Conceptual design of a building with columns and shear walls

Ans 1: The Observations and Conclusions are as follows:

• Restraint of Floor Shrinkage:
  • Observations: Plan (a) has full restraints at the corners, In Plan (b) corners are left free but restraints along the edges, In Plan (c) Non-Uniform restraints.
  • Conclusion: Plan (a) will have higher restraint to shrinkage which leads to cracks. Plan (b) is average. Plan (c) will not effectively restrain the the shrinkage, so possibly less cracks.
• The Lateral Stiffness:
  • Observations: Plan (a) Comparatively Lower Lateral Stiffness in both X and Y. Plan (b) Uniform and comparitively higher lateral stiffness in both X and Y. Plan(c) Non-Uniform Lateral stiffness in both X and Y.
  • Conclusion: Plan(b) will provide higher lateral stiffness for a pure seismic accleration in X and Y directions.
• Torsion with respect to vertical axis:
  • Observations: Plan (a) corner walls will provide more resistance to twist. Plan (b) Edge walls to provide good resistance to twist. Plan(c) Irregular walls provide very poor resistance to twist.
  • Conclusion: Plan (a) will be the best option against torsional resistance whereas plan(c) will be the worst one.
• Vertical reinforcement for similar base capacity:
  • Observations: Plan(a) walls are subjected to nominal flexural moment and heavy twisting moment. Plan(b) walls are subjected to nominal twisting moment. Plan(c) Walls are subjected to heavy flexural and twisting moment.
  • Conclusion: Plan(c) will require higher vertical reinforement and Plan(b) will require least.
• Static Eccentricity:
  • Observations: Plan(a) structurally symmetric, Plan (b) structurally symmetric, Plan (c) un-symmetric.
  • Conclusion: Only Plan(c) will have static eccentricity and its significant.
• System's Redundancy:
  • Observations: Plan(a) Uniform Placement of lateral loads supports in both the direction. Plan(b) Uniform Placement of lateral loads supports in both the direction. Plan(c) Concentrated lateral loads supports in both the axis.
  • Conclusion: Plan(a) and Plan(b) are more reredundant than Plan(c).
• Foundation Systems:
  • Observations: Plan(a) Due to L shape walls, the geometry of foundation and design will be critical. Plan(b) walls are in line easy to fix the geometry and design the foundation. Plan(c) Walls are in line and concentrated, easy to fix the geometry of foundation but critical in design.
  • Conclusion: Plan(a) and Plan(b) shall be in corporated with isolated footing / strip footing while Plan(c) is recomended to have box foundation at its periphery.
• Architectural Constraints:
  • Observations: Plan(a) Walls obstructs only corners, Plan(b) Wall obstruct the faces of the building, Plan(c) vertical wall will not allow passage.
  • Conclusion: Plan(a) is preffered one, Plan(b) will be of discussion, Plan(c) will not be accepted.

Ans 2: The Issue in given framing plan are:

• Indirect lateral load transfer in X and Y direction, the primary beam is prone to shear failure.
• Eccentricity: The longer the distance between center of mass and center of stiffness, the hgher tortional moment of the building.
• Strong beam weak column possiblity: The size of the column is 25*25 cm but the beams have much deeper section 50 cm. Inertia of beam is usually higher than column.

Alternate scheme:

Ans 3: The Observations are as follows:

• Floor paln: the Floor plan of the building is not either uniform or symmetric. So any lateral load induced in the floor will not have 100% influence in same direction. A special lateral load resisting system for these moments should be sccomodated.
• Random Internal Columns: Since the internal columns are random, they are unable to transfer lateral load efficiently nad cannot achieve desireable building responce.
• Floor to Floor Variation in partitions walls and beams: Partition walls provide an important mass control in building and beams play a kry role in shear transfer from floor to beam. all these eleemts afre not in order. so heavy distortion and bistribution of lateral loads will happen.

Suggestions:

• Heavy tortional forces should be controlled by respective lateral load system. So "Corner Shear Walls" are suggested.
• The Proportion of Floor area is grater on the left side than the right side. So corner shear wall on the left side should be heavier than the right side,
• Corner shear wall should be preferably be supported over box foundation. Shear walls should be connceted by links beams to transfer sgear from one to another.
• The Internal column should be supported by isolated footings. Those isolated footings can be connceted with shear walls through tie beams.Ans 1: The Observations and Conclusions are as follows:
  • Restraint of Floor Shrinkage:
    • Observations: Plan (a) has full restraints at the corners, In Plan (b) corners are left free but restraints along the edges, In Plan (c) Non-Uniform restraints.
    • Conclusion: Plan (a) will have higher restraint to shrinkage which leads to cracks. Plan (b) is average. Plan (c) will not effectively restrain the the shrinkage, so possibly less cracks.
  • The Lateral Stiffness:
    • Observations: Plan (a) Comparatively Lower Lateral Stiffness in both X and Y. Plan (b) Uniform and comparitively higher lateral stiffness in both X and Y. Plan(c) Non-Uniform Lateral stiffness in both X and Y.
    • Conclusion: Plan(b) will provide higher lateral stiffness for a pure seismic accleration in X and Y directions.
  • Torsion with respect to vertical axis:
    • Observations: Plan (a) corner walls will provide more resistance to twist. Plan (b) Edge walls to provide good resistance to twist. Plan(c) Irregular walls provide very poor resistance to twist.
    • Conclusion: Plan (a) will be the best option against torsional resistance whereas plan(c) will be the worst one.
  • Vertical reinforcement for similar base capacity:
    • Observations: Plan(a) walls are subjected to nominal flexural moment and heavy twisting moment. Plan(b) walls are subjected to nominal twisting moment. Plan(c) Walls are subjected to heavy flexural and twisting moment.
    • Conclusion: Plan(c) will require higher vertical reinforement and Plan(b) will require least.
  • Static Eccentricity:
    • Observations: Plan(a) structurally symmetric, Plan (b) structurally symmetric, Plan (c) un-symmetric.
    • Conclusion: Only Plan(c) will have static eccentricity and its significant.
  • System's Redundancy:
    • Observations: Plan(a) Uniform Placement of lateral loads supports in both the direction. Plan(b) Uniform Placement of lateral loads supports in both the direction. Plan(c) Concentrated lateral loads supports in both the axis.
    • Conclusion: Plan(a) and Plan(b) are more reredundant than Plan(c).
  • Foundation Systems:
    • Observations: Plan(a) Due to L shape walls, the geometry of foundation and design will be critical. Plan(b) walls are in line easy to fix the geometry and design the foundation. Plan(c) Walls are in line and concentrated, easy to fix the geometry of foundation but critical in design.
    • Conclusion: Plan(a) and Plan(b) shall be in corporated with isolated footing / strip footing while Plan(c) is recomended to have box foundation at its periphery.
  • Architectural Constraints:
    • Observations: Plan(a) Walls obstructs only corners, Plan(b) Wall obstruct the faces of the building, Plan(c) vertical wall will not allow passage.
    • Conclusion: Plan(a) is preffered one, Plan(b) will be of discussion, Plan(c) will not be accepted.

  Ans 2: The Issue in given framing plan are:

  • Indirect lateral load transfer in X and Y direction, the primary beam is prone to shear failure.
  • Eccentricity: The longer the distance between center of mass and center of stiffness, the hgher tortional moment of the building.
  • Strong beam weak column possiblity: The size of the column is 25*25 cm but the beams have much deeper section 50 cm. Inertia of beam is usually higher than column.

  Alternate scheme:

Ans 3: The Observations are as follows:

• Floor paln: the Floor plan of the building is not either uniform or symmetric. So any lateral load induced in the floor will not have 100% influence in same direction. A special lateral load resisting system for these moments should be sccomodated.
• Random Internal Columns: Since the internal columns are random, they are unable to transfer lateral load efficiently nad cannot achieve desireable building responce.
• Floor to Floor Variation in partitions walls and beams: Partition walls provide an important mass control in building and beams play a kry role in shear transfer from floor to beam. all these eleemts afre not in order. so heavy distortion and bistribution of lateral loads will happen.

Suggestions:

• Heavy tortional forces should be controlled by respective lateral load system. So "Corner Shear Walls" are suggested.
• The Proportion of Floor area is grater on the left side than the right side. So corner shear wall on the left side should be heavier than the right side,
• Corner shear wall should be preferably be supported over box foundation. Shear walls should be connceted by links beams to transfer sgear from one to another.
• The Internal column should be supported by isolated footings. Those isolated footings can be connceted with shear walls through tie beams.