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Gates, lifts, stems and accessories shall be of the size, material, and construction as shown on the drawings and specified herein. They shall be Hydro Gate roller gates or approved equal. Similar installations shall have operated successfully for five years or more. All component parts shall be of the type material shown and shall conform to the ASTM specifications designated in the “Materials” section of this specification. The gates shall be of the overflow type or breastwall type as designated in the “Gate Schedule”.
Horizontal and vertical structural reinforcing members and a smooth faceplate shall be assembled and securely welded to provide a flat, box-shaped gate slide. The structural members shall be of the proper size, dimension, and placement to safely withstand the maximum unbalanced head designated in the “Gate Schedule”. The faceplate shall be of sufficient thickness to safely withstand the maximum unbalanced head and shall be attached to structural members by welding. The leaf shall be designed to limit defection to L/360 for overflow-type gates and to a maximum 3/16 in. for breastwall-type gates at upper reinforcing members.
The gate slide shall be fabricated in one or two sections and shall be furnished with a minimum of two rollers per side, per section. A flat bar shall be welded to the outer periphery of the front face of the slide to provide a mounting surface for side and bottom seals. After all other welding on the gate slide has been completed, the raised seating surface shall be machined to a plane parallel to the roller axis and drilled for mounting the rubber seals.
Cast rollers shall be spaced along the sides of the gate slide to carry equal portions of the hydraulic forces. Each roller shall be provided with a heavy, one-piece, self-lubricating bushing. Roller shafts shall be bolted to collars to provide for field assembly of rollers, bushings and shafting.
Adjustable Roller Assemblies (Option)
Rollers shall be furnished with eccentric shafts to provide for field adjustment of approximately ¼ in.
Side seals shall be of rubber of the hollow J-seal type. The bottom seal shall be a flat rubber section. Seals and steel retainer flats shall be provided with holes to match those on the slide. Corners shall be vulcanized.
Fabricated Roller Slot
Shop-fabricated roller slots shall be provided for attaching to the front of concrete or for embedding as shown on the manufacturer’s drawing. The slot shall consist of structural steel shapes of the proper assembled dimension to provide a rubbing surface for the seals, design compression of the seals, and the housing area for the roller assemblies. The seal rubbing surface shall be a stainless steel flat attached to the inside of the roller slot. It shall be finished and polished after all other welding has been completed. The roller slot shall be of sufficient vertical height to provide for full opening of the gate, plus 1 ft, when the slide is fully opened or as otherwise indicated. The assembled slot shall be provided with a means for anchorage in the concrete and attachment to the concrete forms.
Adjustable Sill Plate
The bottom sill plate shall provide a smooth, level, and corrosion-resistant contact surface for the bottom seat for the full width of the invert of the gate. The sill plate shall be adjustable on anchor to permit leveling and alignment with the gate bottom. After the gate has been installed and the sill plate adjusted, it shall be grouted in place.
Manual welding operators performing welding operations on these gates, or accessories, shall currently be qualified either under Section 9, Part A, of the ASME Boiler and Pressure Vessel Code, or under the Standard Qualification Procedure of the American Welding Society.
The surface to be welded shall be properly prepared. Each deposited layer of weld metal shall be thoroughly cleaned before additional weld material is applied. All welds shall have complete fusion with the base metal, shall be of uniform thickness and shall be free from cracks, oxides, slag inclusions and gas pockets.
All sharp edges shall be removed by grinding.
All anchor bolts and assembly bolts shall be of the material shown in the “Materials” section of these specifications and of ample size to safely withstand the forces created by operation of the gate under specified heads. Anchor bolts shall be provided with two nuts each to facilitate installation.
Stems shall be manufactured from round, corrosion-resistant steel bar stock. Stems shall be minimum diameter to safely withstand forces created during gate operation under the unbalanced heads shown in the “Gate Schedule”. Stems shall be furnished with left-hand rolled threads, 29o Modified Acme threads of proper length to provide for complete opening of the gate. All contact surfaces of threads shall be rolled to a 32 micro-inch finish or better. The bottom end of the stem shall be threaded to connect to the cast stem block.
Lifting devices may be of the manually or electrically actuated type depending on gate size and frequency of operation.. For gates where the width is more than twice the height, tandem geared lifts are required.
Enclosed Gear Mechanical Lift
The manual lift mechanism shall be the crank-operated type with either a single or double gear ratio, depending on the lift load. It shall have a cast-bronze lift nut threaded to fit the operating stem. Roller bearings shall be provided above and below the flange on the lift nut to take the maximum thrust developed in opening and closing the gate.
The design of the lift mechanism shall be such that the slide can be operated with no more than a 40-lb effort on the crank. The maximum crank radius shall be 15 in. The direction of rotation to open the gate shall be indicated on the lift mechanism.
Each geared lift shall be as described above. Individual lifts shall be positioned to lift the gate from a point near each top corner of the gate and shall be connected to operate in tandem. The tandem lifts shall be connected with 1-3/8 in. diameter stainless steel or fabricated carbon steel shafting. Each end of the tandem shaft shall be fitted with flexible couplings to transmit the torque from one lift to the other and to compensate for slight misalignment. An intermediate support shall be provided for the tandem shaft when stems for tandem lifts are more than 12 ft apart.
Clean and Paint
All carbon steel surfaces shall be grit-blast cleaned to “near white” (SSPC SP-10) base metal before painting. All carbon steel parts of the gate shall be painted as specified. All machined-steel surfaces shall be suitably protected with a light prime coat or grease.
Drawings for Approval
Drawings showing dimensions and essential details required to locate and install the gate, stem, lift and accessories shall be submitted for the engineer’s approval prior to fabrication.
Installation of all parts shall be done by the contractor in a workmanlike manner. It shall be the contractor’s responsibility to handle, store and install the fabricated roller slots, gate, lift support assemblies, operating mechanism, stem guides and accessories in strict accordance with the manufacturer’s drawings and recommendations.
Materials shall conform to the requirements of the following ASTM specifications.
Hot-Rolled Steel (Flats, Structural Shapes, Plates)
ASTM A36, A283, Grade C or D; or ASTM A306, Grade 60
Cold-Rolled Steel (Shafting for Tandem Lifts)
ASTM A108, Grade 1045
Galvanized Steel (Fasteners)
ASTM A307 (Steel Bolts); ASTM A164 (Galvanized Coating)
Stainless Steel (Structurals, Plates, Flats)
ASTM A167, ASTM A240 or ASTM A276, all Type 304 or 304L
Stainless Steel (Fasteners)
ASTM F593 Alloy Group 1 (Bolts)
ASTM F594 Alloy Group 1 (Nuts)
Stainless Steel (Stems and Shafting)
ASTM A582, Type 303 or ASTM A276, Type 304
ASTM D2000, 1AA625
Ductile Iron Castings (Rollers)
ASTM A536, Grade 60-40-18 or 65-45-12
Bronze (Stem Block)
ASTM B584 C86500