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D:\Works\NepalConsult\Bridge 2008\Chauri Galpa\[ABTMNT Chauri Galpa w pr at toe tapered w-o ver load for stem pr.XLS]Sheet1

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Abutment

General Arrangement

Formation Lvl 504.40

Beam Depth 2.00

Distance between outer edges of beam 3.15 m

Carriageway width 4.25 m

Length of abutment 5.00 m

Saturated weight of soil 18River bed level 498.200 m

H. F. L. 500.90 m

Max discharge 780.00 m

Silt factor, f 5.57

Regime Water Width 57.00

Linear Water way Provided 50.00

Normal scour depth 2.46 m

Increased scour depth due to constriction 2.66

Maximum scour depth 3.38 m

Maxium scour level 497.52 m

Depth of scour below river bed level 0.68 m

Min. grip of foundation 2.79 m

Hence, level of base of footing 494.73 m

Depth of excavation below river bed level 3.47 m

300 800

General Arrangement of Abutment ( Not to Scale)

Calculation of Seismic Coefficient

General arrangement of the abutment is shown below, which has been adopted after a series of trial and

error

2000

1400

2000

9670

1600 1800

6270

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Horizonsl seismic coef., ah = aIb

where

a = Basic seismic coef. Corresponding to zone V = 0.08I = Importamce factor = 1.00

b = Soil factor = 1.20

Horizonsl seismic coef.,ah

0.096

Design of Foundation

5.3.1 Loads from superstructure

Dead Load Reaction 930.00 kN

Max. Live Load Reaction 380.00 kN

Total (Dl + LL) 1310.00 kN

Breaking force on each abutment 38.00 kN

Seismic force on each abutment 89.28 kN

Frictional resistance at the bearing

5.3.2 Calculation of Earth Pressure

a = Angle which earth face of wall makes with vertical 0.00

f = Angle of intenal friction of soil 35.00

d = Angle of friction of earthside wall with the backfill material 10.00

g = Density of earth fill 18.00i = Slope of earth fill 0.00

ah = Horizonsl seismic coef.. 0.096

av = Vertical seismic coef.. 0.048

tan q = ah /(1+av) & 0.046

ah /(1-av) 0.050

q + 5.23

q - 5.76

Case I ) Non seismic condition

Ca = cos2(f-a)/cos

2a / cos(d+a) x [1+{sin(f+d)/cos(a-i) x sin(f-i)/cos(d+a)}

1/2]

-2

0.253

Pah = 1/2 * Ca * g * h2

* cosd * B 1048 kN

MB = 3377 kN-m

Case II ) for +ve av

q 1 = 5.23

f = 35.00

a = 0.00

d = 10.00

C1 = cos2(f-q1-a)/ cos(d+a+q1) 0.78

C2 = sin(f-i-q1)/cos(d+a+q1) 0.51

Ca+ = (1+av) x C1 /cosq1 /cos2a x [1+{sin(f+d)/cos(a-i) x C2}1/2]-2 0.320

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Case III ) for -ve av

q 2 = 5.76

f = 35.00

a = 0.00

d = 10.00

C1 = cos2

(f-q1-a)/ cos(d+a+q1) 0.79C2 = sin(f-i-q1)/cos(d+a+q1) 0.51

Ca- = (1+av) x C1 /cosq1 /cos2a x [1+{sin(f+d)/cos(a-i) x C2}

1/2]

-20.296

Hence dynamic increment,DCa 0.067

DPah 278

DMah 1342

5.3.3 Calculation of Forces ( for the design of foundation )

S. No Vertical

Force

Hor.

Force

eB MB eA MA

kN kN m kN-m m kN-m

1 DL Reaction 930 0 2.95 2744 2.45 2279

2 LL Reaction 380 0 2.95 1121 2.45 931

3 Braking 0 38 7.67 291 -7.67 -291

4 Temperature 0 131 7.67 1005 -7.67 -1005

5 Self Weight I 72 0 2.15 155 3.25 234

6 828 0 2.80 2317 2.60 2152

7 0 0 0.00 0 5.40 0

8 1270 0 2.70 3429 2.70 3429

9 1731 0 1.00 1731 4.40 7617

10 Seismic Force on Superstructure 0 89 7.67 685 -7.67 -685

11 Earth Pressure (Normal) 0 0 0.00 0 5.40 0

i) With Surcharge 0 1048 0.00 3377 0.00 -3377

ii) Without Surcharge 0 1048 0.00 3377 0.00 -3377

12 Earth Pressure during EQ 0 0 0.00 0 5.40 0

i) With Surcharge 0 1325 0.00 4719 0.00 -4719

ii) Without Surcharge 0 1325 0.00 4719 0.00 -4719

13 0 7 8.67 60 -8.67 -60

0 79 4.54 360 -4.54 -360

0 0 1.40 0 4.00 0

0 122 0.70 85 -0.70 -850 0 4.84 0 0.56 0

0 0 0.00 0 5.40 0

14 Uplift Pressure due to Water 0 0 -2.70 0 2.70 0

Combination of Forces

Pv Ph e M pmax pmin

kN kN m kN-m kN/m kN/m

1 DL + LL Temp/Braking 5211 1217 2.30 11969 200 76

2 DL + Surcharge + Temp 4831 1179 2.35 11330 178 77

3 DL + LL + Temp + Seismic 5211 1792 1.81 9437 274 2

4 DL + Surcharge + Temp + Seismic 4831 1754 1.82 8797 253 3

Check against overturning and sliding

Particulars

II

III

IV

(Soil Overburden) V

Seismic Force on Substructure I

II

III

IVV

VI

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OT

Moment

FOS

Sliding

FOS

Overturning

1 DL + LL Temp/Braking 4673 2.47 3.56

2 DL + Surcharge + Temp 4381 2.37 3.59

3 DL + LL + Temp + Seismic 7205 1.68 2.31

4 DL + Surcharge + Temp + Seismic 6914 1.59 2.27

5.3.4 Design of Abutment Raft

pmax = 274.0 kN/m pmin = 1.7 kN/m

1.8

(Toe Slab )

Design of Toe Slab

M = = 340.5 kN- m

For D = 1400.0 mm

deff = 1315.0 mm

For M20 Conc & Fe500 Steel

N = 0.28 j = 0.91 Q = 0.85

=>de reqd = 634 mm

Ast = 1190 mm2

V = 94.6 kN

tv = 0.07 MPa

=> pt = 0.15 %

=> Ast = 1972.5 mm/m

=> Provide 20 - 150 c/c

Design of Heel Slab

Total Downward Pressure = = 182.5 kN/m

M 294.4 kN-m

For M20 Conc & Fe500 Steel

N = 0.280 j = 0.91 Q = 0.85

1.7

1.6 2

274.0

102.6

( Abutment Stem ) ( Heel Slab )

16642

15711

16642

183.2

15711

Stabilising

Moment

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=>de reqd = 590 mm

Provide D = 1400 mm

de = 1315 mm

Ast = 1029 mm2

S. F. V = = 261 kN

tv = = 0.198 MPa

=> pt = 0.190 %

=>Ast 2499 mm/m

=> Provide 25 - 190 c/c

Minimum Distribution Steel

Min. Ast= 0.06 % = 789 mm/m

=> Provide 12 - 140 c/c

Calculation of Forces ( for the design of stem )

300 800

Design of Abutment Stem

Calculation of Earth Pressure

Case I ) Non seismic condition

Ca = 0.253

Pah = 766

6270

2000

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MC = 2112

Case I ) Under seismic condition

DCa 0.067

DPah 203

DMah 839

Calculation of Forces ( for the design of stem )

S. No Vertical

Force

Hor.

Force

eC MC

1 930 1.0 884

2 380 1.0 361

3 38 6.3 238

4 26 6.3 164

5 72 0 0.00 0

6 1204 0 0.00 0

7 0 0 0.00 08

9

10 89 6.3 560

11

766 2112

766 2112

12

969 2952

969 2952

13 7 7.3 50

116 3.1 362

00

0

14 0 -2.7 0

Combination of Forces

1 DL + LL Temp/Braking 2586 830 3759

2 DL + Surcharge + Temp 2206 792 3160

3 DL + LL + Temp + Seismic 2586 1245 5571

4 DL + Surcharge + Temp + Seismic 2206 1207 4972

Max Hor. Force = 1245

Max Hor. Force = 249 kN/m

Max Moment = 5571

Max Moment = 1114 kN-m/m

For M20 Conc. fcb = 6.777 N/mm

For Fe500 Grade Steel. fst = 240 N/mm

DL Reaction

Particulars

IV

LL Reaction

Braking

Seismic Force on Substructure I

II

(Soil Overburden) V

Seismic Force on Superstructure

Temperature

Self Weight I

II

III

Earth Pressure (Normal)

i) With Surcharge

ii) Without Surcharge

Earth Pressure during EQ

i) With Surcharge

ii) Without Surcharge

IIIIV

V

VI

kN/5 m Lt

kN/5 m Lt

Uplift Pressure due to Water

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m = 13.8

j = 0.91

N = 0.28

Q = 0.86

dreqd = 1138 mm

Provide D = 1600 mm

Clear Cover = 75 mm

Using bar dia = 20 mm

d prov = 1519 mm

Ast reqd = 2697 mm2

=>20 -120 c/c

pt = 0.172 %

Tc = 0.189 MPa

Tv = 0.13 MPa

Safe

=> Ast @ toe face = 911.4

=>12 -120 c/c

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300 800

=>12 -120 c/c

=>20 -120 c/c =>12 -120 c/c

6760

=> Provide 12

=> Provide 25 - 190 c/c

=> Provide 20 - 150 c/c

width of Foundation 7.00 m

2000 1600 1800

9670

2000

6270

1400

1600forleftabutment

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- 140 c/c

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