Design of Pipe Culvert
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DESIGN OF PIPE CULVERT 1.0 DATA Discharge through pipe culvert Q = 1.57 cum/sec Velocity of flow through pipe V = 2.00 m/sec Width of road B = 7.50 m Bed level of flow = 100 m Top level of embankment = 103 m Wheel load W = 62.50 kN Impact factor I = 1.50 2.0 DIAMETER OF PIPE Discharge Q = A x V = d = 1.00 m Adopt RCC NP3 heavy duty non pressure pipe for carrying hea Ref. IS: 458-1971, For pipe of Internal Diameter = 1.00 m Outer Diameter = 1.20 m 3.0 LOAD BY EARTH FILL Total height = 3m Considering height of culvert = 1m Height of embankment over pipe = 2m From Table 1 Load by earth fill = 59.50 kN/m 4.0 LOAD BY VEHICLE WHEEL Load by vehicle wheel W = 62.50 kN From Table 2 = 0.032 Load on pipe = = 12.00 kN/m 5.0 CHECK FOR STRENGTH FACTOR H1 H2 ∏/4 x d 2 x V Cs 4 x Cs x I x W
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Transcript of Design of Pipe Culvert
DesignDESIGN OF PIPE CULVERT1.0DATADischarge through pipe culvertQ=1.57cum/secVelocity of flow through pipeV=2.00m/secWidth of roadB=7.50mBed level of flowH1=100mTop level of embankmentH2=103mWheel load W=62.50kNImpact factorI=1.502.0DIAMETER OF PIPEDischargeQ=A x V=/4 x d2 x Vd=1.00mAdopt RCC NP3 heavy duty non pressure pipe for carrying heavy road to traffic. Ref. IS: 458-1971, For pipe of Internal Diameter = 1.00 mOuter Diameter = 1.20 m3.0LOAD BY EARTH FILLTotal height=3mConsidering height of culvert=1mHeight of embankment over pipe=2mFrom Table 1 Load by earth fill=59.50kN/m4.0LOAD BY VEHICLE WHEELLoad by vehicle wheelW=62.50kNFrom Table 2Cs=0.032Load on pipe=4 x Cs x I x W=12.00kN/m5.0CHECK FOR STRENGTH FACTORThe type of non pressure pipe and bedding should be so chosen that underMaximum combination of field loading a factor of safety =1.50(3-Edge Bearing Strength in kN/m / Factor of safety) =(Load on pipe by earthfill in kN/m / Corresponding strength factor) +(Load on pipe by wheel Load in kN/m / Strength factor)Ref. IS:458-1971 codeThree edge beam strength of NP-3 class 1000 mm diameter of pipe is111kN/m111=59.50+12.001.50S.F1.50Strength Factor (S.F)=0.902For First class prepared ground bedding, S.F = 2.3For concrete cradle bedding, S.F = 3.7So, Providing any of these two the S.F is more than its required value of S.F. 6.0REINFORCEMENT IN PIPERef. IS:458-1971,Spiral reinforcement of hard drawn steel wire with permissible stress of 140 N/sq.mm is 44 kg/mLongitudinal reinforcemet of mild steel with a permissible stress of 126.5 N/sq.mm is 5.8 kg/mUsing 12 mm dia bars @ 60 mm centre as Spiral reinforcementaverage diameter of spiral=1.1mWeight of one spiral of 12 mm dia=3.072kgNo. of Spirals in 1 m=16.67Weight of Spiral reinforcement per meter length of pipe=51.20kg/mSo, Spiral steel provided 51.20 kg/m is more that minimum reinforcement of 44 kg/m as specified in IS:485-1971.7.0LONGITUDINAL REINFORCEMENTProviding 6 mm dia mild steel bars as Longitudinal Reinforcement.Weight of each bar=0.22kg/mNo. of bars required=26.10Spacing=132.40mmAdopt 130 mm spacing for the longitudinal reinforcements.
Table1Table 1 : Load on Pipe due to EarthfillPipe Size (d) in mmOuter Dia (D) in mmEmbankment loading on pipe in kN/m for various depths H in metres1234567891050065016.834.954.065.399.0118.5150.0171.0191.0212.060076018.742.662.475.5103.0133.0160.5186.0197.0230.070086020.048.068.086.5118.5154.5174.0209.0228.0246.080098024.255.379.5107.0136.5163.0202.0230.0260.0288.0900110028.358.791.5122.0150.0185.0209.0257.0297.0338.01000120028.659.5101.0132.0163.0202.0228.0259.0324.0357.01200143033.474.0115.0159.0200.0226.0274.0315.0352.0427.5
Table2Table 2 : Influence Coeffcients 'Cs' for Concentrated Surface LoadsPipe Size (d) in mmOuter Dia (D) in mmEmbankment loading on pipe in kN/m for various depths H in metres0.10.20.30.40.50.60.70.80.91.05006500.2460.2280.1980.1690.1170.0830.0600.0170.0080.0056007600.2470.2340.2100.1820.1310.0940.0680.0220.0100.0067008600.2470.2360.2150.1860.1400.1020.0750.0240.0100.0068009800.2490.2400.2200.1960.1490.1100.0830.0270.0130.00790011000.2490.2410.2250.2020.1560.1170.0890.0290.0140.008100012000.2490.2420.2280.2050.1620.1230.0950.0320.0150.010120014300.2490.2420.2300.2090.1710.1310.1040.0360.0200.011
