1. DESIGN OF ISOLATED FOOTING
GIVEN DATA
Dimentions of R.C. Column= 400 X 400 mm
Vertical Load on Column= 50 kN
Safe Bearing Capacity os Soil= 220 kN/m^2
Grade of Concrete= M 20
Grade of Steel= Fe 415
STEP 1: SIZE OF FOOTING
Load on Column= 50 kN
Extra load due to Self-Weight= 5 kN
Total Load (P)= 55 kN
Required Area of Footing (A)= 0.25 m^2
Length (L)= 0.125 m ≈ 2
Breath (B)= 2 m
Net Upward Pressure in Soil (p)= 12.5 kN/m^2
Hence OK
STEP 2: TWO WAY SHEAR
Assume (D)= 250 mm
Diameter of Steel Bar Provided= 12 mm
Clear Cover= 50 mm
Effective Thickness (d)= 182 mm
Sides of Column
a= 400 mm
b= 400 mm
Punching Area= 0.338724
Punching Shear Force= 33.0638
Perimeter of Critical Section= 2328
Punching Shear Stress (tu)= 0.0780366

2. tc= 1.118034 N/mm2 ≈ 1.12
Ks= 1
Allowable Shear Stress= 1.12 N/mm2
Hence OK
So Final D= 350 mm
Clear cover= 50 mm
The effective depth of lower layer of reinforcement, d= 294 mm
The effective depth of upper layer of reinforcement, d= 282 mm
STEP 3 : DESIGN OF FLEXURE
pu= 50 kN/m2
l= 800 mm
Mu= 16 kN-m/m
As per IS 456:2000, to find Ast we have to solve a quadratic equation given in Annex G-1.16
b= 2000 mm
d= 282 mm
y= -14338529.4
x= 16.32815701
Ast= 16.32815701 mm2
pt= 0.002895063 %
STEP 4: ONE WAY SHEAR
Vu= 51.8
tv= 0.091843972
tc= 0.091843972 N/mm2
As per Table 61 in SP 16, Pt= 0.0556 % (After Interpolation)
So Provide Pt= 0.0556 %
Ast= 313.584 mm2
Provide 3 no. of
∅
12 mm diameter bars
Ast provided= 339.12 mm2

3. Hence Ok
STEP 5: CHECK FOR DEVELOPMENT LENGTH
Development Length for 12 mm diameter bars is given by Ld
Ld= 564 mm
Provide 60 mm side cover
Total Length= 740 mm
Hence OK
STEP 6: CHECK FOR BEARING STRESS
Assume load is dispersed from base of column to base of footing at a rate= 2
Side of area of dispersion at the bottom of footing= 1400 mm
Side condidered= 1400 mm
A1= 1.96 m2
A2= 0.16 m2
(A1/A2)^1/2= 3.5
Permissible Bearing Stress= 18 N/mm2
Actual Bearing Stress= 0.3125
Design for Bearing Stress is Satisfactory
STEP 7: DISTRIBUTION OF STEEL
Spacing= 666.6666667 ≈ 670 mm
IS 456:2000 Clause 26.3.3, s<3d Satisfied
IS 456:2000 Clause 26.3.3, s<300mm Unsatisfied
Final Spacing= 300 ≈ 300 mm
FINAL DATA
L= 2 m = 2000 mm
B= 2 m = 2000 mm

4. D= 250 mm
Diameter of Steel Rod= 12 mm
Clear Cover= 50 mm
Develoment Length (Ld)= 740 mm
Side Cover= 60 mm
Spacing= 300 mm

5. m

6. N/mm2

7. H: 1 V
FINAL DATA
L=
B=
D=