2503Pipe Sewers

2503.1DESCRIPTION

This Work consists of constructing pipe sewers using plant-fabricated pipe and other appurtenant Materials installed for conveyance of sewage, industrial wastes, or storm water. Construct manholes and catch basins in accordance with 2506, “Manholes and Catch Basins.” Provide aprons as shown on the Plans and in accordance with 2501, “Pipe Culverts.”

2503.2MATERIALS

A Pipe Provide one of the following types of sewer pipe as specified or allowed as an option on the P lans or in the Special Provisions. Use pipe meeting the lowest strength class specified or greater, as shown on the Plans or specified in the Special Provisions. Perform special fabrication or jointing as shown on the Plans. Provide pipe sewers with the coating type shown on the Plans or specified in the Special Provisions. C Pipe Joint Sealer Materials

2503.3CONSTRUCTION REQUIREMENTS

A General Construct sewer installations in accordance with 2451, “Structure Excavations and Backfills,” for excavation, foundation construction, and backfilling of prefabricatedS tructures and in accordance with the following requirements: B Excavation For locations with cover over the top of the pipe at least 15 feet, ensure the excavation dimensions meet the following:

pipe, provide nearly vertical side slopes

Table 2503.3-1 Maximum Trench Width for Pipe Sewer Pipe Diameter, inch Maximum Trench Width* < 42 Outside diameter plus 24 inches 42 – 54 1.5 times outside diameter > 54 Outside diameter plus 36 inches * 1 foot above pipe

If the Contractor excavates the trench to a width greater than the values specified in Table 2503.3-1, the Engineer may direct the Contractor to provide a higher class of bedding, a higher strength pipe, or both, than that required by the Contract, at no additional cost to the Department. C Laying Pipe C.1 General Lay the pipe to the line and grade shown on the Plans. Use standard or specially manufactured fittings for pipe junctions and turns. At sewer connections with an existing manhole or catch basin, make a suitable connection as approved by the Engineer through the wall of the manhole or catch basin. Use vitrified clay or concrete stoppers sealed in place to plug branch openings or service connections provided for future use. Provide any additional cover required to avoid damage to the pipe during construction. Maintain adequate cover until paving is completed, or until the installation is accepted by the Engineer if paving is not required. Repair or replace pipe damaged by Contractor operations to the satisfaction of the Engineer, at no additional costs to the Department. C.2 Metal Sewer Pipe Lay corrugated metal pipes containing circumferential joints with the outside laps pointing upgrade and with the longitudinal joints on the sides. Use metal connecting bands, centered over the joint, to join metal pipe sections. Place the pipe sections so that the pipe ends are abutting. Tighten the band to ensure a tight joint so that the soil does not infiltrate into the pipe and the sections do not pull apart.

C.3 Concrete Sewer Pipe Lay concrete pipe with the female end of each section upgrade. Tightly join the pipe sections so that the interior of the pipe sections abut each other. Use preformed rubber or bituminous mastic elastic joint sealer Material to provide flexible water-tight joint seals for concrete pipe. Where the pipe is designed to accommodate preformed gasket type seals, seal the joints with the preformed gasket as shown on the Plans and meeting the performance requirements of 3726, “Preformed Gasket Seals for Concrete Pipe.” Keep gaskets and joint surfaces clean and free from soil during installation. Follow manufacturer’s recommendation for fitting or coupling assembly and installation. Use a lubricant, if required, that will not deteriorate the gasket and pipe Materials . Where the pipe is not required to accommodate preformed gasket type seals, seal the joints with bituminous mastic and a full circumferential wrap of geotextile Material extending at least 1 foot on each side of the joint. Secure the circumferential wrap against the outside of the pipe by metal or plastic strapping or by other methods approved by the Engineer . Apply mastic joint sealer Materials as recommended by the manufacturer. Wipe joints clean on the inside after sealing. Plug lifting holes with a precast concrete plug, sealed and covered with mastic or mortar. Use approved fasteners shown on Standard Plate 3145 to tie together concrete pipe sections unless otherwise shown on the Plans or specified in the Special Provisions. Provide backfill Material in accordance with the Plan, modified to 100 percent passing the 3-inch Sieve within 2 feet of the pipe. C.4 Plastic Sewer Pipe Follow bedding, backfill, and trench width requirements shown in the Plan. If cover over plastic pipe is modified from what is shown in the Plan, follow plastic pipe minimum cover and maximum fill height requirements in the Drainage Manual . Provide embedment Material in accordance with the Plan, modified to 100 percent passing the 1-inch Sieve within 2 feet of the pipe. Use the embedment Material to provide 1 foot of fill over the pipe and fill for a trench width as specified by the C ontract. Place pipes and backfill in dry conditions by controlling the water conditions . Dewater groundwater and surface runoff to keep the water level below the pipe foundation. Place pipes on the bedding starting at the downstream end of the pipe installation with the female end of each section upgrade. Make connections with bell and spigot joints using an elastomeric rubber seal (gasket) to provide water-tight joints that do not allow soil, Silt, or water to migrate through the joint. Install joints so connected pipe sections form a continuous surface free of irregularities in the flow line. Tightly join the pipe sections so that the interior of the pipe sections abut each other . Keep gaskets and joint surfaces clean and free from soil during installation . Follow manufacturer’s recommendation for fitting or coupling assembly and installation . Use a lubricant, if required, that will not have deteriorating effects on the gasket and pipe Materials .

Before allowing vehicles or heavy construction Equipment to travel over the pipe trench, maintain a minimum cover depth of Material above the pipe of at least 2 feet and meeting the requirements of AASHTO LRFD Bridge Construction Specifications, Section 30, Table 30.6-1. Perform deflection testing of all plastic pipe at least 30 Calendar Days after installation. Remove obstructions including sediment, standing water, or other obstructions that would interfere with mandrel testing prior to deflection testing. Dewatering and additional Work associated with preparing for and performing deflection testing is included in the bid price of the pipe. Evaluate the pipe to determine if the specific internal diameter of the barrel has deflected more than 5 percent. Use the following methods to perform the deflection test unless otherwise specified in the Plan:

for pipes with an inside diameter 2 feet or smaller. Pull the mandrel through the pipe using non-mechanical means.

the Plans and approved by the Engineer. Direct measurements can only be used on pipes with an inside diameter of 30 inches or greater. If the Department allows direct measurements, the Engineer must take measurements at randomly select locations, but at a minimum once every 10 feet throughout the pipe length and at the pipe ends. Visually inspect the pipe and take additional measurements at any location of observed anomaly or deflection. Ensure personnel making direct measurements meet confined space entry requirements in accordance with 1706, “Employee Health and Welfare.”

when specified in the Plans and approved by the Engineer. The Engineer will not accept pipe that has a deflection of greater than 5 percent or is damaged. Remove unacceptable pipe and install new pipe or reuse undamaged pipe. Retest the relaid pipe for 5 percent deflection after at least 5 Calendar Days after embedment Material is installed to grade. Send deflection testing results to the Hydraulic Engineer with the SP number, pipe location, material type, size, date built, date tested, and results from the mandrel test or other deflection test. D Backfill Backfill sewer installations as shown on the Plans and in accordance with 2451, “Structure Excavations and Backfills.” Surplus excavated Materials not used for backfill shall become the property of the Contractor . Dispose of surplus Material in accordance with the disposal form submitted to and approved by the Engineer. E Installation by Jacking Install pipe by jacking in accordance with 2501.3C.1, “Laying Pipe, General.” F Cleanout Clean sediment and debris from sewers before final acceptance.

G Geotextile Use Geotextile 3733 Type 1 to wrap concrete pipe joints or for other drainage applications .

2503.4METHOD OF MEASUREMENT

A Excavation The Engineer will measure excavation specified or directed as E xtra Work in accordance with 2451.4, “Structure Excavations and Backfills, Method of Measurement,” for prefabricated Structures. B Sewer Pipe The Engineer will separately measure each type of pipe by length along the centerline of the sewer. The Engineer will begin and end measurements at any of the following locations:

The Engineer will measure pipe transition sections as pipe of the larger or more costly size except for special sections designated by the Contract for measurement as a unit. The Engineer will classify sections of metal pipe at the outlets of clay or concrete sewers as metal sewers. Where pipe options are allowed, measurement will be made by length and type of pipe indicated on the Plan, regardless of the type of Material installed. No adjustments will be made for any additional Work required by the Contractor based on choice of Material. The Engineer will measure Department-provided sewer Materials required by the Contract by the length of installed sewer, separated by type but not by size. C Sewer Appurtenances The Engineer will separately measure flap gates and other specially identified appurtenant items of each design by the number of units of each type and size incorporated in the sewerS tructures. D Granular Materials Standard bedding and backfill is not measured but is included in the cost of the relevant sewer Pay Items unless identified otherwise in the Plan.

2503.5BASIS OF PAYMENT

The Contract Unit Price for the Contract Items for sewer pipe of each size, type, kind, and strength class include the costs of providing and installing the pipe complete -in-place as required by the Contract, except as otherwise specified in this section. The Contract Unit Prices for Plastic pipe sewers will include the cost of deflection testing and buoyancy protection as required by the Contract. The Department will pay for elbow, tee, or wye sections and additional connectors directed by the Engineer, but not shown on the Plans, by the invoice cost of the Materials. The Department will pay for installing Department-provided sewer Materials including Work and additional Materials used to complete the sewer installation by the relevant install only C ontract Pay Item, except for “Extra Work” or Work included in other relevant Contract Pay Items. The Department will include the cost of granular Materials for bedding and backfill with the relevant sewer Pay Items unless specified otherwise in the Plan.

The Contract Unit Price for the relevant sewer Contract item includes the costs associated with the disposal of surplus Material associated with sewer installation. If the Engineer approves of sewer pipe installation by the jacking method and C ontract Item does not exist, the Department will pay for a jacking installation on the basis of C ontract Unit Prices relevant for the trenching method. The Department will include the cost of aprons required in connection with the sewer construction with relevant Pay Items in accordance with 2501.5, “Pipe Culverts, Basis of Payment.” The Department will pay for required excavation greater than 1 foot below the bottom of the pipe as shown on the Plans as Extra Work in accordance with 1402, “Contract Revisions.” If the Plans do not include a Contract Pay Item, the Department will pay for the removal of ledge rock or rocks larger than 1/2 cubic yard in volume from the excavation as Extra Work in accordance with 1402, “Contract Revisions.” The Department will identify when pipe Material options are allowed in the Plans. Payment will be made by length and type of pipe indicated on the Plan, regardless of the type of Material installed. The Department will include the costs associated with using an option, such as differences in installation requirements including deflection testing, trench width, bedding Material Specifications and quantities in the Contract Unit Prices of the relevant pipe Pay Items. No adjustments will be made for any additional Work required by the Contractor based on choice of Material. The Department will include the cost of trench excavation with the relevant C ontract Pay Item for sewer installation. The Contract Unit Price for the relevant pipe Contract Item includes the cost of pipe cleaning except when specifically designated under other items. The Department will pay for sewers on the basis of the following schedule: Item No. Item Unit

2503.502 Flap Gate for † Pipe each

2 Install § each

3 Install § linear foot

3 ___” * Pipe Sewer ǁ linear foot

3 ___” Span* Pipe-Arch Sewer ǁ linear foot

3 ___” Span* Elliptical Pipe Sewer ‡ linear foot

3 ___” * Pipe Sewer Design# ǁ linear foot

* Specify kind in accordance with 2503.2A, “Pipe.” ǁ Specify strength class if other than minimum requirement. † Specify size and kind. ‡ Specify HE or VE, and strength class, if other than minimum requirement . # Specify pipe or joint designs and provide Standard Plate number. § Special item name.