2008-213 (5) - Laserfiche WebLink

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Pre -cast manhole sections shall be circular and formed with male and female ends so that when assembled they will make a continuous, uniform manhole. Joints shall be of such design as will permit effective jointing by using a continuous keyed construction joint. Keyed sections shall be joined and sealed using "Ram-Nek" or other mastic sealant approved by the Engineer and capable of preventing leaks between the sections. After placement of the manhole sections, anti -hydro grout shall be used to point all remaining joint surfaces and lifting holes. Alternate designs will be permitted only when they have received approval from the Engineer prior to their fabrication. Pre -cast concrete manholes shall conform with the requirements of ASTM Designation C478, except that the minimum acceptable wall thickness shall be 8 -inches. Manhole steps will not be provided. After the manhole is assembled and before backfilling, all joints shall be filled with anti - hydro grout and pointed to form a dense hard joint. Two coats (minimum of 8 mil dry thickness per coat), of Coal Tar Epoxy coating, or approved equal, shall be applied to the entire surface, inside and outside, of the manhole. These coatings shall be applied in accordance with the manufacturer's directions. Brick collars, above the roof slab or manhole cone, to bring the manhole to finished grade, shall be laid to the thickness and dimensions shown on the Plans. All brick shall be thoroughly wetted before laying and shall be laid in a full bed and joint of mortar. B. Manhole Frames and Covers Manhole frames and covers shall be close -grained gray cast iron castings conforming to ASTM A48, Class 30 iron. Castings shall be of uniform quality, free from blow holes, porosity, hard spots, shrinkage, defects, cracks or other injurious defects. They shall be smooth and well cleaned by shot blasting and, unless otherwise specified shall be coated with coal tar pitch varnish of a type which will make a smooth coating, tough and tenacious when cold, not tacky and not brittle. Frame and covers shall have a minimum total weight of 400 pounds. Manhole covers shall have a minimum thickness along the rim of 2 inches. Covers shall have concealed watertight pick holes. All frames and covers shall be U.S. Foundry and Manufacturing Corporation, No. 420 "B" or approved equal, marked "Sanitary Sewer". C. Resilient Pipe Connectors for Precast Concrete Manholes The connection of any pipe to an existing manhole shall be performed utilizing a resilient connector conforming to ASTM C923-84. All metallic components of the connector shall be stainless steel. Acceptable manufacturers shall be as listed in SECTION 15, "APPROVED MANUFACURES'S PRODUCTS LIST" from the most recent edition of IRCDUS WATER & WASTEWATER STANDARDS. 02531a2 WP 02531 - Gravity Sewer Manholes