625Manholes, Inlets, Catch Basins, and Diversion Boxes

Manholes, Inlets, Catch Basins, and Diversion Boxes

625.1DESCRIPTION

1 This section describes the requirements for constructing manholes, inlets, catch basins, and diversion boxes.

625.2MATERIALS

1 Provide materials in accordance with the following: Materials Subsection Admixtures 801.4 Aggregate for Concrete 803 Asphalt Mastic for Field Coating 804.5 Curing Materials 802.1 Fly Ash 801.2 Frames, Grates, and Covers 815.20 Galvanized Coating 815.14 Joint Material 807 Paint 809 Pipe Joint Mortar 808.14 Portland Cement 801.1 Manhole Risers and Tops 808.1 Reinforcing Steel 811.1 Slide Gates 808.17 Structural Steel 815.1 Structural Timber and Lumber 817.1 Water 814.1 2 Provide Douglas Fir timber for stop gates.

625.3EQUIPMENT

1 Ensure that equipment meets the following: Equipment Subsection Batch Plant 513.3.1 Mixers 513.3.2 Placing Equipment 513.3.3

Manholes, Inlets, Catch Basins, and Diversion Boxes SECTION 625

625.4CONSTRUCTION

625.

4.1General

1 Provide precast manholes, inlets, catch basins, and diversion boxes from plants certified in accordance with Subsection 502.4.1, Plant Certification. 2 Do not place street drainage structures, gratings, or access covers in sidewalk curb ramps or pedestrian paths. 3 Excavate and backfill in accordance with Section 206, Excavation and Backfill for Culverts. 4 Provide and place reinforcing steel in accordance with Section 514, Reinforcing Steel. 5 The department will allow an ⅛ inch per foot [10 mm per meter] taper in walls to ease form removal. 6 Use class B concrete in accordance with Subsection 513.4.4, Mix Design. Form, mix, and place concrete in accordance with applicable sections of Subsection 513.4, Construction. Cure exposed concrete with wet burlap or curing membrane, applied in accordance with Subsection 513.4.13, Curing Concrete, for at least 72 hours. 7 Place pipes in the inlet box or riser as specified. Preform holes for precast barrels and grout outlet pipes with grout approved by the engineer. Grout connections and broken areas smoothly to form a watertight inlet or manhole. Place pipe sections flush on the inside of the structure wall and projecting far enough outside to properly connect with the next pipe section. 8 Form or hand trowel inverts and slope to facilitate water movement in the direction of flow. Slope shelves 1V:12H or steeper. 9 Set metal frames in a full-mortar bed. 625.

4.2Inlets

1 Provide precast concrete inlet structures or cast-in-place. 625. 4.2.1 Median Drains 1 When the inlet box joins two or more pipes, provide a drop of at least 3 in [75 mm] between inverts of the inlet and outlet pipes. Use only one of the three grate types specified.

Manholes, Inlets, Catch Basins, and Diversion Boxes SECTION 625 625.4.2.2 Curb Inlets 1 For a type A inlet, the department will allow substitution of a type B or C. For inlet frames and grates, use cast or fabricated structural steel. Fabricate in accordance with drawings. When using precast inlet lids, warp curb sections and road surfaces to match the lid. 625.

4.3Manholes

1 Use precast concrete cones, riser sections, and slab covers. Use precast or cast- in- place concrete bases for manhole types A, B, C, and D; cast bases in place for type E manholes. Use manhole sleeves with connecting pipes on sanitary sewers to ensure water-tightness. Finish joints inside and out with asphaltic waterproof mortar or mastic. Use mortar within 30 minutes after its preparation. Seal joints outside with asphaltic waterproofing compound or other methods approved by the engineer. Construct reinforced concrete collars around the manhole ring for all manhole types. 625.

4.4Catch Basins and Diversion Boxes

1 Construct catch basins and diversion boxes to the dimensions and grades specified. Locate flow gates for diversion boxes as specified and place as follows:

625.

4.5Cleaning and Painting

1 Paint miscellaneous structural steel pieces or provide as galvanized. Do not paint galvanized pieces. Clean and paint structural steel in accordance with the applicable portions of Subsection 501.4.1.24, Painting, or Subsection 501.4.2.8, Field Painting. Required coats may be applied in the shop or field. Use brown for the final coat. Galvanize in accordance with Subsection 501.4.1.25, Galvanizing. The department does not require the painting of castings or wrought iron items. 625.4. 6 Adjusting Manholes and Inlets 1 When specified, adjust the grade of existing structures by removing frames, covers, and grates and reconstructing walls as required. Reset cleaned frames at the required elevation. After resetting, clean the structure of any foreign matter and keep clean until approval.

Manholes, Inlets, Catch Basins, and Diversion Boxes SECTION 625

625.5MEASUREMENT and PAYMENT

1 The engineer will measure Inlet Type ___, Manhole Type___, Catch Basin Type ___, Diversion Box Type ___, Inlet Adjustment, Manhole Adjustment, and Slide Gate ___ by the each.

2 The department will pay as follows:

Pay Item

Pay Unit Measure to the Nearest Pay to the Nearest Catch Basin Type ___ EA [Ea] EA [Ea] EA [Ea] Diversion Box Type ___ EA [Ea] EA [Ea] EA [Ea] Inlet Adjustment EA [Ea] EA [Ea] EA [Ea] Inlet Type ___ EA [Ea] EA [Ea] EA [Ea] Manhole Adjustment EA [Ea] EA [Ea] EA [Ea] Manhole Type ___ EA [Ea] EA [Ea] EA [Ea] Slide Gate ___ EA [Ea] EA [Ea] EA [Ea]