Buried Duct Network for Upgrading Utility Cables – Recent Field Trials

1. P C S Outside Plant Consulting Services, Inc. Buried Duct Network for Upgrading Utility Cables – Recent Field Trials 2009 AASHTO Right of Way & Utilities Subcommittee Conference Oklahoma City April 20, 2009 Dr. Lawrence M. Slavin Outside Plant Consulting Services, Inc. 973-983-0813 lslavin@ieee.org www.outsideplantconsulting.com

2. Sponsor • Funding: • US Department of Transportation • Technical Oversight: • FHWA Turner-Fairbank Highway Research Center

3. Objectives & Goals • Short-Term: • Develop improved method of buried construction for utility cables (telecommunications, CATV, power) • Long-Term: • Avoid damage to roads and transportation systems • Minimize proliferation of utility poles

4. Background

5. P C S Cable Construction Methods • Overhead Utility Poles • Below ground • Underground conduit • Direct-Buried

6. P C S cables placed directly in trench

7. P C S Direct-Buried Philosophy • Cables directly placed in trench • Robust cable designs • electrically insulated (power, ...) • waterproof • mechanical protection (armor, …) • Sized for “ultimate” future needs

8. Direct-Buried Philosophy • Typically, no convenient means of cable addition, replacement or upgrade* * Sometimes a duct is provided in trench by a utility, but is not a uniform practice across all utilities and regions, or necessarily done in the most cost-effective manner

9. P C S Direct-Buried Philosophy • Does it usually work (successful) ? • Often (in use for several decades) • Does it always work ? • No • new technology • exhausted capacity • cable degradation or damage • new service providers

10. P C S Direct-Buried Philosophy THUS • Cable additions require aggressive construction (open-cut trenching, directional drilling, …) • Possible damage to roads, property, utilities, ... • Safety hazards

11. Buried Duct Network (BDN)

12. P C S Benefits • For buried facilities (requiring future upgrades, maintenance, …), avoids • Road damage (road cuts, ...) • Corresponding traffic delays • Damage to buried lines (gas*, electric,…) • Damage to Intelligent Transportation System (cables, …) * e.g., US DOT - Office of Pipeline Safety

13. Benefits • Consistent with AASHTO & FHWA Recommendations* • Belowground lines • Access and Upgradability • Joint Usage of Infrastructure & Facilities * A Policy for Accommodating Utilities Within Highway Right-of-Way, A Policy on the Accommodation of Utilities Within Freeway Right-of- Way, Guidance on Sharing Freeway and Highway Rights-of-Way for Telecommunications, Highway/Utility Guide.

14. P C S BDN Concept/Design • Hybrid system; combines • Advantages of underground conduit (upgradability) • with • Advantages of direct-buried construction (low cost)

15. BDN Concept/Design Specify standard, optimized, cost-effective Buried Duct Network: • Initially installed distribution cables are selected, sized and directly-buried in joint-use trench, following present recommended (cost-effective) practices • Two large diameter (e.g., 4-in.) main distribution ducts, initially vacant, accessed at common handholes, also placed as an overlay in the same joint-use trench

16. P C S BDN Strategy* • Add minimum duct network for insurance for atypical (but not uncommon) cases when need upgrade • Consistent with shared/joint-usage philosophy • Space-efficient • Cost-effective • * Does not apply to applications that warrant full-scale underground conduit systems (e.g., banks of conduits, manholes, …)

17. Note: for thoroughfare application, possibly omit service lines common (joint) service trench utility terminals/equipment/hardware (power, telephony, CATV) three individual service ducts power handhole tele CATV common (joint) main trench along ROW two vacant large (e.g., 4-in.) ducts through handhole initial distribution cables (direct-buried, w/o duct) initial primary power distribution cables (direct-buried, w/o duct) patent pending BDN Detail

18. Not to Scale 6 knockouts (both sides) flared sides (avoid uplift -- frost, duct, …) lid mouseholes (e.g., 4-in. duct) bottomless patent pending (Nominal 2 ft. wide x 3 ft. long x 36+ inches deep)

19. initial distribution cables (direct buried, w/o duct) e.g., communications (telephone, CATV) handhole two vacant main ducts (HDPE, PVC, …) (future distribution cables) e.g., power (primary and/or secondary) express duct (alternative) cut/sealed duct same (joint) trench patent pending Direct-Buried Initial Cables plus Vacant Main Ducts thru Handhole

20. P C S BDN Concept/Design • Main distribution ducts are initially vacant • Future Use of main distribution ducts efficiently allocated, as necessary (telephone, CATV, power) • Individual, smaller diameter, service wire ducts are routed from terminals to residence or small business, to provide protection for initial service wires, and facilitate future upgrade or replacement

21. P C S BDN Concept/Design • Handhole NOT intended for routine maintenance (no terminals, splices, ... ) -- avoids exposure of communications workers to high voltages • Accessed only if and when the need arises for future addition of cable(s)

22. Alternatives

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26. Phase I (Feasibility) 6 Months

27. Phase II (R&D) 24 Months

28. P C S Phase II Effort • Develop design, construction, maintenance, and management guidelines and practices • ASCE Pipeline Division • “ASCE Manual of Practice for Belowground Pipeline Networks for Utility Cables” • Anticipated availability Summer 2009

29. P C S Phase II Effort • Ensure availability of prototype hardware for future applications, field trials, ... • Handholes (load ratings, ...) • Ducts, conduits • Security system (locks, …) • …..

30. Handholes (TIER 15) Polymer Concrete (Quazite®)

31. Handholes (“20K”) HDPE (Pencell Plastics)

32. P C S Phase II Effort • Arrange appropriate full-scale field trials • Permanent installation • e.g., 1 kft • Road, highway, residential, … • Identify & address various issues • Leverage for future introduction into utility and transportation industry practices

33. P C S Phase II Effort • Completed or planned field trials • Arlington, Texas – November 2008 • Monroe, NC – March 2009 • Danvers, MA – June 2009 • ........

34. Monroe, NC • Road Widening SR1223 (NCDOT) • Moving Verizon and Time Warner Cable • Outer edge of ROW • Tier 15 handholes (NC DOT) • Open-cut trenching • Conventional PVC (adhesive joints) • 1 kft (<800 ft.) • Conduits (and innerduct) for future (and initial) cables

35. Monroe, NC Thanks, Gus !

36. Handhole Locations for Verizon BDN /Time Warner Installation (Monroe, NC) 30” x 48” x 36-in deep handholes (Quazite PG3048) 36” width trench Verizon equipment/pedestal  390 ft.  330 ft. two 4-in. conduits (e.g., Schedule 40 PVC) 2 Time Warner Cable innerducts (outside handholes) Time Warner Cable mini-vault increase trench width in vicinity of handholes initial Verizon cables through one conduit All conduits plugged at all exposed ends Not to Scale

37. Trench Cross-Section for Verizon BDN /Time Warner Cable Installation (Monroe, NC) surface two 4” (Verizon) conduits pull rope  36” fiber cable + pull rope fiber cable + 600 pr copper cable (+ vacant path ?) 36”+ two 2” (Time Warner Cable) innerducts, including tracer wire Not to Scale

38. Martin Luther King, Jr. Blvd (SR 1223)

39. Trenching & Conduit/Handholes video

40. Installed BDN Conduit & Handholes

41. Time Warner Cable Direct-Buried Innerduct video

42. Installed Innerduct

43. Backfilling & Compacting video

44. Backfilling & Compacting

45. Finishing video

46. Finishing

47. P C S Phase II Effort • Implementation issues • Ownership • Joint-usage agreements (compensation, …) • Road and construction permits • ...

48. HOW YOU CAN HELP

49. P C S How You Can Help (Permits, ...) • Encourage (require ?) use of upgradable networks (BDN, other, ...) • Stricter specifications • Uniformity (across states, ...)

50. P C S How You Can Help (Permits, ...) • Suggestions • Existing related efforts ? • Individual states ? • Nationally ? • How to proceed ? • .......