The user requirement is to design a residential building that optimizes square footage, given the intended use by the residents that you imagine, while being structurally sound and in compliance with local building codes and other environmental considerations of the building site including a staircase, with an area per floor of 1,000 sq. meters/11,000 sq. feet.
So, for this, I have chosen a rectangular type having fixed supports at the bottom where in the columns are placed at centre-to-centre distance of 5m. The basement is of 6m high along with the rest of the floors. The staircase is attached to the building covering under 25 sq. meters area.
For the properties under modelling, the following dimensions are considered
1. Dimension of Column= 0.6 x 0.6 m
2. Dimension of Beam= 0.6 x 0.4 m
3. Thickness of Plate = 0.15m
Under Load and Definition, the following loads are taken
1. Dead Load
2. Live load with load pressure of 3 KN/m2
3. Floor load with load pressure of 1.5 KN/m2
Under material, concrete is used. With this the modelling part of the structure is done covering an area of 1000 sq. meters per floor as per user requirement.
After the postprocessing part, we get the following output wherein we get the node displacement and support reaction with beam forces and stresses along with the plate pressure distribution.
1. Stress distribution for the structure is shown below
2. Max Absolute pressure in the plate is shown below
3. Displacement Diagram
4. Bending Moment diagram
5. Shear force diagram
Based on the following output, the structure is analysed and then designed taking M40 grade with Fe550 Grade steel and then computed the concrete design, here is one of the design considerations for a beam and a column.
This design is as per the IS code with specifications and is suitable for the given user requirement.
The foundation is also designed where in the design is as per Indian code. Isolated footing is adopted in this type of structure.
Here is the design of Isolated footing as per code
Input Values
Footing Geomtery
Design Type :Calculate Dimension Footing
Thickness (Ft) :305.000 mm
Footing Length - X (Fl) :1000.000 mm
Footing Width - Z (Fw) :1000.000 mm
Eccentricity along X (Oxd) :0.000 mm
Eccentricity along Z (Ozd) :0.000 mm
Column Dimensions
Column Shape :Rectangular
Column Length - X (Pl) :0.600 m
Column Width - Z (Pw) :0.600 m
Pedestal
Include Pedestal? NoPedestal Shape :N/A
Pedestal Height (Ph) :N/A P
edestal Length - X (Pl) :N/A
Pedestal Width - Z (Pw) :N/A
Design Parameters
Concrete and Rebar Properties
Unit Weight of Concrete : 25.000 kN/m3
Strength of Concrete :25.000 N/mm2
Yield Strength of Steel :415.000 N/mm2
Minimum Bar Size :Ø6
Maximum Bar Size :Ø32
Minimum Bar Spacing :50.000 mm
Maximum Bar Spacing :500.000 mm
Pedestal Clear Cover (P, CL) :50.000 mm
Footing Clear Cover (F, CL) :50.000 mm
Soil Properties
Soil Type :Drained
Unit Weight :22.000 kN/m3
Soil Bearing Capacity :100.000 kN/m2
Soil Surcharge :0.000 kN/m2
Depth of Soil above Footing :0.000 mm
Cohesion :0.000 kN/m2
Min Percentage of Slab :0.000
Sliding and Overturning
Coefficient of Friction :0.500
Factor of Safety Against Sliding :1.500
Factor of Safety Against
Overturning :1.500
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Design Calculations
Footing Size
Initial Length (Lo) = 1.000 m
Initial Width (Wo) = 1.000 m
Uplift force due to buoyancy = 0.000 kN
Effect due to adhesion = 0.000 kN
Area from initial length and width, Ao = Lo X Wo = 1.000 m2
Min. area required from bearing pressure, Amin = P / qmax = 53.369 m2
Note: Amin is an initial estimation. P = Critical Factored Axial Load(without self weight/buoyancy/soil). qmax = Respective Factored Bearing Capacity.
Final Footing Size
Length (L2) = 7.650m
Governing Load Case :# 1Width (W2) = 7.650m
Governing Load Case :# 1Depth (D2) = 0.858 m
Governing Load Case :# 1 Area (A2) = 58.523m2
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Moment Calculation
Check Trial Depth against moment (w.r.t. X Axis)
Critical Load Case = #1
Effective Depth = = 0.802 m
Governing moment (Mu)= 4333.049 kNm
As Per IS 456 2000 ANNEX G G-1.1C
Limiting Factor1 (Kumax) = = 0.479107
Limiting Factor2 (Rumax) = = 3444.291146 kN/m2
Limit Moment Of Resistance (Mumax) = = 16947.361412 kNmMu <= Mumax hence, safe
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Shear Calculation
Check Trial Depth for one way shear (Along X Axis) (Shear Plane Parallel to X Axis)
Critical Load Case= #1
DX = 0.802 mShear Force(S) = 1898.999 kN
Shear Stress(Tv) = 309.520190 kN/m2
Percentage Of Steel(Pt) = 0.2547
As Per IS 456 2000 Clause 40 Table 19
Shear Strength Of Concrete(Tc) = 367.741 kN/m2 Tv< Tc hence, safe
Check Trial Depth for two way shear
Critical Load Case = #1
Shear Force(S) = 5150.246 kN
Shear Stress(Tv) = 1145.106 kN/m2
As Per IS 456 2000 Clause 31.6.3.1
Ks = = 1.000
Shear Strength(Tc)= = 1250.0000 kN/m2
Ks x Tc = 1250.0000 kN/m2
Tv<= Ks x Tc hence, safe------------------------------------------------------
Reinforcement Calculation
Calculation of Maximum Bar Size
Along X Axis
Bar diameter corresponding to max bar size (db) = 32 mm A
s Per IS 456 2000 Clause 26.2.1
Development Length(ld) = = 1.289 m
Allowable Length(ldb) = = 3.475 mldb >=ld hence, safeAlong Z Axis
Bar diameter corresponding to max bar size(db)= 32 mm
As Per IS 456 2000 Clause 26.2.1
Development Length(ld) = = 1.289 m
Allowable Length(ldb) = = 3.475 mldb >=ld hence, safe
Finally, the design and Analysis for G+8 storey building is apt and here is the rendered view from STAAD PRO software.
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