attachment_1_bid_129_25.docx

This specification and the attached drawing entitled, “Gate Details for Pine River Pond Dam Wakefield, NH”, outlines the technical requirements for providing New Hampshire Department of Environmental Services (NHDES) with one (1) dual-leaf stainless steel slide gate system for use at Pine River Pond Dam in Wakefield, New Hampshire.

GENERAL

The fabricated stainless steel dual-leaf slide gate shall be furnished with all necessary accessories and parts for a complete installation which shall allow for complete operation and shall be the latest standard product of a manufacturer regularly engaged in the production of equipment of this type.

The slide gate and appurtenances shall be supplied in accordance with the latest edition of AWWA C561 (Stainless Steel) and as modified herein. The allowable leakage rate for the slide gate in this specification shall not exceed half the allowable leakage rate listed in the latest revision of AWWA C561 (Stainless Steel).

DESIGN SUBMITTAL

The Contractor shall submit no later than eight (8) weeks after issuance of purchase order (PO), for approval by NHDES prior to fabrication, the following data and drawings:

1. Product information to verify that the product meets the requirements set forth in this specification.

2. Certified drawings showing the principal dimensions and general construction.

3. Manufacturer’s recommended installation and operational instructions with detailed drawings showing installation specifications.

4. Affidavits of compliance in accordance with the latest edition of AWWA C561 as applied to structural design criteria and materials. Calculations shall be provided to support the affidavits.

DESIGN

The slide gate shall be fabricated from 304 stainless steel alloys. All structural components of the gate and operators are to be designed and manufactured to meet or exceed the latest edition of all AWWA C561 (Stainless Steel) slide gate standards as applicable, including those defining head and loading calculations, structural strength and deflection requirements, operator and stem forces, and material specifications. All alloys used in the gate’s construction shall be matched.

The gate shall be designed to allow for the following operations:

· The dual-leaf gate shall provide “top movement”.

· The out-to-out frame width shall not exceed 108”. The preferred minimum clear hydraulic opening width is 102”.

· With the gate in the “fully closed” position, the bottom of the lower leaf shall be seated in the invert frame, which shall be flush mounted to the log bay sill at elevation 573.15’. The top of the upper leaf shall be at elevation 582.55’ (total height = 9.4 feet).

· In “weir mode”, the lower leaf shall remain seated, and the top of the upper leaf shall travel from elevation 582.55’ down to elevation 578.35’.

· In “sluice mode”, the dual-leaf system shall travel from the ”fully closed” position up to elevation 577.55’, providing a clear opening height of 4.4 feet, minus the nominal reduction due to the invert frame and associated stand-off distance/grout bed.

PERFORMANCE

The slide gate shall be substantially watertight under a minimum design head of 9.2 feet. Under this design head, the leakage shall not exceed 0.05 U.S. gallons per minute per wetted foot of seating perimeter (i.e. half the allowable leakage rate listed in the latest revision of AWWA C561 (Stainless Steel)).

FRAMES (Stainless Steel 304)

1. The frame assembly, including the guide members, invert member and yoke members, shall be constructed of formed stainless steel plate with a minimum thickness of 1/4- inch. Frame design shall allow mounting directly to vertical concrete surfaces within the existing concrete sluiceway as shown on the plans with stainless steel anchor bolts and grout. Mounting style shall be as shown on the attached drawings.

2. Frame design shall allow mounting directly to existing concrete at elevation 573.15’. Both side frames and the invert frame shall be designed for surface mounting on the side walls of the bay and the floor of the bay.

3. The existing stoplog bay upstream of the proposed gate location, as shown on the attached drawing, must remain functional during and after gate installation.

4. Concrete shall be match drilled in the field using the gate frame holes as a template for locating wall anchors. Attachment to the concrete walls and arrangement of supports and mounting details shall be clearly indicated on the gate manufacturer’s plans. Supports and mounting hardware shall be provided by the gate manufacturer. The structural portion of the frame that incorporates the seat/seals shall be formed into a one-piece shape for rigidity. The frame shall be fabricated to accommodate a one-piece Ultra High Molecular Weight Polyethylene (UHMW) bearing bar/seal or equivalent. This bearing bar/seal is supplied mounted in the frame to reduce friction and wear between the slide/weir plate and frame faces, as well as to form the side seal seats to prevent leakage.

5. The side frames shall extend to accommodate the entire range of motion of the dual-leaf gate, ranging from the fully closed to the fully opened position.

6. The gate is to be a self-contained gate with a yoke provided across the top of the frame. The yoke shall be formed by two structural members affixed to the top of the side frame members to provide a rigid assembly. The yoke shall be designed to allow removal of the slide. The entire gate shall be shipped to the job site complete.

7. A rigid stainless steel invert member shall be provided across the bottom of the opening.

SLIDE PLATES

The slide plates shall be fabricated from minimum 1/4” thickness stainless steel plate and reinforced as required. Deflection under full design head will be no more than 1/720 of the span width of the gate.

SEALS

All gate side frames, slide gate seals, and invert seals shall prevent leakage using a UHMW bearing bar/seal, or approved equivalent, that requires no adjustment. Seal pressure shall be made constant automatically by means of an integrated round section nitrile member within a continuous extruded slot in the bearing bar/seal. The cord shall exert pressure on the UHMW away from the frame face and compressing the seal against the plate face.

The UHMW bearing bar/seal shall be a smooth extrusion with integral flex reliefs made from UV resistant UHMW polymer, and the bearing bar/seal shall be installed in one continuous piece from top to bottom of the guide frame. Saw cut UHMW, polymer that is not UV resistant, or materials installed in multiple vertical sections shall not be permitted. The seal on each side shall be held in place vertically within the guide frame by a restraining plate accessible at the top of the gate frame yoke, and horizontally by permanent weldments. In no case shall removal of the bearing bar/seal require de-watering of the gate, nor shall any of the retainers or retaining hardware require holes within the frame that are potential leak points should the fasteners loosen or fail, or which restrain differential movement between the guide frame and the UHMW.

STEMS

The stem(s) shall be stainless steel rod with accurately machined Acme stub threads. Stem diameter shall be designed for a safety factor of 2 based on a critical buckling compressive load calculated by the Euler Column formula where C=2 and assuming a 50 lb-ft torque on the AWWA nut. Stem pocket(s) shall be welded to the face of the stiffened side of the plate and to the uppermost stiffener. The stem(s) shall fit within the slide plate stem pocket(s) and be attached to the pocket(s) by means of a stainless steel bolt capable of withstanding the full force of the operator stem(s) under full design head with a manual operator, portable drill operator stall torque, or electric actuator stall torque as per AWWA C561, whichever is greater.

Stem guides will be supplied to support the stem(s) as required to meet the stem design criteria and shall be fabricated of the same alloy material as the gate and frame. Stem guides shall have bronze or UHMW bushings to reduce stem friction and wear as required by the installation. Stem guides shall be adjustable in multiple dimensions to allow for alignment with operator and gate stem nut. Non-adjustable stem guides, or guides made from solid polymer shall not be allowed. Stem covers shall be fracture-resistant clear polymer, guaranteed for clarity for 10 years, with vent holes at the top and bottom. The top of the stem cover(s) shall be closed. The bottom end of the stem cover(s) shall be mounted in a housing or adapter for easy field mounting. Stem covers shall be supplied complete with indicator marking tape to indicate gate position.

MANUAL OPERATORS

The gate shall have the ability to be operated by a manual crank-operated gearbox.

1. The gate manufacturer shall select the proper gear ratio to ensure that the gate can be operated with no more than a 40-lb effort when the gate is in the closed position and experiencing the maximum operating head.

2. The lift mechanism shall be capable of withstanding a torque of up to 200 lb-ft without damage to the operator, stem, or gate plate to allow for operation by a power drill.

3. An arrow with the word “OPEN” shall be permanently attached or cast onto the operator to indicate the direction or rotation to open the gate.

4. Crank-operated gearboxes shall be fully enclosed and shall have a cast aluminum or ductile iron housing.

5. Gearboxes shall have either single or double gear reduction depending upon the lifting capacity required.

6. Gearboxes shall be provided with a threaded cast bronze lift nut to engage the operating stem.

7. Bearings shall be provided above and below the flange on the operating nut to support both opening and closing thrusts.

8. Gears shall be steel with machined cut teeth designed for smooth operation.

9. The pinion shaft shall be stainless steel and shall be supported on ball or tapered roller bearings.

10. Positive mechanical seals shall be provided on the operating nut and the pinion shafts to exclude moisture and dirt and prevent leakage of lubricant out of the hoist.

11. The crank shall be cast iron or aluminum with a revolving brass or nylon grip.

12. The crank shall be removable.

ELECTRIC MOTOR ACTUATORS

1. Electric actuators shall be Limitorque MXB Actuators and conform to the requirements of the latest edition of AWWA Standard C542 and be of non-intrusive type. All calibration, configuration, and firmware updates, including the setting of position limits and torque output, shall be possible without removing any covers and without the use of any special tools.

2. Limitorque MXB-20 motor shall be capable of operating on 230VAC 3-phase, 60 hertz power (3 PHASE 3/60/230). Motor duty cycle shall be at least 15 mins.

3. Actuator enclosure shall be at least IP68 weatherproof rating. All external fasteners on the electric actuator will be stainless steel.

4. Manual override shall be by shaft adaptor allowing the use of a supplied removable hand wheel (side-mounted is preferred to top mounted). Manual operation will be via power gearing to minimize required rim pull and facilitate easy change-over from motor to manual operation when actuator is under load. Return from manual to electric mode of operation will be automatic upon motor operation. A seized or inoperable motor shall not prevent manual operation.

5. An arrow with the word "OPEN" shall be permanently attached or cast onto the operator to indicate the direction or rotation to open the gate.

6. Limitorque MX actuator shall include Analog Position Transmitter (APT) option.

7. Limitorque MX actuator shall include DDC-100 Modbus option.

8. Actuator must be capable of the meeting or exceeding the following closing times/operating speeds: approximately 5 inches per minute operating speed.

THREE-PHASE CONVERTER

In addition to the electric actuator, the gate manufacturer shall specify and provide a 3-phase converter of sufficient size and power to provide 3-phase power to the new MXB actuator. A 2-pole (240VAC) single-phase circuit will be furnished by NHDES to provide input power to the specified 3-phase converter. Amperage of this circuit to be determined by load demand of 3-phase converter specified by gate manufacturer.

ANCHORS

Anchor bolts shall be provided by the gate manufacturer for mounting the gate and appurtenances. Size, quantity, and location shall be determined by the gate manufacturer in accordance with the calculations provided in the approved submittals and as shown on the gate drawings. If epoxy type anchor bolts are provided, the gate manufacturer shall provide the studs and nuts only.

DELIVERY

The slide gate system shall be delivered to NHDES, Dam Bureau, 72 Silk Farm Road Maintenance Facility, Concord, NH. Gail Timmins of New Hampshire Department of Environmental Services shall be contacted at 603-271-7868 three (3) business days prior to delivery to coordinate off-loading. Robert Gordon shall be used as a secondary contact for delivery and can be reached at 603-419-9705. Delivery shall occur no later than twenty-four (24) weeks after receiving approval of drawings.

INSTALLATION

The slide gate system will be installed by NHDES staff. The gate manufacturer shall furnish a technician to review installation, field testing, and provide operator training. Two separate trips of one day (8 hours onsite) each shall be included in the bid price as a minimum to meet this requirement.

Please See Attachment 2 for Drawing

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