Retaining Wall

Retaining 1.) General Details Grade of Concrete

M-20

Grade of Steel

Fe-415

SBC Height of Wall

180 kN/m2 7m

Suggested Type of Retaining Wall

Counterfort Retaining Wall

2.) Design Constants σcbc

7 N/mm2

σst

230 N/mm2

Ka (Coefficient of Active Earth Pressure)

1/3

3.) Dimension Control b (Ratio of Length of Toe slab to the Base Width)

3.84

Provided Base SLab Length Final b Length of Toe Slab Thickness of Stem

4.1 4.1m 1.76m 300mm

Length of Heel Slab

2.0m

Thickness of Base Slab

300mm

l (Clear Spacing of Counterforts)

2.86m

4.) Stability of Wall W1

Weight of Stem, per metre length

W2

Weight of Base Slab

W3

Weight of Soil on Heel Slab

S.No.

Designation

1

W1

2

W2

3

W3 ΣW

PH (Horizontal Earth Pressure)

192 kN

MO (Overturning Moment)

512 kN-m

Check for Overturning

Safe

Check for Sliding Unsafe Provide Shear Key under the Base Pressure Distribution

Net Moment Ẍ Eccentricity p1 (Pressure under Toe)

Pressures

p2 (Pressure under Heel) p1' (Pressure Intensity of p1) p2' (Pressure Intensity of p2)

5.) Design of Heel Slab Clear Spacing of Counterforts

3m

Upward Pressure Intensity at Heel (p2')

8.27 kN/m2 Net Downward Pressure

M1 (Max. negative Bending Moment in Heel Slab at Counterforts)

103.4 kN-m

Shear Force V

207 kN

Design Constraints Preliminary Steel % Tc (Shear Strength) Available

0.75% 0.35 N/mm2

Area of Steel at Supports Required (Ast1)

1,129.91mm2

Bar Dia Spacing Required Development Length Check

12 100.0mm c/c

Development Length at Point of Contraflexure

633.0mm

Moment Developed

103.4 kN-m

Curtailment Length

1,300.6mm

Continue these bars by a distance of Lo ( =d =440mm) beyond the point of contraflexure. After that, curtail half the bars, Curtailment, length of each bar available =633+440 = 1073mm >Ld. These bars will be provided at the Top Face of the He Maximum Positive Bending Moment

77.5 kN-m

Area of Bottom Steel (Ast2) Bar Dia Spacing Required Development Length Check

847.43mm2 12 133.4mm c/c

Development Length at Point of Contraflexure

633.0mm

Moment Developed

79.6 kN-m

Curtailment Length

674.7mm

Continue these bars by a distance of Lo ( =d =12mm) beyond the point of contraflexure. After that, curtail half the bars, a Curtailment, length of each bar available =633+12 = 645mm >Ld. These bars will be provided at the Top Face of the Heel

Retaining Wall Design Sheet

Details Weight of Soil

18 kN/m3

Angle of Internal Friction

30˚

Coefficient of Friction b/w Soil and Concrete Angle of Slope over Wall (α)

0.5 0˚

Depth of Foundation

1m

Table yet to be entered

m

Table yet to be entered

Kc

Constants

Jc Rc Kp (Coefficient of Passive Earth Pressure)

3

on Control check (Range of b is from 0.5H to 0.6H)

Consider Minimum Length

Minimum Length of Base Slab

4 4.1m 1.8

Provided Length of Toe Slab

Provide Counterforts over toe slab upto ground level at 3m clear distance.

of Wall Weight of Stem, per metre length Weight of Base Slab Weight of Soil on Heel Slab Force(kN)

Lever Arm (m)

57.8

1.95

30.75

2.05

277.2

3.1

365.7

MR (Resisting Moment)

Factor of Safety for Overturning

2

Factor of Safety for Sliding

1.5

523 kN-m 1.43 0.620m 170.12 kN/m2

No tension will be developed in Slab Safe

8.27 kN/m2 99.06 kN/m2 87.30 kN/m2

91.17 kN/m2

Downward load due to Earth

138.60 kN/m2

Self-weight of Heel Slab

7.50 kN/m2

of Heel Slab

137.83 kN/m2 d (Effective Depth of Counterfort) Required

336mm

Design Constraints Provided d (effective depth of Counterfort) Provided Depth (d+Cover)

440.0mm 500.0mm

Area of Steel at Supports Required

1130.4

Spacing Provided

100.0mm c/c

Shear Force Developed

120 kN

Lo Development Length Required (Ld) Safe

440.0mm 540.0mm

d =440mm) beyond the point of contraflexure. After that, curtail half the bars, and the remaining half throughout the length. At the p 633+440 = 1073mm >Ld. These bars will be provided at the Top Face of the Heel Slab.

Area of Steel at Supports Required

870.408

Spacing Provided

130.0mm c/c

Shear Force Developed

120 kN

Lo Development Length Required (Ld) Safe

12.0mm 540.0mm

d =12mm) beyond the point of contraflexure. After that, curtail half the bars, and the remaining half throughout the length. At the po 633+12 = 645mm >Ld. These bars will be provided at the Top Face of the Heel Slab.

Wall Design Sheet H (Total Height)

8m

H1 (Height of Stem)

7.7m

Height of Wall From ground

7m

13.33 0.289

Formula yet to be entered

0.904

Formula yet to be entered

0.914

Formula yet to be entered

1m

300mm

Moment about toe (kN-m) 112.6125 63.0375 859.32 1034.97

W1 Lever Arm = 1.95m

o tension will be developed in Slab

W2 Lever Arm = 2.05m

Shear Reinforcement Required

Safe Cover

Safe

60

d the remaining half throughout the length. At the point of Slab.

Safe

the remaining half throughout the length. At the point of b.

300mm 500mm wide Counterforts

7m

7.7m 8.0m 7.96m

1.8m

2.0m

4m Dimensions of the Wall

WSD Shear Strength Reference Table (IS 456:2000 Annexure B-5) pt% 0.15 0.25 0.5 0.75 1 1.25 1.5 1.75 2 2.25 2.5 2.75 3

M15 0.18 0.22 0.29 0.34 0.37 0.4 0.42 0.44 0.44 0.44 0.44 0.44 0.44

Grade of Concrete M20 M25 M30 0.18 0.19 0.2 0.22 0.23 0.23 0.3 0.31 0.31 0.35 0.36 0.37 0.39 0.4 0.41 0.42 0.44 0.45 0.45 0.46 0.48 0.47 0.49 0.5 0.49 0.51 0.53 0.51 0.53 0.55 0.51 0.55 0.57 0.51 0.56 0.58 0.51 0.57 0.6

M35 0.2 0.23 0.31 0.37 0.42 0.45 0.49 0.52 0.54 0.56 0.58 0.6 0.62

M40 0.2 0.23 0.32 0.38 0.42 0.46 0.49 0.52 0.55 0.57 0.6 0.62 0.63