Retaining Wall Excel Sheet

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DESIGN OF RETAINING WALL ( THAPAR, DERABASSI )

Design Data

UNITS Table-1

1 Height of Earth to be Retained 1.65 m µ

2 30 DEGREE 0.55 0.52 RADIANS 3 0.45 REF. TABLE 1 0.45 4 170 kN/m2 0.35 5 18 kN/m3 0.6 6 0.90 m 7 0.075 m 8 0 DEGREE 9 0.33 10 3.0

11 Total Height of Retaining Wall 2.48 m

Material Used

M 25

Steel Grade Fe500

Unit Weight of R.C.C 25 kN/m3

Section of Retaining Wall

0.275 m 1.5 m 1.27 m 0.23 m

Height of Wall Above Base Slab, h 2.20 m

Stability Checks Table-2

S.No Designation Force,KN Moment,KNm

1 50.292 31.94

2 12.650 17.52

3 10.313 7.73

4 Pa 18.377 15.16

Soil

Coarse Grained (no silt) Coarse Grained (silt)

Silt Angle of Repose, φ

Coeff. Of Friction b/w Soil & Concrete, µ

Sound Rock

Concrete Grade

Dis. from Heel,m Length of Heel Slab

Stem Thickness Length of Base Slab, B Thickness of Base Slab

Gross Safe Bearing Capacityof Soil

Earth Pressure Coeff., Active Unit Weight of soil, γs

Earth Pressure Coeff., Passive Surcharge Angle,θ Depth of Foundation P.C.C Below Footing 0.64 1.39 0.75 Weight of Soil above Heal (W1)

Weight of Stem (W2) Weight of Base Slab (W3)

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Total (W) 73.25 72.351 * Note Passive Earth Pressure Not Consireded.

0.99 m

Eccentricity e=Z-B/2 0.24 < B/6 = 0.250

Eccentricity less then B/6, so there is no uplifting, Hence Safe Extreme Earth Pressure at the Base, W/B(1±6e/B)

Minimum Pressure 2.41 kN/m2

Maximum Pressure 95.26 kN/m2

Maximum Pressure less than SBC hence safe

Check for Overturn

Resisting Moment about Toe, Mr 37.53 KNm

Overturning Moment about Toe, Mo 15.161 KNm Factor of Safety against Overturning, 0.9*Mr/Mo 2.227945 Factor of Safety greater than 1.4 hence safe

Check for Sliding

Resisting Force Due to Overlying Weight, µW 32.96453 KN Sliding Force, Pa (Active Pressure Force) 18.38 KN Coefficient of Sliding Friction, Fs 1.61 KN Factor of Safety greater then 1.4 hence safe

Dis. Of Point of Application of Resultant Force from Heel end, Z

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2.200 m 8.451 KNm/m 12.676 KNm/m 50 mm 180 mm 1 60.615 mm 2 Calculation of Steel Mu/bd 2 0.391 0.094% (FROM SP-16 ) 169.2 mm2/m 10 mm 78.54 mm2 10 Dia Bars 464 mm C/C Provide 10 300 mm C/C

3 Required Distribution Steel: 276 mm2/m

8mm 50.27 mm2

8 Dia Bars 182 mm C/C

Provide 8 250 mm

4 Calculation of Steel at Outer Face Provide min. % of Steel at Outer Face

0.12% 216 mm2/m 10 mm 78.54 mm2 10 Dia Bars 364 mm C/C Provide 10 300 mm C/C

Effective Depth, deff

Depth Required from B.M

Depth Required is less than Depth Provided hence OK

Design of Vertical Stem

Height of Cantilever above Base, h B.M at Base

Bending Moment (Factored), Mu Clear Cover

Chech for Depth

Diameter of Bar Area of Bar

Required Spacing of

mm Dia Bars @ C/C near each face

Required Percentage of Steel

Ast Required mm Dia Bars @ Diameter of Bar Area of Bar Required Spacing of Area of Bar Required Spacing of mm Dia Bars @

Required Percentage of Steel

Ast Required

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Design of Base Slab

95.263245 kN/m2 81.03 kN/m2 Magnitude, N Distance from c, m Moment About c, KNm Positive iii) 3.060 0.635 1.94 Positive iv) 49.92 0.42 21.13

Negative DL Heel Slab -8.731 0.635 -5.54

Soil -50.292 0.635 -31.94 -14.40 14.40 KNm HOGGING 21.60 KNm 0.05 m 0.225 m Mu/bd2 0.427

Required Percentage of Steel, p 0.11% 252 mm2

10mm

Area of Bar 78.54 mm2

Required Spacing of 10 Dia Bars 311.7 mm C/C

Provide 10 Dia Bars @ 150 mm C/C

330 mm2/m 10mm

Area of Bar 78.54 mm2

Required Spacing of 10 Dia Bars 238.00 mm C/C

Provide 10 Dia Bars @ 200 mm C/C

Load Due to Upward Pressure

Pressure at the junction of Heel and Stem Pressure at outer face of Stem

B.M Calculations per meter width: Crictical Section : Stem Heel junction

DISTRIBUTION STEEL:

Diameter of Bar Clear Cover Effective Depth, deff Downward Weight

Net Moment

Bending Moment (Factored), Mu Net Moment

Ast Required Diameter of Bar

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PROVISION OF PILES UNDER RETAINING BASE

Site Condition at the Location of Boundary Wall is such that the Adjoining Land is lowlying and Regular Erosion of Soil Takes place specifically during rains. In an earlier event the same retaining wall had fallen as the soil below the retaining foundation had eroded thereby leading to overturning of the wall.

So it is proposed to provided piles under the base so that in an event of erosion of soil under the footing shall not render the retaining unsafe and leading to failure

Design Basis for selection of pile configuration

Minimum Pressure under Base = 2.41 kN/m2 Maximum Pressure under Base = 95.26 kN/m2 Average Pressure under Base = 49 kN/m2

Width of Base Footing 1.5 m

Force / Metre under Retaining Wall 73.2545 kN/m

Adopt a Pile Footing of Dia 300 mm ( Single Underreamed) and length of 4 m Capacity of Pile ( Table 1 : IS 2911, Part 3 ) 18.3 Ton

( Compression )

Capacity of Pile ( Table 1 : IS 2911, Part 3 ) 9.75 Ton ( Uplift )

Pile Arrangement suggested is Alternate Pile Under Stem and Heel so as to achieve minimum pile distance of 3 times the dia for fully effective pile capacity in group within given footing width Since Settlement under Stem Side can lead to Uplifting on Heel Side, Average Pile Value

of Compession and Uplift has been used for Design to be on Conservative Side

Average Capacity of Pile 14.025 Ton

Required Spacing of Pile 1.91 m

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Site Condition at the Location of Boundary Wall is such that the Adjoining Land is lowlying and Regular Erosion of Soil Takes place specifically during rains. In an earlier event the same retaining wall had fallen