Transcript SlavinMon130 - AASHTO - Subcommittee Right of Way

Outside Plant Consulting Services, Inc.
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Buried Duct Network for
Upgrading Utility Cables –
Recent Field Trials
Dr. Lawrence M. Slavin
Outside Plant Consulting Services, Inc.
973-983-0813
[email protected]
www.outsideplantconsulting.com
2009 AASHTO Right of Way & Utilities
Subcommittee Conference
Oklahoma City
April 20, 2009
Sponsor
Funding:
US Department of Transportation
Technical Oversight:
FHWA Turner-Fairbank Highway
Research Center
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
Background
Cable Construction Methods
Overhead Utility Poles
Below ground
• Underground conduit
• Direct-Buried
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cables placed directly in trench
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Direct-Buried Philosophy
• Cables directly placed in trench
• Robust cable designs
• electrically insulated (power, ...)
• waterproof
• mechanical protection (armor, …)
• Sized for “ultimate” future needs
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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
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
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Direct-Buried Philosophy
THUS
• Cable additions require aggressive
construction (open-cut trenching,
directional drilling, …)
• Possible damage to roads, property,
utilities, ...
• Safety hazards
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Buried Duct
Network (BDN)
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
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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-ofWay,
Guidance on Sharing Freeway and Highway Rights-of-Way for
Telecommunications,
Highway/Utility Guide.
BDN Concept/Design
Hybrid system; combines
• Advantages of underground conduit
(upgradability)
with
• Advantages of direct-buried construction
(low cost)
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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 (costeffective) 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
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, …)
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Note: for thoroughfare application, possibly omit service lines
utility terminals/equipment/hardware
(power, telephony, CATV)
common (joint)
service trench
three individual
service ducts
handhole
common (joint)
main trench along ROW
two vacant large (e.g., 4-in.)
ducts through handhole
initial primary power distribution cables
(direct-buried, w/o duct)
initial distribution cables
(direct-buried, w/o duct)
patent pending
BDN Detail
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)
initial distribution cables
(direct buried, w/o duct)
e.g., communications (telephone, CATV)
two vacant main ducts (HDPE, PVC, …)
(future distribution cables)
handhole
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
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
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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)
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Alternatives
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Phase I
(Feasibility)
6 Months
Phase II
(R&D)
24 Months
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
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Phase II Effort
Ensure availability of prototype
hardware for future applications, field
trials, ...
• Handholes (load ratings, ...)
• Ducts, conduits
• Security system (locks, …)
• …..
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Handholes (TIER 15)
Polymer Concrete
(Quazite®)
Handholes (“20K”)
HDPE
(Pencell Plastics)
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
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Phase II Effort
Completed or planned field trials
• Arlington, Texas – November 2008
• Monroe, NC – March 2009
• Danvers, MA – June 2009
• ........
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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
Monroe, NC
Thanks, Gus !
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
All conduits plugged at all exposed ends
initial Verizon cables through one conduit
Not to Scale
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
Martin Luther King, Jr. Blvd (SR 1223)
Trenching & Conduit/Handholes
video
Installed BDN Conduit & Handholes
Time Warner Cable Direct-Buried Innerduct
video
Installed Innerduct
Backfilling & Compacting
video
Backfilling & Compacting
Finishing
video
Finishing
Phase II Effort
Implementation issues
• Ownership
• Joint-usage agreements
(compensation, …)
• Road and construction permits
• ...
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HOW
YOU
CAN
HELP
How You Can Help (Permits, ...)
• Encourage (require ?) use of
upgradable networks (BDN, other, ...)
• Stricter specifications
• Uniformity (across states, ...)
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How You Can Help (Permits, ...)
Suggestions
•
•
•
Existing related efforts ?
• Individual states ?
• Nationally ?
How to proceed ?
.......
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Thank You !
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