3.1 LAYOUT OF RETAINING WALL
3.2 OUTLINE OF RETAINING WALL AND DIMENSIONS (SECTION I) The retaining wall is L-shape as shown below B1 B1 = B2 = L1 = D= H1 = H2 =
400 400 1500 600 1100 1800
mm mm mm mm mm mm
GL+ 1.500M
H2 GL- 0.300M H1
D L1
B2
3.3 FORCE DIAGRAM GL+ 1.500M FL1
SURCHARGE LOAD (S) W4 W1
GL- 0.300M yL1
FL2 yL2
W3 (Soil Weight) W2
Liquid Pressure (L)
Bouyant Force (Bf)
TOE
3.4 DESIGN PARAMETER Soil Properties Ø= gs = Ka =
30.0 deg., soil internal friction angle 2 9.0 kN/m , unit weight of soil (Dry) 0.33 Active Pressure Coeficient, (1-SIN Ø)/(1+SIN Ø) ]
Material Properties gc = f'c = Fy =
3
24.0 kN/m , unit weight of reinforced concrete 2 24.0 N/mm , cylindrical compressive strength of concrete 2 390.0 N/mm , yield strength of steel reinforcement
Unit Weight of Loadings gw = gL =
3
10.0 kN/m , unit weight of Ground Water 3 9.0 kN/m , unit weight of Liquid
Allowable Factor of Safety Factor of Safety for Overturning= Factor of Safety for Sliding =
1.5 1.5
Allowable Soil Pressure Allowable Soil Pressure for Permanent Case, qa =
250.0 kN/m
3.5 STABILITY CHECK Lateral Forces Calculation
Item
Force, FL Lever Arm, Mo (kN-m) YL (m) (kN)
gf
Fult
FL1
14.6
2.30
33.6
1.4
20.44
FL2 total =
3.6 18.2
1.15
4.1 37.7
1.4
5.04 25.5
Where :
Mo = Moment about toe gf = Load Factor for Ultimate Loads Fult = Factored Lateral Load
2
Weight Calculation and Resisting Moment (Mr) Item
Force (kN)
W1 W2 W3 W4 Bf total =
27.8 27.4 31.4 24.3 -32.3 78.6
Lever Arm Mr (kN-m) (m) 0.200 5.57 1.150 31.46 0.950 29.78 0.950 23.09 0.950 -30.69 <--- Bouyant Force 59.2
Overturning Check ∑Mr ∑Mo
FOS =
=
1.57
> 1.50, OK!
Soil Bearing Check Compute for Eccentric Moments
Item
Force (kN)
FL1
14.60
FL2 W1
3.60 27.84
Lever Arm, Me (kN-m) y (m) 2.30
33.58
4.14 1.15 0.75 20.88 total = 58.60 where : Me is eccentric moment from centroid of footing Compute for Eccentricity e=
∑Me ∑W
=
58.60 110.9
(No Bouyant Force)
= 0.529 m (L1+B2)/6 = 0.317 m < ∑W qmax= xa A
e, Triangular Pressure Where : A = 1.0m x L a =(2/3) / ( 0.5 - e / L ) L = (L1 + B2) = 175.4 kPa < 250.0 kPa, OK! qmin= 0.0 kPa (Triangular Pressure)
3.6 DESIGN OF WALL 3.6.1 Ultimate Design Forces Lever Arm, Mo (kN-m) y (m)
Item
Force (kN)
FL1
14.6
2.30
FL2 total =
3.6 18.2
1.15
gf
Fult
Muwall
33.58
1.4
20.44
47.01
4.14
1.4
5.04 25.5
5.80 52.81
3.6.2 Ultimate Design Capacity Mucapwall = φb*B*dwall2*f'c*q(1 - 0.59q) φb = B= cc = dwall = Db = Spacing = As = As / Bd = q= Mucapwall =
0.9 1000 50 342 16 200 1005.31 0.00294 0.047767
, strength reduction factor for bending mm, design width mm, concrete cover mm, effective depth mm, rebar diameter mm, rebar spacing 2 mm , area of reinforcement reinforcement ratio
117.28 kN-m
> Muwall, OK!
0.5
Vcapwall = φs*1/6*f'c *dwall φs = Vcapwall =
0.75 , strength reduction factor for shear 209.43 kN > Fult, OK!
3.7. DESIGN OF FOOTING Check for Bottom Bar qult = 1.6 x (qmax + qmin)/2
B= cc =
1000 mm, design width 75 mm, concrete cover
dwall =
515 mm, effective depth
MufBOT = qult*L1 /2 + Muwall
Dbbop =
20 mm, bot rebar dia.
= 210.6 kN-m
Dbtop =
16 mm, toprebar dia.
= 140.3 kPa 2
Mucapbot=
275.64 > MufBOT, OK!
Mucaptop=
Vcapfoot =
52.81
kN-m
178.32 > MufTOP, OK!
Check For Shear Vufoot = qult*L1
200 mm, rebar spacing 2 Asbot = 1570.796 mm ,area of bot bar
Asbot /Bd =
Check for Top Bar MufTOP = MUWALL =
Spacing =
0.00305 reinforcement ratio
q = 0.049564 Astop =
2 1005.31 mm ,area of top bar
Astop /Bd = 0.001952 reinforcement ratio q = 0.031721 = 210.44 kN
315.37 > Vufoot, OK!
