Mission Viejo Municipal Code Div. 16 Manholes

Sewer manholes shall be constructed in accordance with the detail drawings and of the size indicated at the locations shown on the plans. The manholes shall be constructed of precast eccentric concrete manhole units in accordance with the detail drawings of this division. Manholes shall be built without steps.

(Ord. No. 88-12, § 9(7-4-347), 6-27-88)

(a) The manhole base shall be poured in place with portland cement concrete. The manhole stubs and sewer main shall be set before the concrete is placed and shall be rechecked for alignment and grade before the concrete has set. The various inlets and outlets to the manhole shall be located as indicated on the plans and as detailed in the detail drawings. All transition shall be smooth and of the proper radius to give an uninterrupted transition of flow. The concrete shall be class A concrete with three-fourths of an inch maximum size aggregate and shall have a slump not greater than two inches. The concrete base shall be shaped with a wood float and shall receive a hard steel trowel finish prior to the concrete setting.

(b) If additional mortar is required after initial set has taken place, the surface to receive the mortar shall be primed, and the mortar mixed with an approved concrete adhesive in the amounts and proportions as recommended by the manufacturer and as directed by the department in order to secure as chipproof a result as possible.

(c) The bases shall set a minimum of 24 hours before the manhole construction is continued. In certain critical situations the time of setting may be reduced upon approval of the department.

(Ord. No. 88-12, § 9(7-4-348), 6-27-88)

The invert of the manhole base shall be hand worked so as to provide channels conforming in size and shape to the lower portions of the inlets and outlets. The channel shall vary uniformly in size and shape from inlet to outlet, and be constructed as indicated on the detail drawings. The manhole invert channels shall be smooth and accurately shaped. Channels may be formed directly in the concrete base or may consist of half sewer tile laid in the concrete base.

(Ord. No. 88-12, § 9(7-4-349), 6-27-88)

(a) Each manhole section shall be set in a bed of mortar to make a watertight joint and shall be neatly pointed on the inside and shall be set perfectly plumb. Sections of various heights shall be used in order to bring the top of the manhole ring and cover to the elevation established by the engineer.

(b) The precast concrete manhole rings shall be jointed with a minimum thickness of one-half inch of portland cement mortar. Mortar shall be composed of one part portland cement to two parts of clean well-graded sand of such size that all pass a number eight sieve. Cement, aggregate and water for mortar shall conform to the applicable provisions of division 7 of this chapter.

(Ord. No. 88-12, § 9(7-4-350), 6-27-88)

(a) Vitrified clay pipe stubs shall be furnished and installed in manholes at the locations and in conformance with the detail drawings and as shown on the plans. All stubs shall be plugged with stoppers or brick wall plugs as shown on the plans for various sizes of pipe.

(b) Where new construction is started at the stub of an existing manhole the applicant shall brick the opening into the manhole before he removes the plug or stopper from the stub. The bricked opening shall remain in place until the applicant has tested and completed the work.

(Ord. No. 88-12, § 9(7-4-351), 6-27-88)

It is the intent of this division that manholes and appurtenances be as watertight and free from infiltration as possible. Where manholes are to be given a protective lining or coating, they shall be free of any seeping or surface moisture. The adequacy of manholes and appurtenances as to watertightness shall be determined by the department, and shall be tested by filling with water when ordered by the department.

(Ord. No. 88-12, § 9(7-4-357), 6-27-88)

The elevations at which manhole frames and covers are to be set shall conform to the requirements set forth on the plans and detail drawings but in all cases shall be established by the engineer in the field. Where the frame and cover are in existing pavement or in the traveled way of the existing road shoulder, it is to be placed flush with the existing surface. Where the structure is outside the limits of the traveled shoulder but not in the roadside ditch, it should be placed one-tenth foot or more above the existing ground surface. Where the manhole cover falls in the existing roadside ditch or right-of-way, it is to be placed approximately 1½ feet above the existing ground surface or as directed by the department. Manhole frames shall be set at the required grade and shall be securely attached to the top precast manhole shaft unit with a cement mortar bed and fillet as shown on the plans. After the frames are securely set in the place provided herein, covers shall be installed and all necessary cleaning and scraping of foreign materials from the frames and covers shall be accomplished to insure a fine satisfactory fit.

(Ord. No. 88-12, § 9(7-4-358), 6-27-88)

Drop manholes shall be constructed at the location on the plans and in conformance with the detail drawings. Materials and construction of drop manholes shall conform in all respects to the applicable provisions of this division for precast concrete manholes (including frames and covers), with modifications for the addition of drop inlets as set forth on the detail drawings.

(Ord. No. 88-12, § 9(7-4-359), 6-27-88)

New connections to existing manholes wherein stubs have not been provided shall be made by core drilling through the walls and manhole base as directed by the department.

(Ord. No. 88-12, § 9(7-4-360), 6-27-88)