PVC Sewer Pipe Design & Installation

1. PVC Sewer Pipe Design & Installation

2. Flexible Conduit Theory

3. Flexible Pipe Design • Pipe Stiffness • Soil Stiffness • Load on pipe • Earth Load • Live Load

4. PVC Pipe Stiffness ASTM D2412 – “Standard Test Method for External Loading Properties of Plastic Pipe by Parallel Plate Loading” Pipe Stiffness is based on an arbitrary datum of 5% Deflection

5. Pipe Stiffness Equation y F • Where: • F = Recorded load on pipe (lb/in) • y = Recorded deflection (in) • F/y = Pipe stiffness (lb /in-in)

6. PVC Pipe Stiffness

7. Profile Pipe Technology Where: E=Modulus of Elasticity (psi) I=Moment of Inertia, t3/12 in3 r=Mean Radius (in)

8. PVC Sewer Pipe Technologies

9. Flexible Pipe Design • Pipe Stiffness • Soil Stiffness • Load on pipe • Earth Load • Live Load

11. Trench Diagram

12. Flexible Pipe Design • Pipe Stiffness • Soil Stiffness • Load on pipe • Earth Load • Live Load

13. Marston’s Load Formula • Wc = Load on pipe (lb/linear foot) • Cd = Trench Load Coefficient • w = Unit weight of soil (lb/ft3) • Bd = Trench width at top of pipe • Bc = Pipe OD (ft)

15. Trench Condition Load Producing Forces Shearing Force Shearing Force RIGID PIPE FLEXIBLE PIPE

16. PRISM LOAD IS THE MAXIMUM SOIL LOAD ON THE FLEXIBLE PIPE SYSTEM Where: P=Pressure at the top of the pipe due to weight of soil (lb/ft2) =Unit weight of soil (lb/ft3) H=Depth from ground surface to top of pipe (ft)

17. Flexible Pipe Theory • Pipe Stiffness • Soil Stiffness • Load on pipe • Earth Load • Live Load

18. H20 Highway Load Figure Vertical Soil Pressure (LBS/FT2) Vertical Soil Pressure (LBS/FT2)

19. Modified Iowa Equation Where: y/D = Pipe Deflection DL = Deflection Lag Factor K = Bedding Factor W’ = Live Load (psi) P = Prism Load (psi) F = Load on Pipe (lb/in) F/y = Pipe Stiffness (lb/in-in) E’ = Modulus of Soil Reaction (psi)

20. ASTM RECOMMENDS 7.5% DEFLECTION LIMIT

21. Inverse Curvature

22. Uni-Bell Handbook

23. Unstable Native Soils or Embankment Condition

24. Example Calculations • GIVEN • Pipe Diameter = 60 Inch • Maximum Cover Depth = 45 feet • Native Soil = Silt & Clay (ML-CL), with less than 25% coarse grained particles • Will PVC Pipe Work? • What Pipe Stiffness is Appropriate? • What Embedment Design(s) is Required? • Provide Calculations

25. Calculation Worksheet

26. Example Calculation • Given • Pipe Diameter = 54 Inch • Maximum Cover Depth = 62 feet • Native Soil is Sandy Silt (SM) with more than 12% fines • Will PVC Pipe Work? • What Pipe Stiffness is Required • What Embedment Design(s) is Required • Provide Calculations

27. Calculation Worksheet

28. Example Calculation • Given • Pipe Diameters = 54 & 60 Inch • Maximum Cover Depth = 58 feet • Native Soil is well graded sand (SW) with less than 12% fines • Will PVC Pipe Work? • What Pipe Stiffness is Required? • What Embedment Design(s) is Required • Provide Calculations

29. Calculation Worksheet

30. Example Calculation • Given • Pipe Diameter = 36 Inch • Maximum Cover Depth = 22 feet • Native Soil is Poorly Graded Gravel (GP) with less than 12% fines • Will PVC Pipe Work? • What Pipe Stiffness is Required? • What Embedment Design(s) is required? • Provide Calculations

31. Calculation Worksheet

32. Deflections of DR-35 Pipe

33. Deflection vs Soil Pressure

34. REVIEW • PVC pipe will work for most situations! • PS 46 is the Best Choice; we have the greatest options! • Soil Stiffness is the key to preventing deflection! • Calculations are easy, just like my swing!

35. PVC the Sustainable, Strong, Corrosion FreeChoice

36. www.uni-bell.org

40. Dimension Ratio (DR) t O.D. DR = O.D/ t