DESIGN OF RETAINING WALL(CANTILEVER)

Soil Properties

Safe Bearing Capacity=Q= 200

30 Deg

18

Details Retaining Earth

Height of Earth above G.L = 3 m

surcharge angle = 35.5 Deg

Minimum Depth of Foundation =

1.235 m say 1.5

Total Height of Retaining Wall = 4.5 m

Design Constants

Grade of Concrete = M20

Grade of Steel = fe415

Pernissible Bending Stress in

Concrete = sbc = 7 MPa

Permissible Tensile Stress in

Steel = sst = 230 MPa

Modular Ratio =m =280/(3*sbc)= 13.33

k = msbc/(msbc+sst) = 0.2887

j = 1-(k/3) = 0.9038

Q = 0.5*sbc*k*j = 0.9131 MPa

Weight of Concrete = 25

Preliminary Dimensions Of Retaining Wall

Thickness of Stem at top = 200 mm

Thickness of Stem at Bottom = 500 mm

Thickness of baseslab = 200 mm 275

Thickness of Base slab at stem = 350 mm

Width of Base Salb = 3100 mm

Width of Toe Slab = 900 mm

Width of Heel Slab = 2000 mm

Height of wall above Base Slab = 4300 mm

4

3

1 4300

G.L

1500 5

2 200

kN/m2

Angle of Internal Friction =q =

Density of Soil = g = kN/m3

Df = Q*((1-sinq)/(1+sinq))2/g =

kN/m3

900 2200

3100

0.662784077

0.333333333

EarthPressure P1= k1xgH = 53.686 kN/sq.m

EarthPressure P2= k2xgH = 9 kN/sq.m

Check for Stability

Component Weight kN L.A from Moment

Toe kNm

W1 0.2x4.2x25 21.5 1 21.5

W2 0.3x3.1x25 20.688 1.55 32.066

W3 2.0x4.2x18 154.8 2.1 325.08

W4 25.679 2.433 62.484

W5 0.5x0.3x4.2x25 16.125 0.800 12.900

238.791 Ms= 454.030

Earth Pre. P 120.792 Mo = 181.189

Factor of Safety = 2.51 >2.0 Safe

Check for Sliding

0.6

F.S against Sliding

1.19 >1.5 Safe

Check for Max.Base Pressure

Net Moment = 272.842 kNm/m

1.142595169 m

e = B*0.5-X = 0.407404831 < B/6 = 0.516666667

Pmax = (w/B)(1+(6e/B)) 137.7689929 <200

Pmin = (w/B)(1-(6e/B)) 16.2897 No Tension

Design Of Stem

Bending Moment due to Earth Pressure

158.088 kNm

Effective Depth Required = 416.0933677 mm

Overall Depth Required = 476.0933677 say 500

Effective Depth Provided = 440 mm

1728.444408 sq.mm/m

Privide #20@150mmc/c

Design of Toe Slab

Length of Toe =L= 900 mm 102.501

Max.Pressure at end = 137.769 137.769

Pr. at Face of stem= 102.5008254

selfweight =w= 5

Bending Moment at Face of Stem

k1 = cos2(q1)

k2=(1-sinq)/(1+sinq)

0.5x2.0x2.0tanqx18

eW

m =

= m*eW/P =

X = M/eW =

at junction of Heel Slab= k1*g*H3/6 =

Ast = M/sstjd =

kN/m2

kN/m2

kN/m2

Total Load/m =P = 108.1214182 kN/m

Leverarm =a= 0.472017851 m

B.M = M = 46.98523951 kNm

Eff.Depth Required = 226.8413233

Overall Depth Required= 286.8413233 mm say 350 mm

Eff.Depth Provided = 292 mm

774.084 sq.mm

Provide #16 @ 150mmc/c Pt= 0.459

Pressure at deff from face of stem = 113.943

Total Load P1 = 76.521

Shear Force =V=P-w*(L-d) 73.481 kN/m

tv= V/(1000*d) 0.252 MPa

tc = 0.284 MPa

Design of Heel Slab

Length of Heel Slab from face of stem L= 2000 mm

Self weight of Heel Slab =w1= 10 kN/m

Weight of Earth above Heel Slab =w2 154.8 kN/m

Upward Pressure at face of stem = 94.663 kN/sq.m

Total Upward Load =P= 110.953 kN/m

Leverarm from face of stem

for upward load = a = 1.2355 m

Bending Moment at face of stem

M =(w1+w2)*L/2-P*a 27.72222731 kNm

Effective Depth Required = 174.2430681 mm

Overall Depth Required = 232.2430681 mm say 350 mm

Effective Depth provided = 292 mm

Ast = M/sst*j*d = 456.724883 sq.mm

Provide #16 @ 150c/c pt = 0.393

Pressure at deff from face of stem = 83.221 kN/sq.m

Total Upward Load =P1= 84.982 kN/m

Net Load at deff from stem=

V = (w1+w2)*(L-d)/L-P1 55.757 kN

tv = V/1000*d = 0.191 MPa

tc = 0.26 MPa

P*a - wL2/2

Ast = M/sst*j*d =

m

mm

16.290