- 198 - SECTION 405 -- CONDUIT
405.01 Description
1.The Contractor shall furnish and install the size and type of conduit shown in the contract. This applies to underground conduit and conduit in or on bridges, median barriers, retaining walls, tunnels, and similar structures. This includes the conduit, fittings, excavating, backfilling, compacting, and all labor, equipment, tools, materials, a nd incidentals required to complete the work.
2.Special devices or fittings such as hangers, expansion fittings, deflection fittings, junction boxes, drai ns, grounding devices, and all other fittings required for a complete conduit system installation shall be considered subsidiary to the conduit pay item.
405.02 Material Requirements
1.Conduit and fittings shall conform to the requirements of Section 1073. The Contractor may use ca ble in duct in place of cable and conduit on lighting and sign lighting systems only, and the cable in duct shall conform to the requirements of Section 1073.
2.The Contractor may substitute a larger size conduit than specified at no additional cost to the Depar tment if approved by the Engineer.
3.Fittings must be standard conduit fittings and designed for the specific type of conduit used. Galvanized malleable iron or steel fittings shall be used with galvanized rigid steel, intermediate metallic, or electrical metallic tubing conduit. Aluminum or zinc alloy fittings will not be allowed.
405.03 Construction Methods
1.The Contractor shall assemble and install conduit systems in accordance with the NEC , except that in those instances where the Standard Specifications are more stringent than the minimum requirements of the NEC , the Standard Specifications shall prevail.
2.Conduits: a. Field bends must be properly formed with appropriate tools and shall not reduce the conduit cross section area.
b.Exposed field cut threads on metallic conduit and any area where galvanizing has been removed shall be painted with 1 coat of an approved zinc rich paint.
c.All conduit terminations shall have bells or bushings. A standard premolded PVC conduit elbow with integral belled end shall be attached to HDPE conduit to meet this requirement.
d.Spare conduits shall be capped or plugged with standard fittings.
e.Unless otherwise provided or directed by the Engineer, underground conduit shall be placed 30 inches (750 mm) below finished grade.
3.Trenching:
a.The locations of conduit runs indicated in the contract may be altered at the direction of the Engineer to accommodate field conditions. Conduit shall be routed to minimize damage to existing trees and shrubs. Conduit 405.04 - 199 - b. Trenches shall be excavated to true line and grade. Trench width shall be the minimum practical dimension needed to place the conduit. Backfill material shall be free of unsuita ble materials. Backfill shall be placed with care and shall be compacted and/or mounded so that, after natural settlement, the trench surface is level with the surrounding surface.
c.Six-inch wide underground warning tape shall be installed above the conduit at a depth of 12 inches below finished grade.
4.Conduit placed under surfaces which are not to be disturbed may be jacked or bored into the proposed location. Jacking pits shall be at least 2 feet (600 mm) beyond the edge of the pavement. Excessive use of water is not allowed.
5.Conduit installed in or on bridges, retaining walls, median barriers, tunnels, and similar structures shall be capped or plugged in an approved manner to prevent the entrance of water, concrete, or other foreign materials.
6.Conduit under sidewalk shall include replacement of the sidewalk from joint to joint unless the conduit is jacked under the sidewalk. Sidewalk that is damaged by the Contractor shall be removed and replaced as complete panels at no cost to the Department.
7."Conduit Under Roadway" is cond uit that is intended to be trenched in place before the roadway is paved. This conduit may be either metallic or nonmetallic. The Contractor may elect to trench through existing bituminous pavement to install conduit under t he roadway before a new pavement is constructed. The Contractor may instal l the conduit after the paving is in place by either jacking or boring under the pavement at no increase in cost to the State.
8.“Conduit Under Median Surfacing” may be placed by jacking or boring. The Contractor may also elec t to remove and replace the median surfacing and bury the conduit at no additional cost to the Department. Median surfacing shall be removed and replaced in complete panels from joint line to joint line.
9.Metallic junction boxes installed in bridges or median barriers shall be drilled and tapped to receive a grounding lug.
10.All underground conduit raceways terminating in pull boxes, light pole boxes, breakaway transformer bases, pedestal bases, lighting control center cabinets or other in-ground or ground-mounted enclosures, shall enter the enclosure vertically. All conduit ends shall be equipped with bells or bushings prior to installing cable to protect the cable they carry from chafing or abrasion.
405.04 Method of Measurement
1.Conduit shall be measured in linear feet (meter) for each type and size shown in the contract. The length shall be measured horizontally from center to center of poles, pull boxes, junction boxes, and control cabinets and shall not include allowances for vertical rises or bends. Cable in duct will be measured as two separate items, conduit and cable.
405.05 Conduit
- 200 - 405.05 -- Basis of Payment
1.Pay Item Pay Unit _____ Conduit in Trench Linear Foot (LF) [Meter (m)] _____ Conduit in Bridge Linear Foot (LF) [Meter (m)] _____ Conduit in Median Barrier Linear Foot (LF) [Meter (m)] _____ Conduit Under Median Surfacing Linear Foot (LF) [Meter (m)] _____ Conduit on Structure Linear Foot (LF) [Meter (m)] _____ Conduit Under Roadway Linear Foot (LF) [Meter (m)] _____ Conduit Under Sidewalk Linear Foot (LF) [Meter (m)] _____ Conduit, Jacked Linear Foot (LF) [Meter (m)]
2.Payment is full compensation for all work described in this Section. Underground warning tape shall be subsidiary to “Conduit in Trench”. - 201 - SECTION 406 -- PULL BOXES
406.01 Description
1.The Contractor shall construct pull boxes of the size, type, and at the locations shown in the contract. A spare bend, if required, shall be installed in the pull box as shown in the contract. This shall include furnishing and installing the pull box, spare conduit bend, grounding connectors, clean coarse gravel, and all excavation, backfilling, compaction, labor, equipment, tools, and incidentals required to complete the work.
2.The Contractor shall relocate pull boxes as shown in the contract. A spare bend, if required, shall be instal led in the relocated pull box as shown in the contract. “Relocate Pull Box, Type PB _____” shall include removing the existing pull box and spare conduit bends: installing the pull box at the new location: tapping into existing conduit and extending conduit to the relocated pull box; furnishing and installing spare conduit bends, grounding connectors, ground rods, if required, cl ean coarse gravel; and all excavation, backfilling, compaction, labor, equipmen t, tools, and incidentals required to complete the work.
406.02 Material Requirements
1.Pull boxes shall conform to the requirements shown in the contract.
2.Pull boxes shall be on the Depa rtment’s Approved Products List.
3.Fill material shall be a Class B fine aggregate for concrete as shown in Table 1033.02A. Crushed li mestone will not be acceptable.
406.03 Construction Methods
1.Pull boxes shall not be constructed in ditch bottoms, low areas where ponding of water may occur, or where they will be subjected to vehicular traffic.
2.Pull boxes shall not have concrete bottoms.
406.04 Method of Measurement
1.Pull boxes and relocated pull boxes shall be measured by the each.
406.05 Basis of Payment
1.Pay Item Pay Unit Pull Box, Type _____ Each (ea) Adjust Pull Box to Grade, Type ____ Each (ea) Relocate Pull Box, Type _____ Each (ea) 2. Payment is full compensation for all work described in this Section.
Source: Nebraska Standard Specifications for Highway Construction, 2017 Edition. Pages 232–234 of 1,048.