- 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). Concrete Pipe Culverts 720.05 - 631 - 3. Irrigation Structures:
a.When concrete pipe is laid for an irrigation structure, full compression gaskets conforming to the requirements of ASTM C 361 shall be used and installed on each section of the pipe as per the manufacturer's recommendations and standards.
b.In the event that full compre ssion gaskets are not available for the type of pipe specified, a preform ed plastic gasket for concrete pipe joints shall be supplied meeting Federal Specification SS-S-00210, "Sealing Compound, Preformed Plastic for Pipe Joints" Type 1, Rope Form.
c.Hydrostatic Testing: (1) The Contractor shall hydrostatically test all precast concrete pipe laid for irrigation structures. Where the bottom grade of the pipeline at the outlet is less than 4 feet (1.2 m) above the inside top of the pipe at its lowest point, no test will be required. Water fo r making the tests shall be furnished by the Contractor and shall be introduced into the siphons and pipelines in such a manner as to prevent rapid temperature drops in the pipe.
2.Tests shall be made as soon after completion of construction of the structure as prac ticable, but in no event sooner than 20 days after the placing of any concrete that will be subject to hydrostatic pressure during the test. Testing under full operating head or to heads designated by pipe classification will not be required, but the lines shall be tested to the maximum practical head by filling with water to the elevation of the bottom grade of the outlet end or by other methods as directed by the Engineer. After the pipe has been filled to the specified elev ation, it may be allowed to stand for a period not to exceed 15 days to saturate the pipe before testing. The test period shal l be for 24 consecutive hours during which time the water surface in the structure shall be maintained at the specified test elevation.
3.The total amount of leakage during this 24 hour test period shall not exceed 215 gal/inch (20 L/ mm) of internal diameter per mile (kilometer). If the leakage exceeds 60% of the maximum allowed, the Engineer may require the water to be ma intained at the limiting elevation stated above for an additional period of 10 days to allow evidence of excessive leakage at any point to become apparent. Individual leaks, evidenced by appearance of moisture, shall be repaired.
4.The Contractor shall furnish all labor, equipment, materials, tools, water, and water-measuring apparatus required for making the tests; and the cost ther eof shall be included in the unit bid price for the size of pipe being tested.
d.The Contractor shall make al l repairs or replacements, or both, that are necessary to secure the required watertightness.
e.The Contractor shall be responsible for any damage to the structures or adjacent work due to testing.
4.Any pipe which is not true in alignment or to the established grade or which shows any settlement shall be removed and reinstalled by the Contractor at no additional cost to the Department.
720.03 Concrete Pipe Culverts
- 632 - 5. When the contract designates t he extension of a concrete pipe culvert, the connection shall be made by enclosing the connecting joint with a concrete collar. The collar shall be constructed in accordance with the requirements of Section 704; and the st eel reinforcement shall be furnished, handled, and placed in accordance with the requirements of Section 707. In all cases where a concrete headwall is in place, it shall be completely removed.
6.Concrete culvert pipe which is designated to be relaid shall be cleaned of accumulations of soil and debris, hauled, and relaid in accordance with the methods herein described for installing new pipe.
720.04 Method of Measurement
1.Excavation and concrete and reinforcement for headwalls and collars will be measured for payment in accordance with the provisions in Table 720.01. Table 720.01 Method of Measurement Requirement Subsection Excavation for Structures .................................. .702.04 Concrete ........................................................... .704.04 Steel Reinfo rcement ......................................... .707.04
2.See Subsection 718.04 for the methods to measure concrete pipe.
3.Concrete pipe collar connections are measured by the cubic yard (cubic meter) of concrete and pounds (kilograms) of reinforcing steel used.
4.At the junction of new concre te pipes, the measurement shall be extended to the center of the pipe being tapped. This extension shall be the total allowance for building the junction.
720.05 Basis of Payment
1.Payment for excavation and for concrete and reinforcement for headwalls and collars shall be made in accordance with the provisions in Table 720.02. Table 720.02 Basis of Payment Requirement Subsection Excavation for Structures ............................ .702.05 Concrete ...................................................... .704.05 Steel Reinfo rcement .................................... .707.05 Concrete Pipe Culverts 720.05 - 633 - 2. P a y I t e m P a y U n i t _____ inch Reinforced Concrete Pipe Linear Foot (LF) [Meter (m)] _____ inch Round Equivalent Reinforced Linear Foot (LF) Concrete Pipe [Meter (m)] _____ inch Reinforced Concrete Linear Foot (LF) Slotted Pipe [Meter (m)] Relaying Reinforced Concrete Pipe Linear Foot (LF) [Meter (m)] Class ______ Concrete for Cubic Yard (CY) Concrete Collars [Cubic Meter (m3)] Reinforcing Steel for Collars Pound (lb) [ K i l o g r a m ( k g ) ]
3.The cleaning and the hauling of t he pipe from the site of removal or from the place where it is stored to the point or points at which it is to be relaid will not be paid for directly, but shall be considered subsidiary to the work of relaying the pipe.
4.Payment is full compensation for all work described in this Section. - 634 - SECTION 721 -- DRIVEWAY CULVERT PIPE
721.01 Description
1.This work shall consist of furnishing and installing new pipe culverts, typically in round, pipe-arch, or elliptical shapes, of the various types at the locations shown in the contract or designated by the Engineer.
721.02 Material Requirements
1.The pipe furnished shall c onform to the requirements in Table 721.01. Table 721.01 Material Requirements Applicable Materials Section Corrugated Me tal Pipe ............................... .1035 Reinforced Concrete Culvert Pipe .............. .1037 Plastic Pipe ................................................ .1038
721.03 Construction Methods
1.The Contractor shall not order or deliver the pipe until a list of sizes and lengths are furnished by the Engineer.
2.The corrugated metal pipe and reinforced concrete pipe for driveways shall be installed in accordance with the applicable portions of Sections 718, 719, and 720. Plastic pipe for driveways shall be installed in accordance with the contract, ASTM D 2321, and the manufacturer’s recommendations.
3.Deflection Testing: a. When plastic pipe is used or when corrugated metal pipe 48 inch (1200 mm) and larger is used, t he Contractor shall periodically check for pipe deflection during pipe installation 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.
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.
4.Granular bedding and backfill will not be required for driveway culvert pipe unless called for in the contract.
Source: Nebraska Standard Specifications for Highway Construction, 2017 Edition. Pages 664–667 of 1,048.