1044FLAP GATE

1043.05 Expanded Polypropylene (EPP) Adjusting Rings. The EPP

adjusting rings shall be manufactured using a high compression molding process to produce a minimum finished density of 7.5 lb/cu ft (120 g/l). The EPP rings shall be made of materials meeting ASTM D 3575 and ASTM D 4819-13. The grade adjustments shall be designed and tested according to the AASHTO Standard Specifications for Highway Bridges (AASHTO M 306 HS-25). Grade rings shall contain upper and lower keyways (tongue and groove) for proper vertical alignment and sealing. The top ring, for use directly beneath the cast iron frame, shall have keyways (grooves) on the lower surface with a flat upper surface. Adhesive or sealant used for watertight installation of the manhole grade adjustment rings shall meet ASTM C 920, Type S, Grade NS, Class 25, Uses NT, T, M, G, A, and O. EPP adjustment rings shall have no void areas, cracks, or tears. The actual diameter or length shall not vary more than 0.125 in. (3 mm) from the specified diameter or length. Variations in height are limited to ± 0.063 in. (± 1.6 mm). Variations shall not exceed 0.25 in. (6 mm) from flat (dish, bow, or convoluting edge) or 0.125 in. (3 mm) for bulges or dips in the surface. SECTION 1044. FLAP GATE

1044.01 Cover. The cover shall be cast iron, ASTM A 126, Class B, with

necessary reinforcing ribs. It shall be fabricated with a lifting eye for manual operation, and with bosses to provide a pivot point connection with the links. Bosses shall be designed to place the hinge bolt in double shear when the gate is assembled. Pivot bosses shall be designed to limit the double hinge action, preventing the cover from rotating sufficiently to become wedged in the open position.

1044.02 Frame. The one-piece cast iron frame shall be according to

requirements of ASTM A 126, Class B. The frame shall have a raised section around the perimeter of the waterway opening to provide the seating face. The raised section shall provide a seating plane diverging, top to bottom, from the plane of the mounting flange to assist in a positive closure of the cover. The frame shall be flat back or spigot back as designated on the plans. The spigot back gates shall be designed for attaching to corrugated steel pipe. Flap Gate Art. 1044.07

1044.03 Seating Faces. The cast iron seating faces on the seat and the cover

shall be machined to a plane with a minimum 63 micro in. (1.6 µm) finish. The seating faces may be bronze according to the requirements of ASTM B 21 (B 21M) - C48200 and shall be pneumatically impacted into dove-tailed grooves machined to 63 micro in. (1.6 µm) finish for maximum water tightness. Resilient seat, neoprene or Buna-N, when specified, shall be bonded in a groove machined in the frame to provide a wide seating surface for the seating face machined on the cover.

1044.04 Top Pivot Connection. The top connections to the hinge links or

arms shall be with pivot lugs or some other system which has double bosses to place the top hinge bolts in double shear when they are assembled through the links or arms. The connections shall be adjustable in the horizontal plane without removal of the cover from the gate links or arms. The adjustment shall allow the top pivots to be moved toward the gate seat for reduced sensitivity of the cover, or moved away from the gate seat, to provide opening with a minimum differential head.

1044.05 Hinge Links or Arms. The hinge arms connecting the cover and pivot

lugs shall be high-tensile bronze, ASTM B 584-C86500, one-piece heavy duty cast iron, ASTM A 126, Class B, or high strength ductile iron, ASTM A 536, Gr. 65-45-12. Each hinge link or arm shall have two pivot points, an adjustable lower pivot with limited rotation and a threaded upper hinge post to adjust flap gate sensitivity. The bottom of the links or arms shall be provided with an adjusting screw to properly align seating faces on the cover with respect to the seat. The links or arms shall be designed to limit the double hinge action, preventing the cover from rotating sufficiently to become wedged in the open position. Cast iron or ductile iron links or arms shall be provided with a commercial grade bronze bushing at each pivot point. The hinge pins designed in double shear shall be bronze, ASTM B 98 (B 98M) - C65500 or Type 304 stainless steel.

1044.06 Fasteners. All anchor bolts, screws, and nuts shall meet the

requirements of ASTM A 307, and be of ample section to safely withstand the forces created by the operation shown on the manufacturer’s gate schedule. The anchor bolts, screws, and nuts shall be galvanized according to ASTM B 633.

1044.07 Painting. All cast iron parts shall be grit-blast cleaned to base metal

before painting. All ferrous parts of the flap gates shall be painted with a prime coat and shop coat. The paint shall be applied according to the manufacturer's standard practice. All machined surfaces shall be coated with a water-resistant rust preventive coating. Art. 1050.02 Poured Joint Sealers FILLERS, SEALERS, AND WATERPROOFING ITEMS SECTION 1050. POURED JOINT SEALERS

1050.01 Reserved.

1050.02 Hot-Poured Joint Sealer. Hot-poured joint sealer shall be according

to ASTM D 6690, Type II.

1050.03 Polysulfide Joint Sealant. The joint sealant shall be a polysulfide,

Type S or Type M, Grade NS, Class 25 or 12 1/2, Use T, according to ASTM C 920.

1050.04 Polyurethane Joint Sealant. The joint sealant shall be a

polyurethane sealant, Type S, Grade NS, Class 25 or better, Use T (T 1 or T 2), according to ASTM C 920.

1050.05 Fiber Modified Joint Sealer. The crack/joint sealant shall be a fiber-

modified asphalt binder mixed at the jobsite or premixed.