1 Design DataHeight of Back fill 4.75 mDepth of Foundation D = 1.50 m

Safe Bearing capacity qa = 300 kN/m²

Unit weight of back fill γe = 20 kN/m³Angle of shearing resistance ф = 30Coefficient of friction between soil and concrete μ = 0.5Grade of Concrete fck = 25 N/mm²Grade of steel fy = 415 N/mm²Surcharge Pressure Ws = 10 kN/m²

2 Retaining wall ProportionsHeight of Retaining wall h = 6.25 mActive Earth Pressure coefficient Ca = 0.33Passive Earth Pressure coefficient Cp = 3.00spacing of counterforts = 3.00 mThickness of counterforts = 0.41 mThickness of heel slab = 0.50 mThickness of toe slab = 0.50 mThickness of stem slab = 0.41 mLength of Base slab L = 3.50 m

3 Stability against overturningOverturning moment Mo = 336 kNmStabilising moment about toe Mr = 755.72 kNm

Factor of safety (overturning) =0.9 Mr/Mo = 2.022 >1.4 OK

4 Soil pressure at footing baseresultant vertical reaction R = W = 332.69 kNMin Pressure at heel slab = 15.29 kN/m² > 0 OKMax Pressure at toe slab = 174.8 kN/m² < qa = 300 kN/m²

= OK5 Stability against sliding

Sliding force = Pa = 151 kNResisting force F= Rμ = 276.7 kN > Pa(F.S) sliding = 0.9 F/Pa = 1.649 >1.4 OK

6 Design of Toe slabClear cover = 50mmDiameter of bar = 16mmDesign shear force at d from the front face of stem Vu = 162.2 kN/mDesign moment at the face of stem Mu = 168 kNm/m

Provide 16 mm bars @150 mm c/c at the bottom of the toe slabφThe bars should extend atleast a distance Ld = 47 x 16 = 752 mm beyond the front face of the stem on both sidesProvide 12mm bars @ 200 c/c for the transverse reinforcementφ

7 Design of heel slabDia of bar = 16mmClear span = 3mEffective span = 3.410 mMax negative moment at the counterfort location = 147 kNm/mMax midspan moment = 110 kNm/mDesign shear force = 157.8 kN/mDesign of top reinforcementsProvide 16 mm bars @150 mm c/c at the top of heel slabφminimum reinforcement for temperature & shrinkage

= 600.00 mm²

At a distance beyond 1m from the free edge only min. reinforcement need to be providedProvide 16 mm bars @300 mm c/c at the top of heel slab throughout andφintroduce additional 16 mm bars in between two adjacent bars at the counterforts for a φdistance of 1.25m from the free edge.Provide 12mm bars at 200 mm c/c throughout the top of the base slabφDesign of bottom reinforcements

Provide 12 mm bars @150 mm c/c at the bottom of the heel slab throughoutφProvide 12mm bars @ 200 c/c for the transverse reinforcementφ

Design of heel slab for cantilever actionM max = 54.40 kNmProvide 12 mm bars @200 mm c/c at the top of heel slab throughoutφ

8 Design of stem for continuous base actionHeight of stem above base = 5.75 mClear cover = 50mmDia of bars = 12mmEffective span = 3.35 mMax. neg moment at the counterfort location = 58.6 kNm/mMax midspan moment = 43.9 kNm/mDesign shear force = 71.6 kN/mProvide 12 mm bars @150 mm c/c on both faces of the stem (up to one third height i.e 2m φabove base)

At one third height above base and beyondEffective span 3.354mMu, -ve 27.1 kNm/mProvide 12 mm bars (horizontal) @250 mm c/c on both faces of the stem (in the middle φ

one third height)At two thirds height above baseMin.Ast 492 mm²Provide 12 mm bars (horizontal) @250 mm c/c on both faces of the stem (in the upper φone third height)

Design of stem for cantilever actionM max = 39.38 kNmProvide 16 mm bars (vertical) @225 mm c/c on both faces of the stem through out the φheight of the stem

9 Design of Interior Counterfort (on the backfill side)Design of counterfort for T-beam actionThickness of counterforts 410mmMu = 1128.3 kNmVu = 640.4 kNProvide 4 nos 25 bars throughoutφ

Design of horizontal tiesVu,net = 423.6 kNProvide 10 2 legged stirrups @250mm c/c in lower one - third regionφAt one-third height from the base and beyondProvide 8 2 legged stirrups @300mm c/c above one - third heightφ

Design of Vertical tiesProvide 10 2 legged stirrups @100mm c/c upto 1.25m from the free edgeφThe spacing may be increased to 150mm beyond 1.25 m from the free edge