- 636 - SECTION 722 -- SEWERS
722.01 Description
1.This work shall consist of excavating sewer trenches, constructing and laying pipe sewers, and backfilling sewer trenches to the dimensions shown in the contract.
722.02 Material Requirements
1.The type of sewer pipe allowed shall be designated in the bid proposal Schedule of Items. When the ty pe of pipe is not designated in the Schedule of Items, the Contractor may use either Reinforced Concrete Sewer Pipe, High Density Polyethylene Pipe (Smooth Interior), or Polyvinyl Chloride Pipe.
2.All sewer pipes shall conform to the requirements in Table 722.01. Table 722.01 Material Requirements Applicable Materials Section Reinforced Concrete Sewer Pipe ...................... .1037 Plastic Pipe ....................................................... .1038 Cast Iron Pipe ................................................... .1039 Ductile Ir on Pipe................................................ .1039 Acrylonitrile-Butadiene-Styrene (ABS) Composite Se wer Pipe ..................................... .1038
3.The Contractor shall not orde r any pipe until a list of sizes and lengths is furnished by the Engineer.
4.Approved water-tight joints for plastic pipes are shown on the Department’s Approved Products List.
722.03 Construction Methods
1.Except for plastic sewer pipe installations under the roadway prism, all excavation, bedding and backfill shall be performed in accordance with the requirements of Sect ion 702 and the contract.
2.Plastic pipe shall be installed in accordance with the contract, ASTM D 2321, and the manufacturer’s recommendations.
3.Granular bedding and backfill are required for all plastic pipe installed for use in sewers under the roadway prism (or back of curb to back of curb). Plastic pipe installed beyond these limits will not require granular bedding and backfill, but will require installation in accordance with the contract, ASTM D 2321, and the manufacturer’s recommendations.
4.When the Contractor selects the Type 3 Installation shown in the contract, granular bedding and backfill will be optional for concrete pipe.
5.The Contractor s hall lay all pipes to th e line and grade established in the contract.
6.The Contractor shall inspect a nd sound all pipes fo r cracks or other defects and report to the Engineer. Sewers 722.04 - 637 - 7. Pipe alignments shall be marked by the Contractor so that, when joined in the ditch, a sm ooth tube will be formed.
8.All reinforced concrete sewer pipe connections shall be tongue and groove (T&G), or modified tongue and groove type, and have approved water-tight joints. The general method of laying concrete pipe, as required in Section 720, shall apply to the Contra ctor when laying reinforced concrete sewer pipe, with the exception of the joints. When reinforced concrete sewer pipe is used, the following methods shall be used for sealing joints:
a.When called for in the contract, full compression gaskets conforming to the requirements of AST M C 361/C 361M or distorted-type flexible rubber gaskets conforming to the requirements of ASTM C 443/C 443M shall be used and installed on each section of the pipe in accordance with the manufacturer's recommendations and standards.
b.When the use of gaskets is not called for in the contract, all joints shall be sealed with a full compression gaskets described above or filled and pointed both inside and outside of the pipe with a troweling grade of fibered roof coating complying with the requirements of Federal Specification SS-C-153 for Bituminous Plastic Cement, Type I, Asphaltic Base.
9.All plastic pipe installed for sewers shall be connected with an approved water-tight joint.
10.The Engineer shall approve t he Contractor’s method for drawing the pipes together to close the gap.
11.Deflection Testing:
a.When plastic pipe is used, the Contractor shall periodically check for pipe deflection during pipe installation and again not less than 30 days following completion of the roadway embankment. During the required 30-day reinspection of the culverts, the C ontractor must treat the culvert as a “confined space”. Appropriate safety procedures shall be followed. The Contractor shall provide the appropriate safety equipment.
b.Optional devices for deflection testing include electronic deflectometers, calibrated television or video cameras, or properly sized "go, no-go" mandrels. 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.
722.04 Method of Measurement
1.Sewer pipe shall be measured in place by the linear foot (meter) along the axis of the pipe, and the measurement shall be taken between centers of new manholes, flush tanks, cl eanouts, inlets, junctions with other sewers, or dead ends, as the case ma y be; except that in the case of installation of flared-end sections, the measurement shall be taken to the point at which the pipe is joined to the flared-end section.
2.When tapping a structure is calle d for in the contract, measurement for sewer pipe will terminate where the farthest extension of the pipes intersect the inside face of the structure.
722.04 Sewers
- 638 - 3. Where a sewer reduces to a smaller size, the larger sewer will be measured to the point where the sewer is the exact size of the smaller sewer, unless otherwise provided in the contract.
4.Additional allowances for elbows and connecting bands will be made as provided in Tables 718.01 and 718.02.
5.Excavation for sewers shall not be measured for payment. 6. At the junction of a new sewer pipe and a new box culvert, measurement will terminate where the fa rthest extension of the new pipe intersects the inside wall of the new box culvert; and this extension shall be the total allowance for building the junction.
7.At the junction of sewers, measurement shall be taken along the axis of the pipe and shall extend to the points of intersection of the two sewers; and this measurement shall be the total allowance for building the junction.
8.Granular bedding and backfill will not be measured for payment. 722.05 -- Basis of Payment 1. Pay Item Pay Unit ____inch (mm) Storm Sewer Pi pe, Linear Foot (LF) Type____ [Meter (m)] ____inch (mm) Sanitary Sewer Pipe, Linear Foot (LF) Type____ [Meter (m)] ____inch (mm) Round Equival ent Linear Foot (LF) Storm Sewer Pipe, Type____ [Meter (m)]
2.Excavation and backfill for sewers shall be subsidiary to the appropriate sewer pipe pay item.
3.Granular bedding and backfill for sewers shall be subsidiary to the appropriate sewer pipe pay item.
4.If unsuitable material is encount ered, it’s removal and backfill will be paid for as extra work as stipulated in Subsection 109.05.
5.Payment is full compensation for all work described in this Section. - 639 - SECTION 723 -- TAPPING EXISTING DRAINAGE AND SEWER FACILITIES
723.01 Description
1.This item shall consist of all work that is necessary to provide openings in the existing drainage or sewer facilities and for new connections into these structures at the locations and to the dimensions specified in the contract or ordered by the Engineer.
723.02 Construction Methods
1.The Contractor shall tap, seal , and connect pipes to pipes and/or structures in a neat and professional manner as shown in the contract.
723.03 Method of Measurement
1.This work will be measured by the each.
723.04 Basis of Payment
1.P a y I t e m P a y U n i t Tapping Existing _____ Each (ea)
2.Payment is full compensation for all work described in this Section.
Source: Nebraska Standard Specifications for Highway Construction, 2017 Edition. Pages 670–672 of 1,048.