Article 1 — Description
Adjust or cap existing manholes or inlets. Drainage junction boxes will be classified as manholes .
Article 2 — Materials
Reuse removed manhole and inlet rings, plates, grates, and covers if they are in good condition as determined by the Engineer. Provide additional materials in accordance with Item 465, “Junction Boxes, Manholes , and Inlets,” at no cost to the Department. Use single- or multiple -piece prefabricated metal, polymer, plastic, or rubber extension rings for the adjustment of manholes as approved. Limit the height of flexible extension rings to 3 in. Provide concrete that meets Item 421, “Hydraulic Cement Concrete.” Ensure frames and grates or rings and covers above grade are of single- piece cast iron manufactured in accordance with Item 471, “Frames, Grates, Rings, and Covers.” Provide steel riser material compliant with ASTM A36. Provide steel adjustable risers that include a stainless steel adjustable stud with positive lock that adjusts the diameter ± 3/8 in. Provide steel risers that include a minimum of three Allen head set screws that lock the riser to the manhole or catch basin frame. Ensure seating surfaces are flat and true and provide a non-rocking seating surface.
Article 3 — Construction
Perform all work in accordance with Item 465. Excavate and backfill in accordance with Item 400, “Excavation and Backfill for Structures.” Carefully remove manhole and inlet rings, covers, plates, and grates to be reused. Clean mortar and grease from the contact areas of all reused items. Dispose of unused removed material as directed. Use construction methods described in Section 479.3.1., “Lowering the Top of a Manhole or Inlet,” and Section 479.3.2., “Raising the Top of a Manhole or Inlet,” unless otherwise shown on the plans.
3.1 Lowering the Top of a Manhole or Inlet . Remove a sufficient depth of brick courses or concrete to permit
reconstruction on a batter not exceeding 1 in. horizontal to 2 in. vertical. Clean the mortar from the top course of brick where brickwork is present. Rebuild the manhole or inlet to the original top dimensions or to the dimensions shown on the plans. Install the manhole or inlet ring and the cover, plate, or grate to conform to the proposed new surface contour.
3.2 Raising the Top of a Manhole or Inlet . Clean the top surface of brick or concrete. Construct to the proper
new elevation using new rubber extension rings, concrete rings, or Class A concrete. Provide rubber manhole and catch basin risers of minimum 80% by weight recycled rubber and minimum 10% by volume recycled resorcinol -formaldehyde -latex (RFL) coated fiber. Provide rubber manhole and catch basin adjustment risers that are of uniform quality, free of cracks, holes, and any other surface defects. Construction must be suitable for AASHTO H20 live loads. Load certifications for materials will be made available upon request. Install the manhole or inlet ring and the cover, plate, or grate to conform to the proposed new surface contour. Install prefabricated extension rings i n conformance with manufacturer’s instructions.
3.3 Capping an Inlet or Manhole . Remove the inlet or manhole to a minimum of 1 ft. below subgrade elevation
or as shown on the plans. Cap as shown on the plans. 750 4. MEASUREMENT Adjusted or capped manholes or inlets will be measured as each manhole or inlet adjusted.
Article 5 — Payment
The work performed and materials furnished in accordance with this Item and measured as provided under “Measurement” will be paid for at the unit price bid for “Adjusting Manholes,” “Adjusting Inlets,” or “Adjusting Manholes and Inlets.” This price is full compensation for materials, including backfill as required, and for excavation, tools, equipment, labor, and incidentals .