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Eccentric Footing

This document provides design details for a column footing, including: - Column and footing dimensions - Loads and material properties - Calculations for required footing area, shear strength, bearing pressure, and reinforcement details - Checks that the design meets requirements for strength and serviceability The summary checks all design criteria except one-way shear strength, which is insufficient and requires additional reinforcement.

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hemantkle2u
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4K views8 pages

Eccentric Footing

This document provides design details for a column footing, including: - Column and footing dimensions - Loads and material properties - Calculations for required footing area, shear strength, bearing pressure, and reinforcement details - Checks that the design meets requirements for strength and serviceability The summary checks all design criteria except one-way shear strength, which is insufficient and requires additional reinforcement.

Uploaded by

hemantkle2u
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as XLS, PDF, TXT or read online on Scribd
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Column size:

b
230 mm

D
450 mm

Cover
40 mm

d
410 mm

Factored
Pu
637 Kn

Unfactored
P
425 Kn

Fck
20 N/mm2

Fy
415 N/mm2

SBC

250 Kn/m2

167 Kn/m2

Mux =

60 .0Kn-m

D
300 mm

Offset
100 mm

Loads:

T.L.on footing:
(Working)
Area of footing
required:
B.M.at col.base=
Provide area
Area provided
q=
tan =
tan provided=
Length reqd=

467 Kn
2 .80m2

0 .1m
L
2050 mm
2 .829m2

B
1380 mm

0 .150N/mm2
1.19
6.37 Safe
2 .0m

Min.length reqd=

1038 mm

So,provide footing
size
Area =

Bf
Lf
1380 mm
2050 mm
2 .83m2 Safe

Projection
Max projection

606 mm
288 mm

Intensity of soil
Pressure

225 Kn/m2

Depth reqd
Mux=
Reqd.eff.Depth =
So,provide total D=
d=

12 .9Kn-m
58 mm
350 mm
290 mm

Check for Two-way shear =


Perimeter =
1380 mm
Area resi.shear =
317400 mm2
Design shear =

20 Kn Safe

230 mm
Shear resi.by concrete
Ks =
1 .118N/mm2
Vuc =
354 .9Kn

Area of steel reqd.

157 mm2

So,provide =

no.
10

Dia.
10 mm

Ast.provided
785 mm2

Check for One-way shear =


Vud =
18 Kn
Shear resi.by con.
Tuc
Pt.=
0.2 % 0 .432N/mm2
Vuc.=
137 .1Kn Safe
Distribution steel
Ast reqd =
So,provide =

580 mm2
Dia.
8

Spacing
150 mm

Check for bearing pressure:


Actual pressure
6 .155N/mm2
A1 =
0 .28m2
A2 =
0 .10m2
sqrt(A1/A2) =
1.643314666
Permissible ultimate
bearing stress =
13.5 Safe

Ast.provided
141372 mm2

637.5

Pt
<=0.15
0.25
0.5
0.75
1
1.25
1.5
1.75
2
2.25
2.5
2.75
3

M20
0.28
0.36
0.48
0.56
0.62
0.67
0.72
0.75
0.79
0.81
0.82
0.82
0.82

Concrete Grade
M25
M30
0.29
0.36
0.49
0.57
0.64
0.7
0.74
0.78
0.82
0.85
0.88
0.9
0.92
0.25
0.5
0.3366
0.401568

0.36
0.48

Column size:

Loads:

SBC
Mux =
T.L.on footing:
(Working)
Area of footing
required:
B.M.at col.base=
Provide area
Area provided
q=
tan =
tan provided=
Length reqd=
Min.length reqd=
So,provide footing
size
Area =

b
300 mm

D
570 mm

Cover
40 mm

d
530 mm

Factored
Pu
330 Kn

Unfactored
P
220 Kn

Fck
20 N/mm2

Fy
415 N/mm2

400 Kn/m2

267 Kn/m2

D
660 mm

Offset
100 mm

192 .5Kn-m
242 Kn
0 .91m2

0 .6m
L
2250 mm
1 .125m2
0 .196N/mm2
1.27
3.3 Safe
1 .8m
2137 mm
Bf
Lf
500 mm
2250 mm
1 .13m2 Safe

Projection
Max projection

157 mm
1267 mm

Intensity of soil
Pressure

293 Kn/m2

Depth reqd
Mux=
Reqd.eff.Depth =
So,provide total D=
d=

117 .7Kn-m
292 mm
600 mm
540 mm

Check for Two-way shear =


Perimeter =
500 mm
Area resi.shear =
240000 mm2
Design shear =

B
500 mm

144 Kn Safe

480 mm
Shear resi.by concrete
Ks =
1 .118N/mm2
Vuc =
268 .3Kn

Area of steel reqd.

725 mm2

So,provide =

no.
10

Dia.
10 mm

Ast.provided
785 mm2

Check for One-way shear =


Vud =
115 Kn
Shear resi.by con.
Tuc
Pt.=
0.3 % 0 .432N/mm2
Vuc.=
103 .7Kn Unsafe
Distribution steel
Ast reqd =
So,provide =

360 mm2
Dia.
8

Spacing
150 mm

Check for bearing pressure:


Actual pressure
1 .930N/mm2
A1 =
0 .39m2
A2 =
0 .17m2
sqrt(A1/A2) =
1.50048725
Permissible ultimate
bearing stress =
13.5 Safe

Ast.provided
141372 mm2

637.5

Pt
<=0.15
0.25
0.5
0.75
1
1.25
1.5
1.75
2
2.25
2.5
2.75
3

M20
0.28
0.36
0.48
0.56
0.62
0.67
0.72
0.75
0.79
0.81
0.82
0.82
0.82

Concrete Grade
M25
M30
0.29
0.36
0.49
0.57
0.64
0.7
0.74
0.78
0.82
0.85
0.88
0.9
0.92
0.25
0.5
0.3366
0.401568

0.36
0.48

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