Section 604 — Manholes, Inlets, and Catch Basins

Description

604.01This work consists of constructing, adjusting, shifting, or modifying manholes, inlets, and catch basins.

Material

604.02Conform to the following Subsections: Concrete building brick 725.06 Concrete masonry units 725.07 Corrugated metal units 707.09 Frames, grates, covers, and ladder rungs 725.10 Gaskets for concrete pipe 706.08 Gaskets for metal pipe 707.17 General mortar 701.05(a) Neat hydraulic cement grout 701.04(a) (2) Precast concrete units and accessories 725.09 Reinforcing steel 709.01 Sealants, fillers, and seals 712.01

Construction Requirements

604.03General. Excavate and backfill according to Section 209. Separate catch basins and inlets from adjacent concrete structures with at least ½ -inch thick preformed expansion joint. Construct minor concrete according to Section 601.

604.04Concrete Construction. Concrete units may be cast -in-place or precast. Finish surfaces according to Subsection 552.14 as applicable. Finish the flow line in manholes, inlets, and catch basins to match the pipe flow line. Assemble precast concrete manhole sections with flexible gaskets or fillers in the tongue and groove joints. Handle the precast units carefully after the gasket has been attached to avoid damaging the gasket or contaminating the joint. Ensure the proper alignment before the joints are forced home. Seat gasket s uniformly. If mastic is used, apply mastic joint filler according to the manufacturer’s recommendations. Set metal frames in a full mortar bed. Space ladder rungs uniformly on 12 -inch centers and align vertically. Grout ladder rungs into precast concrete walls.

604.05Concrete Masonry Unit Construction. Construct masonry block plumb. Stagger vertical joints and set block with the cells vertical. Moisten blocks before using in work. Butter bearing members and vertical joints full of mortar. Bond block using mortar on sides. Construct joints straight, level, plumb, flush, and ¼ to ½ inch thick. Backfill the structure after the masonry block joints have moist cured for 7 days.

604.06Metal Construction. Fabricate metal drop inlets from the same material and thickness as adjoining metal pipes. Connect metal inlets to adjoining metal pipes according to Subsection 602.05.

604.07Grade Adjustment of Structures. Adjust met al frames and grates to grade before placing the surface course. Remove and clean the frames, covers, and grates. Trim the walls down to solid material. Reconstruct the walls with the same material as existing and reset the cleaned frames at the required e levation. If the existing casting and supporting walls are in good condition, an approved device may be used to adjust the manhole casting cover to the correct grade. Clean each structure of foreign material.

604.08Shifting and Modifying Structures. Shift structures using methods to ensure structural integrity. Reshape the channel flow line in manholes, inlets, and catch basins as necessary to match the pipe flow line. Set and reassemble structures according to the applicable requirements of Subsections 604.04 through 604.07. Provide and install gaskets, seals, and other accessories according to the applicable requirements of Subsections 604.04 through 604.06. Grout or use a preformed joint seal to make joints and openings leak resistant. Finish mortar joints with a bead on the outside and a smooth finish on the inside. When modifying a concrete structure, do not loosen the rei nforcement in the wall. Cut the reinforcing steel flush with the opening wall face. Grout joints and openings cut in the wall. Seal openings no longer required in the structure. Abandon structures according to Subsection 203.06.

604.09Acceptance. Material for metal, concrete brick, concrete masonry, precast concrete units, and cast-in-place concrete (except concrete) units will be evaluated under Subsections 106.02 and 106.03. Construction of metal, concrete brick, and concrete masonry units will be evaluated under Subsections 106.02 and 106.04. Installation of precast concrete units will be evaluated under Subsections 106.02 and 106.04. Shifting, modifying, and adjusting units will be evaluated under Subsections 106.02 and 106.04. Excavation and backfill will be evaluated under Section 209. Minor concrete will be evaluated under Section 601.

Measurement

604.10Measure the Section 604 pay items listed in the bid schedule according to Subsection 109.02 and the following as applicable: When measuring manholes by the linear foot, measure from finished grade to the flow line surface of the manhole. Do not measure metal frames and grates when included as part of the original inlet, manhole, or ca tch basin construction.

Payment

604.11The accepted quantities will be paid at the contract price per unit of measurement for the Section 604 pay items listed in the bid schedule. Payment will be full compensation for the work prescribed in this Section. See Subsection 109.05 .