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3. Where grating depth is not given, grating shall be provided which will be <br /> within allowable stress levels, and which shall not exceed a deflection of <br /> 1/4 inch or the span divided by 180, whichever is less. For standard duty <br /> plank, and safety grating, the loading to be used for determining stresses <br /> and deflections shall be the uniform live load of the adjacent floor or 100 - <br /> psf, whichever is greater or a concentrated load of 1000 pounds. For <br /> heavy duty grating, the loading used for determining stresses and <br /> deflections shall be AASHTO HS-20. - <br /> B. Material <br /> Except where indicated otherwise, bar grating shall be fabricated entirely of aluminum as <br /> follows: Bearing and banding bars, alloy 6061-T6; cross bars, alloy 6063-T5. <br /> C. Standard-Duty Grating: <br /> 1. No single piece of grating shall weigh more than 80 pounds, unless <br /> indicated otherwise. Standard duty grating shall be serrated bar grating. — <br /> 2. Cross bars shall be welded or mechanically locked tightly into position so <br /> that there is no movement allowed between bearing and cross bars. <br /> 2.04 CHECKERED PLATE <br /> A. Checkered plate shall be not less than 1/4-inch thick, and shall have a pattern of <br /> raised lugs on one face and shall be smooth on the opposite face. Lugs shall be <br /> a minimum of one inch in length and raised a minimum of 0.050 inch above the <br /> surface. The lugs shall be located in a pattern in which the lugs are oriented at <br /> 90 degrees from the adjacent lugs in two orthogonal directions. The rows of lugs <br /> shall be oriented at 45 degrees from the edges of the plates. <br /> B. Where no plate material is indicated on the Drawings, aluminum shall be provided. <br /> Unless indicated otherwise, the minimum plate thickness shall be as required to <br /> limit deflection, resulting from a live load of 100 psf, to 1/4-inch or the span <br /> divided by 240, whichever is less. <br /> 2.05 ACCESS HATCHES <br /> A. All hatches shall be fabricated from <br /> Aluminum <br /> 06Tsunless <br /> otherwise <br /> indicated. All hatch hardware shall Type stainesseel Hatches shall <br /> be gutter-type; Bilco Type "J" or"JD" Babcock-Davis type "FT" or"AM" or equal. — <br /> B. The design live load shall be or AASHTO H-20 wheel load in paved areas and <br /> where indicated "traffic load" on the Drawings. Where traffic loads are not <br /> required, the design live load shall be 300 pounds per square foot. <br /> C. Hatch opening sizes, number and direction of swing of door leaves, and <br /> locations, shall be as indicated. Sizes given shall be for the clear opening. <br /> Where the number of leaves is not given, openings larger than 42 inches in either <br /> direction shall have double-leaf doors. Unless indicated otherwise, hinges shall <br /> be located on the longer dimension side. Unless indicated otherwise, ladder _ <br /> Division III-97 NEI Phase II Water and Sewer <br /> July 2007 CIP Nos.7468, 7589,7590 <br />