Conceptual design of a building with columns and shear walls

1.The building shown, 20 × 35 m in plan, has columns on a 5 × 5 m grid and shear walls (with dimensions shown in m, 250 mm in thickness) in three alternative arrangements, (a), (b), (c), all with the same total cross-sectional area of the shear walls. Compare the three alternatives, taking into account the restraint of floor shrinkage, the lateral stiffness and the torsional one with respect to the vertical axis, the vertical reinforcement required for the same total flexural capacity at the base, the static eccentricity, the system’s redundancy, foundation systems, architectural constraints etc. 

A

• This structure is considered as asymmetric in nature.
• cannot  be considered as a horizontal irregularities and the shear wall shape  L.
• There is some uncertainty concerning certain features of the seismic response of non-rectangular walls.
•  lack of tensile capacity configuration.
• These walls have high stiffness and strength in both direction.

B 

• This structure frame can be considered as symmetric shear walls.
• The wall system of this frame could be arranged in two horizontal directions with as much two-way symmetric as possible.
• The shear walls are arranged in similar and symmetric
• It can be considered at every storey to fairly uniform resistant in seismic forces and deformation demands.

C

• For this structure can be considered as asymmetric in nature
• Because of the shear wall are arranged in a two orthogonal horizontal directons.
• The center of mass and center of gravity of such structure will not lie far away from each other enabling transitional modes in the first two principles modes.
• This type of shear wall system will not carry the load equally in either directions,have lack of redundancy.
• On left hand side the wall provide more eccentricity, lateral stiffness is more. Then the  failure will be less. 

2.Discuss the suitability for earthquake resistance of the moment resisting framing plan of a three-storey building depicted here (cross-sectional dimensions in cm), the eccentricity of the centre of mass (as centroid of floor plan) to the centre of stiffness (from the moments of inertia of the columns) are shown. Suggest an alternative. Also, is there torsional flexibility? Are the two fundamental translational modes of vibration larger than the fundamental torsional mode of vibration. Discuss qualitatively. 

• In this structural frame , there is a two-way eccentricity of the center of mass in accordance with the center 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 in failure, when the lateral forces acting the structure.
• Combination of shear wall and column prevent the failure in structure during the seismic forces occur.
• As the frame plan, we can see the alignment of beam is uniformly continuous of] B1 &B2] at X- direction, and[ B11 & B12][B9 & B10] at Y-direction.
• But another all beams are provided at discontinuous of structural frame.
• 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 offset at symmetric .
• The column beams connections should be in proper cross section area, then it achieve lateral stiffness, mass regularity.
• As we consider beam-sway mechanism in strong column/ weak beam design frames is better, because of its achieve a uniformly spread, global inelastic displacement demand at roof level, to all storeys. 
• There fore, we changed the column of [C5 & C8] to considered as a combined footing, because of their loss of center of stiffness due to occur lateral forces about the structure.
• And more we add one more column of C10 is covered that boundary of plan, should maintain the center of mass as well as the center of stiffness about the structure during lateral horizontal force action .

3.A multi-storey building with basement, with a quadrilateral (non symmetrical floor plan) plan as, has interior columns in an irregular (not in a grid) pattern in plan that serves architectural and functional considerations. Partition walls and interior beams supporting the slab have different layout in different stories. However, there is no constraint to the type, location and size of the lateral force resisting components and sub-systems on the perimeter. Proposals are to be made and justified for the choice of the lateral-load-resisting system and its foundation. 

• This plan totally unsuitable for heavy seismic areas.
• The partition wall are provided through the base of the beam, because they support the lateral deformation due to the structure.
• The interior beams will supports the slab and then the lateral load resisting the failure due to earthquakes.
• This plan the interior columns are unsymmetric.
• This irregular columns in plan, we provided the flat slabs, because it is directly stay in column centroidal axis.
• In this plan, the flat sab is more appropriate than a regular beam column junctions, because it is  providing support to the columns without any provision of the beam.
• It reduces the weight of the building and also helps in ductility of the structure by indirectly.
• There fore the beams at different locations is irregular in plan and continuous are disallowed to resist the seismic load .
• The solution of this structure, we provide the shear wall from the foundation of structure through the vertical components because it should minimize the loss of sudden failure occur, due to lateral force acting on structure.