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Isolated Foundation Design XLS
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NUCLEAR POWER CORPORATION OF INDIA LTD.
document.xls
DESIGN OF BI-AXIAL ISOLATED RCC FOOTING (IS 456, 2000)Building Name 2 MW CMCS RoomFooting Number: 2, 3, 6, 12, 13, 14, 15Node number 106, 111, 104, 105, 108, 109, 114
COLUMN Length (l, dim. || Z axis ) = 530 mmBreadth (b, dim. || X axis) = 230 mm
Breadth 2.4 mFOOTINGFoot length (L, dim. || Z axis) = 2.6 mFoot Breadth (B, dim. || X axis) = 2.4 mThickness of footing (t) = 530 mmClear cover of footing = 50 mmMain bar dia of footing = 10 mmEffective depth of footing dz = 475 mm Length 2.6 mEffective depth of footing dx = 465 mmSelfweight of the footing = 82.68 KN
Area of Footing(A) = 6.24
Sect mod of foot about Z axis (Zz) = 2.50
Sec mod of foot about X axis (Zx) = 2.70
MATERIALS OF CONSTRUCTION
25
415
CHECK FOR GROSS BEARING PRESSURE
103
Safe gross bearing pr. = 148.54 (net pr. + depth of foot * soil unit wt)7
Axial load from output (P1) = 504 KN
45.9333333 KN-m
0.93333333 KN-mDepth of top of foot. from ground = 2 m
Unit wt of soil = 18Weight of soil retained above foot = 220.25 KNP = (P1+soil+foot self wt) = 806.93 KN
Maximum bearing pressure = 148.06
Minimum bearing pressure = 110.57
Hence footing is safe against max gross bearing pr.
DESIGN FORCESFactored load comb. no. 7
756 KN
68.9 KN-m
1.4 KN-m
( Pu/Area+ Muz/Zz + Mux/Zx) = 149.28
( Pu/Area - Muz/Zz - Mux/Zx) = 93.03Design of footing is done using above maximum effective soil pressure
m2
m3
m3
Grade of concrete fck = N/mm2
Grade of steel fy = N/mm2
Safe NET bearing pressure = KN/m2
KN/m3
Unfactored load case number =
Moment about Z axis (Mz) =
Moment about X axis (Mx) =
KN/m3
KN/m2
KN/m2
Axial load:(Pu) =
Moment about Z axis (Muz) =
Moment about X axis (Mux) =
Maximum effective soil pressure pe max
KN/m2
Minimum effective soil pressure pe min
KN/m2
globalZ
globalX
global
X
globalZ
Footing Dimensions
globalZ
globalX
global
X
globalZ
Footing Dimensions
globalZ
globalX
global
X
globalZ
Footing Dimensions
PA
±M y
Z y±M x
Zx
PA
±M y
Z y±M x
Zx
PA
±M y
Z y±M x
Zx
NUCLEAR POWER CORPORATION OF INDIA LTD.
document.xls
CALCULATION FOR BOTTOM STEEL
79.95 KN-m per meterMulimit = 778.98 KN-m per meter
The section is singly reinforced
Hence, Ast = 474.302
Min Ast = 636.000 (0.12 % for slab, cl 26.5.2.1)Spacing (reqd.) = 123.49 mm (considering max of above two calculated values of Ast)
pt required = 0.13 % Sp (prov.) = 120 mm Ast (prov.) = 654.50
Hence required 10 mm dia bar @ 123 mm c/c parellel to length of footing ( || to Z)pt (prov.) = 0.14 %
87.87 KN-m per meter
Calc. Ast = 533.791 The section is singly reinforced
Min Ast = 636 (0.12 % for slab, cl 26.5.2.1)Spacing (reqd.) = 123.49 mm (considering max of above two calculated values of Ast)
pt required = 0.13 % Sp (prov.) = 120 mm Ast (prov.) = 654.50
Hence required 10 mm dia bar @ 123 mm c/c parellel to breadth of footing ( || to X)Arrangement of bottom reinforcement as per above design is shown below
pt (prov.) = 0.14 %10 mm dia bar @ 120 mm c/c
10 mm dia bar @ 120 mm c/c
1 1
Footing Length 2600 mm Breadth 2400 mm
Sec 1-1
1005 230705
L1
a a
Z ZN1 N1
a a
L2 L2
560L1 Breadth 2400 mm
530
Mu about X1 X1 = ( pe max x length2/2)=
mm2
mm2
mm2
Mu about N1 N1 = ( pe max x length2/2)=
mm2
mm2
mm2
X1 X
X1 X
Ast=0 .5 f ckf y [1−√1− 4 .6M u
f ck bd2 ]bdAst=
0 .5 f ckf y [1−√1− 4 .6M u
f ck bd2 ]bdAst=
0 .5 f ckf y [1−√1− 4 .6M u
f ck bd2 ]bd
NUCLEAR POWER CORPORATION OF INDIA LTD.
document.xls
Footing Length 2600 mm 610PLAN
NUCLEAR POWER CORPORATION OF INDIA LTD.
document.xls
CHECK FOR ONE WAY SHEAR :
One way shear at critical section L1- L1Distance of critical sec. from edge of footing = 0.56 mShear force Vu =pe max x 0.56 x 1m width of footing = 83.594 KN
Shear stress 0.176
0.280 3.1
tv < tc hence O.K. (Shear chairs not required)
One way shear at critical section L2- L2Distance of critical sec. from edge of footing = 0.61 mShear force Vu =pe max x 0.61 x 1m width of footing = 91.058 KN
Shear stress 0.192
0.283 3.1
tv < tc hence O.K. (Shear chairs not required)
CHECK FOR TWO WAY SHEARRef. cl 34.2.4 and cl.31.6.3 of IS 456 : 2000
0.93396 <1
0.93396
1.25 1.875
1.16745Shear force Vs = 149.275 ( 2.6 x 2.4 - 1.005 x 0.705) = 825.72 KNLength of critical section = 2 x ( 1005 + 705) = 3420 mm
Area of the critical section (length of critical sec x eff. d ) = 1624500
0.508tv < ks tc (Shears chairs not required)
tv = Vs/bd = N/mm2
tc = N/mm2 tc max = N/mm2
tv = Vs/bd = N/mm2
tc = N/mm2 tc max = N/mm2
Allowable shear stress tv allowable = kstc
ks = ( 0.5 + bc) =
Hence, ks=
tc = 0.25 (fck)0.5 = N/mm2 1.5 tc = N/mm2
tv allowable = ks x tc = N/mm2
mm2
Hence shear stress tv = N/mm2
DESIGN OF BI-AXIAL ISOLATED RCC FOOTING (IS 456, 2000)Building Name 2 MW CMCS RoomFooting Number: 1, 4, 10, 16Node number 103, 112, 115, 116
COLUMN Length (l, dim. || Z axis ) = 450 mmBreadth (b, dim. || X axis) = 230 mm
Breadth 1.7 mFOOTINGFoot length (L, dim. || Z axis) = 1.9 mFoot Breadth (B, dim. || X axis) = 1.7 mThickness of footing (t) = 450 mmClear cover of footing = 50 mmMain bar dia of footing = 10 mmEffective depth of footing dz = 395 mm Length 1.9 mEffective depth of footing dx = 385 mmSelfweight of the footing = 36.34 KN
Area of Footing(A) = 3.23
Sect mod of foot about Z axis (Zz) = 0.92
Sec mod of foot about X axis (Zx) = 1.02
MATERIALS OF CONSTRUCTION
25
415
CHECK FOR GROSS BEARING PRESSURE
103
Safe gross bearing pr. = 147.10 (net pr. + depth of foot * soil unit wt)7
Axial load from output (P1) = 240 KN
7.53333333 KN-m
8.2 KN-mDepth of top of foot. from ground = 2 m
Unit wt of soil = 18Weight of soil retained above foot = 112.55 KNP = (P1+soil+foot self wt) = 388.89 KN
Maximum bearing pressure = 136.65
Minimum bearing pressure = 104.15
Hence footing is safe against max gross bearing pr.
DESIGN FORCESFactored load comb. no. 7
360 KN
11.3 KN-m
12.3 KN-m
( Pu/Area+ Muz/Zz + Mux/Zx) = 135.83
( Pu/Area - Muz/Zz - Mux/Zx) = 87.08
m2
m3
m3
Grade of concrete fck = N/mm2
Grade of steel fy = N/mm2
Safe NET bearing pressure = KN/m2
KN/m3
Unfactored load case number =
Moment about Z axis (Mz) =
Moment about X axis (Mx) =
KN/m3
KN/m2
KN/m2
Axial load:(Pu) =
Moment about Z axis (Muz) =
Moment about X axis (Mux) =
Maximum effective soil pressure pe max
KN/m2
Minimum effective soil pressure pe min
KN/m2
globalZ
globalX
global
X
globalZ
Footing Dimensions
globalZ
globalX
global
X
globalZ
Footing Dimensions
PA
±M y
Z y±M x
Zx
PA
±M y
Z y±M x
Zx
Design of footing is done using above maximum effective soil pressure
CALCULATION FOR BOTTOM STEEL
35.70 KN-m per meterMulimit = 538.68 KN-m per meter
The section is singly reinforced
Hence, Ast = 253.124
Min Ast = 540.000 (0.12 % for slab, cl 26.5.2.1)Spacing (reqd.) = 145.44 mm (considering max of above two calculated values of Ast)
pt required = 0.14 % Sp (prov.) = 145 mm Ast (prov.) = 541.65
Hence required 10 mm dia bar @ 145 mm c/c parellel to length of footing ( || to Z)pt (prov.) = 0.14 %
36.69 KN-m per meter
Calc. Ast = 267.150 The section is singly reinforced
Min Ast = 540 (0.12 % for slab, cl 26.5.2.1)Spacing (reqd.) = 145.44 mm (considering max of above two calculated values of Ast)
pt required = 0.14 % Sp (prov.) = 145 mm Ast (prov.) = 541.65
Hence required 10 mm dia bar @ 145 mm c/c parellel to breadth of footing ( || to X)Arrangement of bottom reinforcement as per above design is shown below
pt (prov.) = 0.14 %10 mm dia bar @ 145 mm c/c
10 mm dia bar @ 145 mm c/c
1 1
Footing Length 1900 mm Breadth 1700 mm
Sec 1-1
845 230625
L1
a a
Z ZN1 N1
a a
Mu about X1 X1 = ( pe max x length2/2)=
mm2
mm2
mm2
Mu about N1 N1 = ( pe max x length2/2)=
mm2
mm2
mm2
X1 X
A st=0 .5 f ckf y [1−√1− 4 .6M u
f ck bd2 ]bdA st=
0 .5 f ckf y [1−√1− 4 .6M u
f ck bd2 ]bd
L2 L2
330L1 Breadth 1700 mm
450 Footing Length 1900 mm 340
PLANCHECK FOR ONE WAY SHEAR :
One way shear at critical section L1- L1Distance of critical sec. from edge of footing = 0.33 mShear force Vu =pe max x 0.33 x 1m width of footing = 44.823 KN
Shear stress 0.113
0.279 3.1
tv < tc hence O.K. (Shear chairs not required)
Calculations for shear chairs (if required)
Vus = -65553 N
No. of legs Bar dia. Asv Spacing ofchairs
(nos.) (mm) (mm c/c)
2 8 100.531 -213.182 8 100.531 -213.182 8 100.531 -213.182 8 100.531 -213.182 8 100.531 -213.18
One way shear at critical section L2- L2Distance of critical sec. from edge of footing = 0.34 mShear force Vu =pe max x 0.34 x 1m width of footing = 46.182 KN
Shear stress 0.117
0.283 3.1
tv < tc hence O.K. (Shear chairs not required)
CHECK FOR TWO WAY SHEARRef. cl 34.2.4 and cl.31.6.3 of IS 456 : 2000
1.01111 >1
1
1.25 1.875
1.25Shear force Vs = 135.828 ( 1.9 x 1.7 - 0.845 x 0.625) = 366.99 KN
X1 X
tv = Vs/bd = N/mm2
tc = N/mm2 tc max = N/mm2
Vu - tcbd =
(mm2)
tv = Vs/bd = N/mm2
tc = N/mm2 tc max = N/mm2
Allowable shear stress tv allowable = kstc
ks = ( 0.5 + bc) =
Hence, ks=
tc = 0.25 (fck)0.5 = N/mm2 1.5 tc = N/mm2
tv allowable = ks x tc = N/mm2
Length of critical section = 2 x ( 845 + 625) = 2940 mm
Area of the critical section (length of critical sec x eff. d ) = 1161300
0.316tv < ks tc (Shears chairs not required)
mm2
Hence shear stress tv = N/mm2
globalZ
globalZ
DESIGN OF BI-AXIAL ISOLATED RCC FOOTING (IS 456, 2000)Building Name 2 MW CMCS RoomFooting Number: 5, 11Node number 101, 102
COLUMN Length (l, dim. || Z axis ) = 450 mmBreadth (b, dim. || X axis) = 230 mm
Breadth 1.3 mFOOTINGFoot length (L, dim. || Z axis) = 1.5 mFoot Breadth (B, dim. || X axis) = 1.3 mThickness of footing (t) = 400 mmClear cover of footing = 50 mmMain bar dia of footing = 10 mmEffective depth of footing dz = 345 mm Length 1.5 mEffective depth of footing dx = 335 mmSelfweight of the footing = 19.50 KN
Area of Footing(A) = 1.95
Sect mod of foot about Z axis (Zz) = 0.42
Sec mod of foot about X axis (Zx) = 0.49
MATERIALS OF CONSTRUCTION
25
415
CHECK FOR GROSS BEARING PRESSURE
103
Safe gross bearing pr. = 146.20 (net pr. + depth of foot * soil unit wt)7
Axial load from output (P1) = 89 KN
2.3 KN-m
0.42 KN-mDepth of top of foot. from ground = 2 m
Unit wt of soil = 18Weight of soil retained above foot = 66.47 KNP = (P1+soil+foot self wt) = 174.97 KN
Maximum bearing pressure = 96.04
Minimum bearing pressure = 83.42
Hence footing is safe against max gross bearing pr.
DESIGN FORCESFactored load comb. no. 7
133 KN
0.42 KN-m
2.3 KN-m
( Pu/Area+ Muz/Zz + Mux/Zx) = 73.92
( Pu/Area - Muz/Zz - Mux/Zx) = 62.49
m2
m3
m3
Grade of concrete fck = N/mm2
Grade of steel fy = N/mm2
Safe NET bearing pressure = KN/m2
KN/m3
Unfactored load case number =
Moment about Z axis (Mz) =
Moment about X axis (Mx) =
KN/m3
KN/m2
KN/m2
Axial load:(Pu) =
Moment about Z axis (Muz) =
Moment about X axis (Mux) =
Maximum effective soil pressure pe max
KN/m2
Minimum effective soil pressure pe min
KN/m2
globalZ
globalX
global
X
globalZ
Footing Dimensions
PA
±M y
Z y±M x
Zx
Design of footing is done using above maximum effective soil pressure
CALCULATION FOR BOTTOM STEEL
10.19 KN-m per meterMulimit = 410.94 KN-m per meter
The section is singly reinforced
Hence, Ast = 82.146
Min Ast = 480.000 (0.12 % for slab, cl 26.5.2.1)Spacing (reqd.) = 163.62 mm (considering max of above two calculated values of Ast)
pt required = 0.14 % Sp (prov.) = 160 mm Ast (prov.) = 490.87
Hence required 10 mm dia bar @ 163 mm c/c parellel to length of footing ( || to Z)pt (prov.) = 0.14 %
10.58 KN-m per meter
Calc. Ast = 87.887 The section is singly reinforced
Min Ast = 480 (0.12 % for slab, cl 26.5.2.1)Spacing (reqd.) = 163.62 mm (considering max of above two calculated values of Ast)
pt required = 0.14 % Sp (prov.) = 160 mm Ast (prov.) = 490.87
Hence required 10 mm dia bar @ 163 mm c/c parellel to breadth of footing ( || to X)Arrangement of bottom reinforcement as per above design is shown below
pt (prov.) = 0.15 %10 mm dia bar @ 160 mm c/c
10 mm dia bar @ 160 mm c/c
1 1
Footing Length 1500 mm Breadth 1300 mm
Sec 1-1
795 230575
L1
a a
Z ZN1 N1
a a
Mu about X1 X1 = ( pe max x length2/2)=
mm2
mm2
mm2
Mu about N1 N1 = ( pe max x length2/2)=
mm2
mm2
mm2
X1 X
A st=0 .5 f ckf y [1−√1− 4 .6M u
f ck bd2 ]bd
L2 L2
180L1 Breadth 1300 mm
450 Footing Length 1500 mm 190
PLANCHECK FOR ONE WAY SHEAR :
One way shear at critical section L1- L1Distance of critical sec. from edge of footing = 0.18 mShear force Vu =pe max x 0.18 x 1m width of footing = 13.305 KN
Shear stress 0.039
0.284 3.1
tv < tc hence O.K. (Shear chairs not required)
Calculations for shear chairs (if required)
Vus = -84718 N
No. of legs Bar dia. Asv Spacing ofchairs
(nos.) (mm) (mm c/c)
2 8 100.531 -143.532 8 100.531 -143.532 8 100.531 -143.532 8 100.531 -143.532 8 100.531 -143.53
One way shear at critical section L2- L2Distance of critical sec. from edge of footing = 0.19 mShear force Vu =pe max x 0.19 x 1m width of footing = 14.044 KN
Shear stress 0.041
0.288 3.1
tv < tc hence O.K. (Shear chairs not required)
CHECK FOR TWO WAY SHEARRef. cl 34.2.4 and cl.31.6.3 of IS 456 : 2000
1.01111 >1
1
1.25 1.875
1.25Shear force Vs = 73.917 ( 1.5 x 1.3 - 0.795 x 0.575) = 110.35 KN
X1 X
tv = Vs/bd = N/mm2
tc = N/mm2 tc max = N/mm2
Vu - tcbd =
(mm2)
tv = Vs/bd = N/mm2
tc = N/mm2 tc max = N/mm2
Allowable shear stress tv allowable = kstc
ks = ( 0.5 + bc) =
Hence, ks=
tc = 0.25 (fck)0.5 = N/mm2 1.5 tc = N/mm2
tv allowable = ks x tc = N/mm2
Length of critical section = 2 x ( 795 + 575) = 2740 mm
Area of the critical section (length of critical sec x eff. d ) = 945300
0.117tv < ks tc (Shears chairs not required)
mm2
Hence shear stress tv = N/mm2
globalZ
DESIGN OF BI-AXIAL ISOLATED RCC FOOTING (IS 456, 2000)Building Name 2 MW CMCS RoomFooting Number: 7, 8, 9Node number 107, 117, 113
COLUMN Length (l, dim. || Z axis ) = 600 mmBreadth (b, dim. || X axis) = 230 mm
Breadth 2.5 mFOOTINGFoot length (L, dim. || Z axis) = 2.85 mFoot Breadth (B, dim. || X axis) = 2.5 mThickness of footing (t) = 530 mmClear cover of footing = 50 mmMain bar dia of footing = 10 mmEffective depth of footing dz = 475 mm Length 2.85 mEffective depth of footing dx = 465 mmSelfweight of the footing = 94.41 KN
Area of Footing(A) = 7.13
Sect mod of foot about Z axis (Zz) = 2.97
Sec mod of foot about X axis (Zx) = 3.38
MATERIALS OF CONSTRUCTION
25
415
CHECK FOR GROSS BEARING PRESSURE
103
Safe gross bearing pr. = 148.54 (net pr. + depth of foot * soil unit wt)7
Axial load from output (P1) = 651.333333 KN
9 KN-m
11.2 KN-mDepth of top of foot. from ground = 2 m
Unit wt of soil = 18Weight of soil retained above foot = 251.53 KNP = (P1+soil+foot self wt) = 997.27 KN
Maximum bearing pressure = 146.31
Minimum bearing pressure = 133.63
Hence footing is safe against max gross bearing pr.
DESIGN FORCESFactored load comb. no. 7
977 KN
13.5 KN-m
16.8 KN-m
( Pu/Area+ Muz/Zz + Mux/Zx) = 146.63
( Pu/Area - Muz/Zz - Mux/Zx) = 127.61
m2
m3
m3
Grade of concrete fck = N/mm2
Grade of steel fy = N/mm2
Safe NET bearing pressure = KN/m2
KN/m3
Unfactored load case number =
Moment about Z axis (Mz) =
Moment about X axis (Mx) =
KN/m3
KN/m2
KN/m2
Axial load:(Pu) =
Moment about Z axis (Muz) =
Moment about X axis (Mux) =
Maximum effective soil pressure pe max
KN/m2
Minimum effective soil pressure pe min
KN/m2
globalZ
globalX
global
X
globalZ
Footing Dimensions
PA
±M y
Z y±M x
Zx
Design of footing is done using above maximum effective soil pressure
CALCULATION FOR BOTTOM STEEL
92.79 KN-m per meterMulimit = 778.98 KN-m per meter
The section is singly reinforced
Hence, Ast = 551.983
Min Ast = 636.000 (0.12 % for slab, cl 26.5.2.1)Spacing (reqd.) = 123.49 mm (considering max of above two calculated values of Ast)
pt required = 0.13 % Sp (prov.) = 120 mm Ast (prov.) = 654.50
Hence required 10 mm dia bar @ 123 mm c/c parellel to length of footing ( || to Z)pt (prov.) = 0.14 %
94.45 KN-m per meter
Calc. Ast = 574.639 The section is singly reinforced
Min Ast = 636 (0.12 % for slab, cl 26.5.2.1)Spacing (reqd.) = 123.49 mm (considering max of above two calculated values of Ast)
pt required = 0.13 % Sp (prov.) = 120 mm Ast (prov.) = 654.50
Hence required 10 mm dia bar @ 123 mm c/c parellel to breadth of footing ( || to X)Arrangement of bottom reinforcement as per above design is shown below
pt (prov.) = 0.14 %10 mm dia bar @ 120 mm c/c
10 mm dia bar @ 120 mm c/c
1 1
Footing Length 2850 mm Breadth 2500 mm
Sec 1-1
1075 230705
L1
a a
Z ZN1 N1
a a
Mu about X1 X1 = ( pe max x length2/2)=
mm2
mm2
mm2
Mu about N1 N1 = ( pe max x length2/2)=
mm2
mm2
mm2
X1 X
A st=0 .5 f ckf y [1−√1− 4 .6M u
f ck bd2 ]bd
L2 L2
650L1 Breadth 2500 mm
600 Footing Length 2850 mm 660
PLANCHECK FOR ONE WAY SHEAR :
One way shear at critical section L1- L1Distance of critical sec. from edge of footing = 0.65 mShear force Vu =pe max x 0.65 x 1m width of footing = 95.312 KN
Shear stress 0.201
0.280 3.1
tv < tc hence O.K. (Shear chairs not required)
Calculations for shear chairs (if required)
Vus = -37707 N
No. of legs Bar dia. Asv Spacing ofchairs
(nos.) (mm) (mm c/c)
2 8 100.531 -447.612 8 100.531 -447.612 8 100.531 -447.612 8 100.531 -447.612 8 100.531 -447.61
One way shear at critical section L2- L2Distance of critical sec. from edge of footing = 0.66 mShear force Vu =pe max x 0.66 x 1m width of footing = 96.779 KN
Shear stress 0.204
0.283 3.1
tv < tc hence O.K. (Shear chairs not required)
CHECK FOR TWO WAY SHEARRef. cl 34.2.4 and cl.31.6.3 of IS 456 : 2000
0.88333 <1
0.88333
1.25 1.875
1.10417Shear force Vs = 146.634 ( 2.85 x 2.5 - 1.075 x 0.705) = 933.64 KN
X1 X
tv = Vs/bd = N/mm2
tc = N/mm2 tc max = N/mm2
Vu - tcbd =
(mm2)
tv = Vs/bd = N/mm2
tc = N/mm2 tc max = N/mm2
Allowable shear stress tv allowable = kstc
ks = ( 0.5 + bc) =
Hence, ks=
tc = 0.25 (fck)0.5 = N/mm2 1.5 tc = N/mm2
tv allowable = ks x tc = N/mm2
Length of critical section = 2 x ( 1075 + 705) = 3560 mm
Area of the critical section (length of critical sec x eff. d ) = 1691000
0.552tv < ks tc (Shears chairs not required)
mm2
Hence shear stress tv = N/mm2
globalZ
