Isolated Sloped Footing

DESIGN Project

OF

I S O LAT E D

SLOPED

NATIONAL ENTERPRISE

User

AAM

Date

21-Oct-16

Footing Identifier =

Time

F1

Safe Bearing Capacity of Soil = Depth of Founding Level below Ground

30

T/m2

0

m

(Df) =

Weight Density of Soil & Backfill together

=

1.8

T/m3

Load Factor for Limit State Method

(LF) =

1.5

Factor

Concrete Grade

(Fck) =

20

N/mm2

Steel Grade

(fy) =

415

N/mm2

Column Dimensions: E_W Column Dimensions: N_S Offset from face of column Crack width

(L1) = (B1) = = =

0.23 0.65 50 0.3

m Width m Width mm m

LOAD CASES Case

Load (T) P

I II III IV V VI VII VIII

DL + LL DL + LL DL + LL DL + LL DL + LL DL + LL DL + LL DL + LL

120

Moments (T.M) MZ( @Z ) MX( @X ) M_E-W M_N-S 0

Soil over Stress Factor

0

1 1 1 1 1 1 1 1

Trial Footing Size Length - L Width - B

1.93 2.35

M E_W M N_S

if (P > Pp) then 'Revise Footing Size' Depth of Footing at Centre Eff. Cover to Bott. Reinf. d'

L/B AREA

1.22 4.5355 Section Modulus

Z_NS Z_EW 680 70

1.8 1.5 mm mm

m2 m3 m3 Depth of Footing at Edge de=D-d'=

Distances from CL of to a) Column Face, b) De from & its Distance from Edge, Perimeter & Punching Area for Shear ECT,. For Moment

For punching shear

L1 (E-W) L (E-W) B1 (N-S) B (N-S) Lpu=(L1+De) Bpu=(B1+De)

0.23 1.93 0.65 2.35 0.84 1.26

E-W 0.115 0.85 0.725 0.24

Xf Lf Xd Ld

N-S 0.325 0.85 0.935 0.24

perimeter

4.2

Area of footing @ critical section for one way shear E-W

(((0.23+2*610/1000)+1.93)/2*(344-200)/1000)+((200-70)/1000*1.93)

N-S

(((0.65+2*610/1000)+2.35)/2*(344-200)/1000)+((200-70)/1000*2.35) E-W  J=

0.35 0.27

C=

0.42 M_E-W

Shear due to Moment =

1.525

2.14366413 Overburden Pressure Df - D = 0.00 IF (foundation depth-D) is <= 0, then this component is 0 *Volume of concrete x 2.5 + (Total volume of excavation i.e. L x B x D - volume of concrete) x 1.8 OB Load(Ptot) 1.25 Eb = {M_E-W} / (P + Pob) OB Press(Pob) 0.276 El = {M_N-S} / (P + Pob) R = 0.138 or 0.15 * fck

R=

0.138

X

p-max=Ptot*(1+6*Eb/B+6*El/L) p-min=Ptot*(1-6*Eb/B-6*El/L)

20

P-edge=Ptot*(1+6*Eb/B) P-face=Ptot*(1+12*Eb/B^2*X P-d =Ptot*(1+12*Eb/B^2*Xd M-face = Lf^2*{P-edge/3+P-fa

V-De = Ld*{(P-edge+P-d)*0.5 Punching shear stress = ((A-Ap)*(Ptot-Pob)) / (P.Perimeter*De)+((M_E-W*a*c_E-W) / (0.85J_E-W))+((M_N-S*a*c_N-S) / Case

(0.85*J_N-S))

I I III IV V VI VII VIII

Ptot (P+Pob)/A

26.73

M-(E-W)/ M/Z

M-(N-S)/ M/Z

p-max t/m2

p-min t/m2

0.00

0.00

26.73

26.73

Err:504

26.73

26.73

Err:504 Limit state De = SqRt((Mu / K Fck) * b)

De (cm)=

P-edge t/m2 26.73

Permissible Punching Shear Stress Ks = (0.5 + c) c = L / B c = 0.25 * Sqrt(Fck)

Ks = c =

= Ks * c 0.85 111.80

= t/m2

R = Mu / b * de2 - N/mm2 Pt (Req) = 0.5*Fck/Fy{[1-(1-4.6*Mu/B*de^2)/Fck]^0.5}*b*de Pt (Req) Min = 0.12% Ast - Reinforcement to be required = Pt (req) * A * d Ast - Reinforcement Provided Pt (Provided) @ Efffective depth d from face of column =0.85*sqrt(0.8*Fck)*(sqrt(1+5*)-1)/6* Allowable Shear Stress (t/m2)



=0.8 * Fck / 6.89 * pt Actual Shear stress (t/m2)

8.12

for E_W

Bearing pressure = Pu/bD in t/m2

for N_S

1.20 1.80 4535500 149500

Permissible bearing pressure = 0.45 fck (sqrt(A1/A2))

A1 = (min of (Lf x Bf or ( b + 4Df )x ( D + 4 Df ) A2 = b x D where sqrt(A1/A2) should not be greater than 2

Footing Size Pedestal Dimensions: E_W = Pedestal Dimensions: N_S = Length - L: E_W = Width - B: N_S = Depth = Column face Footing Edge Ast =

8.19

0.23 0.65 1.93 2.35 680 200

m m m m mm Bottom Reinf.

Quantities Footing 1 Excavation 2 PCC 3 RCC 4 Formwork 5 Reinforcement Total reinforcement per cft =

Pedestal 1.95 0.59 1.79 1.7 54

m3 m3 m3 m2 Kgs

1 Concrete 2 Formwork 54

1.79

35.314

AT E D

SLOPED

FOOTING

BY

LIMIT

S TAT E

METHOD

Comments: EXECUTION

13:24

N

0.85

Ld

De

Z-Axis

BP/2

0.24

+ -

Case I No Tension

Lf =

-

W

X - Axis

P-face

P-face

=

E

0.85

B pu =

B 1 = 0.65

B =

2.35

1.26

m

L1 =0.23

Ld

Lf + -

Xf = 0.12 Xd =0.725 Lf Actual / Allowable

P -fa ce P -fa ce

Pd Pd

P e d ge

(P-max - Pob) 26.46 (0.28) (0.28) (0.28) (0.28) (0.28) (0.28) (0.28) 93.54

For SBC

Fdn Size OK

Punching Shear Stress (EW) Stress (NS)

Depth OK Depth OK Depth OK

Depth (bending) Bearing pressure

Depth OK OK

epth of Footing at Edge 610 mm

1.93 m

200

93.54

(actual / allowable allowable) 30.00 0.88 30.00 30.00 30.00 30.00 30.00 30.00 30.00 0.88

Case I No Tension

Case II Tension Allowed

L1 (E-W)= B1 (N-S)= d eff= 610

mm

Dcentre= 680 D (for one way shear) For punching shear

Pedge

S

Ld

P e d ge

0.88

L=

Pd

Lpu = 0.84

+ +

D_os=344 For E-W

area, Ap

Dmin= 200

D_os=344 For N-S

L (E-W)=

1.93 m

&

1.06 =

0.49 m2

(Area of trapaezoid)

=

0.61 m2

(Area of trapaezoid) E-W

N-S 0.45 0.49 0.63

N-S

 1-(1/(1+2/3*SQRT(Lpu/Bpu))) J= [2*(De*Lpu^3)/12]+[2*(Lpu*De^3)/12]+ [De*(Bpu*Lpu^2/2))]

1-(1/(1+2/3*SQRT(Bpu/Lpu)))

C= Lpu/2

Bpu/2

[2*(De*Lpu^3)/12]+[2*(Lpu*De^3)/12

M_N-S 1.08

 (0.85*J_E-W)

M=



concrete) x 1.8

=

2.76 WITH NO TENSION P-edge=Ptot*(1+6*El/L) P-face=Ptot*(1+12*El/L^2*Xf) P-d =Ptot*(1+12*El/L^2*Xd)

-edge=Ptot*(1+6*Eb/B) -face=Ptot*(1+12*Eb/B^2*Xf) -d =Ptot*(1+12*Eb/B^2*Xd) -face = Lf^2*{P-edge/3+P-face/6-Pob/2}L TM

-De = Ld*{(P-edge+P-d)*0.5-Pob}L T/m

P-face t/m2 26.73

FOR - M_E-W only P-d M-face t/m2 tm 26.73

22.46

22.5 33.7 22.79

FOR - M_N-S only V@De t

Punch.sh strs t/m2

14.92

14.92 22.38

49.15

49.15 73.72

Depth OK

P-edge t/m2 26.73

P-face t/m2 26.73

95.46 Depth OK

0.39 0.109 0.12 1720 1414 0.29 38.03 34.76 Depth OK OK

Summary

Long Side (E_W)

Kgs 22

Nos. 18

Pedestal

0.855007

m3 m2

Dia 10

Spacing 135

Short Side (N_S)

Kgs 32

P-face

0.24

Ld

Pedge

Case I No Tension


0.23 m 0.65 m d eff/2= 305

D (for Punching shear) D_ps=536 For E-W


P-face Pd

Case I No Tension

P-face

Pd

Lf

P-face

Pedge

D_ps=536 For N-S

B (N-S) =

2.35 m

Column offset+2xEffective depth D_os Footing base dimension

D min

N-S

+2/3*SQRT(Bpu/Lpu)))

e*Lpu^3)/12]+[2*(Lpu*De^3)/12]+ [(De*Lpu*Bpu^2)/2)]

(0.85*J_N-S)

FOR - M_N-S only P-d t/m2 26.73

M-face tm 18.45

18.45 27.67 22.79

V@De t 12.26

12.26 18.38

0.39 0.109 0.12 1413 1728 0.28 .

37.90 34.76 Depth OK

Nos. 22

Dia 10

Spacing 90

Isolated Sloped Footing

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