Conceptual design of a building with columns and shear walls

1) Restraint of floor shrinkage:

observation:

1. full restraints at all corners
2. corners are left free but restraints along the edge.
3. Non-uniform restraints.

conclusion: option(a) will have higher restraint to shrinkage thus lead to cracks in the floor .option (b) is average .option (c) will not effectively restrain the shrinkage,so possibly less cracks.

The Lateral Stiffness:

observation:

1. Comparatively lower lateral stiffness in both X and Y.
2. Uniform and comparatively higher lateral stiffness in both X and Y.
3. Non uniform lateral stiffness in both X and Y.

conclusion: option(b) will provide higher lateral stiffness for a pure seismic acceleration in X and Y directions.

Torsion with respect to vertical axis:

observation:

1. Corner walls provide more resistance to twist.
2. Edge walls provide good resistance to twist.
3. Irregular walls provide very poor resistance to twist.

conclusion: option(a) will be best option with respect to Torsional resistance where as option(c) is the worst one.

Vertical reinforcement for similar base capacity:

observation:

1. Walls are subjected to nominal flexural moment and heavy twisting moment.
2. Walls are subjected to nominal twisting moment and twisting moment.
3. Walls are subjected to heavy flexural moment and twisting moment.

conclusion: option (c) will require higher vertical reinforcement and option (b) will require the least.

Static eccentricity:

observation:

1. structurally symmetric
2. structurally symmetric
3. un-symmetric

conclusion: only option(c) will have static eccentricity and it is significant

Systems redundancy:

observation:

1. Uniform placement of lateral load supports in both the axis.
2. Uniform placement of lateral load supports in both the axis.
3. Concentrated lateral load supports in both the axis.

conclusion: option (a) and option (b) are more redundant than option(c)

Foundation systems:

observation:

1. Due to L shapes walls, the geometry of foundation and its design will be critical.
2. Walls are in line . Easy to fix the geometry and design of foundation.
3. Walls are in line & concentrated . Easy to fix the geometry of foundation but critical in design.

conclusion: option (b) and option (c) shall be incorporated with isolated footings.strip footings option (a) is recommended to have peripheral box foundation.

Architectural constrants:

observation:

1. Walls obstruct only corners.
2. Walls obsruct the faces of the building.
3. Vertical wall will not allow passage.

conclusion: Architecturally speaking , option (a) is the preferred one. option (b) is subjected to discussion. option(c) will not be accepted both architecturally and commercially.

2)

Issues in the given Framin plan:

Indirect lateral load Transfer in x and y direction: The beams are connecting to another beams which is ineffective during lateral load transfer. In such conditions, the primary beam is prone to share failure

Eccentricity: The longer the distance between center of mass and center of stiffness, the higher torsional moment of the building.As per the given eccentricity the building is subjected to higher torsional moment (Torsional flexibility) in both X and Y directions.

Strong beam weak column possibility : The size of columns majorly mentioned as 25cm and 25cm .But all the beam is visually higher than column. If the column reinforcement is adequately greater than that of beams , we are okay and since due do not have the reinforcement detail,this is doubtful . It is recommended to have slight bigger sizes for column

alternate scheme is by arranging columns both vertically and horizontally without much geometric changes

3)

Observations in the given framing plan:

Floor plan: The floor plan of building is not either uniform or symmetric. so natrurally any lateral load is induced in the floor will not have 100% influence in same direction. Definetly a special lateral load resisting system for these torsional moments should be accommdated .

Random Internal columns: since the internal columns are random , they are unable to transfer lateral loads efficiently and can not achieve desirable building response .so we have to assume and design those columns for only gravity loads.

Floor to floor variations walls and beam: partition walls provide an important mass control in a building and beams play key role in shear transfer from floor to beam .All these elements are not in order . so heavy disortion and distribution of lateral load will happen.

Suggestion on the Lateral load system & its foundation:

• Heavy torsional forces should be controlled by respective lateral load system . so corner shear wall are suggested .
• The proportion of floor area is greater on the left side than the right side ( irregular quadilateral) . so corner shear walls on the left side should be heavier than their right.
• Corner shear walls shall preferably be supported over a box foundation. shear walls should be connected by link beams to transfer shear from one to the other.
• The internal columns shall be supported by isolated footings. Those isolated footings can be connected with shear walls through Tie beams