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footing combined
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square
Page 1
Design of square footing F2:
Ult. column load = 85.5 kN Safe bearing capacity = 55Self weight = 43 kN Overburden height = 0.00
Overburden = 0 kN Area of footing reqd. = 1.61Total load = 128 kN Footing size = 2.75
Column breadth = 400 mm Area of footing prvd. = 7.56Column width = 200 mm Footing thickness = 450
Net upward pressure = 11 Max. cantilever proj. = 1.28
Max. B.M. /m width M = 9 kNm Z = 374
= 0.002 As required /m width = 66Diameter of bars = 12 mm Spacing of bars = 200
As provided/m width = 565
Punch shear = 61 kN Dist. to critical section = 638
Punch shear stress = 0.03 Shear force = 7
Allow.shear stress = 0.33 Shear stress = 0.02
kN/m2
K = M/bd2fcu N/mm2
N/mm2
N/mm2
square
Page 2
m
m
mm
m
mm
mm
mm
kN/m
kN/m2
m2
m2
mm2
mm2
N/mm2
rectangular
Page 3
Design of rectangular footing F11:
Ult. column load = 936 kN Safe bearing capacity = 55Self weight = 64 kN Overburden height = 0.00
Overburden = 0 kN Area of footing reqd. = 12.53
Total load = 1000 kN Area of footing provided = 12.60
Net upward pressure = 74 Footing thickness = 400Short span Long span
Width = 3.00 m Length = 4.20Column width = 200 mm Column breadth = 500Max. cantilever proj. = 1.40 m Max. cantilever proj. = 1.85Max. B.M. /m width = 73 kNm Max. B.M. /m width = 127
= 0.022 = 0.036Z = 315 mm Z = 327
As required /m width = 624 As required /m width = 1052Diameter of bars = 12 mm Diameter of bars = 12Spacing of bars = 150 mm Number of bars/side = 100
As provided/m width = 754 As provided/m width = 1131
Punch shear = 799 kN Dist. to critical section = 688
Punch shear stress = 0.43 Shear force = 86
Allow.shear stress = 0.45 Shear stress = 0.26
kN/m2
K = M/bd2fcu N/mm2 K = M/bd2fcu
mm2
mm2
N/mm2
N/mm2
rectangular
Page 4
m
mmLong span
mmmmkNm
mm
mmmm
mm
kN/m
kN/m2
m2
m2
N/mm2
mm2
mm2
N/mm2
axial+moment
Page 5
Design of footing F2:
Ult. column load = 405 kN Safe bearing capacity = 100Ult. Moment = 170 kNm Overburden height = 0.30
Max. upward pressure = 131 Allowable pressure = 133
Min. upward pressure = 7 Footing thickness = 350
Short span Long spanWidth = 2.10 m Length = 2.80Column width = 300 mm Column breadth = 300Max. cantilever proj. = 0.90 m Max. cantilever proj. = 1.25Max. B.M. /m width = 53 kNm Max. B.M. /m width = 84
= 0.022 = 0.033Z = 268 mm Z = 279
As required /m width = 535 As required /m width = 817Diameter of bars = 12 mm Diameter of bars = 12Spacing of bars = 150 mm Number of bars/side = 120
As provided/m width = 754 As provided/m width = 942
Punch shear = 224 kN Dist. to critical section = 588
Punch shear stress = 0.17 Shear force = 88
Allow.shear stress = 0.46 Shear stress = 0.31
kN/m2
kN/m2
K = M/bd2fcu N/mm2 K = M/bd2fcu
mm2
mm2
N/mm2
N/mm2
axial+moment
Page 6
m
mm
Long spanmmmmkNm
mm
mmmm
mm
kN
kN/m2
kN/m2
N/mm2
mm2
mm2
N/mm2
combined
Page 7
Design of combined footing CF4:
Left column load = 60 Safe bearing capacity = 100Right column load = 984 kN Overburden height = 0.00Self weight = 68 kNOverburden = 0 kN Spacing of columns = 1.98Total load = 1112 kN C.G. of load from left = 1.87
Left column breadth = 200 mm Area of footing reqd. = 7.67 width = 200 mm Length of footing = 4.00Right column breadth = 400 mm Width of footing = 3.00 width = 400 mm Footing thickness = 450
Net upward pressure = 87 Area of footing provided = 12.00
Short span Long spanMax. cantilever proj. = 1.40 m Max. cantilever proj. = 1.69Max. B.M. /m width = 85 kNm Max. cant. moment /m = 124
Max span moment/m = 0
= 0.020 = 0.027Z = 359 mm Z = 372
As required /m width = 642 As required /m width = 898Diameter of bars = 12 mm Diameter of bars = 16Spacing of bars = 150 mm Spacing of bars = 180
As provided/m width = 754 As provided/m width = 1117
Punch shear = 774 kN Dist. to critical section = 784
Punch shear stress = 0.37 Shear force = 78
Allow.shear stress = 0.37 Shear stress = 0.20
Design of combined footing CF2:600 800
Footing is designedfor eccentricity of loads 0.50 3.50
Left column load = 600 kN Safe bearing capacity = 100Right column load = 800 kN Overburden height = 0.00Offset on left = 0.50 mSpacing of columns = 3.50 m C.G. of load from left = 2.50Offset on right = 1.00 m C.G. of reaction = 2.50
Eccentricity of load e= 0.00Left column breadth = 200 mm width = 200 mm Pressure at left edge
Right column breadth = 200 mm P/A + P e/Z = 93 width = 200 mm Pressure at right edge
P/A - P e/Z = 93
Length of footing = 5.00 m Max. allow. ult. pressure = 140Width of footing = 3.00 m
kN/m2
K = M/bd2fcu N/mm2 K = M/bd2fcu
mm2
mm2
N/mm2
N/mm2
combined
Page 8
Footing thickness = 400 mm Point of zero shear on footing
Area of footing provid. A= 15.00 from left edge = ###
Short span Long spanMax. cantilever proj. = 1.40 m Max. cantilever proj. = 0.90Max. B.M. /m width = 91 kNm Max. cant. moment /m = 57
Max span moment/m = ###
K = M/bd2fcu = 0.028 K = M/bd2fcu = ###Z = 315 mm Z = ###
As required /m width = 784 As required /m width = ###Diameter of bars = 12 mm Diameter of bars = 12Spacing of bars = 150 Spacing of bars = 100As provided/m width = 754 As provided/m width = 1131
Punch shear = 662 kN Dist. to critical section = 664
Punch shear stress = 0.40 Shear force = 69
Allow.shear stress = 0.39 Shear stress = 0.20
Design of combined footing F8:680 460
Footing is designed for -510 0axial load and moment: 1.50 1.85
Left column load = 680 kNLeft column moment = -510 kNm Safe bearing capacity = 100Right column load = 460 kN Overburden height = 0.30Right column moment = 0 kNm
Length of footing = 4.05Offset on left = 1.50 m Width of footing = 2.90Spacing of columns = 1.85 m Footing thickness = 450Offset on right = 0.70 m Area of footing provid. A= 11.75
Left column breadth = 700 mm Right column breadth = 300 width = 300 mm width = 300
Pressure at left edge
C.G. of load from left = 2.25 m P/A + P e/Z = 65C.G. of footing = 2.03 m Pressure at right edge
Eccentricity of load e= -0.22 m P/A - P e/Z = 129
Max. allow. ult. pressure = 133 Point of zero shear on footingfrom left edge = 2.71
Pressure at left edge
C.G. of load from left = 1.80 m P/A + P e/Z = 130C.G. of footing = 2.03 m Pressure at right edge
Eccentricity of load e= 0.23 m P/A - P e/Z = 65
Max. allow. ult. pressure = 133 Point of zero shear on footingfrom left edge = 2.08
m2
N/mm2
mm2
mm2
N/mm2
N/mm2
Case I Axial loads only:
kN/m2
Case II Axial loads and moments:
kN/m2
combined
Page 9
Short span Long spanMax. cantilever proj. = 1.30 m Max. cantilever proj. = 1.15Max. B.M. /m width = 109 kNm Max. cant. moment /m = 88
Max span moment/m = -55
K = M/bd2fcu = 0.025 K = M/bd2fcu = 0.019Z = 363 mm Z = 374
As required /m width = 816 As required /m width = 634Diameter of bars = 12 mm Diameter of bars = 12Spacing of bars = 125 Spacing of bars = 150As provided/m width = 905 As provided/m width = 754
Punch shear = 328 kN Dist. to critical section = 650
Punch shear stress = 0.13 Shear force = 84
Allow.shear stress = 0.37 Shear stress = 0.22
N/mm2
mm2
mm2
N/mm2
N/mm2
combined
Page 10
m
mm
mmmm
Long spanmkNmkNm
mm
mmmm
mm
kN
1.00
m
mmm
kN/m2
m2
m2
N/mm2
mm2
mm2
N/mm2
kN/m2
kN/m2
kN/m2
kN/m2
combined
Page 11
m
Long spanmkNmkNm
mm
mm
mm
kN
0.70
m
mmmm
mmmm
m
m
N/mm2
mm2
mm2
N/mm2
kN/m2
m2
kN/m2
kN/m2
kN/m2
kN/m2
combined
Page 12
Long spanmkNmkNm
mm
mm
mm
kN
N/mm2
mm2
mm2
N/mm2
combined (2)
Page 13
Design of combined footing F:
Column 1 600 0.00 0.00Column 2 400 0.00 2.00Column 3 700 3.00 0.00Column 4 500 3.00 2.00
Column sizeColumn 1 400 200 0.68Column 2 400 200Column 3 400 200 1.46Column 4 400 200 Length of footing = 6.20
Width of footing = 3.00
Safe bearing capacity = 100 Footing thickness = 500Overburden height = 0.90 m
Area of footing required = 18.57
Self weight = 117 Area of footing provided = 18.60Overburden = 375Total load = 2692 kN C.G.x = 1.64
Net upward pressure = 118.3 C.G.y = 0.82
X Direction Y DirectionBottom
Max. B.M./m under column = 178 kNm Max. B.M./m under column = 27
As required /m width = 1180 As required /m width = 275Diameter of bars = 16 mm Diameter of bars = 12Spacing of bars = 150 mm Spacing of bars = 200
As provided/m width = 1340 As provided/m width = 565Top
Max span moment/m 0 kNm Max span moment/m = 43
As required /m width = 0 As required /m width = 275Diameter of bars = 12 mm Diameter of bars = 12Spacing of bars = 200 mm Spacing of bars = 200
As provided/m width = 565 As provided/m width = 565
= 273 kN = 213
Shear stress = 0.21 Shear stress = 0.08
Allow.shear stress = 0.32 Allow.shear stress = 0.43
Max. Punch shear stress = 0.14 Allow.punch shear stress 0.37
LoadkN
Column location x m y m
bx
mmby
mm
kN/m2
kN/m2
mm2
mm2
mm2
mm2
Shear force at critical section
Shear force at critical section
N/mm2
N/mm2
N/mm2
C1
C2
C3
C4
y
combined (2)
Page 14
m 0.32m 1.46 1.74
mm 0.68
m
m
Y DirectionBottom
kNm
mmmm 114%
206%Top
kNm
mmmm
206%
kN
ShearOK
m2
m2
mm2
mm2
mm2
mm2
N/mm2
N/mm2
N/mm2
x
eccentric
Page 15
Design of eccentric footing:
Load on conc. footing = 137 kN 154 137Load on ecc. footing = 154 kN 6.40Spacing of columns = 6.40 mEdge of ecc. footingto centre of column = 0.15 mConc. footing length = 1.35 m 0.58 width = 1.35 m 169 122Ecc. footing length = 1.45 m
width = 1.45 m Safe bearing capacity = 100Reaction on Reaction on eccentric footing = 169 kN concentric footing = 122
Design of strap beam STB1:
Width = 200 mm Max. B.M. M = 79Depth = 500 mm Max. S.F. V = 15
= 0.068 A's required = 0
Z = 404 mm As required = 526
As provided = 603
Design shear v = 0.17 Diameter of stirrups = 8
Design concrete shear vc = 0.56 Spacing of stirrups reqd. = 200
K = M/bd2fcu N/mm2
N/mm2
N/mm2
eccentric
Page 16
kN
kNmkN
mm
mm
kN/m2
mm2
mm2
mm2
strip-base
Page 17
Design of base for footing F9:
Total column load = 149 kN Area of footing provid. = 15.00
Net upward pressure = 10 Max. cantilever proj. = 1.00Footing thickness = 300
Max. B.M. /m width = 5 kNm
= 0.003 As required /m width = 58Z = 232 mm Spacing of bars = 150
Diameter of bars = 12 mm As provided/m width = 754
Dist. to critical section = 488 mm Shear force = 5
Shear stress = 0.02 Allow.shear stress = 0.48
kN/m2
K = M/bd2fcu N/mm2
N/mm2
strip-base
Page 18
mmm
mm
kN/m
m2
mm2
mm2
N/mm2
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