water tank

Data sheetBased on RCC design B.C. punmia example 21.3DESIGN OF CIRCULAR WATER TANK (Rigid joint)Nameof work:-1Tank capacity400K ltr400000ltr2Depth of water4.00mtr4000mm3Free board0.20m200mm4ConreteM20unit weight25000N/m3scbc7N/mm2m13.35Steelfy415Tensile stress115N/mm26Nominal Cover35mmEffective Cover40mm7ReinforcementVertivcal12mm F120mm c/cHoops Ringupto25% height12mm F170mm c/cupto50% height12mm F200mm c/cupto75% height12mm F220mm c/cupto100% height12mm F440mm c/cFloor (both direction)8mm F200mm c/c1701160017012mm f Ring100%440mm c/c1.00m12mm f Bars240mm c/c75%12mm f Ring1.00m220mm c/c400012mm f Ring50%200mm c/c0.60m12mm f Bars120mm c/c8mm f Ring200mm c/c12mm f Ring1.40m8mm f Ring170mm c/c200mm c/c17075pk_nandwana@yahoo.co.in

pk_nandwana@yahoo.co.in

Design151152045334418402041204018401634163426DESIGN OF CIRCULAR WATER TANK (Rigid joint)Nameof work:-0Tank capacity400K ltr400000mmDepth of water4.00m4000mmFree board0.20m200mmConreteM20Steelfy415N/mm2Tensile stess=115N/mm2scbc7N/mm2m=13.3Nominal cover35mmEffective cover=40mm1Design Constants:-For HYSD BarsCocrete M=20sst=115N/mm2wt. of concrete=25000N/mm2scbc=7N/mm2m=13.33.143k=m*c=13.3x7=0.447m*c+sst13.3x7+115j=1-k/3=1-0.447/3=0.851R=1/2xc x j x k=0.5x7x0.851x0.447=1.3322Dimention of tank:-Effective depth of tank=4.00-0.20=3.80mIf D is the inside diameter of tank, we have = x D2x3.80=400000x100041000x1000\ from which D400x4=11.57msay=11.60m3.143x3.80Provide a diameter of=11.60m3Determination of bending moment and hoop tension:-Thickness of wall from empirical formula=3H+5=3x4.00+5=17cm170mmH2=4.00x4.00=8h=H/3=4.00/3=1.333mDT11.60x0.17The height above base, upto which cantilever action will be there is given byH/3 or1 m which ever is heigherMaximum ring tension at this level, per meter height=w (H-h)Dwhere w=9800N/m22pressure at h/3=9800x (4.00-1.3333333333)x11.60=151573.333333333N2Maximum prerssure at bottom =wH=9800x4.00=39200N\ maximum cantilever B.M. =Mf=1x39200x1.3333333333x1.3333333333=11615N-m/m234Design of setion for cantilever action:-if d is the effective thickness of tank wall,D =Mf=11615x1000=93.00mm1000 R1000x1.33\ Total thickness =d +cover=93+35=128=say130mmHowever, provide a minimum thickness equal to the greater of following;(I) 150mm(II)30H+ 50 =30x4.00+50=170Hence provide T=170mmProviding35mm cover to the center of reinforcement, availble d=135mmArea of steel for cantilever bending is given by=Ast =Mf=11615x1000=879.2712516734mm2sst . J .d115x0.851x135using12mm barsA=3.14xdia2=3.14x12x12=113mm24 x1004x100Spacing of hoop Bars =1000x113/879=129say=120mmHence Provided12mm F bar, @120mm c/c upto height of1.40m from baseAbove this height, curtail half bars and continue the other half upto top. Let us test this for devlopment lengthpk_nandwana@yahoo.co.inLd=f .sst=12x115=431mm say0.43m4. tbd4x0.8Hence half bars may be curtailed at1.40mheight above the base. These vertical bars are to beprovided inner face . Keep a clear cover of=25mm5Design of section for hoops action;Maximum hoops tension151573Nat1.33m above the base\ area of ring, Ash =151573/115=1318mm2Let us provide rings atboth faseHence of area of ring in each face=659mm2using12mm barsA=3.14xdia2=3.14x12x12=113mm24 x1004x100Spacing of hoop Bars =1000x113/659=172say=170mmHence Provided12mm F bar, @170mm c/c upto height of1.40m from baseand above this, the spacing may be increasedActual , Ast=2x1000x113=1330mm2170\ sct=151573=0.813