2504.01DESCRIPTION.
This work shall consist of construction of sanitary sewers together with the utility access, lamp holes, and other incidentals, in accordance with the contract documents and the following requirements. In addition to these specifications, it shall be the Contractor's duty to comply with local ordinances and requirements that may apply to the work. The provisions of Section 2403 shall apply.

2504.02 MATERIALS.
Materials used in sanitary sewers shall meet requirements of Division 41 for the respective materials.

All steel reinforcing bars used in utility accesses shall be ASTM A 615/A 615M, Grade 60 (400).

2504.03 CONSTRUCTION.
The construction of sanitary sewers shall conform to the following requirements. In addition, if plastic pipe is specified, the requirements of ASTM D 2321 and the recommendations of the manufacturer shall also apply, unless otherwise noted in the contract documents.

A. Preparation of Trenches for Pipe Placing.
Trenches shall be open cut except with written permission of the Engineer. Permission for tunnel work may be given for crossing under crosswalks and house drives or under service pipes when such tunnels will not exceed 10 feet (3 m) in length.

The length of trench to be opened at one time may be limited when, in the opinion of the Engineer, such limitation is necessary.

Trenches shall be of sufficient width to provide free working space on each side of the pipe of not less than 4 inches (100 mm), and not more than 30% the nominal diameter of the pipe for pipes larger than 12 inches (300 mm). Trench widths greater than these must be approved by the Engineer.

Trenches shall be kept free from water during the installation of the pipe.

When the contract documents require or field conditions necessitate limitations on the top width of trench; sheeting, shoring, and bracing shall be employed to the extent necessary to provide adequate safety to the workers engaged in the work.

Sheeting, shoring, and bracing shall remain in place until backfilling has progressed to a stage that its removal will not result in damage to pipelines or other structures or injury to personnel.

B. Preparation of Foundation for Pipe Placing.
The final bedding surface on which the pipe rests shall be firm earth or approved granular material free of rocks, stones, roots, or other objectionable material greater than 3 inches (75 mm) in diameter.

If the pipe can not be bedded in firm earth, excavation shall be carried below the required elevation at the discretion of the Engineer, then backfilled with granular material meeting requirements of Section 4120, or sand containing no particles retained on a 3/4 inch (19 mm) sieve and not more than 10% passing the No. 200 (75 µm) sieve. If the foundation is in rock, the excavation shall be carried to an elevation which will provide for a bedding course not less than 12 inches (0.3 m) thick below the body of the pipe. This bedding course shall be suitable earth or sand free from rocks, roots, sod, or vegetable matter, and shall be firmly tamped in place before shaping the bed to fit the pipe.

Before pipes are placed, the bottom of the trench shall be shaped to give full support to the lower 25% of the pipe circumference. Adequate bell holes shall be made, when necessary, to provide a uniform support along the barrel of the pipe.

C. Pipe Placing.
Pipe placing shall commence at the lowest point so that the tongue or spigot ends point in the direction of the flow. All pipes shall be placed with the ends abutting and true to line and grade. The grade and line of each pipe shall be checked to ensure proper placement.

Pipe joints shall be clean prior to installation.

Unless otherwise specified, the pipe joints shall be sealed by either a joint sealer or gasket.

If a joint sealing compound is used, it shall meet the requirements of Article 4149.08, or with a compound approved by the Engineer.

D. Backfilling.
Before any backfill is placed, the pipeline shall be checked with a light. Each unit shall show a good light circle throughout its length. Backfill shall be placed in a manner that the pipe is not displaced from the required line and grade.

Backfill shall be suitable earth free from boulders, frozen clods, large roots, or excessive sod or other vegetation. Backfill shall first be carefully hand tamped under and around the pipe, up to 6 inches (150 mm) above the top of the pipe, in lifts not to exceed 4 inches (100 mm) of loose thickness. Care shall be used to place and tamp this bedding course to not disturb joints, alignment, or grade of the pipe. Filling shall be carried on simultaneously on both sides of the pipe.

When the pipeline is placed beneath a roadway or driveway, or within 5 feet (1.5 m) of the edge of an existing or proposed pavement or base course; after hand tamping, the remainder of the backfill shall be consolidated in 6 inch (150 mm) lifts to the surface with a mechanical tamper of an approved type.

When the pipeline is clear of roadways or driveways to a distance of 5 feet (1.5 m) or more, after hand tamping, the remaining backfill shall be consolidated in 6 inch (150 mm) lifts with a mechanical tamper or, when permitted by the Engineer, by flooding with water. Settlements which develop after flooding shall be filled to the top of the trench.

E. Utility Access.
Utility access shall have an inside diameter of not less than 4 feet (1.2 m) and shall be built of brick, segmental concrete blocks, or precast concrete utility access units. Each utility access shall be built in accordance with the contract documents, on a level concrete base and at proper elevation, using Class C concrete.

Walls of brick utility access shall be 8 inches (200 mm) thick consisting of header courses with brick laid to break joints. Mortar joints between courses shall not exceed 1/2 inch (12 mm) in thickness and vertical joints between bricks shall not exceed 1/4 inch (6 mm) on the inside. All joints shall be shove joints completely filled with mortar.

At the top, the courses may be drawn in at the rate of 1 inch (25 mm) per course to fit the cast iron cover ring.

Segmental concrete block utility access shall be built with mortar joints not more than 1/2 inch (12 mm) in thickness between courses. Blocks shall be laid to break joints, and all joints shall be completely filled with mortar.

The entire outside surface of utility access constructed of brick or segmental concrete blocks shall be plastered with a layer of mortar having a thickness not less than 1/2 inch (12 mm).

Precast concrete utility access units shall meet the requirements of Article 4149.04. The length of any section of pipe through which notches or holes are cut or framed shall be at least twice the greatest dimension of the largest hole or notch, measured parallel to the centerline of the pipe.

Precast concrete sections shall be set in mortar or shall be provided with a rubber gasket to produce a waterproof joint.

Utility access steps shall be installed only when specifically required in the contract documents. When required, steps shall be placed in the utility access walls at the intervals specified but at a spacing of not more than 16 inches (0.4 m).

Inlet pipes shall not project into the well and outlet pipes shall not project beyond the inside face of the sidewall.

A concrete fillet shall be placed in the bottom of the utility access approximately as shown in the contract documents. Special shaping of this fillet is required to provide a smooth channel through the intake. The top surface of the fillet shall slope at a rate of approximately 12:1 toward the channel. Half-pipe sections bedded in concrete to form the flow line through the utility access shall be accurately joined to the sections built into the walls. Pipe sections to be installed in the utility access shall be furnished by the Contractor for the lines of pipe. The Contractor may be required to make adjustments to the proposed sewer lines for proper connection to the utility access.

The Contractor shall install accessory units (spacer, utility access top, casting, etc.) as necessary to obtain utility access elevations as shown in the contract documents.

Details for drop utility access, lamp holes, or other special construction features will be shown in the contract documents.

2504.04 CLEANING UP.
After completion of the work, the Contractor shall thoroughly clean and smooth the disturbed area and remove excess dirt and material.

2504.05 METHOD OF MEASUREMENT.
The quantity of sanitary sewer pipe, in feet (meters), to the nearest foot (0.1 m), of each size of sanitary sewer placed will be the quantity shown in the contract documents. The number of utility accesses and lamp holes will be the quantity shown in the contract documents. When the contract documents provide for the construction of paved inverts through the utility access, and they have been constructed, pipe will be measured from center to center of utility access. Pipe will be measured from the near inside wall of one utility access to the near inside wall of the next utility access along the same line of pipe. Any length of pipe used to construct vertical drops outside of utility access will also be measured for payment.

Aprons and appurtenances of the type specified will be measured in accordance with Articles 2416.05 or 2417.06.

2504.06 BASIS OF PAYMENT.
When the contract documents indicate the depth of sanitary sewer excavation and the pipes have been laid substantially to the elevation of the flow line indicated, the Contractor will be paid the contract unit price per linear foot (meter) of sanitary sewer complete and the contract unit price for each lamp hole and utility access complete. The Contractor will be paid the contract unit price for sanitary sewer pipe of the type and size specified per linear foot (meter).

Aprons and appurtenances of the type specified will be paid in accordance with Articles 2416.06 or 2417.07.

When the contract documents do not indicate the depth of sanitary sewer excavation, or when the flow line has been changed by 1 foot (0.3 m) or more from the elevation indicated, or when unexpected solid rock excavation is encountered, the contract unit price per linear foot (meter) of sanitary sewer shall be as provided in the contract, at the contract unit price as though no overdepth excavation or unexpected solid rock had been encountered. Additional payment will be made for the overdepth excavation or unexpected solid rock excavation or both as provided for storm sewers in Article 2503.05, A, B, and C. The contract unit price for utility access and lamp holes will be adjusted as provided in Article 2503.05, D, except that price adjustment will not be made because of class of excavation encountered.

The payment for each Lamp Hole shall be full compensation for furnishing all material, labor, and equipment necessary to complete the work including excavation, backfilling, constructing lamp holes, special shaping through lamp holes, and removal of excess material from the project. It shall include furnishing sections of pipe for inlet and outlet lines through walls of lamp holes.

The payment for Utility Access shall be full compensation for furnishing all material, labor, and equipment necessary to construct the utility access to the depth required, including accessory units, as necessary; excavation; backfilling; special shaping through utility accesses; frames and covers, and constructing drop inlet pipe and concrete encasement, if required.