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Durability of Concrete Pipe

Durability of Concrete Pipe. Durability of Concrete Pipe. The extreme durability has led to a lack of durability studies Unlike CMP, corrosion not typically significant

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Durability of Concrete Pipe

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  1. Durability of Concrete Pipe

  2. Durability of Concrete Pipe • The extreme durability has led to a lack of durability studies • Unlike CMP, corrosion not typically significant • Sewer lines and Sulfuric Acid are a major issue. Different producers have different methods to deal with durability in sewers

  3. Introduction to Presentation • Based on a variety of information gathered from different studies. • Some references to other pipe materials, as the study used concrete pipe as baseline and studied durability of “alternative” products • There will be no single formula for predicting design life: Study will show that concrete storm drain pipe should last 100 years plus.

  4. Why Concrete Pipe • What makes concrete pipe so durable? • Low w/c ratio • Concrete Compressive strength • High density • Quality control measures

  5. What are Other Engineers Doing?

  6. U.S. Army Corps of EngineersNo. 1110-2-2902 Engineering and DesignConduits, Culverts, and Pipes (31 March 1998) • The Army Corps spends a lot of money and has an aversion to risk. • They do more than dams and wetlands • This culvert design manual applies to all departments having civil works responsibilities.

  7. U.S. Army Corps of EngineersNo. 1110-2-2902 Engineering and DesignConduits, Culverts, and Pipes (31 March 1998) • Who are they? • Water resources and other civil works projects • Designing and managing the construction of military facilities for the Army and Air Force. • Providing design and construction management support for other Defense and federal agencies.

  8. U.S. Army Corps of EngineersNo. 1110-2-2902 Engineering and DesignConduits, Culverts, and Pipes (31 March 1998) • CONCRETE- Most studies estimated product service life for concrete pipe to be between 70 and 100 years.Of nine state highway departments, three listed the life as 100 years, five states stated between 70 and 100 years, and one state gave 50 years. • (2) STEEL - Corrugated steel pipe usually fails due to corrosion of the invert or the exterior of the pipe.Properly applied coatings can extend the product life to at least 50 years for most environments. • (3) ALUMINUM- Aluminum pipe is usually affected more by soil-side corrosion than by corrosion of the invert. Long-term performance is difficult to predict because of a relatively short history of use, but the designer should not expect a product service life of greater than 50 years. • (4) PLASTIC- Many different materials fall under the general category of plastic. Each of these materials may have some unique applications where it is suitable or unsuitable. Performance history of plastic pipe is limited. A designer should not expect a product service life of greater than 50 years. Excerpt from Para. 1-4 Life Cycle Design 1998

  9. U.S. Army Corps of EngineersNo. 1110-2-2902 Engineering and DesignConduits, Culverts, and Pipes (31 March 1998) • “For major infrastructure projects, designers should use a minimum project service life of 100 years when considering life cycle design.” • “In general, concrete pipe can be expected to provide a product service life approximately two times that of steel or aluminum.”

  10. U.S. Army Corps of EngineersNo. 1110-2-2902 Engineering and DesignConduits, Culverts, and Pipes (31 March 1998) • Site Inspection • Surface settlement. • Surface water. • Dip in pavement. • Settlement of manholes or control structure.

  11. U.S. Army Corps of EngineersNo. 1110-2-2902 Engineering and DesignConduits, Culverts, and Pipes (31 March 1998) • Failures • a. Leaking joints. • b. Separated joints. • c. Crushed pipe wall. • d. Perforated pipe wall. • e. Misaligned pipe sections. • f. Root penetration of pipe. • g. Material deposition. • h. Change in loading condition.

  12. U.S. Army Corps of EngineersNo. 1110-2-2902 Engineering and DesignConduits, Culverts, and Pipes (31 March 1998) www.usace.army.mil/inet/usace-docs/eng-manuals/em1110-2-2902/toc.htm

  13. American Association of State Highway and Transportation Officials (AASHTO) - Model Drainage Manual (1991) • Material selection shall include consideration of service life which includes abrasion and corrosion. • Culverts shall be located and designed to present a minimum hazard to traffic and people.

  14. American Association of State Highway and Transportation Officials (AASHTO) - Model Drainage Manual (1991) • The material selected shall be based on a comparison of the total cost of alternate materials over the design life of the structure which is dependent upon the following: • durability (service life), • structural strength, • hydraulic roughness, • bedding conditions, • abrasion and corrosion resistance, and • water tightness requirements.

  15. American Association of State Highway and Transportation Officials (AASHTO) - Model Drainage Manual (1991) • “The material selection shall consider replacement cost and difficulty of construction as well as traffic delay.” • The selection shall not be made using first cost as the only criteria.”

  16. American Association of State Highway and Transportation Officials (AASHTO) - Model Drainage Manual (1991) • “Culvert alternatives shall be selected which satisfy: • topography, and • design policies and criteria. • Alternatives shall be analyzed for: • environmental impact, • hydraulic efficiency, and • risk and cost.

  17. American Association of State Highway and Transportation Officials (AASHTO) - Model Drainage Manual (1991) • The chosen culvert shall meet the selected structural and hydraulic criteria and shall be based on: • construction and maintenance costs, • risk of failure or property damage, • traffic safety, • environmental or aesthetic considerations, • political or nuisance considerations, and • land use requirements.

  18. Missouri Highway and Transportation Department – Division of Materials and Research, Life Expectancy Determination of Zinc-Coated Corrugated Steel and Reinforced Concrete Pipe Used in Missouri, (December 1990) • “The field evaluation included 2,255 CSP and 1,642 RCP stratified by age to obtain as representative nonbiased sample as possible ... • Those pipe in need of replacement are 45.6% of the CSP and 0.3% of the RCP surveyed.”

  19. Missouri Highway and Transportation Department – Division of Materials and Research, Life Expectancy Determination of Zinc-Coated Corrugated Steel and Reinforced Concrete Pipe Used in Missouri, (December 1990) • “Reinforced Concrete Pipe (RCP) has shown to be more durable and significantly outlasts Corrugated Steel Pipe (CSP).” • “RCP appears to be more-cost effective, despite the lower, initial installation cost of CSP.” • “Despite its lower, initial installation cost, CSP most likely would have to be installed one to four times during the life of one RCP.”

  20. Illinois Department of Transportation - IDOT Pipe Committee Report (July 1994) • “There is an element of risk involved when a piping system is dependent upon backfill materials and procedures. • The committee feels it is appropriate to mitigate this risk by differentiating where rigid and flexible pipes are allowed. • This approach is not to say that flexible pipes are expected to fail. Rather, it is a means to address the risks, system wide, associated with a piping material that is very dependent upon proper construction procedures for its performance, in the case of plastic pipes; and as a means to address the differences in long-term durability, in the case of CMP’s.”

  21. Illinois Department of Transportation - IDOT Pipe Committee Report (July 1994) • Reinforced Concrete Pipe is required for pipe culverts on all roadways with more than 3,000 vehicles per day. • Reinforced Concrete Pipe is required for storm sewers on roadways with more than 1,500 vehicles per day.

  22. Wisconsin Department of Transportation - Evaluation of the Department’s Guidelines and Specifications for the Use of Alternative Storm Sewer Materials - 1997 • “The consequences of having to replace a failed (storm) sewer pipe are usually serious. Typically this would require expensive reconstruction and rerouting of traffic.” • “Rigid Pipe (i.e., Concrete Pipe) is more tolerant of poor backfill compaction than flexible pipe (i.e., plastic and metal)”. • “Given reduced staff levels, it is not realistic to expect continuous inspection of storm sewer installations.”

  23. Wisconsin Department of Transportation - Evaluation of the Department’s Guidelines and Specifications for the Use of Alternative Storm Sewer Materials - 1997 • “Where the design year traffic volume exceeds 4,500 ADT, the new materials may be specified for storm sewer located outside of traffic lanes” • i.e., Concrete Pipe only under Traffic Lanes with more than 4,500 cars per day

  24. Other Specifications of Interest • Kansas Department of Transportation • Urban Drainage and Flood Control District, City and County of Denver • Georgia Department of Transportation • Kentucky Department of Transportation • Pennsylvania Department of Transportation

  25. Pennsylvania Department of Transportation - Alternate Pipe Selection Criteria Based Upon Type of Installation - 1998 • RCP is considered 100 year design life • CMP can have increased design life if metal gauge is increased. Most DOT’s CMP gauge tables would equate to a 25 year design life in PDOT spec. • HDPE shown as 50 year design life. Not allowed under the pavement. Deep burial not allowed.

  26. Colorado T-Rex Pipe Investigation • 84” RCP Pipe was removed as freeway reconstructed • Pipe Age – 44 Years • Original Pipe Class – Class I • D-Load Testing • Initial D-Load (.01 crack) – 2,414 lb/ft/ft (in excess of Class IV)

  27. T-Rex Investigation

  28. T-Rex Investigation

  29. T-Rex Investigation

  30. T-Rex Investigation

  31. Ohio Culvert Durability Study • Completed 1982 – After a ten year investigation • Extremely Technical 173 Page Report • 1,616 Culverts Studied • Reinforced Concrete and Corrugated Metal Pipe were included

  32. Ohio Culvert Durability Study • FHWA requested culvert surveys as it became evident that service life of CMP was seriously affected by the trend of designing to minimum gauge thickness (based solely on structural considerations) • FHWA Technical Advisory T5040.2 “Corrugated Metal Pipe Durability Guidelines” March 21, 1978 • The designer must make a determination that two or more products or materials are equal to perform their intended function for the design life of the product.

  33. Ohio Culvert Durability Study • Investigation Procedures • Investigation started in 1971 • Culverts 42” and larger were used • Culverts selected randomly • Samples divided by age • 1940 and older • 1941 to 1950 • 1951 to 1960 • 1961 and newer

  34. Ohio Culvert Durability Study • General Data Considerations: • Pipe Size • Pipe Type • Manufacturer, if available • Type of Pipe Protection • Wall Thickness • General Topography • Date and Time

  35. Ohio Culvert Durability Study • Durability Considerations: • Depth of Flow • Velocity • Abrasiveness • Protection Rating • Pipe Material Rating • Test Readings (pH, resistivity, etc.) • Cores from Metal Pipe Culverts • Hydraulic/Structural Considerations (Sag or deflection, joint problems, etc.)

  36. Ohio Culvert Durability Study • Most Important Factor in Pipe Corrosion: • Low Water pH • Abrasive Bedloads • Abrasion not a concern for rcp in typical installations

  37. Ohio Culvert Durability Study

  38. Ohio Culvert Durability Study

  39. Ohio Culvert Durability Study

  40. Ohio Culvert Durability Study • Concrete Pipe Culverts:

  41. Ohio Culvert Durability Study • Because of Extremely Long Service Life of Concrete Pipe: Predictive equations based on pipes located in acid coal mine drainages • Service life in excess of 300 years for water pH levels of 7.0. • Service life in excess of 100 years for water pH levels of 4.0 and above.

  42. Ohio Culvert Durability Study • Years to Poor = (0.349(pH)1.204)7.758 (Slope)0.824

  43. Can Concrete Pipe be excavated and re-used?

  44. Ottawa, Canada • Environmental Cleanup of Coal Tar Site • 110 meters of RCP installed in 1964 • Horizontal Elliptical Pipe 43” x 68” • 33 years in aggressive environment • Pipe was cleaned, gasketed, and re-installed • Cost Savings to City of $54,500

  45. Ottawa Re-Use

  46. Ottawa Re-Use

  47. Ottawa Re-Use

  48. Gloucester, Canada • Environmental Cleanup involving hydrocarbons • 45 meters of 54” RCP • Re-install changed loading on pipe from trench to embankment • Contractor requested strength tests • Pipe was removed, steam cleaned, fitted with new gaskets and re-installed.

  49. Gloucester, Canada • Strength Tests indicated that: • Pipe had gone from 2,000 lb/ft/ft (Class IV) to 4,000 lb/ft/ft (excess of Class IV) • Actual need was 1,350 lb/ft/ft (Class III) • The safety factor of pipe was 2.96 (in addition to design safety factors)

  50. Aggressive Factors to Precast Concrete Pipe • Abrasion • Not significant for normal flows , 20 fps • Sulfates • US BUREC – No problems in precast rcp • Resistance by w/c ratio < 0.40 • Fly ash increases sulfate resistance • Typically not a concern for precast concrete pipe

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