Conceptual design of a building with columns and shear walls
1.Ans.:
| PARAMETERS | SHEAR WALL ARRANGEMENT (a) | SHEAR WALL ARRANGEMENT (b) | SHEAR WALL ARRANGEMENT (c) |
| Restraint of fllor shrinkage | The shear walls are arranged at the corners therefore it will restraints at all the four corner | The shear wall are arranged on the periphery region,thus restraints occurs along the edges | The shear wall arrangement has non-symmetric therefore non-uniform restraints occur |
| Lateral stiffness | The lateral stiffness becomes comparatively low along both the direction | Uniform and comparatively higher lateral stiffness along X and Y directions | Non-uniformity in lateral stiffness |
| Torsion | Torsional resistance will be more at corner walls on the structure | Torsion resists at the edge sides of the wall | Less torsional resistance due to non-uniform arrangement of walls |
| Vertical Reinforcement | Walls are subjected to nominal flexure moment with more twisting moment | Walls are subjected to nominal twisting moment | Walls are subjected to heavy flexural moment and twisting moment |
| Static Eccentricity | Symmetrical structure | Symmetrical structure | Unsymmetrical |
| System Redundancy | As the wall arrangement are symmetric uniform lateral load supports on both axis | As the wall arrangement are symmetric uniform lateral load supports on both axis | Concentrated lateral load supports in both the axes |
| Foundation System | Due to L shaped wall,the foundation design will be critical | Walls are in the form of straight line,the foundation design will be easy to fix | Walls are in straight line and concentrated.therefore it is easy to fix but critical at design |
| Architectural Constraints | Obstruction occur at corners | Obstruction at the face of the buildings | Obstruction at passage |
2. Ans.:
- In this structural frame,there is a two-way eccentricity of the centre of mass in accordance with centre of stiffness,which is eccentricity of X-direction is larger than Y-direction.
- In this structure beams are provided at stronger than column,so it can consider as weak column strong beam design in nature.
- Therefore this structure need some shear wall to resist the column failure,when the lateral forces acting about the structure.
- Combination of shear wall and column tends to prevent the failure about the structure during the seismic forces occur.
- As the frame plan,we can see about the alignment of beam is uniformly continuous of B1 and B2 at X-direction,and B11 & B12,B9 & B10 at Y-direction.
- But another all beams are provided at discontinuous of structural frame,so here cause too difficult of transmission of load evenly at entire structure due to action of lateral forces.
- Beams with long span may have their top reinforcement at the supports governed by factored gravity load,rather than by the seismic design situations.
- Therefore,this structure will alternate to better portal of better offset at symmetric in nature.
- The column beams connections should be in proper cross section area,then it achieve lateral stiffness,mass regularity,moment resisting factor.
- As we consider beam-sway mechanism in strong column/weak beam design frames is better,because of its achieve a uniformity spread,global inelastic displacement demand at roof level,to all storeys.
3. Floor Plan :
The floor plan of the building is not uniform or symmetric.So naturally any lateral load induced in the floor will not have 100% influence in same direction.Definitely a special lateral load resistance system for these torsional moments should be accomodated.
Random internal columns :
Since the internal columns are random,they are unable to transfer the lateral loads efficiently and cannot achieve desirable building response.So we have to assume and designed those columns for only gravity loads.
Floor to floor variation in partition walls and beams :
Partition was provide an important mass control in and building and Beams plan key role in shear transfer from floor to beam.All these elements are not in order.So heavy distortion distribution of loads will happen. - This plan is totally unacceptable for heavy seismic zone areas.
- In this plan interior columns are in unsymmetrical.
- The partition wall are provided through to the base of beam,should support the lateral deformation due to the structure.
- The interior beams will support the slab,then the lateral load resisting the failed due to earthquakes.
- For this irregular columns in plan,there we provide the flat slab because it directly stay in column centroid axis.
- For here the beams at different locations is irregular in plan are the continuous and is disallowed to resist the seismic load in the region.
- The solution of the structure,we provide the shear wall from the foundation of the structure through vertical components,it should minimise the lord of second failure occur due to lateral forces acting on structure.