Job No
Date
Design By
SRV
PROJECT
EGP-01
17.08.14
Chk'd By
UDHYA
Rev
P1
App. By
1.0 Design Of Isolated Footing
1.1 General details
Type of foundation
Foundation Level below NGL
Hs
Square
2
gs
18
Allowable Net SBC
180
kN/m
kN/m
Overburden pressure
kN/m
Density of soil
m
3
Height of pedestal from T.O.F
= 2 - 0.4
1.6
Allowable SBC (for DL+LL case)
= 180 + 1.6 x 18
208.80
kN/m
Allowable SBC (for lateral load case) = 180 x 1.25+28.8
253.80
kN/m
Size of Column ( a x b)
0.23
0.3 m
Size of pedestal
0.23
0.3 m
Axial load on column (p) un factored
428
kN
Assuming increasing % of load
10
Not Consider
Not Consider
Soil Self Weigth
= Fdn Area x ht x18
0.00
%
kN
Foundation self weigth
= Fdn Area xThkx25
0.00
kN
Total Axial load on Foundation (P)
470.80
kN
Foundation size (in m) ( L x B x (D1-D2))
p 428
FGL
1.75
1.75
p 0
kN
0.4
0.15
kN
d
0.343
0.000
P
471
0.40
P
0
0
0.15
a
X
b
B =
B =
1.75 m
0.15
0.00 m
2m
Y
L=
Y
1.75
m
Square Footing
L=
0.00 m
Rectangular
Job No
Date
Design By
SRV
PROJECT
EGP-01
17.08.14
Chk'd By
UDHYA
Rev
P1
App. By
1.2 Size of Footing
= 470.8 / 180
Area of Footing (AxB)
2.62
Required Size of square footing (L x B)
1.62
m
1.62 m
Provided Size of square footing (L x B)
1.75
1.75 m
LxB
3.063
0.767
0.77 x b
= 0.77 x B x B
2.62
= BxB
3.41
0.00
m
m
0.00
OK
For Rectangular Footing
= 0.3 / 0.23
a/b Ratio of column
2
2
Required Size of rectangular footing (L x B)
0.00
0.00 m
Provided Size of rectangular footing (L x B)
0.00
0.00 m
LxB
SBC Check
= 470.8 / 3.06
Max base Pressure
SBC Check
153.73
kN/m
= 208.8 >153.73
OK
1.3 Net Soil Pressure At Ultimate Load
=
1.5
230.60
Code used For Design
IS456:2000
Compressive Strength of concrete fck
M20
Factored Consider
Net upward pressure (qu)
= 470.8 x 1.5 / 1.75 x 1.75
Ref Table-18
kN/m
1.4 Design Data
N/mm
20
Yield Strength of steel, Fy
Fe415
Clear cover to the reinforcement, C
50
Diameter of Reinforcement, (x-direction)
10
415
N/mm
mm
Cl.26.4.2.2
mm
Diameter of Reinforcement, (y-direction)
10
mm
1.5 Check For One Way Shear
For max. Shear(Vu1), take section along the breadth in the YY-direction at a distance ' d '
from the column space
Max Shear is
Length of moment section
Breath of section
(1750 - 0.23 )/ 2
Vu1
Area x force
760
mm
1750
mm
Job No
Date
Design By
SRV
PROJECT
EGP-01
17.08.14
Chk'd By
UDHYA
Rev
P1
App. By
Assume Percentage of steel
Pt
0.15
Design Strength of concrete (table19:IS456:2000)
tc
0.28
N/mm
Design Strength of concrete
tc
VC1/ bxd
Vc1
N/mm
0.28 x1.75 x d
Vu1
1750 x (760 - d ) x 0.231
Here, Vu1<VC1
1750 x (760 - d ) x 0.231 < 0.28 x1.75 x d
d
343.23
mm
398.23
mm
1.75 m
327.43
B =
d
a
343.23
Critical sec for one
way shear
Critical sec for one way shear
Y
L=
1.75
For Shear(Vu1), take section along the length in the XX-direction at a distance ' d '
from the column space
Max Shear is
Vu1
Area x force
725
mm
Length of section
1750
mm
Assume Percentage of steel
Pt
0.15
Design Strength of concrete (table19:IS456:2000)
tc
0.28
N/mm
Design Strength of concrete
tc
VC1/ bxd
Vc1
N/mm
0.28 x1.75 x d
Vu1
1750 x (725 - d ) x 0.231
Breath of moment section
(1750 - 0.3 )/ 2
Here, Vu1<VC1
1750 x (725 - d ) x 0.231 < 0.28 x1.75 x d
d
327.43
mm
382.43
mm
Job No
Date
Design By
SRV
PROJECT
EGP-01
17.08.14
Chk'd By
UDHYA
Rev
P1
App. By
Final Depth
The effective depth from oneway shear
Req overall depth of fdn
= 343.23 +50 + 5
The overall depth provided
The provided eff depth
= 400 -10 - 5
343.23
mm
398.23
mm
400
mm
OK
345
mm
OK
2.66
604.51
kN
1.6 Check For Two Way Shear
Taking section 'd/2' around column, we get
= 2 x 0.23 + 2 x 0.3 + 4 x 0.4
Critical perimeter
Critical shear (V)
= 230.6 { 1.75 x 1.75 - (0.23 +0.4 ) (0.3 +0.4 )
Critical shear
Design shear stress
tp
tp
tc
tc
= 604.51 / 2.66
Max shear strength ( clause 31.6.3.1, IS456:2000)
Here, tp < tc
V/( 2a+2b+4d) * d
2
0.23
N/mm
0.25 SQRT fck
2
1.12
N/mm
= 0.23 < 1.12
N/mm OK
1.7 Calculate bending moment
1. Bending moment at X-X
= 230.6 x 1.75 x 0.725^2 x 0.5
Mx
106.06
kNm
My
116.54
kNm
Mu / Bd
= 116.54 x 10^6 / 1750 x 345 x 345
0.56
2. Bending moment at Y-Y
= 230.6 x 1.75 x 0.76^2 x 0.5
1.8 Calculate reinforcement
1. Longitudinal reinforcement (For A s1)
R
% of steel
2
2
N/mm
Pt req
= { fck x 100 [1-SQRT(1-4 x R) / (0.87 x fck)] } / 2 x fy
Pt req
= { 20 x 100 [1-SQRT(1-4 x 0.56) / (0.87 x20)] } / 2 x 415
Pt req
0.160
Job No
Date
Design By
SRV
PROJECT
EGP-01
17.08.14
Chk'd By
UDHYA
Rev
P1
App. By
Minimum reinforcement
Ast min
Ast min
0.12 % BD
2
840
0.14
mm
%
Pt
0.160
Ast req
Nos
13.00
mm
Sp
126.00
mm
Ast pro
1021.02
Here, Ast req < Ast pro
= 0.12 x 1750 x 400 / 100
Pt (min)
Finally the max reinforcement % is
Ast (req)
=0.16 x 1750 x 345 / 100
967.87886 mm2
Use 10 mm dia bars
No.of.bras
= Ast req / Area of single bar
No.of.bras
=967.88 x 4 / 3.14 x 100
Spacing =(1750 - ( 2 x 50 ) - 10 ) x 4 / 3.14 x100
mm
1021.02 > 967.88
OK
2. Shorter reinforcement (For A s1)
R
= 106.06 x 10^6 / 0 x 345 x 345
R
% of steel
Mu / Bd
0.51
2
2
N/mm
Pt req
= { fck x 100 [1-SQRT(1-4 x R) / (0.87 x fck)] } / 2 x fy
Pt req
= { 20 x 100 [1-SQRT(1-4 x 0.51) / (0.87 x20)] } / 2 x 415
Pt req
0.145
Minimum reinforcement
Ast min
Ast min
0.12 % BD
2
840
Pt (min)
0.14
mm
%
Pt
0.150
Ast req
905.63
mm
Nos
13.00
mm
Sp
126.15
mm
Ast pro
1021.02
Here, Ast req < Ast pro
= 0.12 x 1750 x 400 / 100
Finally the Max reinforcement % is
Ast (req)
=0.15 x 1750 x 345 / 100
Use 10 mm dia bars
No.of.bras
= Ast req / Area of single bar
No.of.bras
=905.63 x 4 / 3.14 x 100
Spacing =(1750 - ( 2 x 50 ) - 10 ) x 4 / 3.14 x100
mm
1021.02 > 905.63
OK
Job No
Date
Design By
SRV
PROJECT
EGP-01
17.08.14
Chk'd By
UDHYA
Rev
P1
App. By
1.9 Result
Footing Size
Dir
Dia
1.75 x 1.75 x (0.40.15)
X-Dir
10
126.00
115.00
Y-Dir
10
126.15
125.00
Sp req C/C Sp req C/C
One Way
Two Way
OK
OK
2.0 Diagram
0.343
0.343 m
10 mm@ 115 mm c/c
10 mm@ 125 mm c/c
0.4
0.15
1.75
50 mm (min) Cover
Section A-A
10 mm@ 115 mm c/c
A
1.75
X Dir
10 mm@ 125 mm c/c
Y Dir
L
1.75
Plan
