Conceptual design of a building with columns and shear walls

• QUESTION 1

• The building shown 20 X 35m in plan has column on a 5 X 5 m grid and shear wall in three alternatives arrangements (a),(b),(c), all with the same total cross sectional area of the sear walls.Compare the threealternatives ,taking into accounting the restraint floor shrinkage ,the lateral stiffness and the torsonal one with respect to the vertical axis.The vertical reinforcement required for the same total flexural capacity at the base,the static eccemtricity, the system redundancy,foundation systems,architectural constraints,etc

• ANEWER
• CASE 1)
• CRITERIA FOR CASE 1:
• 1.Restraint of floor shrinkage:
• Observation:
• Full restraints at all corner
• Conclusion:
• In this case will have higher restraint to shrinkage thus lead to creaksin the floor

• 2.The lateral stiffness
• Observation:
• It have low lateral stiffness in the both x and y

• 3.Torsion with respect to vertical axis
• Observation:
• The corner wall provided that is more resistance to twist

• 4.Vertical reinforcement for similar base capacity
• Observation:
• The walls in this case are subjected to nominal flexural moement and heavy twisting moment

• 5.Static eccentricity
• This case is structural symmentric

• 6.System redundancy
• Observation:
• The shear walls are uniform placement of lateral load support in both axis

• 7.Foundation system
• Observation:
• Due to L shaped walls,,the geometry of foundation and its design will be critical

• Conclusion:
• For this case recommended to have peripheral box foundation due to L shape of walls

• Architectural constrains:
• Observation:
• Walls obstruct only corners
• Conclusion:
• As per architectural point,this case is more prefferred because this is obstract less

• 8.Architectural Constrains
• Observation
• Walls abstract only corners
• Conclusion
• As per architectural point,this case is more preferred because this is obstruct less

• Case 2:
• 1.Restraint of floor shrinkage
• Observation:
• Corners are left free but restraint along the edge
• Conclusion
• In this case it provide average restrains

• 2. The lateral stiffness
• Observation:
• It has uniform and comparatively higher lateral stiffness in both x and y axes

• 3.Torsion with respect to vertical axes:
• Observation:
• Wall edges provided good resistance to twist

• 4. Vertical reiniforcement for similar base capacity
• Observattion:
• The walls are subjected to nominal twisting moment and regular flexural moment
• Conclusion
• In this case it required least vertical reinforcement

• 5.Static eccentricity
• Observation
• It is structurally symmetric

• 6.Systems redundancy
• Observation:
• The uniform placement of lateral load supports in both the axes

• 7. Fundamental system
• Observation:
• In this case the walls lines easy to fix the geometry and design of foundation
• Conclusion:
• For this plan or structure the isolated and strip footings are suitable

• 8.Architectural constrains
• Observation:
• The walls are obestruct the faces of the building

• Case:3
• Restraint of floor shrinkages:
• Observation:
• It is not effectively restrain the shrinkage ,so possibly less cracks

• 2.The lateral stiffness
• Observation:
• The uniform lateral stiffness in both x and y axes

• 3.Torsion with respect to vertical axes
• Observation:
• The irregular walls provides very poor resistance to twist
• Conclusion:
• THis case have very worst option with respect to torsional resistance

• 4.Vertical reinforcement for similar base capacity
• Observaton:
• It has static eccentricity lateral load is supported in both x and y axes
• Conclusion:
• The structure is less redundant than other 2 case

• 5.Static eccentricity
• Observation:
• It has static eccentricity and it is significant

• 6.Syetem redundancy
• Observation:
• The concentrated lateral load is supported in both x and y axes

• 7.Foundation System:
• Observation:
• The walls are in lines and concentrated easy to fix ggeometry of foundation but critical in design because of heavier forces

• 8.Architectural COnstrains:
• Observation:
• Vertical walls will not allow passage
• Conclusion:
• It is not accepted both architecturally and commercially because it obstruct the full sides

• QUESTION:2
• Discuss the sustainabillity for earthquake resistance of the moment resisting framing plan of a three storet building depicted here.Thhe eccentricity of the centre of mass to the centre of stiffness are shown.Suggest an alternatives,also is there torsional flexibility? Are the two fundamental modes of vibration larger than the fundamental torsional mode of vibraton ,discuss qualitatively

• ANSWER:
• Issues in framing plan is givrn below
• Indirect lateral load transfer in X and y direction
• The beams are connecting to another beams which is inefffective during lateral load transfer in such conditions the primary to shear failure
• Eccentricity
• Longer distance between centre if mass and centre of stiffness the higher stiffness the higher torsional moment of the building
• As per given plan eccentricity ,the building is subjected to higher torsional moment in both x and y direction
• Strong beam weak colun possibility
• As per given information thhe column having size 25 X25cm =,and beam size is 25 X50cm,the depth of beam is 50cm,itis larger than column site
• If reinforcement of column is greater than beam then ok,but reinforcent details are not given ,so it create a confusion
• So increase the size of column ,It the size of column is not increased then column is failure first

• QUESTION :3
• A multi storey building with basement with a quadrilateral plan as has interior column in an irregular pattern in plan that serves architectural and functional consideration.Partion walls and interior beams supporting the slab have diffrent layout in diffrent stories,However ,there is no constraint to the type,locaton and size of the lateral force resisting componentts and sub systems on the perimeter ,Proposals are to be made and justified for the choice of the lateral load resisting and its foundation

• 

• ANSWER:
• Observsation in the given plan :
• Floor plan
• The floor plan of this building is non uniform and symmetric
• So that lateral load is induced in the floor will not have 100% influence in same direction
• The special lateral load resisting system for this torsional moments should be accomodated

• Random internal column:
• The internal column are random so they transfer lateral load efficently and can not achieved desirable building response
• So we have to assume and design those column for only gravity load

• Floor to floor variation in portion walls and beams
• The partition wall provide mass control in building where beam key role in shear tranfer from floor to floor beam,and this element is not provided in order ,so heavy ditortation and distribuition of lateral load will happen

• Suggestion on the lateral load systems and its foundatiom
• Heavy torsional force can be controlled by resp. lateral load system.socorner shear walls is provided
• The proportional floor area is greater in left side and less in right side so corner sheare walls in left side s heavier than right side
• The corner shear wall is supported over a box foundation and this walls should be connected by link of beam to transfer the shear load from one another
• Internal column is supported by isolated footing ,this footinf can be connected woth shear wall through tie beam.