02584 Final Underground Ducts and Utility Structures.pdf

Offutt Air Force Base

02584-1 (Repair Taxiway Circuits A & B)

(072060) 2009 by FEI

SECTION 02584

UNDERGROUND DUCTS AND UTITLITY STRUCTURES

PART 1 - GENERAL

1.1 RELATED DOCUMENTS

A. Drawings and general provisions of the Contract, including General and Supplementary Conditions and Division 1 Specification Sections, apply to this Section.

1.2 SUMMARY

A. Section Includes:

1. Conduit and accessories for direct-buried duct banks, and in single duct runs.

2. Handholes and pull boxes.

1.3 DEFINITION

A. RNC: Rigid nonmetallic conduit.

B. RGS: Rigid galvanized steel conduit.

C. HDPE: High density polyethylene conduit.

1.4 SUBMITTALS

A. Product Data: For the following:

1. Ducts and conduits and their accessories, including elbows, end bells, bends, fittings, and solvent cement.

2. Accessories for manholes, handholes, pull boxes, and other utility structures.

3. Warning tape.

B. Shop Drawings for Factory-Fabricated Handholes, Pull Boxes and Manholes: Include dimensioned plans, sections, and elevations, and fabrication and installation details, including the following:

1. Duct entry provisions, including locations and duct sizes.

2. Cover design.

3. Grounding details.

4. Frame and cover design and manhole frame support ring.

5. Grounding details.

6. Dimensional location of cable rack insert, pulling-in and lifting irons, and sumps.

7. Joint details.

C. Duct-Bank Coordination Drawings: Show duct profiles and coordination with other utilities and underground structures.

1. Include plans and sections, drawn to scale, and show bends and locations of expansion fittings.

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2. Drawings shall be signed and sealed by a qualified professional engineer.

D. Product Certificates: For concrete and steel used in precast concrete, pull boxes and handholes, comply with ASTM C 858.

E. Qualification Data: For qualified professional engineer and testing agency.

F. Source quality-control reports.

G. Field quality-control reports.

1.5 QUALITY ASSURANCE

A. Comply with IEEE C2.

B. Comply with NFPA 70.

1.6 DELIVERY, STORAGE, AND HANDLING

A. Deliver ducts to Project site with ends capped. Store nonmetallic ducts with supports to prevent bending, warping, and deforming.

B. Store precast concrete and other factory-fabricated underground utility structures at Project site as recommended by manufacturer to prevent physical damage. Arrange so identification markings are visible.

C. Lift and support precast concrete units only at designated lifting or supporting points.

1.7 PROJECT CONDITIONS

A. Interruption of Existing Electrical Service: Do not interrupt electrical service to facilities occupied by Owner or others unless permitted under the following conditions and then only after arranging to provide temporary electrical service according to requirements indicated:

1. Notify Contracting Officer’s Representative no fewer than 14 calendar days in advance of proposed interruption of electrical service.

2. Do not proceed with interruption of electrical service without Contracting Officer’s Representative written permission.

1.8 COORDINATION

A. Coordinate layout and installation of ducts, handholes, pull boxes and manholes with final arrangement of other utilities, site grading, and surface features as determined in the field.

B. Coordinate elevations of ducts and duct-bank entrances into handholes and pull boxes with final locations and profiles of ducts and duct banks as determined by coordination with other utilities, underground obstructions, and surface features. Revise locations and elevations as required to suit field conditions.

PART 2 - PRODUCTS

2.1 CONDUIT

A. Rigid Steel Conduit: Galvanized. Comply with ANSI C80.1.

02584-3 (Repair Taxiway Circuits A & B)

B. RNC: NEMA TC 2, Type EPC-40-PVC, UL 651, with matching fittings by same manufacturer as the conduit, complying with NEMA TC 3 and UL 514B.

C. HDPE: NEMA TC7, Smoothwall coilable PE Electrical plastic conduit, Schedule 40, conforms to UL 651 A & B.

2.2 NONMETALLIC DUCTS AND DUCT ACCESSORIES

A. Manufacturers: Subject to compliance with requirements, available manufacturers offering products that may be incorporated into the Work include, but are not limited to, the following:

1. Lamson & Sessions; Carlon Electrical Products.

B. Duct Accessories:

1. Warning Tape: Underground-line warning tape specified in Division 16 Section "Electrical Identification.”

2.3 SOURCE QUALITY CONTROL

A. Test and inspect precast concrete utility structures according to ASTM C 1037.

PART 3 - EXECUTION

3.1 CORROSION PROTECTION

A. Aluminum shall not be installed in contact with earth or concrete.

3.2 UNDERGROUND DUCT APPLICATION

A. Ducts for Electrical Cables over 600 V: RNC, NEMA Type EPC-40 or HDPE TC7 in direct buried duct bank unless otherwise indicated.

B. Ducts for Electrical Feeders 600 V and Less: RNC, NEMA Type EPC-80 Type EPC-40-PVC, in direct-buried duct bank unless otherwise indicated.

C. Ducts for Electrical Branch Circuits: RNC, NEMA Type EPC-40-PVC or HDPE TC7, Schedule 40, in direct-buried duct bank unless otherwise indicated.

D. Underground Ducts Crossing Roadways and Railroads: RNC NEMA Type EPC-40-PVC, routed through existing casing.

3.3 UNDERGROUND ENCLOSURE APPLICATION

A. Manholes: Precast or cat-in-place concrete.

1. H-20 structural load rating according to AASHTO HB 17.

3.4 EARTHWORK

A. Excavation and Backfill: Comply with Division 2 Section "Earthwork," but do not use heavy-duty, hydraulic-operated, compaction equipment.

B. Restore surface features at areas disturbed by excavation and reestablish original grades unless otherwise indicated. Replace removed sod immediately after backfilling is completed.

02584-4 (Repair Taxiway Circuits A & B)

C. Restore areas disturbed by trenching, storing of dirt, cable laying, and other work. Restore vegetation and include necessary topsoiling, fertilizing, liming, seeding, sodding and mulching.

Comply with Division 2 Sections "Lawns and Grasses".

3.5 DUCT INSTALLATION

A. Curves and Bends: Use 5-degree angle couplings for small changes in direction. Use manufactured standard radius bends both horizontally and vertically, at other locations unless otherwise indicated. All stub-ups above grade shall be PVC coated rigid galvanized steel conduit.

B. Joints: Use solvent-cemented joints in ducts and fittings and make watertight according to manufacturer's written instructions. Stagger couplings so those of adjacent ducts do not lie in same plane.

C. Duct Entrances to Concrete and Polymer Concrete Handholes/Manholes: Use field core drilled opening and link-seal conduit penetration.

D. Sealing: Provide temporary closure at terminations of ducts that have cables pulled. Seal spare ducts at terminations. Use sealing compound and plugs to withstand at least 15-psig (1.03-MPa) hydrostatic pressure.

E. Pulling Cord: Install 100-lbf- (445-N-) test nylon cord in ducts, including spares.

F. Direct-Buried Duct Banks and Conduit:

1. Excavate trench bottom to provide firm and uniform support for duct bank. Prepare trench bottoms as specified in Division 2 Section "Earthwork" for pipes less than 6 inches (150

mm) in nominal diameter.

2. Install backfill as specified in Division 2 Section "Earthwork."

3. Install ducts with a minimum of 3 inches (75 mm) between ducts for like services and 6 inches (150 mm) between power and signal ducts.

4. Depth: Install top of duct bank at least 36 inches (900 mm) below finished grade unless otherwise indicated.

5. Set elevation of bottom of duct bank below the frost line.

6. Install manufactured PVC coated rigid galvanized steel conduit elbows for stub-ups at poles and equipment and at building entrances through the floor.

a. Couple steel conduits to ducts with adapters designed for this purpose, and encase coupling with 3 inches (75 mm) of concrete.

b. For equipment mounted on outdoor concrete bases, extend PVC coated rigid steel conduit horizontally a minimum of 60 inches (1500 mm) from edge of equipment pad or foundation. Install insulated grounding bushings on terminations at equipment.

7. Warning Tape: Bury warning tape approximately 12 inches (300 mm) above all concrete-encased ducts and duct banks. Align tape parallel to and within 3 inches (75 mm) of the centerline of duct bank. Provide an additional warning tape for each 12 inch (300-mm) increment of duct bank width over a nominal 18 inches (450 mm). Space additional tapes 12 inches (300 mm) apart, horizontally.

02584-5 (Repair Taxiway Circuits A & B)

3.7 GROUNDING

A. Ground underground ducts and utility structures according to Division 16 Section "Grounding and Bonding."

3.8 FIELD QUALITY CONTROL

A. Perform the following tests and inspections:

1. Demonstrate capability and compliance with requirements on completion of installation of underground ducts and utility structures.

2. Pull aluminum or wood test mandrel through duct to prove joint integrity and test for out-of-round duct. Provide mandrel equal to 80 percent fill of duct. If obstructions are indicated, remove obstructions and retest.

B. Correct deficiencies and retest as specified above to demonstrate compliance.

C. Prepare test and inspection reports.

END OF SECTION