(2) Footing Design

8/6/2019 (2) Footing Design

1/15

FOOTING DESIGN PROGRAMME USING LIMIT STATE METHOD

S = 300 260.87

C = 20 fcd=0.85*fck/1.5 9.07

0.90

= 0.5fctd(1+50*rho) = 672.90

Allowable bearing pressure, s (KPa) 200

= 0.25fctd(1+50*rho) = 336.45

3.00

18.00

Column width, a (m) 0.30

Footing Group F1

229.00

Footing Dimension, L * L (m) 1.50 1.50

2.25

Depth, D (m) 0.25

Effective depth, d (m) = D - 0.05 = 0.20

Own Weight of Footing, Wc (KN) = 18.28

Soil Weight , Ws(KN) = 144.79

= Ps+Wc+Ws = 392.07 174.25

Checking Bearing Capacity = 174.25

Punching Shear, Vp (kN) = 203.56

Punching Shear Stress, Vup (KPa) = 508.89

= 40.71

= 203.56

= 18.32

N = 0.051

B 1 -(1 - 2*N)^0.5 0.052

As B*fcd*b*d/fyd 360.48

Asmin 0.5/fyk*b*d 333.33

Asing (3.14*d^2/4) 12.00 113.14

Spacing for As Asig*1000/As 313.87

Spacing for Asmin Asig*1000/Asmin 339.43

Final use 812 c/c 240

Take rho = rmin

= 0.002

fctd = 0.21*((fck)^0.67)/1.5=

Allowable punching resistance of

concrete, Vup(KPa)

Allowable wide beam shear

resistance of concrete, vud

(KN/m2)

Foundation depth, fd

(m)

Unit weight of soil, gs (KN/m3)

Super-structural load, Ps(KN)

Footing Area, A(m2)

=1.3*Af*d*g

s

= 1.3*Af*(f

d-D)*g

s

Total load on footing, PT (KN)

= PT/A

=Ps*(1-((a+d)/L)^2)

= Vp/(4(a+d)*d)

Wide beam Shear, Vw

(KN) = Ps/A

f(L/2-d-a/2)

Wide beam Shear stress Vuw(KN/m2) = Vw/(b*d)

Design Moment, Md (KN-m/m)

= (Ps/A

f)*((L-

a /2 ^2*0.5= (M

d*10E+6/f

cd*b*d^2)


2/15

FOOTING DESIGN PROGRAMME USIN

S = 300

C = 25

1.04

= 0.5fctd(1+50*rho)

200

= 0.25fctd(1+50*rho)

1.50

18.00


Footing Group F2

390.00

Footing Dimension, L * L (m) 1.60

2.56

Depth, D (m) 0.30

Effective depth, d (m) = D - 0.05

Own Weight of Footing, Wc (KN)

Soil Weight , Ws(KN)

= Ps+Wc+Ws

Checking Bearing Capacity

Punching Shear, Vp (kN)

Punching Shear Stress, Vup (KPa)

= Ps/Af(L/2-d-a/2)

Take rho = rmin

= 0.002

fctd

= 0.21*((fck

)^0.67)/1.5=

Allowable punching resistance ofconcrete, Vup(KPa)Allowable bearing pressure, s(KPa)

Allowable wide beam shearresistance of concrete, v

ud

(KN/m2

)Foundation depth, f

d(m)

Unit weight of soil, gs(KN/m3)

Super-structural load, Ps

(KN)

Footing Area, A(m2)

=1.3*Af

*d*gs

= 1.3*Af*(f

d-D)*g

s

Total load on footing, PT

(KN)

= PT/A

=Ps*(1-((a+d)/L)^2)

= Vp/(4(a+d)*d)

Wide beam Shear, Vw

(KN)


3/15

= Vw/(b*d)

N

B 1 -(1 - 2*N)^0.5

As B*fcd*b*d/fyd

Asmin 0.5/fyk*b*d

Asing (3.14*d^2/4) 14.00

Spacing for As Asig*1000/As

Spacing for Asmin Asig*1000/Asmin

Final

Wide beam Shear stress Vuw(KN/

Design Moment, Md

(KN-m/m) = (Ps/Af)*((L-a)/2)^2*0.5

(Md*10E+6/fcd*b*d^2


4/15

LIMIT STATE METHOD

260.87

fcd=0.85*fck/1.5 11.33

= 781.41

= 390.71

1.60

= 0.25

= 24.96

= 71.88

= 486.84 190.17

= 190.17

= 343.92

=625.30

= 60.94


5/15

= 243.75

= 32.18

= 0.045

0.047

505.22

416.67

154.00

304.82

369.60

se 714 c/c 300


6/15

FOOTING DESIGN PROGRAMME USING LIMIT STATE METHO

S = 300 260.87

C = 25 fcd=0.85*fck/1.5 11.33

1.04

= 0.5fctd(1+50*rho) = 781.41

200

= 0.25fctd(1+50*rho) = 390.71

1.50

18.00


Footing Group F3

310.00

Take rho = rmin

= 0.002

fctd

= 0.21*((fck

)^0.67)/1.5=

Allowable punching resistance ofconcrete, Vup(KPa)Allowable bearing pressure, s(KPa)

Allowable wide beam shearresistance of concrete, v

ud

(KN/m2)


(m)




7/15

Footing Dimension, L * L (m) 1.40 1.40

1.96

Depth, D (m) 0.25

Effective depth, d (m) = D - 0.05 = 0.20

Own Weight of Footing, Wc (KN) = 15.93

Soil Weight , Ws(KN) = 57.33

= Ps+Wc+Ws = 383.26

Checking Bearing Capacity = 195.54

Punching Shear, Vp (kN) = 270.46

Punching Shear Stress, Vup (KPa) = 676.15

= Ps/Af(L/2-d-a/2) = 55.36

= Vw/(b*d) = 276.79

= 23.92

N = 0.053

B 1 -(1 - 2*N)^0.5 0.054

Footing Area, A(m2)

=1.3*Af*d*g

s

= 1.3*Af*(f

d-D)*g

s


(KN)

= PT/A

=Ps*(1-((a+d)/L)^2)

= Vp/(4(a+d)*d)

Wide beam Shear, Vw

(KN)


Design Moment, Md

(KN-m/m) = (Ps/Af)*((L-a)/2)^2*0.5

(Md*10E+6/fcd*b*d^2


8/15

As B*fcd*b*d/fyd 471.29

Asmin 0.5/fyk*b*d 333.33

Asing (3.14*d^2/4) 14.00 154.00

Spacing for As Asig*1000/As 326.76

Spacing for Asmin Asig*1000/Asmin 462.00

Final use 614 c/c 300


9/15


10/15

195.54


11/15


12/15

FOOTING DESIGN PROGRAMME USIN

S = 300

C = 25

1.04

= 0.5fctd(1+50*rho)

200

= 0.25fctd(1+50*rho

1.50

18.00


Footing Group F4

210.00

Footing Dimension, L * L (m) 1.20

1.44

Depth, D (m) 0.20

Effective depth, d (m) = D - 0.05

Own Weight of Footing, Wc (KN)

Soil Weight , Ws(KN)

Take rho = rmin

= 0.002

fctd

= 0.21*((fck

)^0.67)/1.5=

Allowable punching resistance ofconcrete, Vup(KPa)Allowable bearing pressure, s

(KPa)Allowable wide beam shearresistance of concrete, v

ud

(KN/m2)


(m)



Footing Area, A(m2)

=1.3*Af*d*g

s

= 1.3*Af*(f

d-D)*g

s


13/15

= Ps+Wc+Ws

Checking Bearing Capacity

Punching Shear, Vp (kN)

Punching Shear Stress, Vup (KPa)

= Ps/Af(L/2-d-a/2)

= Vw/(b*d)

N

B 1 -(1 - 2*N)^0.5

As B*fcd*b*d/fyd

Asmin 0.5/fyk*b*d

Asing (3.14*d^2/4) 14.00

Spacing for As Asig*1000/As

Spacing for Asmin Asig*1000/Asmin

Final


(KN)

= PT/A

=Ps

*(1-((a+d)/L)^2)

= Vp/(4(a+d)*d)

Wide beam Shear, Vw

(KN)


Design Moment, Md

(KN-m/m) = (Ps/Af)*((L-a)/2)^2*0.5

(Md*10E+6/fcd*b*d^


14/15

G LIMIT STATE METHOD

260.87

fcd=0.85*fck/1.5 11.33

= 781.41

= 390.71

1.20

= 0.15

= 9.36

= 43.80


15/15

= 263.16 182.75

= 182.75

= 180.47

= 668.40

= 43.75

= 291.67

= 14.77

= 0.058

0.060

388.95

250.00

154.00

395.94

616.00

se 514 c/c 350

Documents

(2) Footing Design