SECTION 702 — MANHOLES, INLETS, AND CATCH BASINS 700-9 — MANHOLES, INLETS, AND CATCH BASINS
702.01 Description.
Manholes, Catch Basins, and Inlets. This work includes the construction of manholes, inlets, and catch basins in reasonably close conformity to the required dimensions and details. Deep Sump Catch Basin. This work includes constructing deep sump catch basin according to the required dimensions and details. Leaching Catch Basin. This work includes constructing leaching catch basin according to the required dimensions and details. The catch basin includes perforated vertical walls and/or an open or perforated bottom. Sediment Removal Device. This work includes the installation of a sediment removal device (SRD) to the required lines and grades. Stormwater Discharge Structure. This work includes constructing stormwater discharge structures according to the required dimensions and details.
702.02 Materials.
Masonry Unit Construction.
a.General. Provide clay brick, concrete masonry units, lime, mortar, frames, grates, covers, and ladder rungs that conform to Subsection M04.03.
b.G ravel Borrow . Provide gravel borrow that conforms to Subsection M01.02.
c.Concrete. Provide concrete for the structures that conforms to SECTION 601.
d.Reinforcing. Provide reinforcing bars that conform to Subsection M05.02
e.Wire Fabric Reinforcing. Provide w ire fabric reinforcing that conforms to Subsection M05.02.1. All materials used in the construction of drainage structures will be subject to acceptance testing by the Engineer. Provide sufficient time for the Engineer to test and inspect the materials before their incorporation into the work.
Part 700 — Drainage and Selected Utility Accessories August 2025
700-10 SECTION 702 — MANHOLES, INLETS, AND CATCH BASINS Precast Concrete Construction.
a.General. Precast concrete drainage structures are acceptable alternatives to the corresponding masonry unit structures when the latter are specified in the Contract documents.
b.P recast Concrete Structures . Provide precast concrete that conforms to SECTIONS 601 and 809.
c.P recast Concrete Catch Basins and Manholes . Provide precast concrete that is designed and manufactured according to ASTM C478, Precast Concrete Manhole Sections . Provide a concrete mix design that conforms to Class XX in SECTION 601.
d.O ther Materials . Materials and their inspection as specified under Subsection 702.02.1, Paras. a, b, d, and e also apply to precast concrete drainage structures. Deep Sump Catch Basin. Unless otherwise indicated on the Plans, use a deep sump catch basin that conforms to the applicable material requirements of Subsection 702.02. Leaching Catch Basin. Unless otherwise indicated on the Plans, use a leaching catch basin that conforms to Subsection 702.02. Sediment Removal Device. Use precast concrete for the sediment removal device that conforms to SECTION 701. Ensure that the sediment removal device or the approved equal meets the following requirements: • Ensure that the wall thickness is not less than 6 in. or as shown on the dimensional drawings. Ensure that the wall thickness is not less than the minimum thickness necessary to sustain the loading requirements. • Use sections that have tongue and groove or ship- lap joints with a butyl mastic sealant conforming to ASTM C 990. • Use Class XX c oncrete with a minimum 28 -day compressive strength of 4000 psi that conforms to SECTION 601. • Ensure that all sections are cured by an approved method. Do not ship the sections until the concrete has attained a compressive strength of 4000 psi or until five days after fabrication and/or repair, whichever is longer. • Size the pipe openings to accept pipes of the specified size(s) and material(s), and ensure that the openings are sealed as specified in SECTION 701. • Use brick or masonry to build the manhole frame to grade that conforms to ASTM C 32 or ASTM C 139.
Part 700 — Drainage and Selected Utility Accessories August 2025
SECTION 702 — MANHOLES, INLETS, AND CATCH BASINS 700-11 • Provide casting for manhole frames and covers that comply with ASTM A48, CL.35B, and AASHTO M105. • Ensure that the structures have a 30-in. minimum manhole frame and cover. Use frames, covers, and grates that conform to SECTION 702. • Use pipes and fittings that conform to SECTION 701. • Provide steps within the chamber pit for access that are steel reinforced copolymer , polypropylene plastic step that comply with ASTM C478 or approved equal. • Ensure that all components and appurtenances conform to the manufacturer ’s recommendations, applicable ASTM technical standards, US Federal specifications, and RIDOT Specifications and are approved by the Engineer. Stormwater Discharge Structure. Use a stormwater discharge structure that is precast reinforced concrete and that conforms to the required lines, grades, dimensions, and elevations. Comply with the following: • Concrete. Use Class XX c oncrete that has a minimum 28-day compressive strength of 4000 psi and that conforms to SECTION 601. • P ipe and Fittings . Use pipes and fittings that conform to SECTION 701. • Manhole Cover. Provide stormwater discharge structures with a 30- in. minimum frame and cover that conforms to SECTION 702. • M anhole Steps . Provide steps within the chamber pit that are steel reinforced copolymer polypropylene plastic step that comply with ASTM C478 or approved equal. • Fi lter Fabric . Ensure that the filter fabric is non-woven material that conforms to Subsection 703.02.2. • Tr ash Racks . Provide trash racks that conform to the required lines, dimensions, material, and elevations. • Div ersion Weir . If applicable, install the diversion weir at the required elevations and dimensions. Use a diversion weir made of reinforced concrete, masonry, or metal as approved by the Engineer.
702.03 C Onstruction Methods.
Masonry Unit Construction.
a.L ocation. If obstructions are encountered at drainage structure locations that cannot be conveniently removed, the Engineer will direct that the structures be constructed at either slightly revised or alternat ive locations. If the drainage is associated with directing stormwater to a Stormwater Treatment Unit, provide a Shop Drawing.
b.E xcavation. Perform e xcavation for drainage structures according to SECTION 203 . Excavate to the required horizontal cross section and to a sufficient depth to accommodate the concrete bases and/or bedding of the various drainage structures. Grade and compact the bottom of the excavation before placing concrete bases.
Part 700 — Drainage and Selected Utility Accessories August 2025
700-12 SECTION 702 — MANHOLES, INLETS, AND CATCH BASINS
c.Replacement of Unsuitable Material . If the excavation cannot support the drainage structures, the Engineer will order additional excavation. When the unsuitable material has been removed, compact the bottom of the excavation by hand and refill with compacted gravel borrow.
d.C oncrete Bases . Construct applicable concrete bases of drainage according to Subsection 808.03.2.
e.R estrictions on Certain Masonry Units . Do not provide concrete brick as a construction material for drainage structures. Concrete masonry block will only be allowed for the vertical riser portions of structures and will not be allowed in the corbeling portions. Use clay brick for corbeling up to the bottom of the metal frames.
f.P recast Concrete Sump . Where applicable, use a precast concrete sump section for standard 4-ft round catch basins.
g.B ackfill. After construction of the drainage structures has proceeded to their design heights, backfill and compact the excavation according to Subsection 203.03.5(c).
h.U nauthorized Excavation. If the bottom of any drainage structure excavation is below the required grade, correct the grade by filling with appropriate material.
i.Fi nal Cleanup. Upon completion of construction, clean and maintain each drainage structure of any accumulation of silt, earth, debris, or foreign matter until final acceptance of the work. Catch basins, manholes, and inlets that require subsequent cleaning through no fault of the Contractor will be paid according to SECTION 708. Precast Concrete Construction.
a.Testing and Inspection. The Engineer will inspect precast concrete drainage structure units both at the point of manufacture and at the Project site. Remove and replace any units exhibiting defects or damage that cannot be corrected to the satisfaction of the Engineer at no additional cost to the Department.
b.O ther Construction Requirements . Adhere to the c onstruction methods in Subsection 702.03.1, paras. a, b, c, d, g, h, and i equally to precast concrete drainage structures. Deep Sump Catch Basin. Ensure that c onstruction is according to SECTION 702. I nstall the deep sump catch basins according to the Contract or as directed by the Engineer. Ensure that sumps are a minimum of 4 ft below the lowest invert in the catch basin. Leaching Catch Basin. Ensure that construction is according to SECTION 702. Install the leaching catch basins according to the Contract or as directed by the Engineer.
Part 700 — Drainage and Selected Utility Accessories August 2025
SECTION 702 — MANHOLES, INLETS, AND CATCH BASINS 700-13 Wrap the structure around all exterior sides and bottom with filter fabric and surrounded by a crushed stone layer to prevent clogging. Install the crushed stone per the Contract or as specified by the manufacturer. Ensure that the crushed stone has minimum dimensions of 6-in. bedding stone below the structure and 12 -in. stone surrounding the structure. Provide complete S hop Drawings, and any necessary documentation for the leaching catch basins. Leaching catch basins and all materials will be approved by the Engineer in writing 14 days before being brought onsite. Sediment Removal Device. Construct the sediment removal device according to the Contract or as directed by the Engineer. Place the structure on a compacted granular subbase as shown in the Contract, as determined by the manufacturer ’s specifications, and/or as directed by the Engineer. Check the granular subbase for level before setting and check for level at all four corners after it is set. If the slope from any corner to another corner exceeds 0.5 percent, remove the base section and relevel the granular subbase material. Before setting subsequent sections, place sealant in conformance with SECTION M04 and/or as required by the manufacturer. Ensure that the holes for installation of ladder steps line up to allow for continuous access from top to bottom. After setting the precast roof section of the sediment removal device, set precast concrete manhole riser sections to the height required to raise the cast iron manhole covers to grade so that the sections are vertical and in true alignment , with a ¼ -in. maximum tolerance allowed. Backfill in a careful manner, raising the fill up in 6-in. lifts on all sides. If leaks appear, clean the inside joints and caulk with lead wool to the satisfaction of the Engineer. Set precast sections so that the joint is watertight. Ensure that the installation of the sediment removal device conforms to ASTM specification C 891 “Standard Practice for Installation of Underground Precast Utility Structures.” Plug holes made in the concrete sections for handling or other purposes with a non -shrink grout or by using grout in combination with concrete plugs. Where holes must be cut in the precast sections to accommodate pipes, perform all cutting before setting the sections in place to prevent any subsequent jarring which may loosen the mortar joints. Stormwater Discharge Structure. Ensure that construction is according to SECTION 702. Install the leaching catch basins according to the Contract or as directed by the Engineer. Wall, ceiling and floor thicknesses may be increased as necessary by the precast manufacturer to meet the design criteria in this Subsection. Ensure that the i nside dimensions of the stormwater discharge chambers are not reduced. Use joints for riser sections that are the shiplap type sealed with a field formed, fiber
Part 700 — Drainage and Selected Utility Accessories August 2025
700-14 SECTION 702 — MANHOLES, INLETS, AND CATCH BASINS reinforced joint sealant system. Install the stormwater discharge structures on a crushed stone base that is wrapped in filter fabric. Provide complete S hop drawings and design computations for each stormwater discharge structure stamped by a Professional Engineer registered in Rhode Island. Provide complete Shop Drawings, computations, and any necessary documentation as part of the submittal documents.
702.04 Method of Measurement.
Manhole, Catch Basin, and Inlet. New Manhole, Catch Basin, and Inlet of the various types and sizes and between zero to 12 ft in depth will be measured by the number of drainage structures installed. The Additional Depth of Manhole, Catch Basin, and Inlet (Over 12 ft) will be measured by the vertical height in linear feet of drainage structure from the 12-ft depth to the top of the base slab. Metal Frame and Grate and/or Cover. Metal Frames and Grates and Metal Frames and Covers of the various types and sizes will be measured by the number of assemblies installed. Inlet and Apron Stones – All Sizes and Types. Inlet Stones and Apron Stones of the various types and sizes will be measured by the number of units installed. Deep Sump Catch Basin. Deep Sump Catch Basin will be measured by the number of each catch basin installed. Leaching Catch Basin. Leaching Catch Basins will be measured by the number of each leaching catch basin installed. Sediment Removal Device. Sediment Removal Device will be measured by the number of each device installed. Stormwater Discharge Structure. Stormwater Discharge Structure will be measured by the number of each unit installed.
702.05 Basis of Payment.
The Department will pay for the completed and accepted quantities as follows.
Part 700 — Drainage and Selected Utility Accessories August 2025
SECTION 702 — MANHOLES, INLETS, AND CATCH BASINS 700-15 Pay Item Pay Unit Manhole, Catch Basin, and Inlet (between 0.0 and 12 ft in depth) EA Additional Depth of Manhole, Catch Basin and Inlet (over 12 ft) Vertical LF Metal Frame and Grate EA Metal Frame and Cover EA Inlet Stone – All Sizes and Types EA Apron Stone – All Sizes and Types EA Deep Sump Catch Basin EA Leaching Catch Basin EA Sediment Removal Device EA Stormwater Discharge Structure EA Structure Excavation – Rock and Structure Excavation; Rock – Mechanical will not be included in the Contract unit prices but will be paid for separately as set forth in Subsections 203.04.1 and 203.05. Manhole, Catch Basin, and Inlet. For new Manhole, Catch Basin, and Inlet between zero and 12 ft in depth, t he prices constitute full compensation for the new frames and grates (all types), frames & cover s (all types), all adjustments to grade, which includes all interim adjustments during construction and adjustments to final grade, including all labor, materials, and equipment for providing structures , including excavation (except rock excavation), placing and compacting backfill, steps, ½ -in. thick cement mortar coating on both the inside and outside wall surfaces (except for precast structures), the disposal of all surplus excavated and/or unsuitable material, and all incidentals required to finish the work, complete and accepted. For Additional Depth of Manhole, Catch Basin, and Inlet o ver 12 ft, t he price constitutes full compensation for all labor, materials, and equipment for providing the additional structure depth, complete and accepted. Metal Frame and Grate and/or Cover. For Metal Frame and Grate and Metal Frame and Cover the prices constitute full compensation for all adjustments to grade, which includes all interim adjustments during construction and adjustments to final grade, including all labor, materials, and equipment for providing the assemblies and for all incidentals required to finish the work, complete and accepted. Inlet and Apron Stone. For Inlet Stone and Apron Stone, the prices constitute full compensation for all labor, materials, and equipment for providing the units and for all incidentals required to finish the work, complete and accepted.
Part 700 — Drainage and Selected Utility Accessories August 2025
700-16 SECTION 702 — MANHOLES, INLETS, AND CATCH BASINS Deep Sump Catch Basin. The price constitutes full compensation for all labor, materials, equipment, and tools for furnishing and placing each deep sump catch basin and all other incidentals necessary to finish the work, complete and accepted. Leaching Catch Basin. The price constitutes full compensation for all labor, materials, equipment, and tools, for furnishing and placing each basin, crushed stone, bedding, filter fabric, install ing the frame and cover or frame and grate, and all other incidentals necessary to finish this work, complete and accepted. Sediment Removal Device. The price constitutes full compensation for all labor, materials, and equipment for furnishing and placing the units including excavation, dewatering, stone bedding, backfill, compaction, and all other incidentals required to finish the work, complete and accepted. Stormwater Discharge Structure. The price constitutes full compensation for all excavation (except for Trench Excavation – Rock, Trench Rock Excavation – Mechanical) and excavation of unsuitable material below grade to a depth equal to the invert of the proposed structure; for the manhole frame and cover, manhole steps, trash racks, pipes and fittings, and laying, setting, and jointing all sections, including connections to existing drainage structures or pipes ; for placing and compacting backfill and for furnishing, placing, and subsequently removing all temporary sheeting, bracing, or shoring; for the proper disposal of all excess or unsuitable excavated materials ; and for all labor, materials, equipment, tools, and all other incidentals necessary to finish the work, complete and accepted.
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Source: Standard Specifications for Road and Bridge Construction (Blue Book), 2022 (Aug 2025 compilation) Edition. Pages 334–341 of 951. View official source ↗