Footing Design

December 14, 2017 | Author: Balaji Rao Ch | Category: Strength Of Materials, Classical Mechanics, Solid Mechanics, Continuum Mechanics, Materials
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FOOTING FOR COLUMN (450 x 230)(F1) MAX M ZZ CASE INPUT DATA ( FACTORED LOADS) Node-LC Vertical Load = 814.426 kN Moment @x-x Mx = 21.816 kN-m Moment @y-y My = 2.673 kN-m =

25

kN/m3

= = =

21 20 415

kN/m3 Mpa Mpa

= =

1.8 1.8

m m

= =

0.3 0.3

m m

Depth of Founding lvl(H) Ht. of Pedestal above G.L.

= =

3 0

m m

Net S.B.C

=

250

kN/m2

Gross S.B.C. Load factor Clear cover to footing Dia of bar used Assumed depth of foundation

= = = = =

250 1.5 50 12 0.45

kN/m2

DESIGN CALCULATION (UNFACTORED LOADS) Direct load from footing Self weight of footing Dead weight of soil over footing Total vertical load Moment @x-x Mx Moment @y-y My

= = = = = =

543.0 36.5 120.5 699.9 14.5 1.8

KN KN KN KN kN-m kN-m

Area of footing required

=

2.17

m

Area of footing provided

=

3.24

m2

Unit wt. of conc.gc Unit wt. of soil gs Ch. Strength of conc. Yield Strength of steel SIZE OF FOOTING Length @ x-x ; Lx Length @ y-y ; Ly SIZE OF COLUMN Length @ x-x ; bx Length @ y-y ; by

NODES:-

2,5,6,8

Y Lx

My-y Mx-x Ly X

bx by

Mx-x My-y

X

by bx Y

Grade Level

mm mm m

1

2

1

2

D

2

O.K.

Zx-x

=

0.97

m2

Zy-y

=

0.97

m

P/ A

=

216.02

KN/m2

Mx-x / Zx-x

=

14.97

KN/m2

My-y / Zy-y

=

1.84

KN/m2

2

Gross maximum & minimun pressure under the footing are :1 Pmax

=

232.83

KN/m2

Pmin.

=

199.21

KN/m

Pgross at face of pedestal

=

218.82

KN/m2

Paverage at face of pedestal

=

225.83

KN/m

Pnet at face of pedestal

=

162.83

KN/m2

=

68.69

kN.m

2

O.K. NO TENSION

s Pmin. =

s' q s1

199.21

213.22

Pmax = 218.82

2

For 415 grade of steel.

Effective depth required

=

158

Effective depth Provided Mu / bd 2 % of steel required

= = =

394 0.44 0.125

mm

Ast required Dia of barto be used Ast required Min required Spacing of reinforcement Provide 12 % Ast provided

= =

561 12 540 201.53

mm

= mm dia bars@ = 0.140

mm Hence O.K

From SP-16 2

mm 180

Check for One way shear: Critical section is "d" from the face of the column. Pgross at 'd' from face of pedestal =

226.18

KN/m2

P average at 'd' from face of pedestal =

229.51

KN/m2

Pnet at 'd' from face of pedestal = Max shear at 'd' from face of pedestal = Tv =

166.51 88.91 0.23

KN/m kN Mpa

2

2

PRESSURE DIAGRAM ON SOIL

Structural design

M = 0.138 x f ck x b x d

q s2

2

1

Max moment at face of pedestal

2

mm C / C. in both the directions.

232.83

% of steel provided Tc

= =

0.14 0.28

Mpa > Tv (Table - 19 , IS - 456-2000 ) Hence SAFE FOR ONE WAY SHEAR

Check for two way shear: Critical section is considered at a distance d/2 from thr periphery of the face of the column or pedeatal. 2

Pgross at 'd/2' from face of pedestal =

222.50

KN/m

P average at 'd/2' from face of pedestal =

227.67

KN/m2

Pnet at 'd/2' from face of pedestal =

164.67

KN/m

BxL a+d b+d

= = =

2

2

3.24 0.694 0.694

m m m

681.31 2776 0.62

kN mm Mpa

a+d

b+d The max force V = p( BxL - ( a+d)(b+d)) = b o = 2((a+d) + (b+d)) = Shear stress Tv = V / b o .d =

b a L

Calculation of allowable shear stress:(CL:31.6.3.1 of IS-456) ks x Tc 1 ks =0.5 + beta beta 1 Tc =0.25sqrt(fck) Allowable shear stress Tc Tc =

= = = =

1 1.000 1.118033989 1.12

should not greater 1 shortside / long side of column or pedestal Mpa > Tv

Hence SAFE FOR TWO WAY SHEAR

B

FOOTING FOR COLUMN (450 x 230)(F1) MAX M ZZ CASE INPUT DATA ( FACTORED LOADS) Node-LC Vertical Load = 479.993 kN Moment @x-x Mx = 22.142 kN-m Moment @y-y My = 3.974 kN-m =

25

kN/m3

= = =

21 20 415

kN/m3 Mpa Mpa

= =

1.4 1.4

m m

= =

0.3 0.3

m m

Depth of Founding lvl(H) Ht. of Pedestal above G.L.

= =

3 0

m m

Net S.B.C

=

250

kN/m2

Gross S.B.C. Load factor Clear cover to footing Dia of bar used Assumed depth of foundation

= = = = =

250 1.5 50 12 0.3

kN/m2

DESIGN CALCULATION (UNFACTORED LOADS) Direct load from footing Self weight of footing Dead weight of soil over footing Total vertical load Moment @x-x Mx Moment @y-y My

= = = = = =

320.0 14.7 68.6 403.3 14.8 2.6

KN KN KN KN kN-m kN-m

Area of footing required

=

1.28

m

Area of footing provided

=

1.96

m2

Unit wt. of conc.gc Unit wt. of soil gs Ch. Strength of conc. Yield Strength of steel SIZE OF FOOTING Length @ x-x ; Lx Length @ y-y ; Ly SIZE OF COLUMN Length @ x-x ; bx Length @ y-y ; by

NODES:-

3,4,9,11,14,17,20

Y Lx

My-y Mx-x Ly X

bx by

Mx-x My-y

X

by bx Y

Grade Level

mm mm m

1

2

1

2

D

2

O.K.

Zx-x

=

0.46

m2

Zy-y

=

0.46

m

P/ A

=

205.77

KN/m2

Mx-x / Zx-x

=

32.28

KN/m2

My-y / Zy-y

=

5.80

KN/m2

2

Gross maximum & minimun pressure under the footing are :1 Pmax

=

243.85

KN/m2

Pmin.

=

167.69

KN/m

Pgross at face of pedestal

=

213.93

KN/m2

Paverage at face of pedestal

=

228.89

KN/m

Pnet at face of pedestal

=

165.89

KN/m2

=

37.64

kN.m

2

O.K. NO TENSION

s Pmin. =

s' q s1

167.69

197.61

Pmax = 213.93

2

For 415 grade of steel.

Effective depth required

=

117

Effective depth Provided Mu / bd 2 % of steel required

= = =

244 0.63 0.180

mm

Ast required Dia of barto be used Ast required Min required Spacing of reinforcement Provide 12 % Ast provided

= =

539 12 360 209.97

mm

= mm dia bars@ = 0.209

mm Hence O.K

From SP-16 2

mm 180

Check for One way shear: Critical section is "d" from the face of the column. Pgross at 'd' from face of pedestal =

227.20

KN/m2

P average at 'd' from face of pedestal =

235.53

KN/m2

Pnet at 'd' from face of pedestal = Max shear at 'd' from face of pedestal = Tv =

172.53 79.19 0.32

KN/m kN Mpa

2

2

PRESSURE DIAGRAM ON SOIL

Structural design

M = 0.138 x f ck x b x d

q s2

2

1

Max moment at face of pedestal

2

mm C / C. in both the directions.

243.85

% of steel provided Tc

= =

0.21 0.33

Mpa > Tv (Table - 19 , IS - 456-2000 ) Hence SAFE FOR ONE WAY SHEAR

Check for two way shear: Critical section is considered at a distance d/2 from thr periphery of the face of the column or pedeatal. 2

Pgross at 'd/2' from face of pedestal =

220.57

KN/m

P average at 'd/2' from face of pedestal =

232.21

KN/m2

Pnet at 'd/2' from face of pedestal =

169.21

KN/m

BxL a+d b+d

= = =

2

2

1.96 0.544 0.544

m m m

422.36 2176 0.80

kN mm Mpa

a+d

b+d The max force V = p( BxL - ( a+d)(b+d)) = b o = 2((a+d) + (b+d)) = Shear stress Tv = V / b o .d =

b a L

Calculation of allowable shear stress:(CL:31.6.3.1 of IS-456) ks x Tc 1 ks =0.5 + beta beta 1 Tc =0.25sqrt(fck) Allowable shear stress Tc Tc =

= = = =

1 1.000 1.118033989 1.12

should not greater 1 shortside / long side of column or pedestal Mpa > Tv

Hence SAFE FOR TWO WAY SHEAR

B

FOOTING FOR COLUMN (450 x 230)(F1) MAX M ZZ CASE INPUT DATA ( FACTORED LOADS) Node-LC Vertical Load = 336.502 kN Moment @x-x Mx = 19.743 kN-m Moment @y-y My = 2.927 kN-m =

25

kN/m3

= = =

21 20 415

kN/m3 Mpa Mpa

= =

1.2 1.2

m m

= =

0.3 0.3

m m

Depth of Founding lvl(H) Ht. of Pedestal above G.L.

= =

3 0

m m

Net S.B.C

=

250

kN/m2

Gross S.B.C. Load factor Clear cover to footing Dia of bar used Assumed depth of foundation

= = = = =

250 1.5 50 12 0.3

kN/m2

DESIGN CALCULATION (UNFACTORED LOADS) Direct load from footing Self weight of footing Dead weight of soil over footing Total vertical load Moment @x-x Mx Moment @y-y My

= = = = = =

224.3 10.8 45.9 281.1 13.2 2.0

KN KN KN KN kN-m kN-m

Area of footing required

=

0.90

m

Area of footing provided

=

1.44

m2

Unit wt. of conc.gc Unit wt. of soil gs Ch. Strength of conc. Yield Strength of steel SIZE OF FOOTING Length @ x-x ; Lx Length @ y-y ; Ly SIZE OF COLUMN Length @ x-x ; bx Length @ y-y ; by

1,7,10,12,13,15,16,18,19, 21,22,23,24

NODES:Y Lx

My-y Mx-x Ly X

bx by

Mx-x My-y

X

by bx Y

Grade Level

mm mm m

1

2

1

2

D

2

O.K.

Zx-x

=

0.29

m2

Zy-y

=

0.29

m

P/ A

=

195.19

KN/m2

Mx-x / Zx-x

=

45.71

KN/m2

My-y / Zy-y

=

6.78

KN/m2

2

Gross maximum & minimun pressure under the footing are :1 Pmax

=

247.68

KN/m2

Pmin.

=

142.70

KN/m

Pgross at face of pedestal

=

208.31

KN/m2

Paverage at face of pedestal

=

228.00

KN/m

Pnet at face of pedestal

=

165.00

KN/m2

=

25.06

kN.m

2

O.K. NO TENSION

s Pmin. =

s' q s1

142.70

182.07

Pmax = 208.31

2

For 415 grade of steel.

Effective depth required

=

95

Effective depth Provided Mu / bd 2 % of steel required

= = =

244 0.42 0.119

mm

Ast required Dia of barto be used Ast required Min required Spacing of reinforcement Provide 12 % Ast provided

= =

356 12 360 318.08

mm

= mm dia bars@ = 0.209

mm Hence O.K

From SP-16 2

mm 180

Check for One way shear: Critical section is "d" from the face of the column. Pgross at 'd' from face of pedestal =

229.66

KN/m2

P average at 'd' from face of pedestal =

238.67

KN/m2

Pnet at 'd' from face of pedestal = Max shear at 'd' from face of pedestal = Tv =

175.67 54.28 0.22

KN/m kN Mpa

2

2

PRESSURE DIAGRAM ON SOIL

Structural design

M = 0.138 x f ck x b x d

q s2

2

1

Max moment at face of pedestal

2

mm C / C. in both the directions.

247.68

% of steel provided Tc

= =

0.21 0.33

Mpa > Tv (Table - 19 , IS - 456-2000 ) Hence SAFE FOR ONE WAY SHEAR

Check for two way shear: Critical section is considered at a distance d/2 from thr periphery of the face of the column or pedeatal. 2

Pgross at 'd/2' from face of pedestal =

218.99

KN/m

P average at 'd/2' from face of pedestal =

233.33

KN/m2

Pnet at 'd/2' from face of pedestal =

170.33

KN/m

BxL a+d b+d

= = =

2

2

1.44 0.544 0.544

m m m

292.31 2176 0.55

kN mm Mpa

a+d

b+d The max force V = p( BxL - ( a+d)(b+d)) = b o = 2((a+d) + (b+d)) = Shear stress Tv = V / b o .d =

b a L

Calculation of allowable shear stress:(CL:31.6.3.1 of IS-456) ks x Tc 1 ks =0.5 + beta beta 1 Tc =0.25sqrt(fck) Allowable shear stress Tc Tc =

= = = =

1 1.000 1.118033989 1.12

should not greater 1 shortside / long side of column or pedestal Mpa > Tv

Hence SAFE FOR TWO WAY SHEAR

B

Node 24 13 22 10 16 1 18 12 19 21 15 23 7

Force-Y kN Moment-X kNm Moment-Z kNm 191.938 -14.209 2.554 203.267 -3.659 -0.032 204.143 6.348 2.334 204.668 -3.866 -0.113 228.156 2.498 -1.693 260.593 4.319 -2.927 276.786 -15.252 -0.485 281.241 -15.659 -0.102 284.383 7.706 1.838 296.023 -10.603 0.443 300.97 -19.743 -0.321 329.165 5.586 1.808 336.502 -1.638 2.023

4 3 14 11 17 9 20

364.721 390.185 442.814 443.681 464.299 478.081 479.993

-3.908 -22.142 13.558 11.623 3.71 -21.095 -1.223

-1.645 -3.974 -0.078 -0.384 -1.488 -0.223 2.165

6 2 8 5

549.36 644.235 764.428 814.426

-21.816 15.046 13.313 19.718

0.426 -2.547 2.504 -2.673

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