Live Load: Cooper E-80 Railroad Load on Buried PE Pipe
This calculation based on normal RR loading and analyzed for depths of cover from 6 to 14 feet. The calculation only accounts for up to 80,000 lb/ft railway load, with impact factor.
Dead/Earth Load
A. Prism Load
ππΒ =Β π€π»
ππΒ = Vertical Soil Pressure,[lb/ft2]
π€ = Unit Weight of Soil,[lb/ft2]
π» = Height of Soil Above Pipe Crown,[ft]
B. Marston Load (ASCE Manual No.60)
ππΒ =Β πΆππ€π΅π
ππΒ = Vertical Soil Pressure,[lb/ft2]
π€ = Unit Weight of Soil,[lb/ft2]
π΅πΒ = Trench Width at Pipe Crown,[ft]
πΆπΒ = Load/Trench Coefficient
πΒ = Base of Natural Logarithm,[2.71828]
πΎΒ = Rankine Earth Pressure Coefficient
πΎΒ =Β π‘ππ2Β Β
πΒ = Angle of Internal Soil Friction, [Β°]
π’Β = Coefficient of Friction between Backfill and Trench Sides
C.Β Combined Prism and Marston Load
For flexible pipe, a more conservative method is to use a soil pressure load in between prism and Marston load:
ππΒ = 0.6ππΒ + 0.4ππ
ππΒ = Combined Load or Modified Arching Soil Pressure, [lb/ft2]
Live Load: Cooper E-80 Railroad Load on Buried PE Pipe
ππΏΒ =Β πΉπΈ80(π»)
ππΏΒ = Vertical Soil Pressure due to Surcharge Load [lb/ft2]
πΉπΈ80Β = Live Load Transfer to Pipe [lb/ft2] (see table)
π»Β = Soil Height above Pipe Crown [ft]
* Simulates a 20-ton truck traffic load, with impact factor
β Simulates an 80,000 lb./ft railway load, with impact factor
β‘ Applies to 180,000 lb. dual-tandem gear assembly, with 26 in. spacing between tires and 66 in. center to center spacing between fore and aft tire under a rigid 12 in. pavement, with impact factor
Β§ Negligible influence of live load on buried pipe
Pipe Deflection is calculated using Spanglerβs Modified Iowa Formula:
βπΒ = Horizontal Deflection[in]
π·πΒ = Mean Diameter[in]
πΎπΒ = Bedding Factor
πΏπ·πΏΒ = Deflection Lag Factor
ππΈΒ = Vertical Soil Pressure due to Earth Load[lb/ft2]
ππΏΒ = Vertical Soil Pressure due to Live Load]lb/ft2]
πΈΒ = Apparent Modulus of Elasticity of Pipe Material[psi]
πΈβ²Β = Modulus of Soil Reaction[psi]
πΉπΒ = Soil Support Factor
π·π Β = Standard Dimension Ratio DRΒ
π·πΒ = Pipe Outside Diameter [in]
π‘Β = Minimum Pipe Wall Thickness [in]
Modulus of Soil Reaction (E’) – Average Values for Iowa Formula (see table in section 2.0)
Modulus of Soil Reaction (E’) – Values of E’ for Pipe Embedment (see table in section 2.0)
Values of E’n Native Soil Modules of Soil Reaction (see table in section 2.0)
Soil Support Factor (see table in section 2.0)
Pipe Wall Compressive Stress
π = Pipe Wall Compressive Strength [psi]
ππΈΒ = Vertical Soil Pressure due to Earth Load[lb/ft2]
πLΒ = Vertical Soil Pressure due to Live Load [lb/ft2]
π·π = Standard Dimension Ratio DRΒ
π·πΒ = Pipe Outside Diameter [in]
π‘ = Minimum Pipe Wall Thickness [in]
Input Parameters
To create a new case, click the βAdd Caseβ button
Select the Live Load: Cooper E-80 Railroad Load on Buried PE Pipe application from the Polyethylene Pipe β Design & Stress Analysis module list.
Enter Case Name, Location, Date and any necessary notes.
Fill out all required fields.
Make sure the values you are inputting are in the correct units.
Click the CALCULATE button.
Reference: ASTM F 1962
HDPE Typical Apparent Modulus of Elasticity
Duration Time
Reference: Allowable Compressive Strength
For PE Pipe Material Designation Code:
Reference: Safe Deflection Limits for Pressurized Pipe
Pipe DR/SDR
Reference: Typical Impact Factor for Paved Road
Depth of Cover
Select Earth/Dead Load Calculation Method
Pipe Soil Envelope Data
Unit Weight of Soil
Soil Height above Pipe Crown
Bd – Trench Width at Pipe Crown
For Soil:
Friction Force Coefficient Ku
E’ – Modulus of Soil Reaction
E’n- Native Soil Modulus of Soil Reaction
Deflection Lag Factor (Typically 1.0 – 1.5)
Bedding Factor (Typically 0.1)
Pipe Data
Do – PE Pipe Outside Diameter
PE Pipe DR or SDR
PE Pipe Apparent Modulus of Elasticity
Safe Deflection as % of Diameter
Allowable Compressive Stress
Outputs/Reports
View the results.
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