Conceptual design of a building with columns and shear walls

1)

1)

	(a)	(b)	(c)
Restraint of floor shrinkage	Shear walls are constrained at four edges which will reduce floor shrinkage	Floor shrinkage is less in the shear wall edges.	Floor shrinkage will be more in this arrangement.
Lateral stiffness	Shear walls are provided only at the corners which will impact during lateral load excitation and this arrangement have less lateral stiffness	Symmetrical arrangement of shear walls which is good in lateral stiffness in both the axis.	Poor lateral stiffness
Torsional with respect to vertical axis	Shear walls are provided only at the corners which is eccentric arrangement.Hence there will be a huge torsion.	Less torsion	More torsion
Vertical reinforcement requirement for the capacity at the base	Since the torsion is more. More reinforcement is required.	Arrangement is symmetrical which leads to uniform mass and stiffness distribution. So less vertical reinforcement is required.	More vertical reinforcement is required.
static eccentricity	Symmetrical arrangement	Symmetrical arrangement	Unsymmetrical arrangement
System's redundancy	Number of shear walls are less which will be more redundant	More reduntant	less redundancy
Foundation systems	Mat foundation beneath the RC wall	Strip foundation	Mat or raft foundation.
Architectural constraints	Openings and door arrangements are not possible at the corners	Facade will be difficult to provide.	10m wall will constraint the architectural requirements.

2)

• Earthquake resistance for the above frame is poor because strong beam weak column concept is followed here. Columns are of size 250mm x 250mm whereas beams are of 250mmx500mm.
• Unsymmetrical arrangement of columns. Beams are of same sizes are adopted, primary and secondary beam concepts are not adopted.
• Centre of mass is not coincide with centre of the stiffness which shows the eccentric behaviour of the structure.There will be torsion in X and Y directions which will affect the transferring of loads to the vertical elements.The two fundamental translational modes of vibration will be larger than the fundamental torsional mode of vibration.

Alternative arrangement of the plan:

3)

Layout of the building and column location of the building is unsymmetrical which leads to poor lateral load resisting system.

The below alterantive arrangement can be used for the better seismic behaviour. Shear walls on the corners of the building and shear wall in the inclined direction also.

Foundation arrangement for the above layout can be provided as isolated footing for the individual columns and box foundation beneath the shear walls. If the area of the layout is less , then raft foundation can also be adopted.