Rigid Pipe Design Challenges

1. Derek Light, P.Eng. Rigid Pipe Design Challenges www.concrete-pipe.org

2. 2 • What’s up in Western Canada? • Design Methods Reviewed • NFL Break • Indirect vs Direct Design www.concrete-pipe.org

3. What are the design options for rigid pipe? • Do Nothing? • Indirect Design • Fill height tables • Hand calculations – Design Data 9 • PipePac software • Direct Design • Hand calculations • Pipecar software • Axial Designs – ASCE 27 Rigid Pipe Design Options www.concrete-pipe.org

4. Western Canada www.concrete-pipe.org

5. Western Canada www.concrete-pipe.org

6. Western Canada • Square mile equivalent to Alaska, Texas, California, and West Virginia combined - 1.1 Million Square miles • Population equivalent to Ohio – 11.5 Million www.concrete-pipe.org

7. Western Canada - Regions www.concrete-pipe.org

8. Current Design Practice – Zero Structural Design 75% 10% 30% 43% 25% www.concrete-pipe.org

9. Zero Structural Design • “Just finished my hydraulic design, and I am feeling fine” • “Let’s go to the bar!” www.concrete-pipe.org

10. Zero Structural Design – Common Assumptions • “Product selection is the responsibility of the contractor” • “Its on the approved product list, what further design work needs to be done?” • “The manufacturer is responsible for the design, they told me not to worry” • “Pipe failures don’t occur that often, I am not overly concerned about the structure” www.concrete-pipe.org

11. EDMONTON DESIGN STANDARDS Volume 3 Drainage, Structural Design for Pipe

12. Current Design Practice – Fill Height Tables 13% 80% 60% 29% 8% www.concrete-pipe.org

13. Fill Height Tables • Based on indirect design. • The right idea, but can you really trust these guys to get it done? www.concrete-pipe.org

14. Current Design Practice – PipePac and Pipecar 13% 5% 10% 67% 28% www.concrete-pipe.org

15. PipePac and Pipecar • Tried, tested, and true! • These guys know what it takes to get the job done. www.concrete-pipe.org

16. Current Design Breakdown – Western Canada www.concrete-pipe.org

17. Rigid Pipe Design Options • What are the design options for rigid pipe? • Do Nothing? • Indirect Design • Fill height tables • Hand calculations – Design Data 9 • PipePac software • Direct Design • Hand calculations • Pipecar software • Axial Designs – ASCE 27 www.concrete-pipe.org

18. Fill Height Table www.concrete-pipe.org

19. Fill Height Table www.concrete-pipe.org

20. Fill Height Table www.concrete-pipe.org

21. Rigid Pipe Design Options • What are the design options for rigid pipe? • Do Nothing? • Indirect Design • Fill height tables • Hand calculations – Design Data 9 • PipePac software • Direct Design • Hand calculations • Pipecar software • Axial Designs – ASCE 27 www.concrete-pipe.org

22. Indirect design (ASTM C76) Empirical Most common method Determine Pipe Class Indirect Design Method

23. Indirect Design – The Proof 3EB Test is an external load crushing test Confirms product was manufactured correctly

24. 3 Edge Bearing Test Hairline flexural crack - indicates load has shifted to reinforcement

25. Standard Trench Installation

26. Standard Embankment Installation

27. Standard Installation Soils & Minimum Compaction Requirements

28. Standard Installations – Pressure Distribution

29. Indirect Design Process • Determine pipe installation method • Select bedding and compaction • Calculate load • Determine bedding factor • Factor of safety • Calculate D-Load

30. Step 1 – Installation Type Trench Embankment Jacked, bored or tunnelled

31. Step 2 – Standard Installations

32. Step 3 – Dead and Live Load Live load Dead load Pipe

33. Step 4 – Bedding Factor MTEST Bf= MFIELD Where: Bf = Bedding factors MFIELD = Maximum load in pipe under field loads before failure, N/m (inch-pounds) MTEST = Maximum load in pipe under three-edge bearing test before failure, N/m (inch-pounds)

34. Step 5 – Factor of Safety Reinforced concrete pipe use 1.0 for the 0.3mm (0.01”) crack strength

35. Step 6 – Calculate Pipe Strength • Determine pipe strength: • D-Load = WE + WL * FS • Bfe BfLL D • Where: • WE = Earth load, kg/m (lbs/ft) • WL = Live load, kg/m (lbs/ft) • Bfe = Earth load bedding factor • BfLL = Live load bedding factor • D = Pipe diameter, mm (ft) • FS = Factor of safety

36. Pipe Strength • Class II = 50 N/m/mm or 1000 lbs/ft/ft • Class III = 65 N/m/mm or 1350 lbs/ft/ft • Class IV = 100 N/m/mm or 2000 lbs/ft/ft • Class V = 140 N/m/mm or 3000 lbs/ft/ft

37. PipePac Applies to all applications Free software http://www.concretepipe.org/pipe-box-resources/software/pipepac/ Input versatility Pipe shape and type Wall thickness Geotechnical properties Live load Height of Fill Installation type Bedding type (1-4) Standard compliance options (ASTM – CSA)

38. NFL Video Intermission www.concrete-pipe.org

39. Rigid Pipe Design Options • What are the design options for rigid pipe? • Do Nothing? • Indirect Design • Fill height tables • Hand calculations – Design Data 9 • PipePac software • Direct Design • Hand calculations • Pipecar software • Axial Designs – ASCE 27 www.concrete-pipe.org

40. Direct Design Direct design (ASCE 15-98) Limit State Design method Factored loads Pipecar

41. Indirect vs Direct www.concrete-pipe.org

42. Pipecar Software • Applies to all applications • Input versatility • Pipe shape and type • Wall thickness • Geotechnical properties • Material properties – Steel & Concrete • Pressure Distribution • Live load • Height of Fill • Bedding type (1-4) • Standard compliance options (ASTM – CSA) www.concrete-pipe.org

43. Shear Mitigation • Increased Concrete Strength • Increased Wall Thickness • Tighter Steel Spacing • Stirrups www.concrete-pipe.org

44. Direct Design

45. Flexure Controlled Design

46. Diagonal Tension Controlled

47. Radial and Diagonal Tension Controlled

48. Indirect vs Direct

49. Indirect vs Direct

50. Indirect vs Direct