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Underground Pipe Stress Check

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Design Calculation
Project No.
Project Title:Checked By:Date:Oct/15/14Date:
PIPE STRESSES - WHEELS ON RIGID PAVEMENTEarth Loading
Pipe Size =
42
in.Conc. Thick. hc =
8
in.O.D. =42in.wd = Cd w Bd^2 = 1316.6 lb / lin ft.where:w =
120
lb/ft^3 soil unit wt.Bd =
5
ft. (actual width)Bd =5.0ft. (effective width)Bc = O.D. =3.50ftCd = 1 - e^ (-2 ku'(H/Bd))=0.439H =
2.33
ft.ku' =
0.13
lb / in^3ku' = modulus of subgrade reactionSaturated clay = 0.110Ordinary clay = 0.130Saturated topsoil = 0.150Sand and gravel = 0.165Bd max. = Transitional trench width from table below
Ref. 1
=
5
ft.
Table 13 to 28
Bd = Max. effective transitional trench width
Bd
Pipe Cover = H ( ft. )
Pipe Dia.5678910152061.421.51.581.671.751.752.082.3381.751.831.92222.082.422.75122.52.582.752.832.9233.333.671633.083.173.253.333.423.834.25183.423.53.583.753.833.924.334.75244.254.334.54.584.674.835.255.67304.835.175.335.425.585.676.176.67365.425.756.176.256.426.587.087.58425.926.336.677.087.257.427.928.42486.56.927.257.678.088.178.839.33547.087.427.838.178.5899.6710.25607.6788.428.759.089.510.511.08For shallow depths (< 4ft.) use :wd = H Bc w =978.6 lb / lin ft.Therefore wd =978.6 lb / lin ft.+ wt. of concrete =350lb / lin. Ft.wd total = 1328.6 lb / lin ft.
N:\civil\spreadsh\UGPipes\u-g pipe.xls
(1 of 3)
Wheel Loading
2 ku'
Underground Pipe Stress Check - UGP 2
BcBdHP
X P1P4
hc
From Individual Wheel LoadsTire Pressure =
80
psi.Impact Factor = Fi =1.2671.5 at surface
Ref. 2 , 4.7.2.2.2
1.0 @ H = 5 ft.k mod. of subgrade reaction
200
lb / in^3Ec conc. =
3400000
psi
Ref. 4
WheelPXA contactLH / LX / LPress. Coef.Pressure#( lbs. )( ft. )( ft. ^2 )( ft. )
( C from below)
Top Pipe (lb./ft^2)1
175000.00
1.922.450.950.00
0.0825
Ref 4
1204.22
175007.00
1.922.450.952.86
0.013
Table 1
189.73
1750021.20
1.922.450.958.67
0
0.04
1750020.00
1.922.450.958.18
0
0.05
0.00
0.002.450.950.000.06
0.00
0.002.450.950.000.0Total: = 1393.9
Pressure Coeficient CC
X / LH / L0.00.40.81.21.62.02.42.83.23.640.00.1130.1050.0890.0680.0480.0320.0200.0110.0060.0020.0000.40.1010.0950.0820.0650.0470.0330.0210.0110.0040.0010.0000.80.0890.0840.0740.0610.0450.0330.0220.0120.0050.0020.0011.20.0760.0720.0650.0540.0430.0320.0220.0140.0080.0050.0031.60.0620.0590.0540.0470.0390.0300.0220.0160.0110.0070.0052.00.0510.0490.0460.0420.0350.0280.0220.0160.0110.0080.0062.40.0430.0410.0390.0360.0300.0260.0210.0160.0110.0080.0062.80.0370.0360.0330.0310.0270.0230.0190.0150.0110.0090.0063.20.0320.0300.0290.0260.0240.0210.0180.0140.0110.0090.0073.60.0270.0260.0250.0230.0210.0190.0160.0140.0110.0090.0074.00.0240.0230.0220.0200.0190.0180.0150.0130.0110.0090.0074.40.0200.0200.0190.0180.0170.0150.0140.0120.0100.0090.0074.80.0180.0170.0170.0160.0150.0130.0120.0110.0090.0080.0075.20.0150.0150.0140.0140.0130.0120.0110.0100.0080.0070.0065.60.0140.0130.0130.0120.0110.0100.0100.0090.0080.0070.0066.00.0120.0120.0110.0110.0100.0090.0090.0080.0070.0070.006Total Wheel Pressure at Top of Pipe =1393.9lb / ft.^2
Pipe Stresses
Pipe Dia. O.D. =42in.Young's Mod. E =
30000000
psi.Wall thickness t =
0.50
in.Poisson's Ratio =
0.3
Pipe Grade =
X65
Coef. Thermal Exp. =
0.0000065
per deg FSMYS =
65000
psi.Pipe Operating Pres. =
1000.0
psi.Temp. @ Pipe Installation =
10
deg. FSMYS design factor F =
0.8
Max./Min. Operating Temp. =
170
deg. F
Circumferential Stress Due to Earth Load
Ref. 2
She = Khe Be Ee lamda D = 2756.3psi.where:Khe = soil/pipe stiffness coef. = 4500
Fig. 3
t / d =0.011905
(set E' = 1.0)
Value by Ref 1 (above) = 978.6psi.Be =0.21
Fig. 4
where H/Bd =0.665714
(Soil Type B for trenches)
Use largest Value set SHe =2756.3psi.Ee =1
(for trenched constuction)
+ wt. Concrete = She tot. = 2756.9psi.lamda = unit wt. Soil =120lb / ft^3D = 42in
(2 of 3)
Wheel Load Stress
w =9.68psi. from above
X
X
Sum loadsat this pointr P2P3
L
where:KHh = circumf. stiffness factor =12.5
Fig. 14
Cyclic Circumferential Stress where: t / d =0.011905
Set Er = 10
SHh = KHh GHh R L Fi wGHh = geometry factor =
0.96
from Fig. 15
= 86.10psi.
GHh
H, soil cover ( ft. )
Fig. 15
Pipe dia.3 - 46810Cyclic Longitudinal Stress61.451.150.90.7121.281.050.850.67SLh = KLh GLh R L Fi w181.080.950.770.63= 55.96psi.241.120.850.730.58301.070.80.680.54361.010.760.640.5
Internal Pressure Circumferential Stress
420.960.720.60.46480.920.690.550.43Shi = p (D - t ) / 2 t540.870.660.510.41= 41500psi.600.850.630.470.38R = pavement factor =
0.90
Ref. 2
==>L = Axle configuration =
0.65
Table 2
Limits of Calculated Stress
KLh = long. Stiffness factor =10
Fig. 16
1.) Check Pressure Stress using Barlow formula
where t / d = 0.011905
Set Er = 10
GLh = geometry factor =
0.78
from Fig. 17
SHi (Barlow) = p D / 2 t< or = F E T SMYS (natural gas)
GLh
H, soil cover ( ft. )
Fig. 17
< or = F E SMYS (liquids)Pipe dia.3 - 4681061.551.451.351.25where:F = design factor =
0.8
Ref. 3
101.231.110.9E = joint factor =
1.0
Ref. 2
121.151.020.880.8T = temp. derating =
1.0
181.10.930.830.7241.020.870.750.57300.940.80.690.53SHi (Barlow) = 42000psi360.860.730.630.48< =52000
(nat. gas)
OK420.780.650.580.44< =52000
(liquids)
OK480.70.580.520.4540.620.510.460.36600.540.440.410.322.) Check Total Effective StressSeff =SQRT [ 1/2 ( (S1 - S2)^2 + (S2 - S3)^2 + (S3 - S1)^2)] < or = SMYF FS1 = SHe + SHr + SHi =44343psiS2 = SLr - Es Coef. Thermal Exp. (T2 - T1) + poisons ratio ( SHe + SHi) =44533psiS3 = - P =-1000.0psiS eff =32130psi< or =52000psi
OK -- Stress within allowables
References:
1. )Concrete Pipe Design Manual ACPA 5th Printing June 19802. )API Recommended Practice 1102 Steel Pipelines Crossing Railroads and Highways 6th Editition 19933. )CAN/CSA Z183 - M904. )PCA Vertical Pressure on Culverts Under Wheel Loads on Concrete Pavement Slabs5. )PCA Concrete Floors on Ground(3 of 3)
Design Calculation
Project No.
Project Title:014173Checked By:Date:Oct/15/14Date:
PIPE STRESSES - WHEELS ON UNPROTECTED FILLEarth Loading
Pipe Size =
42
in.O.D. =42in.wd = Cd w Bd^2 = 1666.6 lb / lin ft.
Ref. 1
where:w =
120
lb/ft^3 soil unit wt.Bd =
5
ft. (actual width)Bd =5.0ft. (effective width)Bc = O.D. =3.50ftCd = 1 - e^ (-2 ku'(H/Bd))=0.556H =
3
ft.ku' =
0.13
lb / in^3ku' = modulus of subgrade reactionSaturated clay = 0.110Ordinary clay = 0.130Saturated topsoil = 0.150Sand and gravel = 0.165Bd max. = Transitional trench width from table below
Ref. 1
=
5
ft.
Table 13 to 28
Bd = Max. effective transitional trench width
Bd
Pipe Cover = H ( ft. )
Pipe Dia.5678910152061.421.51.581.671.751.752.082.3381.751.831.92222.082.422.75122.52.582.752.832.9233.333.671633.083.173.253.333.423.834.25183.423.53.583.753.833.924.334.75244.254.334.54.584.674.835.255.67304.835.175.335.425.585.676.176.67365.425.756.176.256.426.587.087.58425.926.336.677.087.257.427.928.42486.56.927.257.678.088.178.839.33547.087.427.838.178.5899.6710.25607.6788.428.759.089.510.511.08For shallow depths (< 4ft.) use :wd = H Bc w =1260.0 lb / lin ft.Therefore wd =1260.0 lb / lin ft.
N:\civil\spreadsh\UGPipes\u-g pipe.xls
(1 of 3)
Wheel Loading
From Individual Wheel Loads2 ku'
Underground Pipe Stress Check - UGP 1
BcBdHP
X P1P4

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