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38-W-4 Carbon Steel Galvanized GratingsModel Specification for type 38-W-4 Carbon Steel Galvanized Grating as Manufactured by Direct Metals®, 3775 Cobb International Blvd. Kennesaw, GA 30152-4390 or approved equal. NOTE: The specifier will need to edit this specification to reflect the options in this document shown in Red. Some editing can be accomplished by deleting unnecessary requirements. SECTION 05 53 00 Metal Fabrications – Metal Gratings Part 1: General 1.1 Section Includes A. Prefabricated heavy duty carbon steel bar gratings.B. Prefabricated Support Frames for gratings.C. Miscellaneous installation hardware and accessories.1.2 References A. ASTM A-36 Carbon SteelB. ASTM A-510 Carbon Steel Wire RodsC. ANSI/NAAMM- MBG-532-09 Heavy Duty Metal Bar Grating Manual1.3 Action Submittals A. Product Data: The contractor shall submit the manufacturer’s catalog pagesincluding load tables, anchor details and standard installation details.B. Shop drawings: The contractor shall submit for approval shop drawings for thefabrication and erection of all gratings, based on construction drawings of currentissue. Include plans, elevations, and details of sections and connections asrequired. Show type and location of all fasteners.C. Samples of Grating and Anchorage system shall be submitted for approval.1.4 Quality Assurance A. Manufacturer Qualification: A company specializing in the manufacture ofmetal bar gratings with not less than 10 years of documented experience.B. Fabrication tolerances shall be in accordance with applicable provisions andrecommendations of ANSI/NAAMM 532-09 Metal Bar Grating Manual.

Part 2: Products 2.1 Source Requirements: Design is based upon use of gratings as manufactured by Direct Metals® and terminology used herein may include reference to the specific performance or product of this manufacturer. Such reference shall be construed only as establishing the quality of materials, operational features and workmanship to be used under this Section and shall not, in any way, be construed as limiting competition. 2.2 Manufacturers: Acceptable Manufacturers include Direct Metals®, 3775 Cobb International Blvd. Kennesaw, GA 30152-4390, 800-711-4939, www.directmetals.com, or approved equal. 2.3 Manufactured Units: A. Description: Grating: Type 38-W-4 Heavy Duty Carbon Steel Grating withGalvanized finish. Fabricated by welding heavy duty cross bars (3/8” Dia forbearing bars up to 2-1/2” deep or 1” deep x 1/4” thick for main bearing bars3” or deeper) perpendicular to heavy duty main bearing bars. Cross bars areinserted in slots or notches in the main bearing bars and fillet welded at onecorner of each main bearing bar / heavy cross bar intersection.1. Main Bearing Bar Spacing: 2-3/8” on center.2. Bearing bar thickness: 1/4” (or 5/16” or 3/8”) as shown on thedrawings.3. Main Bearing Bar depth is to be based on loading requirementsand the clear span shown on the drawings.4. Cross Bar Spacing: 4” on center.5. Top of main bearing bars are to be smooth (or serrated as shownon the drawings).B. Fabrication: Load Band ends of grating with bars of same thickness as themain bearing bars. Weld banding flush with the top surface of the grating.Depth of banding to be ½” less than the depth of the main bearing bars asshown on the drawings. Include welded anchor blocks ¼” from the bottomsurface with hole to accept washer and attachment bolts.C. Steel Frames: Carbon Steel ASTM A-36 frames shall be provided as shownon the contract drawings to support and attach the gratings. Include anchorsas shown for locking frame into concrete as shown on the plans. Galvanizeframes after fabrication per ASTM A123.D. Design Criteria:1. Loading: Unless shown otherwise on the contract drawings,gratings shall be designed and manufactured to meet the live loadconditions of AASHTO HS 20 with 30% impact factor. MainBearing bar depth shall be as shown on the contract drawings or as

recommended by the manufacturer to meet the loading requirements, and clear span conditions. E. Materials: Main Bearing bars and rectangular cross bars are to be CarbonSteel type ASTM A-36 Carbon Steel. Round Cross bars are to be per ASTMA-510. Banding is to be Carbon Steel type ASTM A-36.F. Fabrication Tolerances shall be in accordance with ANSI/NAAMM MBG532-09 Metal Bar Grating Manual.G. Finish: Gratings and frames shall be Hot-Dip Galvanized per ASTM A123(or powder coat painted black as shown on the drawings).2.4 Accessories: Provide appropriate fasteners for type, grade, and class required for the approved anchorage system. Include lifting devices as shown on the drawings. Part 3: Execution 3.1 Field Verification: Contractor is to provide field measurements prior to preparation of final shop drawings and fabrication where required to ensure proper fitting of the work. 3.2 Installation A. Prior to grating installation, contractor shall inspect supports for correctalignment and conditions for proper attachment and support of the gratings. Anyinconsistencies between contract drawings and supporting structure deemeddetrimental to grating placement shall be reported in writing to the Engineer,Architect or owner’s agent prior to placement.B. Install grating in accordance with shop drawings and standard installationclearances as recommended by ANSI/NAAMM MBG-532-09 Metal Bar GratingManual.3.3 Grating Attachment: Use approved attachment system and fasteners to secure grating to supporting members as shown on plans.