Eccentric Footing design example

Eccentric Footing (Give Input only in Yellow  Box)

Grade of Concrete

M

25

Grade of Steel

Fe

500 kN/m2

S.B.C of the Soil

150

size of the footing (assumed)

1.8

x

Thickness of Footing

300

mm

Dimentions of column

0.3

X

Depth of the footing

1.75

m

Density of Soil

18

KN/m3

Axial load from the column

81

kN

Moment from the column

50

kNm

Gap between column face and Found

400

mm

Self weight of foundation

32.4

kN

Weight of soil above Foundation (Rec)

110.403 kN

Total load on foundation except Axial Load

142.803 kN

C.G of footing from top

1.2

m

C.G of column from top

0.55

m

C.G of the load from top

0.965

m

Eccentricity from C.G of footing

0.235

m

Moment due to eccentricity

52.65

kNm

2.4

m d

0.3

m

Total Load P

223.803 m

Total moment M

102.65 kNm

Ecentricity Maximum Pressure

0.458662306 M     >

0.4

111.8113926 kN/m2 Safe

Footing Contact 2.224013083 m Length Top Reinforcement Required Intensity at

0

kN/m2

other end Moment Mu

92.17422222 kN/m2

Ast Required

914.9775591 KN‐m

Ast Min

360

Dia of Bar Spacing of Bar Required

mm2

12

123.6066769 mm C

Spacing of Bar Provided Ast Provided

110

mm

1028.16

mm2

Check for Shear load Coming on Footing Due to Soil & Foundation

33.6 Kn/m

Shear at critical face 15.68833 kN ζv

0.09413 N/mm

2

pt

0.411

β

7.06

ζc

0.45098 N/mm 2 Safe in Shear

Wu

77.70938

Two Way Shear

Stress

Vu

317.5399 kN

ζv

0.907257 N/mm

β

1.5

Ks ζc

1

1.25

N/mm 2

Check for Over Turning Total overturning Moment 

102.65 kNm

Resisting Moment due to Soil Above Footing and foundation weight

171.36 kNm

Factor of Safety

2

1.5

Safe

Safe in Shear

0.55

1.2 CG of whole System

2.4 0.235252

CG of Dead Load

250

m

o

1.8

One Way Shear

175.82

250 Critical Section For Oneway Shear

250

250 84.16036 2.4 1.85 33.6 Kn/m

0 1.8

125

125

0.425

125

0.55

1.8

2.4