balancing tank

Capacity of the tank = 14000 litres = 14 cubic metresClear dimensions of the tank L = 5 m

B = 3 mDepth of water provided = 2.15 mFree Board = 0 mTotal Depth of Vertical Wall = 2.15 m

Design Parameters :Grade of Concrete = M 20Reinforcement = Fe 415

Permissible Compressive Stress due to bending 7 MPa

Permissible Tensile Stress due to bending 1.7 MPa

Permissible Direct Tensile Stress 1.2 MPaPermissible Shear Stress 1.7 MPa

Tensile Stress in Members under Direct Tension150 MPa

Tensile Stress in Members in Bending(a) On liquid Retaining Faces 150 MPa(b) On Faces away from Liquid For members <225mm Th. 150 MPa(C)On Faces away from liquid For members >=225mm Th. 190 MPa

Tensile Stress in Shear Reinforcement(a) <225mm th. 150 MPa(b) >=225mm th. 175 MPa

Compressive Stress in Columns 175 MPa

Design constants:13.33

0.3836 150 Mpa0.3294 190 Mpa0.2887 230 Mpa

j = 1-k/3 = 0.8721 150 Mpa0.8902 190 Mpa0.9038 230 Mpa

1.1708 150 Mpa1.0263 190 Mpa0.9131 230 Mpa

Permissible Stresses in Concrete( Table 1 IS 3370 Part II -1981)

scbc

stbcstsv

Permissible Stresses in Reinforcement( Table 2 IS 3370 Part II -1981)

stsst

sst

sc

Modular Ratio = m= 280/(3xscbc)

k = mscbc/(mscbc+sst) = for sst= for sst= for sst=

for sst= for sst= for sst=

Q = 0.5 x k x j xscbc = for sst= for sst= for sst=

Bulk Density of soil 19.64 kN/m3 Density of Water 10 kN/m3

32 Deg = 0.5585 radCohesion C= 2 kN/m2

0.3073

SHORT WALL:

(a.) Size of panel: height a = 2.15 Mwidth b = 3 Mb/a = 1.395

Moment Coefficients (From Table 3 of IS 3370 - Part-IV) (I.) Vertical moment Coefficient (-)ve 0.06

Vertical moment Coefficient (+)ve 0.016

(ii.) Horizontal moment coefficient (-)ve 0.04Horizontal moment coefficient (+)ve 0.021

Case ( I.) Tank full earth pressure outside neglectedMv(-ve) = ax(-ve) * w *a3 = 5.963 KNm

Mv(+ve) = ax(+ve) * w *a3 = 1.590 KNm

Mh(-ve) = ay(-ve) * w *a3 = 3.975 KNm

Mh(-ve) = ay(+ve) * w *a3 = 2.087 KNm

Case (ii.) Tank empty earth pressure outside

10.757

Mv(-ve) = ax(-ve) * p *a2 = 2.983 KNm

Mv(+ve) = ax(+ve) * p *a2 = 0.796 KNm

Mh(-ve) = ax(-ve) * p *a2 = 1.989 KNm

Mh(-ve) = ax(+ve) * p *a2 = 1.044 KNm

d = sqrt(M/Q*1000) d required = 71.4 mmThickness of the wall provided = 175 mm

Maximum Design Vertical Moment = 5.963025

Ast(ver) =

Ast(ver) = 314.35 sqmmSpacing of #10 bars Reqd= 249.719 mmProviding #10 @ 200 mm c/c 397.5 sqmm

Maximum Design Horizontal Moment = 3.975 kNm

Ast(hor) = Max Hor. Moment/(sst*j*d)

Ast(hor) = 225.09 sqmmSpacing of #10 bars Reqd= 322.051 mmProviding #10 @ 200 mm c/c 397.5 sqmm

Minimum Reinforcement(Ast min) = 487.500 sqmm

1000 397.5 Check for tensile stresses:

175 Resistance against cracking:

Area A X AX Iself 397.5175000 87.5 15312500 1339843750 446614583

4901.175 30 147035.25 4411057.5 04901.175 145 710670.375 0

Angle of internal friction f =

Coefficient of Active Earth Pr. =Ka = (1-sin(f))/(1+sin(f)) =

Earth Pressure P = Ka*g*H -2*Csqrt(K)= kN/m2

Max Ver.Moment/(sst*j*d)

AX2

184802.35 16170205.6 1344254807.5 446614583

Yt=AX/A = 87.5 mm

1790869390.83

Ina = Itop-Ayt^2 = 375976398.646

Zt = Ina/Yt = 4296873.12738ft,fb = M/Zt = 1.388 Mpa <1.7MPa

57.7812 KN.

Ast due to tension = 385.2 sqmm

Total Ast = 610.30 sqmmSpacing of #10 bars Reqd= 128.625 mmProviding #10 @ 125 mm c/c 628 sqmm

Stress due to direct tension X = T/A

X = 0.303 MPa

1000 628 Check for tensile stresses:

175 Resistance against cracking: Area A X AX AX^2 Iself 628

175000 87.5 15312500 1339843750 4466145837743.24 30 232297.2 6968916 07743.24 145 1122769.8 162801621 0

190486.48 16667567 1509614287 446614583

Yt=AX/A = 87.5 mm

1956228870.33

Ina = Itop-Ayt^2 = 497816757.833

Zt = Ina/Yt = 5689334.37524Check for Stresses:

fb =M/Z = 0.70 N/sqmmft = T/A = 0.30 N/sqmm

X/Permissile stress due to tension + (M/Z)/Permissible stress due to bending

(fb/fb')+(ft/ft') = 0.664 <1.0 Safe

LONG WALL :

(a.) Size of panel: height a = 2.15 Mwidth b = 5 Mb/a = 2.33 S

Moment Coefficients (From Table 3 of IS 3370 - Part-IV) (I.) Vertical moment Coefficient (ax-)ve 0.1

Vertical moment Coefficient (ax+)ve 0.01234

(ii.) Horizontal moment coefficient (ay-)ve 0.06924

Horizontal moment coefficient (ay+)ve 0.027

Case ( I.) Tank full earth pressure outside neglectedMv(-ve) = ax(-ve) * w *a3 = 9.938 KNm

Mv(+ve) = ax(+ve) * w *a3 = 1.226 KNm

Mh(-ve) = ay(-ve) * w *a3 = 6.881 KNm

Mh(+ve) = ay(+ve) * w *a3 = 2.683 KNm

Case (ii.) Tank empty earth pressure outside

10.76

Mv(-ve) = ax(-ve) * p *a2 = 4.972 KNm

Mv(+ve) = ax(+ve) * p *a2 = 0.614 KNm

Itop =Iself+AX2 mm4

mm4

mm3

Direct Tension T = 0.5 x gw x h2 x L /2

Itop =Iself+AX2 mm4

mm4

mm3

Earth Pressure P = Ka*g*H -2*Csqrt(K)= kN/m2

Mh(-ve) = ax(-ve) * p *a2 = 3.443 KNm

Mh(-ve) = ax(+ve) * p *a2 = 1.343 KNm

d = sqrt(M/Q*1000) d required = 92.13 mmThickness of the wall provided = 175 mm

Maximum Design Vertical Moment = 9.938

Ast(ver) =

Ast(ver) = 524.010071 sqmmSpacing of #12 bars Reqd= 215.84 mmProviding #12 @ 125 mm c/c 904.8 sqmm

Maximum Design Horizontal Moment = 6.88 kNm

Ast(hor) = Max Hor. Moment/(sst*j*d)

Ast(hor) = 389.70 sqmmSpacing of #12 bars Reqd= 290.22 mmProviding #10 @ 150 mm c/c 523.33 sqmm

Minimum Reinforcement(Ast min) = 487.50 sqmm

1000 904.8 Check for tensile stresses:

175 Resistance against cracking: Area A X AX AX^2 Iself 904.8

175000 87.5 15312500 1339843750 44661458311156.184 31 345841.704 10721092.824 011156.184 144 1606490.5 231334631.424 0

197312.368 17264832.2 1581899474.25 446614583

Yt=AX/A = 87.5 mm

2028514057.58

Ina = Itop-Ayt^2 = 517841240.081


34.67 KN.

Ast due to tension = 231.12 sqmm

Total Ast = 620.83 sqmmSpacing of #10 bars Reqd= 126.445 mmProviding # 10 @ 125 mm c/c 628 sqmm

Stress due to direct tension X = T/A

X = 0.182 N/sqmm

1000 628 Check for tensile stresses:

175

Max Ver.Moment/(sst*j*d)

Itop =Iself+AX2 mm4

mm4

mm3

Direct Tension T = 0.5 x gw x h2 x L /2 =

Resistance against cracking: 175

Area A X AX AX^2 Iself 628175000 87.5 15312500 1339843750 446614583

7743.24 42 325216.08 13659075.36 07743.24 133 1029850.92 136970172.36 0

190486.48 16667567 1490472997.72 446614583

Yt=AX/A = 87.5 mm

1937087581.1

Ina = Itop-Ayt^2 = 478675468.553

Zt = Ina/Yt = 5470576.78347Check for Stresses:

fb =M/Z = 1.26ft = T/A = 0.18

X/Permissile compressive stress + (M/Z)/Permissible tensile stress

(fb/fb')+(ft/ft') = 0.89 <1.0 Safe

Design of tank floor slab:

Size of panel: Lx = 3.4Ly = 5.4

Ly/Lx = 1.59Load Calculations:Upward Pressure = (Wall load+ self Weight)/area

= (((0.175*2.15*3*25)+(0.175*2.15*5*25))*2+(0.20*25*3.4*5.4)+(0.15*3.175*5.175*25))/(3.4*5.4)W = 16.55 KN/sqm

Net Upward pressure w = 11.6 KN/sqm

Edge condition : One longe edge continuous

FOR LY/LX=1.670.089 0.067 0.043

B.M Mu(kNm) Ast SpacingMx(-ve) = x1*w*Lx^2 = 11.89 534.55 146.852Mx(+ve) = x2*w*Lx^2 = 8.95 402.42 195.072My(+ve) = y1*w*Lx^2 = 5.74 258.27 194.566

Depth required = sqrt(M/Q*1000) = 100.76 mmThickness of the slab provided = 200 mm

Ast =

Ast = 542.86 sqmmSpacing of #10 bars Reqd= 144.605 mmProviding #10 @ 150 mm c/c 530 sqmm

Minimum Reinforcement(Ast min) = 542.857 sqmm1000 530

Check for tensile stresses:200 Resistance against cracking:

Area A X AX AX^2 Iself 530200000 100 20000000 2000000000 6666666676534.9 31 202581.9 6280038.9 06534.9 169 1104398.1 186643278.9 0

213069.8 21306980 2192923317.8 666666667

Yt=AX/A = 100 mm

2859589984.47

Ina = Itop-Ayt^2 = 728891984.467


Itop =Iself+AX2 mm4

mm4

mm3

ax1= ax2 = ay2 =

Max Moment/(sst*j*d)

Itop =Iself+AX2 mm4

mm4

mm3

Design of tank roof slab:

size of panel:Lx = 5.175Ly = 3.175Ly/Lx = 1.6299

Thickness of the slab provided = 150 mmLoad on the floor: Live Load = 5 KN/sqmSelf Weight = 0.15*25 = 3.75 KN/sqmFloor Finish = 1 KN/sqmTOTAL LOAD = 9.75 KN/sqm

Bending moment coefficients (IS 456 - 2000 Table 26)Edge condition: All edges discontinuous

0.1 0.056

Moment AstMx(+) = 9.8286 KNm 365.2400 sqmm

My(+) = 5.5040 KNm 204.53442 sqmm

Depth Required = sqr(M/(Q*1000) = 91.6152117961

Ast = 365.24 sqmmSpacing of #8 bars Reqd= 137.64 mmProviding #8 @ 125 mm c/c

Ast = 204.53 sqmm

ax = ay =

balancing tank

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