moments

• INTERNAL COLUMNS

since the columns are placed randomly they could not resist any lateral loads so they are designed to carry only gravity loads

• VARIATION IN FLOOR PLAN

since the partition walls and beams are not in the proper position the structure cannot transfer the lateral loads efficiently because beams play a major role in the transfer of shear loads

ALTERNATE PLAN

• to resist torsional forces shear walls should be provided
• shear walls should be laid on box type foundation and they should be connected with each other by providing link beams to transfer loads
• internal columns should be supported by an isolated foundation
• the proportion of floor area is greater on the left side than the right side care should be taken to provide heavier members on the left side