Footing Design

SBC

200.0 kN/m2

250 kN/m2

Load

Case

Joint

No

Load

Case

No P MX MZ P/A Mx/Zx My/Zy

Net Up.

Pre.

Load

Factor

Design

Pressure

Critical

Design

Pressure

DL+LL 1 14 416.67 0.21 0.83 1.6 1.6 162.8 0.31 1.22 164 200 Ok 1.5 246

15 312.09 0.23 28.28 1.6 1.6 121.9 0.34 41.43 164 250 Ok 1.5 246

16 452.77 0.63 29.58 1.6 1.6 176.9 0.92 43.33 221 250 Ok 1.5 332

17 306.05 29.45 0.36 1.6 1.6 119.6 43.14 0.53 163 250 Ok 1.5 245

18 458.81 29.84 0.94 1.6 1.6 179.2 43.71 1.38 224 250 Ok 1.5 336

19 346.33 0.22 28.1 1.6 1.6 135.3 0.32 41.16 177 250 Ok 1.2 212

20 487 0.64 29.76 1.6 1.6 190.2 0.94 43.59 235 250 Ok 1.2 282

21 340.29 29.44 0.54 1.6 1.6 132.9 43.13 0.79 177 250 Ok 1.2 212

22 493.04 29.85 1.12 1.6 1.6 192.6 43.73 1.64 238 250 Ok 1.2 286

DL CASE

EQ/WL CASE

FOOTING GROUPING

Check for

' SBC '

336

Size of

Footing

DL

+E

Q/W

LD

L+

LL

+E

Q

/WL

S.No Group GridsCritical

Grid

Load

Case

No

DL

or

EQ-WL

SIZEP

kN

Mx

kNm

My

kNm

Factored

Design Pr

KN/m2

1 F1 1,21,24 24 17 EQ 1.7x1.7

2 F2 2,4,5,8,12,17,23, 12 15 EQ 1.9x1.9

3 F3 3,9,13,16,22 9 16 EQ 2.0 x 2.0

4 F4 20,18,19 19 16 EQ 2.2 x 2.2

5 F5 6,7,11,15 15 18 EQ 2.4 x 2.4

6 F6 14,10, 10 14 DL 2.6x2.6

ABSTRACT

DATA:

Safe bearing capacity of soil Sbc 312.5 kn/sqm

Grade of concrete in footing Fcki 25 N/sqmm

Grade of concrete in pedestal Fckii 25 N/sqmm

Yield strength of steel Fe 500 N/sqmm

Size of pedestal(square) Lii 530 mm

Size of footing Li 1400 mm

Overall depth of footing D 300 mm

Eff. cover to main steel Ec 50 mm

Dia. of main steel bar dsi 10 mm

Spacing of main steel bars Si 150 mm

Loading case

Load on the column Wi 190.00 kn

Moment on major axis Mxi 11.00 Knm

Moment on minor axis Myi 43.00 Knm

Modulus of section (li/100)^3/6 Zx 0.46 m3

Zy 0.46 m3

DESIGN :

Design max upward pressure Qu 321.0 Kn/sqm

Bending moment at the face of pedestal

qu*(li/100*(li/100-lii/100)^2)/8 Mi 43 Knm

Length/Width of footing bi 1400 mm

Approximate Depth required from Shear Consideration 14.51 0.33 274 mm

Provided Total Depth D 300

Provided Eff. depth D-Ec di 250 mm

Area of steel required

(bi*10*di*10*50/100)*(1-@sqrt(1-(4.6*mi*10^6)/(fcki*bi*10*di*di*100)))/(fe/fcki)

Ast 400 sqmm

Minimum Steel : 0.2%ofArea Minimum Ast 700 sqmm

Area of steel Required 700 sqmm

Spacing of bars (@pi*dsi^2/4*li*10/ast)/10 157 mm c/c

Provide 10 mm bars Si 150 mm c/c

Check for one way shear:

Critical section for oneway shear is at a distance of "di" from face of the pedestal

Shear force at critical section

qu*li/100*((li-lii)/200-di/100) Vi 83 Kn

Footing Width at critical section Li bii 1400 mm

Depth at critical section di 250 mm

Shear stress Vi*1000/(bii*10*dc*10) towu 0.24 n/sqmm

Percentage of steel at critical section

bii*10*@pi*dsi^2/4*100/(si*10*bii*10*dc*10) pt 0.21

@max((0.8*fcki)/(6.89*pt),1.0) beeta 13.86

Permisible shear stress

(0.85*@sqrt(0.8*fcki)*(@sqrt(1+5*beeta)-1.0))/(6*beeta)

towc 0.34 N/sqmm

CHECK: @if(towu<towc,"safe","Not safe") SAFE

Design for two way shear:

The critical section for two way shear is at di/2 from the face of the pedastal

Shear force

qu*((Li/100)^2-(Lii/100+(D-Ec)/100)^2) vii 434 kn

Depth of footing at critical section

di-((0.5*di)/((Li-Lii)*0.5))*(D-de) di 250 mm

Nominal shear stress

vii*1000/((Lii*10+di*10)*4*dci*10) towui 0.56 N/sqmm

Shear strength of Concrete

0.25*@sqrt(fcki) towci 1.25 N/sqmm

CHECK @if(towci>towui,"safe","Not safe") SAFE

Load transfer from Column to Footing:

Nominal bearing stress in column concrete

1.5*Wi*1000/(Lii*Lii*) 1.01 N/sqmm

Allowable bearing stress

0.45*Fckii 11.25 N/sqmm

SAFE

DESIGN OF FOOTING - F1

DATA:











Loading case





Zy 0.97 m3

DESIGN :



qu*(li/100*(li/100-lii/100)^2)/8 Mi 153 Knm







Ast 1038 sqmm














@max((0.8*fcki)/(6.89*pt),1.0) beeta 11.2289



towc 0.3701 N/sqmm




Shear force











1.5*Wi*1000/(Lii*Lii*) 3.58 N/sqmm



SAFE


DATA:











Loading case





Zy 1.33 m3

DESIGN :



qu*(li/100*(li/100-lii/100)^2)/8 Mi 170 Knm







Ast 888 sqmm














@max((0.8*fcki)/(6.89*pt),1.0) beeta 17.32



towc 0.31 N/sqmm




Shear force











1.5*Wi*1000/(Lii*Lii*) 1.61 N/sqmm



SAFE


DATA:











Loading case

Load on the column Wi ####### kn




Zy 1.77 m3

DESIGN :



qu*(li/100*(li/100-lii/100)^2)/8 Mi 239 Knm







Ast 1252 sqmm














@max((0.8*fcki)/(6.89*pt),1.0) beeta 17.32



towc 0.31 N/sqmm




Shear force












1.5*Wi*1000/(Lii*Lii*) 2.70 N/sqmm



SAFE


DATA:











Loading case





Zy 2.30 m3

DESIGN :



qu*(li/100*(li/100-lii/100)^2)/8 Mi 361 Knm







Ast 1709 sqmm














@max((0.8*fcki)/(6.89*pt),1.0) beeta 12.83



towc 0.35 N/sqmm




Shear force











1.5*Wi*1000/(Lii*Lii*) 3.11 N/sqmm



SAFE


DATA:











Loading case





Zy 3.28 m3

DESIGN :



qu*(li/100*(li/100-lii/100)^2)/8 Mi 517 Knm







Ast 2230 sqmm














@max((0.8*fcki)/(6.89*pt),1.0) beeta 14.12



towc 0.335 N/sqmm




Shear force











1.5*Wi*1000/(Lii*Lii*) 3.72 N/sqmm



SAFE






Size of pedestal, Length Lp 600 mm

Breadth Bp 450 mm

Size of footing, LENGTH L 2000 mm

BREADTH B 1500 mm



Dia. of main steel bar Dsi 12 mm

Dia. of main steel bar Dsii 12 mm

Spacing parellel to Long span Si 125 mm

Spacing parellel to Short span Sii 125 mm

Loading case I (DL+LL)

Load on the column Wi 626 kn




Steel Parellel to long span Direction:

Bending moment @ face of pedestal Parellel to long span Direction.

qu*(bf/100*(li/100-lii/100)^2)/8 Mi 154 Knm

B 1500 mm

Provided Total D 500 mm

Provided Eff. depth D-Ec DI 440 mm



Asti 828 sqmm

Mimum Ast 1320 sqmm

Ast-long 1320 sqmm

Spacing of bars parellel to long span direction (@pi*dsi^2/4*li*10/asti)/10 129 mm

12 mm bars Si 125 mm

Steel Parellel to short span Direction:

Bending moment @ face of pedestal Parellel to short span Direction.

qu*(li/100*(bf/100-bp/100)^2)/8 Mii 116 Kn/sqm

L 2000 mm

D 500 mm

Provided Eff. depth D-Ec-dsi/2 DII 434 mm


(li*10*dii*10*50/100)*(1-@sqrt(1-(4.6*mii*10^6)/(fcki*Li*10*dii*dii*100)))/(fe/fcki)

Astii 622 sqmm

Mimum Ast 1736 sqmm

Ast-short 1736 sqmm

Spacing of bars parellel short long span direction (@pi*dsi^2/4*bfi*10/astii)/10 130 cm

12 mm bars Sii 125 mm

DESIGN OF RECTANGULAR FOOTING -RF1

Check for one way shear

A)Critical section for oneway shear is at a

distance of "di" from face of the pedestal parellel to short span direction:


qu*bf/100*((li-lii)/200-di/100) Vi 164 Kn

Footing Width at critical section B 1500 mm

Depth at critical section DI 440 mm

Shear stress Vi*1000/(bii*10*dc*10) TOWU1 0.25 N/sqmm


bii*10*@pi*dsi^2/4*100/(si*10*bii*10*di*10) PT1 0.21

@max((0.8*fcki)/(6.89*pt),1.0) Beeta1 14.12



TOWC1 0.33 N/sqmm


B)Critical section for oneway shear is at a

distance of "di" from face of the pedestal parellel to long span direction:


qu*Li/100*((bf-bp)/200-dii/100) Vii 76 kn

Footing Width at critical section L 2000 mm

Depth at critical section DII 434 mm

Shear stress Vi*1000/(lii*10*dc*10) TOWU2 0.09 N/sqmm


bii*10*@pi*dsi^2/4*100/(si*10*bii*10*dii*10) PT2 0.21

@max((0.8*fcki)/(6.89*pt),1.0) Beeta2 13.92



TOWC2 0.34 N/sqmm

CHECK: if(towuii<towcii,"safe","Not safe") SAFE

Design for two way shear :

The critical section for two way shear is at di/2 from facs of the pedastal

Shear force

qu*((li/100*bf/100)-((Lii/100+(D-Ec)/100)*(Bp/100+(D-Ec)/100))) V 918 kn

Depth of footing at critical section DI 440 mm


vii*1000/(((Lii*10+di*10)*2+(Bp*10+di*10)*2)*dci*10) TOWU3 0.54 N/sqmm


x=0.5+(Bp/Lii) x 1.25

if(x<1, "ks=x","ks=1) ks 1.00

ks*0.25*Sqrt(fcki)

@if(towci>towui,"safe","Not safe") TOWC3 1.25 N/sqmm

CHECK: SAFE


Nominal bearing stress in column concrete 1.5*Wi*1000/(Lii*10*Lii*10) 0.31 N/sqmm

Allowable bearing stress0.45*Fckii 11.25 N/sqmm

SAFE






Breadth Bp 450 mm


BREADTH B 1500 mm














qu*(bf/100*(li/100-lii/100)^2)/8 Mi 259

B 1500

Provided Total D 500

Provided Eff. depth D-Ec DI 440



Asti 1413

Mimum Ast 1320

Ast-long 1413

Spacing of bars parellel to long span direction (@pi*dsi^2/4*li*10/asti)/10 120

12 mm bars Si 120



qu*(li/100*(bf/100-bp/100)^2)/8 Mii 141

L 2400

D 500

Provided Eff. depth D-Ec-dsi/2 DII 434



Astii 758

Mimum Ast 2083

Ast-short 2083

Spacing of bars parellel short long span direction (@pi*dsi^2/4*bfi*10/astii)/10 130

12 mm bars Sii 120






qu*bf/100*((li-lii)/200-di/100) Vi 294

Footing Width at critical section B 1500

Depth at critical section DI 440

Shear stress Vi*1000/(bii*10*dc*10) TOWU1 0.45



@max((0.8*fcki)/(6.89*pt),1.0) Beeta1 13.55



TOWC1 0.34

CHECK: @if(towu<towc,"safe","Not safe") INCREASE THE DEPTH




qu*Li/100*((bf-bp)/200-dii/100) Vii 93

Footing Width at critical section L 2400

Depth at critical section DII 434

Shear stress Vi*1000/(lii*10*dc*10) TOWU2 0.09



@max((0.8*fcki)/(6.89*pt),1.0) Beeta2 13.37



TOWC2 0.34




Shear force

qu*((li/100*bf/100)-((Lii/100+(D-Ec)/100)*(Bp/100+(D-Ec)/100))) V 1187

Depth of footing at critical section DI 440


vii*1000/(((Lii*10+di*10)*2+(Bp*10+di*10)*2)*dci*10) TOWU3 0.70


x=0.5+(Bp/Lii) x 1.13

if(x<1, "ks=x","ks=1) ks 1.00

ks*0.25*Sqrt(fcki)

@if(towci>towui,"safe","Not safe") TOWC3 1.25

CHECK: SAFE


Nominal bearing stress in column concrete 1.5*Wi*1000/(Lii*10*Lii*10) 0.32

Allowable bearing stress0.45*Fckii 11.25

SAFE

Knm

mm

mm

mm

sqmm

sqmm

sqmm

mm

mm

Kn/sqm

mm

mm

mm

sqmm

sqmm

sqmm

cm

mm


Kn

mm

mm

N/sqmm

N/sqmm

INCREASE THE DEPTH

kn

mm

mm

N/sqmm

N/sqmm

kn

mm

N/sqmm

N/sqmm

N/sqmm

N/sqmm






Breadth Bp 450 mm


BREADTH B 1900 mm














qu*(bf/100*(li/100-lii/100)^2)/8 Mi 353 Knm

B 1900 mm

Provided Total D 500 mm

Provided Eff. depth D-Ec DI 440 mm



Asti 1933 sqmm

Mimum Ast 1672 sqmm

Ast-long 1933 sqmm

Spacing of bars parellel to long span direction (@pi*dsi^2/4*li*10/asti)/10 111 mm

12 mm bars Si 100 mm



qu*(li/100*(bf/100-bp/100)^2)/8 Mii 297 Kn/sqm

L 2600 mm

D 500 mm

Provided Eff. depth D-Ec-dsi/2 DII 434 mm



Astii 1618 sqmm

Mimum Ast 2257 sqmm

Ast-short 2257 sqmm

Spacing of bars parellel short long span direction (@pi*dsi^2/4*bfi*10/astii)/10 130 cm

12 mm bars Sii 100 mm






qu*bf/100*((li-lii)/200-di/100) Vi 400 Kn

Footing Width at critical section B 1900 mm

Depth at critical section DI 440 mm

Shear stress Vi*1000/(bii*10*dc*10) TOWU1 0.48 N/sqmm



@max((0.8*fcki)/(6.89*pt),1.0) Beeta1 11.29



TOWC1 0.37 N/sqmm

CHECK: @if(towu<towc,"safe","Not safe") INCREASE THE DEPTH




qu*Li/100*((bf-bp)/200-dii/100) Vii 328 kn

Footing Width at critical section L 2600 mm

Depth at critical section DII 434 mm

Shear stress Vi*1000/(lii*10*dc*10) TOWU2 0.29 N/sqmm



@max((0.8*fcki)/(6.89*pt),1.0) Beeta2 11.14



TOWC2 0.37 N/sqmm




Shear force

qu*((li/100*bf/100)-((Lii/100+(D-Ec)/100)*(Bp/100+(D-Ec)/100))) V 1737 kn

Depth of footing at critical section DI 440 mm


vii*1000/(((Lii*10+di*10)*2+(Bp*10+di*10)*2)*dci*10) TOWU3 0.95 N/sqmm


x=0.5+(Bp/Lii) x 1.23

if(x<1, "ks=x","ks=1) ks 1.00

ks*0.25*Sqrt(fcki)

@if(towci>towui,"safe","Not safe") TOWC3 1.25 N/sqmm

CHECK: SAFE


Nominal bearing stress in column concrete 1.5*Wi*1000/(Lii*10*Lii*10) 3.00 N/sqmm

Allowable bearing stress0.45*Fckii 11.25 N/sqmm

SAFE

DATA

SBC of soil = 312 kN/sq.m

Design Load Factor 1.2

Column load, P1 = 854 kN


Spacing of Loads, P1 & P2 = 1.65 m

Moment along Length dir Mx1 = 71 kN-m

Moment along Width dir My = 205 kN-m



Pedastal Width a1 = 750 mm

Pedastal Width b1 = 750 mm



Concrete Strength Fck = 25 N/sq.mm

Steel Fy = 500 N/sq.mm

Length of footing = 3.60 m

Breadthof footing = 2.10 m

= 16 mm

= 16 mm

= 16 mm

Depth of Footing = 500 mm

Effective Depth ( d1) 460 mm


DESIGN

Total load, P = 1249 kN

Netupward Pressure = 277.3 kN/sq.m

Gross Pressure = 293.8 kN/sq.m

< 312 KN/sq.m

OK

CG of load from P1 395 * 1.7 / 1249 = 0.52 m

CG of load from P1 395 * 1.7 / 1249 = 0.52 m

Cantilever from P1 3.60 / 2.0 - 0.522 = 1.28 m


Cantilever from P2 3.60 - 1.65 = 0.67 m

Load per metre run = 582 kN/m

Reaction at P2 = 663 kN


Combined Footing Design- CF1

Dia of Main bars for BM 1


Dia of Transverse Reinforcement

1.28 1.65 0.67

582 kN/m

SF is zero at 2.46 m

582 * 2.461 * 2.461 /

- 1433 * ( 2.461 - 1.28

= 68 kN-m TENSION AT BOTTOM

= 582 *( 1.3 - 0.375 )**2 / 2

= 238

= 582 *( 0.7 - 0.375 )**2 / 2

= 26

= 238 kN-m "TENSION AT BOTTOM"

Mu/bd2 = 0.18

pt = 0.043

Minimum pt 0.200

= 0.200

Area of Steel = 920 sq.mm

Using 16 mm = 218 c/c

= 150 c/c

0.29 %

Mu/bd2 0.64

pt 0.152

Pt Provided

Reinforcement For BM 2

P1 P2

1433 663

Sagging/Hogging Moment between Columns BM1

Sagging Moment

Cantilever Moments

Cantelever BM at face of P1


Max Cantilever BM 2


Actual Pt

Spacing Requred

Spacing Provided

Minimum pt 0.200

= 0.200

Area of Steel 920 sq.mm


= 150 c/c

0.29 %

Shear Force at Left Edge 258 kN

Shear Force at Right Edge -95 kN

Maximum S.F 258 kN

Shear Stress 0.321 N/mm^2

Tc (Permissible Stress) 0.390 N/mm^2 OK

Under Column Load P1

= 1.65 m

413 kN/sq.m

Cantilever = 0.68 m

Bending Moment = 94.01 kN-m

Mu/bd2 = 0.55

pt = 0.20



= 200 c/c

0.22 %

Shear Force 1043 kN

Shear Stress 0.300 N/mm^2 < 0.34 N/mm^2 (Permissible Stress)


= 1.65 m

191 kN/sq.m

Cantilever = 0.68 m


Mu/bd2 = 0.26

pt = 0.20



= 200 c/c

0.218 %

Effective Width

Actual Pt

Spacing Requred

Spacing Provided

Pt Provided

Check For One Way Shear

Design of Transeverse Reinforcement

Effective Width

Net Upward Pressure

Spacing Requred

Spacing Provided

Pt Provided



Net Upward Pressure

Spacing Requred

Spacing Provided

Pt Provided

Shear Force 482 kN


Check For Two Way Shear Under Column P1

Size of Critical Plane around Column 1.21 x 1.21

Perimeter = 4.84 m

Punching Shear Force = 1027 kN

Shear stress = 0.55 N/mm2

Permissible Shaer Stress = 1.25 N/mm2 OK



Perimeter = 4.84 m




2

)

kN-m

kN-m

1339.73

1339.73

1662

OK

1662

OK

DATA

SBC of soil = 312 kN/sq.m

Design Load Factor 1.2



Spacing of Loads, P1 & P2 = 2.1 m









Concrete Strength Fck = 25 N/sq.mm

Steel Fy = 500 N/sq.mm

Length of footing = 4.40 m

Breadthof footing = 2.40 m

= 16 mm

= 16 mm

= 16 mm

Depth of Footing = 550 mm



DESIGN

Total load, P = 2071 kN

Netupward Pressure = 286.0 kN/sq.m

Gross Pressure = 305.6 kN/sq.m

< 312 KN/sq.m

OK

CG of load from P1 1031 * 2.1 / 2071 = 1.05 m

CG of load from P1 1031 * 2.1 / 2071 = 1.05 m



Cantilever from P2 4.40 - 2.1 = 1.15 m

Load per metre run = 686 kN/m



Combined Footing Design -CF4



Dia of Transverse Reinforcement

1.15 2.1 1.15

686 kN/m

SF is zero at 2.21 m

686 * 2.210 * 2.210 /

- 1517 * ( 2.210 - 1.15

= 76 kN-m TENSION AT BOTTOM

= 686 *( 1.2 - 0.375 )**2 / 2

= 209

= 686 *( 1.1 - 0.375 )**2 / 2

= 204

= 209 kN-m "TENSION AT BOTTOM"

Mu/bd2 = 0.15

pt = 0.034

Minimum pt 0.200

= 0.200



= 150 c/c

0.26 %

Mu/bd2 0.40

pt 0.094

Pt Provided


P1 P2

1517 1504

Sagging/Hogging Moment between Columns BM1

Sagging Moment

Cantilever Moments



Max Cantilever BM 2


Actual Pt

Spacing Requred

Spacing Provided

Minimum pt 0.200

= 0.200

Area of Steel 1020 sq.mm


= 150 c/c

0.26 %

Shear Force at Left Edge 185 kN

Shear Force at Right Edge 179 kN

Maximum S.F 185 kN

Shear Stress 0.181 N/mm^2

Tc (Permissible Stress) 0.373 N/mm^2 OK


= 1.75 m

360 kN/sq.m

Cantilever = 0.83 m


Mu/bd2 = 0.58

pt = 0.20



= 150 c/c

0.26 %

Shear Force 1155 kN



= 1.75 m

357 kN/sq.m

Cantilever = 0.83 m


Mu/bd2 = 0.58

pt = 0.20



= 150 c/c

0.263 %

Effective Width

Actual Pt

Spacing Requred

Spacing Provided

Pt Provided


Design of Transeverse Reinforcement

Effective Width

Net Upward Pressure

Spacing Requred

Spacing Provided

Pt Provided



Net Upward Pressure

Spacing Requred

Spacing Provided

Pt Provided

Shear Force 1145 kN




Perimeter = 5.04 m






Perimeter = 5.04 m




2

)

kN-m

kN-m

1339.73

1339.73

2350

OK

2350

OK

1 1.6 1.6 336

21 1.7 1.7 329

24 1.7 1.7 329

2 1.8 1.8 339

4 1.8 1.8 300

5 1.9 1.9 320

8 1.9 1.9 327

12 1.9 1.9 339

17 1.9 1.9 333

23 1.9 1.9 332

3 2.0 2.0 289

9 2.0 2.0 329

13 2.0 2.0 321

16 2.0 2.0 325

22 2.0 2.0 307

20 2.1 2.1 319

18 2.2 2.2 286

19 2.2 2.2 303

6 2.3 2.3 280

7 2.4 2.4 293

11 2.4 2.4 300

15 2.4 2.4 300

14 2.5 2.5 283

10 2.6 2.6 279

Documents

Footing Design