NUCLEAR POWER CORPORATION OF INDIA LTD.

DESIGN OF BI-AXIAL ISOLATED RCC FOOTING (IS 456, 2000) Building Name 2 MW CMCS Room Footing Number: 2, 3, 6, 12, 13, 14, 15 Node number 106, 111, 104, 105, 108, 109, 114 COLUMN Length (l, dim. || Z axis ) = Breadth (b, dim. || X axis) = FOOTING Foot length (L, dim. || Z axis) = Foot Breadth (B, dim. || X axis) = Thickness of footing (t) = Clear cover of footing = Main bar dia of footing = Effective depth of footing dz = Effective depth of footing dx = Selfweight of the footing = Area of Footing(A) = Sect mod of foot about Z axis (Zz) = Sec mod of foot about X axis (Zx) = MATERIALS OF CONSTRUCTION Grade of concrete fck = Grade of steel fy =

530 mm 230 mm Breadth 2.4 m 2.6 2.4 530 50 10 475 465 82.68 6.24 2.50 2.70 m m mm mm mm mm mm KN m2 m3 m3

global X

global Z

global Z global
Length 2.6 m

Footing Dimensions

2 25 N/mm 2 415 N/mm

CHECK FOR GROSS BEARING PRESSURE Safe NET bearing pressure = 103 Safe gross bearing pr. = 148.54 Unfactored load case number = 7 Axial load from output (P1) = 504 Moment about Z axis (Mz) = 45.933333 Moment about X axis (Mx) = 0.9333333 Depth of top of foot. from ground = 2 Unit wt of soil = 18 Weight of soil retained above foot = 220.25 P = (P1+soil+foot self wt) = 806.93 Maximum bearing pressure = 148.06 Minimum bearing pressure = 110.57 Hence footing is safe against max gross bearing pr. DESIGN FORCES Factored load comb. no. Axial load:(Pu) = Moment about Z axis (Muz) = Moment about X axis (Mux) = Maximum effective soil pressure pe max ( Pu/Area+ Muz/Zz + Mux/Zx) = Minimum effective soil pressure pe min

KN/m2 KN/m3 KN KN-m KN-m m KN/m3 KN KN KN/m2 KN/m2

(net pr. + depth of foot * soil unit wt)

M Mx P P M y y M x A A ZZ ZxZx y y

7 756 KN 68.9 KN-m 1.4 KN-m

2 ( Pu/Area - Muz/Zz - Mux/Zx) = 93.03 KN/m Design of footing is done using above maximum effective soil pressure

194858335.xls.ms_office

NUCLEAR POWER CORPORATION OF INDIA LTD.

CALCULATION FOR BOTTOM STEEL Mu about X1 X1 = ( pe max x length2/2)=

Ast =

0.5 f ck 4 .6 M u 1 - 1 bd fy f ck bd 2

79.95 KN-m per meter Mulimit = 778.98 KN-m per meter The section is singly reinforced

2 Hence, Ast = 474.302 mm 2 Min Ast = 636.000 mm (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.) = Hence required 10 mm dia bar @ 123 mm c/c parellel to length of footing ( || to Z) pt (prov.) = 0.14 % Mu about N1 N1 = ( pe max x length2/2)= 87.87 KN-m per meter 2 Calc. Ast = 533.791 mm The section is singly reinforced 2 Min Ast = 636 mm (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.) = 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

654.50 mm2

654.50 mm2

10 mm dia bar @ 120 mm c/c

Footing Length 2600 mm

Breadth 2400 mm

Sec 1-1 1005 705 L1 X1 X 230

Z N1 a L2 560 L1 530 Footing Length 2600 mm PLAN X1 X a L2

Z N1

Breadth 2400 mm 610

194858335.xls.ms_office

NUCLEAR POWER CORPORATION OF INDIA LTD.

CHECK FOR ONE WAY SHEAR : One way shear at critical section L1- L1 Distance of critical sec. from edge of footing = 0.56 m Shear force Vu =pe max x 0.56 x 1m width of footing = 2 tv = Vs/bd = Shear stress 0.176 N/mm 2 tc = tc max = 0.280 N/mm tv < tc hence O.K. (Shear chairs not required)

83.594 KN
2 3.1 N/mm

One way shear at critical section L2- L2 Distance of critical sec. from edge of footing = 0.61 m Shear force Vu =pe max x 0.61 x 1m width of footing = 2 tv = Vs/bd = Shear stress 0.192 N/mm 2 tc = tc max = 0.283 N/mm tv < tc hence O.K. (Shear chairs not required)

91.058 KN
2 3.1 N/mm

CHECK FOR TWO WAY SHEAR Ref. cl 34.2.4 and cl.31.6.3 of IS 456 : 2000 Allowable shear stress tv allowable = kstc ks = ( 0.5 + bc) = Hence, ks= tc = 0.25 (fck)
0.5

0.93396 <1 0.93396

1.5 tc = 825.72 KN 3420 mm 2 1624500 mm

2 1.875 N/mm

tv allowable = ks x tc = Shear force Vs = 149.275 ( 2.6 x 2.4 - 1.005 x 0.705) = Length of critical section = 2 x ( 1005 + 705) = Area of the critical section (length of critical sec x eff. d ) = 2 Hence shear stress tv = 0.508 N/mm tv < ks tc (Shears chairs not required)

194858335.xls.ms_office

DESIGN OF BI-AXIAL ISOLATED RCC FOOTING (IS 456, 2000) Building Name 2 MW CMCS Room Footing Number: 1, 4, 10, 16 Node number 103, 112, 115, 116 COLUMN Length (l, dim. || Z axis ) = Breadth (b, dim. || X axis) = FOOTING Foot length (L, dim. || Z axis) = Foot Breadth (B, dim. || X axis) = Thickness of footing (t) = Clear cover of footing = Main bar dia of footing = Effective depth of footing dz = Effective depth of footing dx = Selfweight of the footing = Area of Footing(A) = Sect mod of foot about Z axis (Zz) = Sec mod of foot about X axis (Zx) = MATERIALS OF CONSTRUCTION Grade of concrete fck = Grade of steel fy =

450 mm 230 mm Breadth 1.7 m 1.9 1.7 450 50 10 395 385 36.34 3.23 0.92 1.02 m m mm mm mm mm mm KN m2 m3 m3

global X

global Z global Length 1.9 m Footing Dimensions

global Z

2 25 N/mm 2 415 N/mm

CHECK FOR GROSS BEARING PRESSURE Safe NET bearing pressure = 103 Safe gross bearing pr. = 147.10 Unfactored load case number = 7 Axial load from output (P1) = 240 Moment about Z axis (Mz) = 7.5333333 Moment about X axis (Mx) = 8.2 Depth of top of foot. from ground = 2 Unit wt of soil = 18 Weight of soil retained above foot = 112.55 P = (P1+soil+foot self wt) = 388.89 Maximum bearing pressure = 136.65 Minimum bearing pressure = 104.15 Hence footing is safe against max gross bearing pr. DESIGN FORCES Factored load comb. no. Axial load:(Pu) = Moment about Z axis (Muz) = Moment about X axis (Mux) = Maximum effective soil pressure pe max ( Pu/Area+ Muz/Zz + Mux/Zx) = Minimum effective soil pressure pe min

KN/m2 KN/m3 KN KN-m KN-m m KN/m3 KN KN KN/m2 KN/m2

(net pr. + depth of foot * soil unit wt)

M y Mx P A Zy Zx

7 360 KN 11.3 KN-m 12.3 KN-m

2 ( Pu/Area - Muz/Zz - Mux/Zx) = 87.08 KN/m Design of footing is done using above maximum effective soil pressure

CALCULATION FOR BOTTOM STEEL Mu about X1 X1 = ( pe max x length2/2)=

Ast =

0.5 f ck 4 .6 M u 1 - 1 bd fy f ck bd 2

35.70 KN-m per meter Mulimit = 538.68 KN-m per meter The section is singly reinforced

2 Hence, Ast = 253.124 mm 2 Min Ast = 540.000 mm (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.) = Hence required 10 mm dia bar @ 145 mm c/c parellel to length of footing ( || to Z) pt (prov.) = 0.14 % Mu about N1 N1 = ( pe max x length2/2)= 36.69 KN-m per meter 2 Calc. Ast = 267.150 mm The section is singly reinforced 2 Min Ast = 540 mm (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.) = 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

541.65 mm2

541.65 mm2

10 mm dia bar @ 145 mm c/c

Footing Length 1900 mm

Breadth 1700 mm

Sec 1-1 845 625 L1 X1 X 230

Z N1 a L2 330 X1 X a L2

Z N1

L1 450 Footing Length 1900 mm PLAN CHECK FOR ONE WAY SHEAR : One way shear at critical section L1- L1 Distance of critical sec. from edge of footing = 0.33 m Shear force Vu =pe max x 0.33 x 1m width of footing = 2 tv = Vs/bd = Shear stress 0.113 N/mm 2 tc = tc max = 0.279 N/mm tv < tc hence O.K. (Shear chairs not required) Calculations for shear chairs (if required) Vu - tcbd = Vus = -65553 N No. of legs (nos.) 2 2 2 2 2 Bar dia. (mm) 8 8 8 8 8 Asv Spacing of chairs 2 (mm ) (mm c/c) -213.18 -213.18 -213.18 -213.18 -213.18

Breadth 1700 mm 340

44.823 KN
2 3.1 N/mm

100.531 100.531 100.531 100.531 100.531

One way shear at critical section L2- L2 Distance of critical sec. from edge of footing = Shear force Vu =pe max x 0.34 x 1m width of footing = 2 tv = Vs/bd = Shear stress 0.117 N/mm
2 tc = 0.283 N/mm tv < tc hence O.K. (Shear chairs not required)

0.34 m 46.182 KN tc max =

CHECK FOR TWO WAY SHEAR Ref. cl 34.2.4 and cl.31.6.3 of IS 456 : 2000 Allowable shear stress tv allowable = kstc ks = ( 0.5 + bc) = Hence, ks= tc = 0.25 (fck)
0.5

1.01111 >1 1
2 1.25 N/mm 2 1.25 N/mm

1.5 tc = 366.99 KN 2940 mm 2 1161300 mm

2 1.875 N/mm

tv allowable = ks x tc = Shear force Vs = 135.828 ( 1.9 x 1.7 - 0.845 x 0.625) = Length of critical section = 2 x ( 845 + 625) = Area of the critical section (length of critical sec x eff. d ) = 2 Hence shear stress tv = 0.316 N/mm tv < ks tc (Shears chairs not required)

global

DESIGN OF BI-AXIAL ISOLATED RCC FOOTING (IS 456, 2000) Building Name 2 MW CMCS Room Footing Number: 5, 11 Node number 101, 102 COLUMN Length (l, dim. || Z axis ) = Breadth (b, dim. || X axis) = FOOTING Foot length (L, dim. || Z axis) = Foot Breadth (B, dim. || X axis) = Thickness of footing (t) = Clear cover of footing = Main bar dia of footing = Effective depth of footing dz = Effective depth of footing dx = Selfweight of the footing = Area of Footing(A) = Sect mod of foot about Z axis (Zz) = Sec mod of foot about X axis (Zx) = MATERIALS OF CONSTRUCTION Grade of concrete fck = Grade of steel fy = CHECK FOR GROSS BEARING PRESSURE Safe NET bearing pressure = Safe gross bearing pr. = Unfactored load case number = Axial load from output (P1) = Moment about Z axis (Mz) =

450 mm 230 mm Breadth 1.3 m 1.5 1.3 400 50 10 345 335 19.50 1.95 0.42 0.49 m m mm mm mm mm mm KN m2 m3 m3

global X

global Z global Length 1.5 m Footing Dimensions

global Z

2 25 N/mm 2 415 N/mm

103 146.20 7 89 2.3

KN/m2 KN/m3 KN KN-m KN-m m KN/m3 KN KN KN/m2 KN/m2

(net pr. + depth of foot * soil unit wt)

Moment about X axis (Mx) = 0.42 Depth of top of foot. from ground = 2 Unit wt of soil = 18 Weight of soil retained above foot = 66.47 P = (P1+soil+foot self wt) = 174.97 Maximum bearing pressure = 96.04 Minimum bearing pressure = 83.42 Hence footing is safe against max gross bearing pr. DESIGN FORCES Factored load comb. no. Axial load:(Pu) = Moment about Z axis (Muz) = Moment about X axis (Mux) = Maximum effective soil pressure pe max ( Pu/Area+ Muz/Zz + Mux/Zx) = Minimum effective soil pressure pe min

M y Mx P A Zy Zx

7 133 KN 0.42 KN-m 2.3 KN-m

2 ( Pu/Area - Muz/Zz - Mux/Zx) = 62.49 KN/m Design of footing is done using above maximum effective soil pressure

CALCULATION FOR BOTTOM STEEL Mu about X1 X1 = ( pe max x length2/2)=

Ast =

0.5 f ck 4 .6 M u 1 - 1 bd fy f ck bd 2

10.19 KN-m per meter Mulimit = 410.94 KN-m per meter The section is singly reinforced

2 Hence, Ast = 82.146 mm 2 Min Ast = 480.000 mm (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.) = Hence required 10 mm dia bar @ 163 mm c/c parellel to length of footing ( || to Z) pt (prov.) = 0.14 % Mu about N1 N1 = ( pe max x length2/2)= 10.58 KN-m per meter 2 Calc. Ast = 87.887 mm The section is singly reinforced 2 Min Ast = 480 mm (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.) = 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

490.87 mm2

490.87 mm2

10 mm dia bar @ 160 mm c/c

Footing Length 1500 mm

Breadth 1300 mm

Sec 1-1 795 575 L1 X1 X 230

Z N1 a L2 180 X1 X a L2

Z N1

L1 450 Footing Length 1500 mm PLAN CHECK FOR ONE WAY SHEAR : One way shear at critical section L1- L1 Distance of critical sec. from edge of footing = 0.18 m Shear force Vu =pe max x 0.18 x 1m width of footing = 2 tv = Vs/bd = Shear stress 0.039 N/mm 2 tc = tc max = 0.284 N/mm tv < tc hence O.K. (Shear chairs not required) Calculations for shear chairs (if required) Vu - tcbd = Vus = -84718 N No. of legs (nos.) 2 2 2 2 2 Bar dia. (mm) 8 8 8 8 8 Asv Spacing of chairs 2 (mm ) (mm c/c) -143.53 -143.53 -143.53 -143.53 -143.53

Breadth 1300 mm 190

13.305 KN
2 3.1 N/mm

100.531 100.531 100.531 100.531 100.531

One way shear at critical section L2- L2 Distance of critical sec. from edge of footing = Shear force Vu =pe max x 0.19 x 1m width of footing = 2 tv = Vs/bd = Shear stress 0.041 N/mm
2 tc = 0.288 N/mm tv < tc hence O.K. (Shear chairs not required)

0.19 m 14.044 KN tc max =

CHECK FOR TWO WAY SHEAR Ref. cl 34.2.4 and cl.31.6.3 of IS 456 : 2000 Allowable shear stress tv allowable = kstc ks = ( 0.5 + bc) = Hence, ks= tc = 0.25 (fck)
0.5

1.01111 >1 1
2 1.25 N/mm 2 1.25 N/mm

1.5 tc = 110.35 KN 2740 mm 2 945300 mm

2 1.875 N/mm

tv allowable = ks x tc = Shear force Vs = 73.917 ( 1.5 x 1.3 - 0.795 x 0.575) = Length of critical section = 2 x ( 795 + 575) = Area of the critical section (length of critical sec x eff. d ) = 2 Hence shear stress tv = 0.117 N/mm tv < ks tc (Shears chairs not required)

global

DESIGN OF BI-AXIAL ISOLATED RCC FOOTING (IS 456, 2000) Building Name 2 MW CMCS Room Footing Number: 7, 8, 9 Node number 107, 117, 113 COLUMN Length (l, dim. || Z axis ) = Breadth (b, dim. || X axis) = FOOTING Foot length (L, dim. || Z axis) = Foot Breadth (B, dim. || X axis) = Thickness of footing (t) = Clear cover of footing = Main bar dia of footing = Effective depth of footing dz = Effective depth of footing dx = Selfweight of the footing = Area of Footing(A) = Sect mod of foot about Z axis (Zz) = Sec mod of foot about X axis (Zx) = MATERIALS OF CONSTRUCTION Grade of concrete fck = Grade of steel fy =

600 mm 230 mm Breadth 2.5 m 2.85 2.5 530 50 10 475 465 94.41 7.13 2.97 3.38 m m mm mm mm mm mm KN m2 m3 m3

global X

global Z global Length 2.85 m Footing Dimensions

global Z

2 25 N/mm 2 415 N/mm

CHECK FOR GROSS BEARING PRESSURE Safe NET bearing pressure = 103 Safe gross bearing pr. = 148.54 Unfactored load case number = 7 Axial load from output (P1) = 651.33333 Moment about Z axis (Mz) = 9 Moment about X axis (Mx) = 11.2 Depth of top of foot. from ground = 2 Unit wt of soil = 18 Weight of soil retained above foot = 251.53 P = (P1+soil+foot self wt) = 997.27 Maximum bearing pressure = 146.31 Minimum bearing pressure = 133.63 Hence footing is safe against max gross bearing pr. DESIGN FORCES Factored load comb. no. Axial load:(Pu) = Moment about Z axis (Muz) = Moment about X axis (Mux) = Maximum effective soil pressure pe max ( Pu/Area+ Muz/Zz + Mux/Zx) = Minimum effective soil pressure pe min

KN/m2 KN/m3 KN KN-m KN-m m KN/m3 KN KN KN/m2 KN/m2

(net pr. + depth of foot * soil unit wt)

M y Mx P A Zy Zx

7 977 KN 13.5 KN-m 16.8 KN-m

2 ( Pu/Area - Muz/Zz - Mux/Zx) = 127.61 KN/m Design of footing is done using above maximum effective soil pressure

CALCULATION FOR BOTTOM STEEL Mu about X1 X1 = ( pe max x length2/2)=

Ast =

0.5 f ck 4 .6 M u 1 - 1 bd fy f ck bd 2

92.79 KN-m per meter Mulimit = 778.98 KN-m per meter The section is singly reinforced

2 Hence, Ast = 551.983 mm 2 Min Ast = 636.000 mm (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.) = Hence required 10 mm dia bar @ 123 mm c/c parellel to length of footing ( || to Z) pt (prov.) = 0.14 % Mu about N1 N1 = ( pe max x length2/2)= 94.45 KN-m per meter 2 Calc. Ast = 574.639 mm The section is singly reinforced 2 Min Ast = 636 mm (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.) = 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

654.50 mm2

654.50 mm2

10 mm dia bar @ 120 mm c/c

Footing Length 2850 mm

Breadth 2500 mm

Sec 1-1 1075 705 L1 X1 X 230

Z N1 a L2 650 X1 X a L2

Z N1

L1 600 Footing Length 2850 mm PLAN CHECK FOR ONE WAY SHEAR : One way shear at critical section L1- L1 Distance of critical sec. from edge of footing = 0.65 m Shear force Vu =pe max x 0.65 x 1m width of footing = 2 tv = Vs/bd = Shear stress 0.201 N/mm 2 tc = tc max = 0.280 N/mm tv < tc hence O.K. (Shear chairs not required) Calculations for shear chairs (if required) Vu - tcbd = Vus = -37707 N No. of legs (nos.) 2 2 2 2 2 Bar dia. (mm) 8 8 8 8 8 Asv Spacing of chairs 2 (mm ) (mm c/c) -447.61 -447.61 -447.61 -447.61 -447.61

Breadth 2500 mm 660

95.312 KN
2 3.1 N/mm

100.531 100.531 100.531 100.531 100.531

One way shear at critical section L2- L2 Distance of critical sec. from edge of footing = Shear force Vu =pe max x 0.66 x 1m width of footing = 2 tv = Vs/bd = Shear stress 0.204 N/mm
2 tc = 0.283 N/mm tv < tc hence O.K. (Shear chairs not required)

0.66 m 96.779 KN tc max =

CHECK FOR TWO WAY SHEAR Ref. cl 34.2.4 and cl.31.6.3 of IS 456 : 2000 Allowable shear stress tv allowable = kstc ks = ( 0.5 + bc) = Hence, ks= tc = 0.25 (fck)
0.5

0.88333 <1 0.88333

1.5 tc = 933.64 KN 3560 mm 2 1691000 mm

2 1.875 N/mm

tv allowable = ks x tc = Shear force Vs = 146.634 ( 2.85 x 2.5 - 1.075 x 0.705) = Length of critical section = 2 x ( 1075 + 705) = Area of the critical section (length of critical sec x eff. d ) = 2 Hence shear stress tv = 0.552 N/mm tv < ks tc (Shears chairs not required)

global