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Buried Duct Network for Upgrading Utility Cables – Recent Field Trials P S C Outside Plant Consulting Services, Inc. Dr. Lawrence M. Slavin Outside Plant.

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Presentation on theme: "Buried Duct Network for Upgrading Utility Cables – Recent Field Trials P S C Outside Plant Consulting Services, Inc. Dr. Lawrence M. Slavin Outside Plant."— Presentation transcript:

1 Buried Duct Network for Upgrading Utility Cables – Recent Field Trials P S C Outside Plant Consulting Services, Inc. Dr. Lawrence M. Slavin Outside Plant Consulting Services, Inc AASHTO Right of Way & Utilities Subcommittee Conference Oklahoma City April 20, 2009

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

6 cables placed directly in trench P S C

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

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 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 P S C

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

11 Buried Duct Network (BDN)

12 Benefits * e.g., US DOT - Office of Pipeline Safety 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, …) P S C

13 Benefits * 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. Consistent with AASHTO & FHWA Recommendations* Belowground lines Access and Upgradability Joint Usage of Infrastructure & Facilities

14 BDN Concept/Design P S C 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 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, …) P S C

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

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

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

20 Main distribution ducts are initially vacant BDN Concept/Design 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 P S C

21 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) P S C

22 Alternatives

23 P S C

24 P S C

25 P S C

26 Phase I (Feasibility) 6 Months

27 Phase II (R&D) 24 Months

28 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 P S C

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

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

31 Handholes (20K) HDPE (Pencell Plastics)

32 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 P S C

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

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

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

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

39 Trenching & Conduit/Handholes video

40 Installed BDN Conduit & Handholes

41 video Time Warner Cable Direct-Buried Innerduct

42 Installed Innerduct

43 Backfilling & Compacting video

44 Backfilling & Compacting

45 Finishing video

46 Finishing

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

48 HOW YOU CAN HELP

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

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

51 Thank You ! P S C


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