3399.1SCOPE
Provide flap-type drainage control gates for direct attachment to the outlet ends of C ulvert and sewer pipe as shown on the Plans or required by the Special Provisions. If shown on the Plans or required by the Special Provisions, provide gates with attachment to the outlet Structure.
3399.2REQUIREMENTS
A Base Metal Provide frame, flap, flange, hinge bars, and other basic components of the gate assembly made of cast iron, cast steel, structural steel, or other metals approved by the Engineer . Provide hinge bushings and pins made of non-corrosive metal approved by the Engineer. Do not use bronze or brass fittings on gates attached to aluminum alloy drainage structures. Provide iron castings meeting the requirements of ASTM A48, Standard Specification for Gray Iron Castings, Class 30B or better, ASTM A47, Standard Specification for Ferritic Malleable Iron Castings, Grade 32510. Provide steel castings meeting the requirements of 3306, “Low-Carbon Structural Steel,” or better. Provide steel components in accordance with 3306, “Low-Carbon Structural Steel,” or 3309, “High- Strength Low-Alloy Structural Steel.” B Dimensions and Design Provide flap gates designed to permit direct attachment to pipe of the type and size required by the Contract, or to the outlet Structure as shown on the Plans or required by the Special Provisions. Ensure the gates provide practical water tightness against a face pressure and open automatically under a back head allowing free outflow. Provide a double pivoted flap hinge or a flap hinge otherwise designed to provide accurate seating of the flap and frame and ensure complete closure of the flap using its own mass . Use a design that limits the hinge movement to prevent the flap from becoming lodged in the frame opening. Provide gates designed to adequately withstand the seating head as shown on the P lans. If the plans do not show seating head requirements, provide gates designed to withstand a 10 feet seating head. Provide gates designed or installed to hang closed at all times. Provide suitable flange or hinge fastening adjustments that provide a vertical frame seat when installed . Include provisions for attaching the gate assembly to the pipe or Structure as shown in the Plans or required by the Special Provisions, using bolts, flanges, and compression bands or other devices. For metal pipe installations, the Contractor may shop assemble the gates on a 24 inch section of pipe with rivets or bolts. Install the stub section of pipe, with gate attached, on a zero or flat grade when feasible.
The Engineer will approve all critical dimensions and design details of the gate assembly . Provide shop drawings to the Engineer upon request. C Fabrication and Assembly Provide castings and fabricated steel components that are free of defects that affect its ability to function for its intended purpose. Machine mill or grind the contact surfaces between frame and flap to provide true bearing around the entire circumference. Galvanize cast steel and fabricated steel components of the gate assembly, including steel bolts, nuts, and washers in accordance with ASTM A153, Standard Specification for Zinc Coating (Hot-Dip) on Iron and Steel Hardware for the appropriate class of Material. In lieu of galvanizing, the Contractor may paint steel specified in 3309, “High-Strength Low-Alloy Structural Steel,” in accordance with 2478, “Organic Zinc-Rich Paint System,” with an aluminum finish coat. Paint iron castings with an asphalt or coal-tar pitch varnish, or galvanize as required for steel castings. Paint and galvanize after fabrication and before assembly.
3399.3SAMPLING AND TESTING
Ensure the manufacturer prepared and tested physical test specimens for the tests required in accordance with this section at no additional cost to the Department . Submit to the Engineer the Certified Test Reports provided by the manufacturer showing the results of each test before delivering the Material to the Project. The Engineer may require the manufacturer make check tests, if results of previous tests are not conclusive. Posts
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