ITEM 604 MANHOLES, CATCH BASINS, INLETS, INSPECTION WELLS, JUNCTION CHAMBERS, precast Reinforced Concrete outlets,
OR MONUMENTS

604.01 Description

604.02 Materials

604.03 Construction Methods, General

604.04 Excavation and Backfill

604.05 Brick and Block Masonry

604.06 Precast Concrete Modular Construction

604.07 Concrete (Cast-In-Place)

604.08 Method of Measurement

604.09 Basis of Payment

604.01 Description. This work consists of constructing or reconstructing manholes, catch basins, inlets, inspection wells, junction chambers, precast reinforced concrete outlets, or monuments of the type and sizes specified; or adjusting existing castings to grade, as specified.

Use all suitable material in the work. Alternatively legally use, recycle, or dispose of all excavated materials according to 105.16 and 105.17.

604.02 Materials. Furnish materials conforming to:

Structure concrete, Class C.................................. 499, 511

Brick and masonry units.............................................. 704

Precast reinforced concrete manhole,

.... catch basin, and inlet sections............................. 706.13

Precast reinforced concrete outlet........................... 706.15

Preformed expansion joint fillers............................. 705.03

Epoxy coated reinforcing steel................... 509.02, 709.00

Cast frames, grates, and covers. 711.12, 711.13, or 711.14

Welded frames and grates........................... 513.17, 711.01

Steps......................................... 711.13, 711.30, or 711.31

Structural backfill, Types 1, 2 and 3………………703.11

Resilient and flexible gasket joints........................... 706.11

Curing materials.......................................... 705.05, 705.07

Mortar.......................................................................... 602

604.03 Construction Methods, General. Construct the specified structures according to the plans. Place inlets, catch basins, inspection wells, junction chambers, monuments, or precast outlets at the locations and elevations shown in the plans according to the standard construction drawings or as directed by the Engineer. Place manhole castings at the elevation and station with offset to the center of the casting or as directed by the Engineer. Place the manhole base at the elevation and station with offset to agree with the pipe station, offset and pipe invert elevation according to the standard construction drawings or as directed by the Engineer. Use flat slab top manholes as shown on the standard construction drawing. Do not remove the flat slab top manhole lifting devices.

If the Engineer changes the structure elevation by more than 1 foot (0.3 m), the Department will pay according to 109.05.

Thoroughly mortar with a flush mortar joint the underdrain outlet pipe to the precast reinforced concrete outlet. Furnish and place lateral sewer connections including drops and leads except pipe included in Item 603.

Locate or cut conduits as shown on the standard construction drawings so they do not protrude inside the structure walls.

Take adequate precautions to prevent structure concrete or mortar cement from freezing. Preheat the brick, concrete block, or precast concrete structure throughout the entire mass to a temperature between 50 to 80 °F (10 to 27 °C) before placing mortar if the ambient temperature is 40 °F (4 °C) or less.

Set iron frames, tops, and covers of the type shown on the plans in a mortar bed with a flush mortar joint.

Prevent earth or debris resulting from construction operations from entering the manholes, catch basins, junction chamber, inlets, and precast reinforced concrete outlets. Remove any debris.

A. Reconstruction to grade

1. Carefully remove and clean the existing castings.

2. Remove the existing walls of manholes down to the spring line or below as necessary.

3. Remove existing walls of catch basins and inlets below the window openings, grates, or any points of wall failure.

4. Using the salvaged casting, reconstruct the structure to the new grade, conforming as nearly as practicable to the existing dimension and type of construction.

B. Adjustment to grade

1. Carefully remove and clean the existing frame, adjust the height of supporting walls, and reset the existing frame in a bed of concrete mortar or structure concrete to the new grade.

2. Carefully remove the existing cover or grate and install a casting or an approved adjusting device on file at the Laboratory or an adjusting device approved by the Engineer to the new grade and install per the manufacturer’s recommendations.

604.04 Excavation and Backfill. Excavate to dimensions that provide ample room for construction.

The Engineer will require the removal of unsuitable material below the structure bedding. Replace unsuitable material with Item 603 Structural Backfill. When the Engineer requires the removal and replacement of unsuitable material below the bedding for precast structures and below the structure for cast-in-place structures, the Department will provide compensation according to the Contract or by Supplemental Agreement.

Ensure that the backfilling follows the completion of the work as closely as the type of construction will permit. Do not disturb the structure while backfilling. Backfill structures located within the pavement area with structural backfill to the subgrade according to Item 603, Type A or B conduit. Backfill structures outside of the pavement area according to Item 603, Type C conduit.

604.05 Brick and Block Masonry. Thoroughly wet brick and concrete block masonry units before laying in the mortar, and lay the brick and masonry units with a flush mortar joint.

Take adequate precautions to prevent concrete and mortar from freezing. Do not set brick and masonry units having a temperature of 40 °F (4 °C) or less with mortar until heated. When required, heat to ensure that a temperature of 50 to 80 °F (10 to 27 °C) is obtained throughout the entire mass of the material.

Cure the exposed surfaces of all brick and block masonry by covering with wet burlap for 48 hours or by applying curing membrane according to Item 511.

604.06 Precast Concrete Modular Construction. Furnish precast bases on a compacted structural backfill bed having a minimum thickness of 3 inches (75 mm). Ensure that the structural backfill bed is level and uniformly support the entire area of the base.

After placing pipe, thoroughly grout all openings in the structures with mortar. Seal all joints between modules with materials specified in Item 603 for Type A, B, C, D, or F conduit.

Cure median inlets with the same materials and methods specified in 622.07.

The manufacturer of precast modular items must be certified according to Supplement 1073.

604.07 Concrete (Cast-In-Place). Place and furnish structure concrete as shown on the plans.

604.08 Method of Measurement. The Department will measure Manholes, Inlets, Catch Basins, Monument Assemblies, Reference Monuments, Inspection Wells, Junction Chambers, and Precast Reinforced Concrete Outlets, whether new, reconstructed, or adjusted to grade, by the number of each type of structure complete and accepted.

604.09 Basis of Payment. The Department will pay for accepted quantities at the contract prices as follows:

Item unit Description

604 Each Manholes

604 Each Inlets

604 Each Catch Basins

604 Each Monument Assemblies

604 Each Reference Monuments

604 Each Inspection Wells

604 Each Junction Chambers

604 Each Manhole, Catch Basin or
Inlet Reconstructed to Grade

604 Each Manhole, Catch Basin,
Inlet, or Monument Box Adjusted to Grade

604 Each Precast Reinforced Concrete Outlet