MNA navlock deck grating purchase

1. INTENT

Contractor shall furnish and deliver eight (8) new metal bar grating assemblies to McNary Lock and Dam. Each assembly will consist of multiple sections of metal bar grating with at least 2 (two) sections having a minimum width dimension (perpendicular to bearing bars) of approximately 36 inches.

1. SCOPE

The Contractor shall be required to deliver the metal bar grating to McNary Dam by the date shown in the Shipment and Delivery Section below and shall provide documentation and other items, as stated in the specifications. All materials shall conform to the “Buy American Act.”

1. SPECIFICATIONS

   1. Metal Bar Grating:

Metal bar grating shall be 15-W-4 heavy duty galvanized carbon steel grating conforming to ANSI/NAAMM MBG 532 and the following characteristics:

1. 1. 1. Welded type.  Welding shall be in accordance with ANSI/NAAMM MBG 532 & ANSI/NAAMM 533.  No welds anywhere on the grating will be ground unless otherwise specifically callout.
2. 1. 1. Bearing Bars:
3. 1. 1. 1. Maximum bearing bar spacing 15/16 inch center to center.
4. 1. 1. 1. Size of bearings bars to be 2-1/2 inch x 3/8 inch.
5. 1. 1. 1. 1. Bearing bars to be coped 1/4 inch x 3-1/2” on each of the bottom ends.
6. 1. 1. 1. Bearing bar material shall have mechanical properties equal to, or greater than ASTM A1018 Grade 36 for hot rolled carbon steel coil.
7. 1. 1. Cross Bars:
8. 1. 1. 1. Maximum cross bar spacing 4 inch center to center.
9. 1. 1. 1. Cross bar material:

For rectangular sections: cross bars and connecting bars shall have mechanical properties equal to, or greater than ASTM A1011/A1011M Commercial steel (Type B) for hot rolled carbon steel sheet and strip.

For circular sections: cross bars and connecting bars made of wire rod shall conform to ASTM A510/A510M for carbon steel wire rods and coarse round wire, except that permissible tolerance on diameter of course round wire shall be +/- 0.005 inch.

1. 1. 1. Banding: Trench band metal bar grating ends that run perpendicular to bearing bars with a maximum of ¼ inch less than the depth of grating to permit drainage.  Banding bars shall have a minimum thickness of ¼ inch.  Banding shall be attached by welding to each bearing bar (load banding) in accordance with ANSI/NAAMM MBG 532 & ANSI/NAAMM MBG 533.
2. 1. 1. Surface to be plain (smooth).
3. 1. 1. Finish:
4. 1. 1. 1. After fabricating metal bar grating assemblies, coating to be galvanized and shall have exposed surfaces zinc-coated by the hot dip process in accordance with ASTM A123/A123M.  Galvanized surfaces shall not be “passivated” or “stabilized”.
5. 1. 1. 1. If damage occurs to galvanized surface follow ASTM A780/A780M, cold galvanizing repair compound.
6. 1. 1. Dimensions of metal bar grating assembly:
7. 1. 1. 1. Fabrication tolerances of metal bar grating shall be in accordance with NAAMM MBG 532. All materials shall be in accordance with ASTM A6/A6M tolerances.

Additionally, overall metal bar assembly tolerances must be so that the assemblies are able to fit within the existing recessed trench slots.  Field measurements of the recessed grating trench slots are 32-3/8 inch span by 160-3/4 inch wide.  Metal bar grating assemblies must be fabricated to meet the following tolerances:

Overall span for grating sections: 31-5/8 inch +/- ¼ inch.

Overall width of grating assembly: 159.75 +/- ½ inch.

1. SUBMITTALS

Before acceptance, submit manufacturers catalog cuts, specification sheets, technical specifications and warranty to the Contract Specialist.

1. Warranty

Each metal bar grating assembly shall be covered by a minimum one-year warranty on all parts, labor, and workmanship from factory defects.

1. SHIPMENT AND DELIVERY

   1. All materials shall be delivered FOB destination no later than 10 weeks after contract award.  The contractor shall be responsible for packing and shipping the components in a manner that will ensure undamaged and complete arrival to McNary Lock and Dam.
2. 1. Notify the Government of delivery prior to shipment by providing the date & estimated time of arrival.
3. 1. Shipments are only allowed during normal business hours of Monday – Thursday, 7:00 AM to 4:00 PM. No shipments shall be accepted on Federal Holidays. All shipments shall be delivered to:

McNary Lock and Dam

82790 Devore Rd.

Umatilla, OR 97882-1441