- 627 - SECTION 719 -- FLEXIBLE PIPE CULVERTS (CORRUGATED METAL AND PLASTIC )
719.01 Description
1.This work shall consist of fu rnishing and installing new corrugated metal pipe, helical corrugated metal pipe, slotted pipe, pipe-arches, high density polyethylene (corrugated interior), high density polyethylene (smooth interior), and polyvinyl chloride pipe, and the relaying of existing corrugated metal pipe, helical corrugated metal pipe, slotted pipe, pipe-arches, high density polyethylene (corrugated interior), high density polyethylene (smooth interior), and polyvinyl chloride pipe at the locations shown in the contract or ordered by the Engineer in accordance with the requirements of these Specifications.
719.02 Material Requirements
1.Flared end sections for flexible pipe shall be metal and shall conform to the requirements of Section 1036.
2.Approved water-tight and soil-tight joints are shown on the Department’s Approved Products List.
3.Flap gates shall conform to t he requirements of Section 1043.
4.Corrugated metal pipe, helical corrugated metal pipe, and pipe-arches shall be Zinc Coated (Galvanized) Pipe, Aluminum Coated Pipe, or Polymer Coated Pipe and shall conform to the requirements of Section 1035.
5.Slotted pipe shall conform to the requirements shown in the contract.
6.Unless otherwise specified in the contract, the minimum gage or sheet thickness shall conform to Sections 1035 and 1036.
7.Plastic pipe shall conform to the requirements of Section 1038.
8.The Contractor shall not order or deliver the pipe until a list of sizes and lengths is furnished by the Engineer.
719.03 Construction Methods
1.Excavation and backfilling shall be performed by the Contractor in accordance with the requirements of Section 702 and the contract.
2.The Contractor shall lay the pipe true to the lines and grades shown in the contract or as directed by the Engineer. Any pipe which is not true in alignment or to the established grade or which shows any settlement after laying shall be taken up and relaid by t he Contractor at no additional cost to the Department.
3.Deflection Testing: a. When plastic pipe is used or when corrugated metal pipe 48 inch (1200 mm) or larger is used, the Contractor shall periodically check for pipe deflection during pipe installa tion and again not less than 30 days following completion of the roadway embankment. The internal diameter of plastic pipe shall not be reduced by more than 5% of its design diameter. The internal diameter of corrugated me tal pipe shall not be reduced by more than 7.5% of its design diameter. If t he installation does not meet these requirements, the pipe shall be remo ved and replaced at no additional cost to the Department.
719.03 Flexible Pipe Culverts (Corrugated Metal and Plastic)
- 628 - b. During the required 30-day reinspection of the culverts, the Contractor must treat the culvert as a “confined space”. Appropriate safety procedures shall be followed. The Cont ractor shall provide the appropriate safety equipment.
c.Optional devices for deflection testing include electronic deflectometers, calibrated television or video cameras, or properly sized "go, no-go" mandrel. Deflection measurements can be made directly with extension rulers or tape measures at 10 feet (3 m) increments in pipes that allow safe entry. To ensure accurate measurements, the pipe should be cleaned before testing.
d.Deflection testing will not be required on corrugated metal pipe extensions of less than 25 feet (7.6 m).
4.Pipe Joints: a. All flexible pipe installed under the roadway prism shall be connected with an approved water-tight joint. All flexible pipe installed outside of the roadway prism shall be connected with an approved soil-tight joint.
b.If the contract calls for the extension of a corrugated metal pipe culvert, the pipes shall be connected with an approved water-tight connecting band. In all cases where an existing concrete headwall is in place, the old concrete shall be completely removed.
5.The Contractor shall clean accumulations of soil and debris, haul, and relay all culvert pipe designated to be relaid in accordance with the methods herein described for installing new pipe. The Contractor shall carefully remove the pipe from its existing location, transport it to and install it in the new location in accordance with the methods herein described for installing new pipe. Pipe damaged by the Contractor shall be replaced with pipe of similar type by the Contractor without additional compensation. New metal bands or joint material shall be supplied and installed when necessary.
6.The Contractor shall strut or take other action recommended by the manufacturer for all corrugated metal culverts with diameters greater than 48 inches (1200 mm) to insure that the pipe’s final shape is properly aligned.
7.Instead of strutting corrugated metal pipe 48 inches (1200 mm) or larger in diameter, the Contractor may furnish corrugated metal pipe with the vertical axis fabricated out of round 5% of the normal diameter from end to end of the pipe. The elongation shall be made by approved shop methods, and any coating damaged or destroyed shall be repaired or replaced. If helical metal pipe 48 in ches (1200 mm) or larger in diameter is furnished with the vertical axis fabricated out of round instead of strutting, then field connections shall be made with match-marked connecting pipe to assure that the helical sections match when the ve rtical axis of the pipe sections are brought together.
8.All flexible pipe installed under the roadway prism shall be bedded and backfilled as shown in the contract. Granular bedding and backfill will not be required for corrugated metal pipe extensions unless called for in the contract. Flexible Pipe Culverts (Corrugated Metal and Plastic) 719.05 - 629 - 9. Plastic pipe shall be installed by the Contractor in accordance with the contract, ASTM D 2321, and the manufacturer’s recommendations.
10.When polymer pre-coated pipe is used, in order to protect the coated pipe, the Contractor shall us e padded or nonmetallic slings and padded straps when handling the pipe. This includes unloading, moving and installation.
719.04 Method of Measurement
1.Excavation, concrete, and reinforcement for headwalls will be measured for payment in accordance with the provisions in Table 719.01. Table 719.01 Method of Measurement Requirement Subsection Excavation for St ructures ................ 702.04 Concrete ......................................... 704.04 Reinforcem ent ................................ 707.04
2.Flexible pipe shall be measured as described in Subsection 718.04.
3.Granular bedding and backfill will not be measured for payment, but shall be considered subsidiary to the pipe being installed.
719.05 Basis of Payment
1.Pay Item Pay Unit ____inch (mm) ____Pipe Linear Foot (LF) [meter (m)] Relaying Corrugated Metal Pipe Linear Foot (LF) [meter (m)] ____inch (mm) Round Equiva lent Linear Foot (LF) Corrugated Metal Pipe [meter (m)] ____inch (mm) Corrugated Linear Foot (LF) Metal Slotted Pipe [meter (m)] Table 719.02 Basis of Payment Requirement Subsection Excavation for St ructures ................... 702.05 Concrete ............................................ 704.05 Reinforcem ent ................................... 707.05
2.Payment for excavation, concrete, and reinforcement for headwalls shall be made in accordance with the provisions shown in Table 719.02.
3.Payment is full compensation for all work described in this Section. - 630 - SECTION 720 -- CONCRETE PIPE CULVERTS
720.01 Description
1.This work shall consist of furnishing and installing new reinforced concrete culvert pipe (round, pipe-arch, and elliptical) and reinforced concrete slotted pipe and the relaying of existing reinforced concrete pipe at locations shown in the contract and in accordance with the requirements of these Specifications.
720.02 Material Requirements
1.The Contractor shall not orde r the pipe until a list of sizes and lengths is furnished by the Engineer.
2.Reinforced concrete culvert pi pe shall conform to the requirements of Section 1037.
3.Reinforced concrete slotted pi pe shall conform to the requirements shown in the contract.
4.Approved preformed plastic gaske ts are shown in the Department’s Approved Products List.
720.03 Construction Methods
1.Excavation and backfilling shall be performed by the Contractor in accordance with the requirements of Section 702.
2.Joints:
a.The Contractor shall lay t he pipe true to established lines and grades with groove ends upstream and tongue ends fully entered into the adjacent sections of pipe.
b.All reinforced concrete pipe under the roadway prism shall be tongue and groove (T&G) or modified tongue and groove type, and have water-tight joints using fibered roof coating or gaskets.
c.Bell And Spigot Pipe: (1) When a bell and spigot section of pipe is laid, the lower portion of the hub, bell, or groove of the preceding pipe shall be filled on the inside with sufficient mortar to bring the inner surface of the abutting pipes flush and even.
2.After the pipe is laid, the remainder of the joint shall be filled and packed with cement mortar; and sufficient additional material shall be used to form a bead around the joint.
3.The inside of the joint shall be wiped and finished smooth. (4) After the initial set, the cement mortar on the outside shall be protected from the sun with a moist earth covering.
d.As an alternate to mortared joints, rubber gaskets or flexible plastic gaskets meeting the specific ation requirements of AASHTO M 198 may be used if the design of the joints is in conformance with this AASHTO designation.
e.After the pipe is laid, all lift holes shall be filled with cement mortar (1 part cement and 2 parts sand).
Source: Nebraska Standard Specifications for Highway Construction, 2017 Edition. Pages 661–663 of 1,048.