Conceptual design of a building with columns and shear walls

Ans 1

criteria
Restraints of floor shrinkage	observation	Full restraints at all corners	corners are left free but restraints along the edge	Non- uniform restraint
	conclusion	option a will have higher restraints to shrinkage,thus lead to cracks in floor. Option b is average. Option c will not effectively restraints the shrinkage, so possibly less cracks.
The lateral stiffness	observation	comparatively lower lateral stiffness in both X & Y direction	uniformly and comparatively higher lateral stiffness in both X & Y direction	Non- uniform lateral stiffness in both X & Y direction
	conclusion	option b will bprovide higher lateral stiffness for a pure seismic acceleration in X and Y direction
Torsion with respect to vertical axis	observation	corner walls provide more resistance to twist	Edge walls provide good resistance to twist	Irregular walls provide very poor resistance to twist
	conclusion	option a will eb the best option with respective to the torional whereas option C is worst
vertical rei forcement for similar base capacity	observation	walls are subjected to nominal flexural moment and heavy twisting moment	walls are subjected to nominal twisting moment	walls are subjected to heavy flexural moment and heavy twisting moment
	conclusion	option b will require higher vertical reinforcement and option B will require the least.
Static eccentricity	observation	structurally symmetric	structurally symmetric	un-symmetric
	conclusion	only option c will have static eccentricity and it is significant
system's redundancy	observation	uniform placement of lateral load support in both the axes	uniform placement of lateral load support in both the axes	Concentrated load support in both the axes
	conclusion	option a & b are more redundant than option c
Foundation systems	observation	Due to L shaped wall, the geometry of foundation and its design will be critical	walls are in line. Easy to fix the geometry and design of foundation	walls are line & concentrated. Easy to fix the geometry of foundation but critical in design
	conclusion	Option b & c shall be incorporated with isolated footings/ strip footing. Option a is recommended to have peripheral box foundation
Architectural constraints	observation	walls obstruct only corners	wall obstruct the faces of building	vertical wall will not allow passage
	conclusion	option a is preferred one. Option b is subjected to discussion. Option c will be not accepted both architecturally and commercially

Ans 2

Indirect lateral load Transfer in X and Y direction

The beams are connecting to another beam which is ineffective during lateral load Transfer. In such cases the primary beam prone to shear failure

Eccentricity

The longer distance between centre of mass and centre of stiffness, the higher torsional moment of the building. As per the give plan eccentricity, the building subjected to higher torsional moment in X & Y direction

Strong beam weak column prossibility

The size of column majorly mentioned 25 x 25cm. But all the beams have much deeper section. Interia of beam is visually higher than column. If the column reinforcement is adequately greater than that of beams, we are okay and since we have no reinforcement details, this is doubtful. It is recommended to have slight bjgger sizes for column.

Ans 3

Floor Plan -

The floor plan of building is not either symmetric or uniform. So naturally any lateral load included in the floor will not have 100% influence in same direction. Definitely a special lateral load resisting system for these torsional moment should be accommodated.

Random internal columns-

Since internal columns are random, they are unable to transfer the lateral load efficiently and can't achieve deriable building response. So we have to assume and design those columns for only gravity load.

Floor to Floor variation in partition walls and beam -

Partition walls provide an important mass control in building and beam play key role in shear transfer from floor to beam. All these elements are not in order. So heavy distortion and distribution of lateral load will happen

Suggestions on the lateral load system & its foundation

• Heavy torsional force should be controlled by resoective lateral load system. So corner shear wall suggested
• The proportion of flooar area is greater in left side than the right side. So corners shear wall on the left side should be heavier than the right
• Corner shear wall shall preferably be supported over a box foundation. Shear walls should be connected by link beam to transfer shear from one to the other.
• The internal columns shall be supported by isolated footings. The isolated footings can be connected with shear wall through Tie beams.