counter fort retaining walls

Malana-II Design of counterfort retaining wall:

13.2

47

Top level of retaining wall EL 590 EL 590.00 0.50 βBottom level of counterfort EL 578

12

Surcharge angle β 14 deg θ

Angle of repose ф 30 deg

Unit weight of concrete 25

Unit weight of Backfill material 22

Bearing capacity of soil SBC 150

Co-efficient of internal friction 0.58Partial factor of safety FOS 1.5

Grade of concrete fck 20 EL 578.00 2 5.00

Yield stress of steel fy 415 0.85

Cover provided C 0.04 m 7.5Dimensioning of retaining wall: Toe Heel

Height of stem h 12 mThickness of stem 0.50 m (Assume)Spacing of counterforts L 4.00 mThickness of counterfort 0.40 m

Toe width 2.00 mBase width B 7.50 m 0.54545455

Heel width 5.00 m 0.8593887 4Base slab thickness 0.85 m 3.0 6Height of retaining wall H 12.85 m

Active earth pressure co-efficient 0.367 (Surcharge angle) 0.21043771Height of backfill at the end of base slab 13.247 m 0.78956229Height of backfill at the end of base slab+base slab 14.097 m

Active Earth Pressure 802.53 kN

Horziontal Component 778.69 kN (Act at 1/3 of H)

Vertical component 194.15 kN (Act at end of Heel)Weight of earth fill W3 1388.57 kN

Stability Analysis:Assume of 1m strip of retaining wall for stability analysis:

S.No Load Description UnitMagnitude

Vertical Horizontal1 W1 Weight of stem kN 150.00 - 2.25 337.502 W2 Weight of base slab kN 159.38 - 3.75 597.663 W3 Weight of earth Fill kN 1388.57 - 5.00 6942.834 W4 Earth pressure kN - 778.69 4.70 3658.995 W5 Earth Pressure kN 194.15 - 7.50 1456.13

Total 1892.09 kN 9334.11 3658.99Total Vertical load W 1892.09 kNTotal Horizontal load P 778.69 kN

kN/m3

kN/m3

kN/m2

N/mm2

N/mm2 C D

A B

b1

b2

Ka

We

Wh

Wv

Distance from point A

Resisting moment

Overturning moment

W4`

W3

W5`W1

W2

Factors of safety:Against oveturning:

FOS 2.55 SafeAgainst sliding:

FOS 1.40 Unsafe, Shear Key RequiredEccentricity calculation:

403.

77

322.

97

302.

78

100.

79

z 3.00e 0.751 m

Pressure Distribution

At Toe 403.77 > 150 7.50

At Heel 100.79 < 150Upward Pressure not exceding the Bearing capacity of soil

Design of stem:

Pressure Intensity P 103.82

Factored Pressure 155.73

Factored Moment 207.64 kNm

Thickness required 0.274 m

Effective depth provided 0.46 m

Area of steel required #VALUE!Dia of bar 20 mmSpacing required #VALUE! mm Horizonatal reinf

Distribution reinf: 552Dia of bar 12 mmSpacing required 200.00 mm Vertical reinfCheck for Shear:Shear Force at the base 275.64 kN

Shear stress devoloped 0.55127

Area of steel provided #VALUE!Percentage of steel provided #VALUE! %

Allowable shear stress #VALUE!#VALUE!

Check for development length:

1213 mm

940 mm IS456:2000

Safe in Development LengthPoint of contraflexure:

Point of contraflexure: 1.00 m

Also main reinforcement shall be reduced at the top

Pmax kN/m2 A B

Pmin kN/m2

kN/m2

Pu kN/m2

Mu

dreqd

deff

Ast mm2/m

mm2/m

N/mm2

mm2/m

N/mm2

M/V+L∅ L∅=12*dia or depth whichever is greater

Ld

M/V+L∅≥Ld

For fixed support with udl the point of contraflexure occurs at 0.211*L, so the main reinforcement has to be extended upto pt of contraflexure from both the supports. At mid, 3/4 th of reinforcement shall be provided.

Since it may be difficult for detailing of reinforcement the same reinforcement shall be provided at both the tension and compression face

D

f e

c

Design of Toe Slab:Maximum Bending moment acting on the toe slab is calculated by considering moments of all forces about the point c


Vertical Horizontal1 Wup1 Upward Pressure (ACEF) kN 726.74 - 1.04 753.673 W6 Weight of Toe slab kN -42.50 - 1.00 -42.50

Total 684.24 711.17Maximum working moment 711.17 kNmFactored moment 1066.76 kNmThickness required 0.62 mEffective Thickness Provided 0.81 m

Area of steel required #VALUE!Dia of bar 25 mmSpacing required 100.00 mm (Parallel to the length of retaining wall)

Distribution reinf: 972Dia of bar 16 mmSpacing required 200.00 mm (Parallel to counterfort)

Area of steel provided 4908.739

Distance from point C

Moment about C

Ast3 mm2/m

Ast4 mm2/m

mm2/m

Percentage of steel provided 0.606 %Check for Shear: (Toe Slab)

Critical section for shear is at d distance from face of the stem. i.e 1.19 m from AShear Force 407.12 kN

Shear Stress 0.503


Design of Heel Slab:Maximum Bending moment acting on the toe slab is calculated by considering moments of all forces about the point b

Weight of soil on strip 277.71

Self weight of heel slab 21.25

Total doward force 298.96

Upward pressure 100.79

Net Downward Pressure 198.17Maximum negative moment 264.23 kNmFactored Moment 396.35 kNmDepth Provided 0.81 m

Area of steel requried #VALUE!

Minimum reinforcement required 972 0.12% of c/s areaDia of bar 25 mmSpacing required 100.00 mmPercentage of reinforcement provided 0.61 %

Distribution reinforcement:

Area of steel required 972 0.12% of c/s areaDia of bar 16 mmSpacing required 200.00 mm

Check for Shear:Shear force developed V 396.35 kNShear stress developed 0.47


Design of counterforts:Thickness of counterfort b 0.40 mTop width of counterfort 0.5 mBottom width of counterfort 5.50 mInclination angle of counterfort θ 22.62 degDepth from face of the stem 4.58 mEffective depth of counterforts d 5.08 mMaximum bending moment 13753.43 kNmFactored Bending moment 20630.14 kNm

Area of steel required #VALUE!

Min reinforcement required 5197.7

Dia of bars f 25 mmNo. of bars n #VALUE! nos

N/mm2

N/mm2

kN/m2

kN/m2

kN/m2

kN/m2

kN/m2

mm2/m

mm2/m

mm2/m

τv N/mm2

τc N/mm2

mm2/m

mm2/m

Check for Shear: 0d' 5.50 m

Shear force V 916.97 kN

0.45

Percentage of steel provided #VALUE! %


Curtailment of Counterfort bars:Half the bars shall be curtailed at distance of 3.64 m from top

Connection between counterfort and stem: .Horizontal force 339.24Factored Force 508.86

Steel required 1409.40Dia of bar required 20 mmSpacing required 200.00 mm

Connection between counterfort and Heel slab:

Tension transferred in 1m width of counterfort near the heel 693.61Factored force 1040.41 kN


Design of shear Key:

Co-efficient of passive pressure 2.72

Upward pressure near the key P 322.97Let depth of shear key a 0.50 mWidth of the shear key 0.50 m

Passive pressure developed 879.69

Total passive pressure 439.84 kN

Weight of earthfill in the key 82.5 kNSelf weight of the key W 1892.09 kNFOS against sliding 2.03

Cost Estimation:Cost compuatation for counterfort spacing

S.No ComponentC/s area Quantity Rate Cost

m Rs1 Stem 6.00 4.00 24.00 4500.00 108000.002 Base Slab 6.38 4.00 25.50 4500.00 114750.003 Counter forts 30.00 0.40 12.00 4500.00 54000.004 Steel in Stem #VALUE! 45000.00 #VALUE!5 Toe Slab 0.738 45000.00 33213.2956 Heel Slab 1.845 45000.00 83033.2367 Counterfort (1 No.) 4.726 45000.00 212665.84

Total cost #VALUE!

τv N/mm2

Pt

τc N/mm2

mm2/m

kN/m2

mm2/m

Kp

kN/m2

Kp*P kN/m2

Pp *a

Wa

Thicness/Length

m2 m3 Rs/m3

Top level of retaining wall EL 1403 0.4Bottom level of counterfort EL 1393

10.00

Surcharge angle 0 degAngle of repose 30 deg


Unit weight of Backfill material 18Bearing capacity of soil SBC 150 kN/m2

Co-efficient of internal friction 0.5

Dimensioning of retaining wall:Height of stem H 10 mThickness of stem 0.4 m (Assume) 1.5 4.1Spacing of counterforts L 3.5 m

###Toe width 1.5 mBase width B 6 m 6

Heel width 4.1 mBase slab thickness 0.7 m

Active earth pressure co-efficient 0.33333 (Surcharge angle)

Stability Analysis:Assume of 1m strip of retaining wall for stability analysis:

S.No Load Description Unit Magnitude

1 W1 Weight of stem kN 100.00 1.70 170.0002 W2 Weight of base slab kN 105.00 3.00 315.0003 W3 Weight of earth Fill kN 738.00 3.95 2915.1004 W4 Horizontal earth pressur kN 300.00 3.33 1000.00

Total 1243.00 3400.10 1000.00

Total Horizontal load W 943.00 kNTotal Vertical load P 300.00



FOS 1.57 Safe

kN/m3

kN/m3

b1

b2

Ka

Distance from Heel

Resisting moment

Overturning moment

Malana-II Design of Cantilever retaining wall:

Top level of retaining wall EL 1398

3.00

0

Bottom level of counterfort EL 1393 EL 1398.00 0.250 0Surcharge angle β 0 deg

3.00



Unit weight of Backfill material 18

Bearing capacity of soil SBC 125Co-efficient of internal friction 0.50Partial factor of safety FOS 1.5

Grade of concrete fck 20

Yield stress of steel fy 415Cover provided C 0.04 m

Dimensioning of retaining wall: EL 1393.00 0.70 0.45 1.85Height of stem h 5 m

0.45height of back fill 3 mHeight of retaining wall H 5.45 mThickness of stem at Top 0.250 m (Assume) A 3.00Thickness of stem at Bottom 0.45 m

Toe width 0.70 mBase width B 3.00 m

Heel width 1.85 mBase slab thickness 0.45 m

Active earth pressure co-efficient 0.333 (Surcharge angle)Height of backfill at the end of base slab 3.000 m

Height of backfill at the end of base slab+base slab 3.450 m

Active Earth Pressure 35.71 kN

Horziontal Component 35.71 kN (Act at 1/3 of H)

Vertical component 0.00 kN (Act at end of Heel)Weight of earth fill W3 99.90 kN


Vertical Horizontal

1 W1 Weight of stem kN31.25 1.025 32.0312.50 0.83 10.42

2 W2 Weight of Base slab kN 33.75 1.50 50.633 W3 Weight of Earth fill kN 99.90 2.08 207.294 W4 Earth Pressure kN 35.71 1.15 41.06

W5 Earth Pressure kN 0.00 3.00 0.00

Total 177.40 35.71 300.37 41.06Total vertical Load 177.40 kNTotal Horizontal Load 35.71 kN



FOS 2.48 Safe, Shear Key Not RequiredEccentricity calculation:

z 1.46e 0.038 m

63.6

7

61.5

5

60.1

9

54.6

0Pressure Distribution

At Toe 63.67 < 125

At Heel 54.60 < 125 3.00Design of stem:

Height of stem 3.00 mMoment at the base M 27.00 kNm

Factored Moment 40.50 kNmThickness required d 0.121 mThickness Provided dpro 0.41 m

Area of steel required Ast #VALUE!Min reinforcement 492

Dia of bar provided 32 mmSpacing provided #VALUE! mm

Reinforcement provided #VALUE!Percentage of reinforcement provided pt #VALUE! %

Distribution reinf:Area of steel required 492.00Dia of bar provided 10 mmSpacing provided 150.00 mm

Check for shear:Shear force developed 35.71 kN

Shear stress developed 0.09

Permissible shear stress #VALUE!#VALUE!

Design of heel slab:

S.No Load Description UnitMagnitude Moment about B

Vertical Horizontal +ve -ve1 W2 Weight of heel slab kN 20.81 0.925 19.25156252 W3

Weight of earth fillkN 0.00 0.00 0.00

kN/m3

kN/m3

kN/m2

N/mm2

N/mm2

b1

b2

Ka

H1

We

Wh

Wv


Resisting moment

Overturning moment

Pmax kN/m2

Pmin kN/m2 A B

Mu

mm2/m

mm2/m

mm2/m

N/mm2

N/mm2

Distance from point B

D

f

c

3 W4Weight of earth fill

kN 35.71 1.00 35.714 W5 Upward Pressure kN 106.18 0.94 99.8131393

Total 162.70 54.96 99.81

Net downward force 56.52 kNNetupward force 106.18 kNNet force -49.66 kNNet working moment M 44.85 kNmFactored moment Mu 67.28 kNmDepth required dreqd 0.16 m

dprov 0.41 mReinforcement reqd Ast #VALUE!

Min reinf 492Dia of bar 20 mmSpacing reqd #VALUE! mm

Reinforcement provided #VALUE!Percentage of steel #VALUE! %

Check for Shear:Shear force developed -49.66 kN

Shear stress developed -0.12

#VALUE!#VALUE!

Minimum reinforcement:

Min reinf 492Dia of bar 10 mmSpacing reqd 150.00 mm

Design of toe slab:

S.No Load Description UnitMagnitude Moment about C

Vertical Horizontal +ve -ve1 W1 Weight of toe slab kN 7.88 0.35 2.75625

W2 Upward Pressure kN 43.83 0.35 15.4253158Total 51.70 2.76 15.43

Total vertical force 35.95 kNNet working moment M 12.67 kNmFactored moment Mu 19.00 kNmDepth required dreqd 0.08 m

d prov 0.41 m

Reinforcement reqd Ast #VALUE!

Min reinf 492.00Dia of bar 20 mmSpacing reqd #VALUE! mm

Reinforcement provided #VALUE!Percentage of steel provided #VALUE! %

Minimum reinforcement:

Min reinf 492.00Dia of bar 10 mmSpacing reqd 150.00 mm






Weight of earthfill in the key 18.9 kNSelf weight of the key W 177.40 kNFOS against sliding 4.56

Cost Estimation:


m Rs1 Stem 1.75 17.885 31.30 3500.00 109545.6252 Base slab 1.35 17.885 24.14 3500.00 84506.6253 Steel in stem #VALUE! 38000.00 #VALUE!4 Steel in Heel slab #VALUE! 38000.00 #VALUE!5 Steel in Toe slab #VALUE! 38000.00 #VALUE!

#VALUE!

Cost Comparison:a) Cantilever Retaining wall #VALUE! Rsb) Counterfort Retaining wall #VALUE! RsIt is suggested to provide Counterfort type retaining walla) The retaining wall height is greater than 6.0m, it is economical to proivde counterfort type retaining wall.

mm2/m

mm2/m

N/mm2

N/mm2

mm2/m


mm2/m

mm2/m

mm2/m

mm2/m

Kp

kN/m2

Kp*P kN/m2

Pp *a

Wa

Thicness/Length

m2 m3 Rs/m3

Design of counterfort retaining wall:

8.00

0


8




Unit weight of Backfill material 18 312.29179308



Grade of concrete fck 25 EL 582.00 0.75 3.75


Cover provided C 0.04 m 5Dimensioning of retaining wall: Toe Heel

Height of stem h 8 m 6250Thickness of stem 0.50 m (Assume)Spacing of counterforts L 3.00 m #VALUE!Thickness of counterfort 0.40 m #VALUE! 4

Toe width 0.75 m #VALUE! #VALUE!Base width B 5.00 m 0.545

Heel width 3.75 m 0.859 4Base slab thickness 0.50 m #VALUE! 3.0 6Height of retaining wall H 8.50 m 50

Active earth pressure co-efficient 0.490 (Surcharge angle) 0.210Height of backfill at the end of base slab 8.000 m 0.790Height of backfill at the end of base slab+base slab 8.500 m 0.137

Active Earth Pressure 318.81 kN 0.050

Horziontal Component 318.81 kN (Act at 1/3 of H) 3.101

Vertical component 0.00 kN (Act at end of Heel) 0.016Weight of earth fill W3 540.00 kN 0.127

1.526Stability Analysis:

Assume of 1m strip of retaining wall for stability analysis:




kN/m3

kN/m3

kN/m2

N/mm2

N/mm2 C D

A B

b1

b2

Ka

We

Wh

Wv


Resisting moment

Overturning moment

W4`

W3

W5`W1

W2



FOS 1.10 Unsafe, Shear Key RequiredEccentricity calculation:

312.

29

260.

75

226.

40

-31.

29

z 1.48e 1.019 m 0.83


At Toe 312.29 < 400 5.00

At Heel -31.29 < 400Upward Pressure not exceding the Bearing capacity of soil

Design of stem:

Pressure Intensity P 70.60 564.81476724

Factored Pressure 105.90 282.40738362

Factored Moment 79.43 kNm 282.40738362

Thickness required 0.152 m 1035.4937399 547.85319


Area of steel required #VALUE!Dia of bar 20 mm 314.159265 #VALUE!Spacing required #VALUE! mm Horizonatal reinf #VALUE!

Distribution reinf: 552Dia of bar 12 mmSpacing required 200.00 mm Vertical reinfCheck for Shear:Shear Force at the base 150.82 kN

Shear stress devoloped 0.30164 256345.5

Area of steel provided #VALUE! 2.922535E-05Percentage of steel provided #VALUE! % 7.4917875



987 mm

940 mm IS456:2000




Pmax kN/m2 A B

Pmin kN/m2

kN/m2

Pu kN/m2

Mu

dreqd

deff

Ast mm2/m

mm2/m

N/mm2

mm2/m

N/mm2


Ld

M/V+L∅≥Ld



D

f e

c




Total 205.52 79.48Maximum working moment 79.48 kNmFactored moment 119.23 kNmThickness required 0.19 mEffective Thickness Provided 0.46 m

Area of steel required #VALUE!Dia of bar 25 mmSpacing required 100.00 mm (Parallel to the length of retaining wall)

Distribution reinf: 552Dia of bar 16 mmSpacing required 200.00 mm (Parallel to counterfort)

Area of steel provided 4908.739Percentage of steel provided 1.067 %

Check for Shear: (Toe Slab)Critical section for shear is at d distance from face of the stem. i.e 0.29 m from AShear Force 29.80 kN

Shear Stress 0.065



Weight of soil on strip 144.00


Total doward force 156.50

Upward pressure -31.29

Net Downward Pressure 187.79Maximum negative moment 140.84 kNmFactored Moment 211.27 kNmDepth Provided 0.46 m


Minimum reinforcement required 552 0.12% of c/s areaDia of bar 25 mmSpacing required 100.00 mmPercentage of reinforcement provided 1.07 %

Distribution reinforcement:

Area of steel required 552 0.12% of c/s areaDia of bar 16 mmSpacing required 200.00 mm



Design of counterforts:Thickness of counterfort b 0.40 mTop width of counterfort 0.5 mBottom width of counterfort 4.25 mInclination angle of counterfort θ 25.11 degDepth from face of the stem 3.36 mEffective depth of counterforts d 3.86 mMaximum bending moment 2550.49 kNmFactored Bending moment 3825.74 kNm


Min reinforcement required 3277.2

Dia of bars f 32 mm


Moment about C

Ast3 mm2/m

Ast4 mm2/m

mm2/m

N/mm2

N/mm2

kN/m2

kN/m2

kN/m2

kN/m2

kN/m2

mm2/m

mm2/m

mm2/m

τv N/mm2

τc N/mm2

mm2/m

mm2/m

No. of bars n #VALUE! nosCheck for Shear: 0

d' 4.26 mShear force V 284.86 kN

0.18



Curtailment of Counterfort bars:Half the bars shall be curtailed at distance of 2.83 m from top

Connection between counterfort and stem: .Horizontal force 176.50Factored Force 264.76



Tension transferred in 1m width of counterfort near the hee 469.48Factored force 704.22 kN







Weight of earthfill in the key 45 kNSelf weight of the key W 702.50 kNFOS against sliding 2.01



m Rs1 Stem 4.00 3.00 12.00 4500.00 54000.002 Base Slab 2.50 3.00 7.50 4500.00 33750.003 Counter forts 15.00 0.40 6.00 4500.00 27000.004 Steel in Stem #VALUE! 45000.00 #VALUE!5 Toe Slab 0.219 45000.00 9858.12936 Heel Slab 1.049 45000.00 47223.0867 Counterfort (1 No.) 3.134 45000.00 141010.82

Total cost #VALUE!

τv N/mm2

Pt

τc N/mm2

mm2/m

kN/m2

mm2/m

Kp

kN/m2

Kp*P kN/m2

Pp *a

Wa

Thicness/Length

m2 m3 Rs/m3

Design of counterfort retaining wall:

8.00

0


8




Unit weight of Backfill material 22 175.100



Grade of concrete fck 25 EL 582.00 1.5 4.00


Cover provided C 0.04 m 6Dimensioning of retaining wall: Toe Heel

Height of stem h 8 m 6250Thickness of stem 0.50 m (Assume)Spacing of counterforts L 3.00 m #VALUE!Thickness of counterfort 0.40 m #VALUE! 4

Toe width 1.50 m #VALUE! #VALUE!Base width B 6.00 m 0.545

Heel width 4.00 m 0.859 4Base slab thickness 0.50 m #VALUE! 3.0 6Height of retaining wall H 8.50 m 50

Active earth pressure co-efficient 0.333 (Surcharge angle) 0.210Height of backfill at the end of base slab 8.000 m 0.790Height of backfill at the end of base slab+base slab 8.500 m 0.137

Active Earth Pressure 264.92 kN 0.050

Horziontal Component 264.92 kN (Act at 1/3 of H) 3.101

Vertical component 0.00 kN (Act at end of Heel) 0.016Weight of earth fill W3 704.00 kN 0.127

1.526Stability Analysis:

Assume of 1m strip of retaining wall for stability analysis:




kN/m3

kN/m3

kN/m2

N/mm2

N/mm2 C D

A B

b1

b2

Ka

We

Wh

Wv


Resisting moment

Overturning moment

W4`

W3

W5`W1

W2



FOS 1.66 Safe, Shear Key Not RequiredEccentricity calculation:

175.

10

160.

80

156.

03

117.

90

z 2.80e 0.195 m 1.00


At Toe 175.10 < 400 6.00

At Heel 117.90 < 400Upward Pressure not exceding the Bearing capacity of soil

Design of stem:

Pressure Intensity P 59 469.33333333

Factored Pressure 88 234.66666667

Factored Moment 66 kNm 234.66666667

Thickness required 0.138 m 860.44444444 499.40383


Area of steel required #VALUE!Dia of bar 20 mm 314.159265 #VALUE!Spacing required #VALUE! mm Horizonatal reinf #VALUE!

Distribution reinf: on each face 276Dia of bar 12 mmSpacing required 400 mm Vertical reinfCheck for Shear:Shear Force at the base 126 kN

Shear stress devoloped 0.252 256345.5

Area of steel provided #VALUE! 2.922535E-05Percentage of steel provided #VALUE! % 7.4917875



984 mm

940 mm IS456:2000




Pmax kN/m2 A B

Pmin kN/m2

kN/m2

Pu kN/m2

Mu

dreqd

deff

Ast mm2/m

mm2/m

N/mm2

mm2/m

N/mm2


Ld

M/V+L∅≥Ld



D

f e

c




Total 233.17 177.56Maximum working moment 178 kNmFactored moment 266 kNmThickness required 0.28 mEffective Thickness Provided 0.46 m

Area of steel required #VALUE!Dia of bar 25 mmSpacing required 100 mm (Parallel to counterfort)

Distribution reinf: on each face 276Dia of bar 12 mmSpacing required 200 mm (Parallel to the length of retaining wall)

Area of steel provided 4909Percentage of steel provided 1.067 %

Check for Shear: (Toe Slab)Critical section for shear is at d distance from face of the stem. i.e 1.04 m from AShear Force 121 kN

Shear Stress 0.264



Weight of soil on strip 176


Total doward force 189

Upward pressure 118

Net Downward Pressure 71Maximum negative moment 53 kNmFactored Moment 79 kNmDepth Provided 0.46 m


Minimum reinforcement required 552 0.12% of c/s areaDia of bar 20 mmSpacing required 250 mmPercentage of reinforcement provided 0.27 %

Distribution reinforcement:on each face

Area of steel required 276 0.12% of c/s areaDia of bar 12 mmSpacing required 200 mm



Design of counterforts:Thickness of counterfort b 0.40 mTop width of counterfort 0.50 mBottom width of counterfort 4.50 mInclination angle of counterfort θ 26.57 degDepth from face of the stem 3.54 mEffective depth of counterforts d 4.04 mMaximum bending moment 2119 kNmFactored Bending moment 3179 kNm


Min reinforcement required 3432

Dia of bars f 32 mm


Moment about C

Ast3 mm2/m

Ast4 mm2/m

mm2/m

N/mm2

N/mm2

kN/m2

kN/m2

kN/m2

kN/m2

kN/m2

mm2/m

mm2/m

mm2/m

τv N/mm2

τc N/mm2

mm2/m

mm2/m

No. of bars n #VALUE! nosCheck for Shear:

d' 4.51 mShear force V 235 kN

0.15



Curtailment of Counterfort bars:Half the bars shall be curtailed at distance of 2.83 m from top To be seen later

Connection between counterfort and stem: .Horizontal force 147Factored Force 220

Steel required 506Dia of bar required 16 mmSpacing required 375 mm


Tension transferred in 1m width of counterfort near the hee 176Factored force 265 kN

Steel required 609Dia of bar required 16 mmSpacing required 325 mm



Upward pressure near the key P 161Let depth of shear key a 0.50 mWidth of the shear key 0.50 m

Passive pressure developed 482

Total passive pressure 241 kN

Weight of earthfill in the key 66 kNSelf weight of the key W 879 kNFOS against sliding 2.69



m Rs1 Stem 4.00 3.00 12.00 4500 540002 Base Slab 3.00 3.00 9.00 4500 405003 Counter forts 16.00 0.40 6.40 4500 288004 Steel in Stem #VALUE! 45000 #VALUE!5 Toe Slab 0.384 45000 172936 Heel Slab 0.341 45000 153507 Counterfort (1 No.) 2.797 45000 125853

Total cost #VALUE!

τv N/mm2

Pt

τc N/mm2

mm2/m

kN/m2

mm2/m

Kp

kN/m2

Kp*P kN/m2

Pp *a

Wa

Thicness/Length

m2 m3 Rs/m3

counter fort retaining walls

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