STEEL DECKING COMPOSITE
SPEC WRITER NOTE: Delete between
// ---- // if not applicable to project. Also delete any other item or paragraph
not applicable in the section and renumber the paragraphs.
PART 1 GENERAL
This section specifies material and services required for installation of composite steel decking including // shear connector studs and // miscellaneous closures required to prepare deck for concrete placement as shown and specified.
1.2 RELATED WORK:
Materials testing and inspection during construction: Section 01410,TESTING LABORATORY SERVICES.
1.3 DESIGN REQUIREMENTS:
A. Design steel decking in accordance with American Iron And Steel Institute publication "Specifications for the Design of Cold Formed Steel Structural Members", except as otherwise shown or specified.
B. Structural values of composite concrete slab consisting of deformed subfloor deck units, acting in combination with the concrete, shall be substantiated by computations developed from approved test made by an accredited independent testing laboratory.
A. Submit in accordance with Section 01340, SAMPLES AND SHOP DRAWINGS.
B. Shop Drawings: Shop and erection drawings showing decking unit layout, connections to supporting members, and information necessary to complete the installation as shown and specified, including supplementary framing, cant strips, cut openings, special jointing or other accessories. Show welding, side lap, closure, deck reinforcing and closure reinforcing details. Show openings required for work of other trades, including openings not shown on structural drawings. Indicate where temporary shoring is required to satisfy design criteria.
C. Manufacturer's Literature and Data: Showing steel decking section properties and specifying structural characteristics as specified herein.
D. Manufacturer's written recommendations for:
1. Shape of decking section to be used.
2. Cleaning of steel decking prior to concrete placement.
E. Test Report - Establishing structural characteristics of composite concrete and steel decking system.
F. Test Report - Stud base qualification.
G. Welding power setting recommendation by shear stud manufacturer.
H. Shear Stud Layouts: Submit drawings showing the number, pattern, spacing and configuration of the shear studs for each beam and girder.
I. Certification: For each type and gauge of metal deck supporting concrete slab or fill, furnish certification of the specified fire ratings. Certify that the units supplied are U.L. listed as a Steel Floor and Form Unit.
1.5 QUALITY ASSURANCE:
SPEC WRITER NOTE: Delete below
when UL listed floor deck units not required. Review required ratings
with Architect. Confirm locations for ratings and where deck will need
spray applied fireproofing.
A. Underwriters Label: Provide metal floor deck units listed in Underwriters Laboratories Fire Resistance Directory, with each deck unit bearing the UL label and marking for specific system detailed.
1.6 APPLICABLE PUBLICATIONS:
A. Publications listed below form a part of this specification to extent referenced. Publications are referenced in text by basic designation only.
B. American Iron and Steel Institute (AISI):
Specification and Commentary for the Design of Cold-Formed Steel Structural Members (1996).
C. American Society of Testing and Materials (ASTM):
A36/A36M-00 Standard Specification for Carbon Structural Steel
A108-99 Standard Specification for Steel Bars, Carbon, Cold Finished, Standard Quality
A653/A653M-99 Standard Specification for Steel Sheet, Zinc-Coated (Galvanized) or Zinc-Iron Alloy-Coated (Galvannealed) by the Hot-Dip Process
D. American Institute of Steel Construction (AISC):
1. Specification for Structural Steel Buildings Allowable Stress Design and Plastic Design (ninth Edition, 1989)
2. Load and Resistance Factor Design Specification for Structural Steel Buildings (second edition, 1994)
E. American Welding Society (AWS):
D1.1-00 Structural Welding Code - Steel
D1.3-89 Structural Welding Code - Sheet Steel
E. Military Specifications (Mil. Spec.):
MIL-P-21035B Paint, High Zinc Dust Content, Galvanizing Repair
PART 2 - PRODUCTS
SPEC WRITER NOTE: For galvanizing
treatment use coating class G60 for normal conditions, and G90 for extreme
exposure (salt air, etc.)
A. Steel Decking and all Flashings: ASTM A653, Structural Quality // suitable for shear stud weld-through techniques //.
B. Galvanizing: ASTM A653, // G90 // G60 //.
C. Shear connector studs: ASTM A108, Grades 1015-1020, yield 350 Mpa (50,000 psi) minimum, tensile strength - 400 Mpa (60,000 psi) minimum, reduction of area 50 percent minimum. Studs of uniform diameter; heads shall be concentric and normal to shaft; stud, after welding free from any substance or defect which would interfere with its function as a shear connector. Studs shall not be painted or galvanized. Size of studs as shown on drawings. Studs manufactured by a company normally engaged in the manufacturer of shear studs and can furnish equipment suitable for weld-through installation of shear studs.
D. Galvanizing Repair Paint: Mil. Spec. MIL-P-21035B.
E. Miscellaneous Steel Shapes: ASTM A36.
F. Welding Electrode: E60XX minimum.
G. Sheet Metal Accessories: ASTM A653, galvanized, unless noted otherwise. Provide accessories of every kind required to complete the installation of metal decking in the system shown. Finish sheet metal items to match deck including, but not limited to, the following items:
1. Metal Cover Plates: For end-abutting deck units, to close gaps at changes in deck direction, columns, walls and openings. Same quality as deck units but not less than 1.3 mm (18 gauge) sheet steel.
2. Continuous sheet metal edging: at openings and concrete slab edges. Same quality as deck units but not less than 1.3 mm (18 gauge) steel. Side and end closures supporting concrete and their attachment to supporting steel shall be designed by the manufacturer to safely support the wet weight of concrete and construction loads. The deflection of cantilever closures shall be limited to 3 mm (1/8 inch) maximum.
3. Metal Closure Strips: For openings between decking and other construction, of not less than 1.3 mm (18 gauge) sheet steel of the same quality as the deck units. Form to the configuration required to provide tight-fitting closures at open ends of flutes and sides of decking.
4. Seat angles for deck: Where a beam does not frame into a column.
A. Steel decking depth, gage, and section properties as shown. Provide edges of deck with vertical interlocking male and female lip providing for a positive mechanical connection.
B. Fabricate deck units with integral embossments to provide mechanical bond with concrete slab. In combination with concrete slab, capable of supporting total design loads on spans shown.
C. Steel decking capable of safely supporting total normal construction service loads without damage to decking unit.
D. Steel decking units shall include an integral system which provides a simple point of attachment for light duty hanger devices for flexibility for attaching hangers for support of acoustical, lathing, plumbing, heating, air conditioning and electrical items. System shall provide for minimum spacing pattern of 300 mm (12 inches) on centers longitudinally and 600 mm or 900 mm (24 or 36 inches) on centers transversely. Suspension system shall be capable of safely supporting a maximum allowable load of 45 kg (100 pounds) concentrated at any one hanger attachment point. System may consist of fold-down type hanger tabs or a lip hanger.
PART 3 - EXECUTION
A. Do not start installation of metal decking until corresponding steel framework has been plumbed, aligned and completed and until temporary shoring, where required, has been installed. Remove any oil, dirt, paint, ice, water and rust from steel surfaces to which metal decking will be welded.
B. Coordinate and cooperate with structural steel erector in locating decking bundles to prevent overloading of structural members.
C. Do not use floor deck units for storage or working platforms until permanently secured. Do not overload deck units once placed. Replace any deck units that become damaged after erection and prior to casting concrete at no cost to the Government.
D. Erect steel deck in accordance with manufacturer's printed instructions.
E. Ship steel deck units to project in standard widths and cut to proper length.
F. Provide steel decking in sufficient lengths to extend over 3 or more spans, except where structural steel layout does not permit.
G. Place steel decking units on supporting steel framework and adjust to final position before being permanently fastening. Bring each unit to proper bearing on supporting beams. Place deck units in straight alignment for entire length of run of flutes and with close registration of flutes of one unit with those of abutting unit. Maximum space between ends of abutting units is 13 mm (1/2 inch). If space exceeds 13 mm (1/2 inch), install closure plates at no additional cost to Government.
H. Ceiling hanger loops if used, must be flattened or removed to obtain bearing of units on structural steel.
SPEC WRITER NOTE: All UL fire tests
for rated floors are run with welded side laps (not screws). Welded
side laps may be mandatory in seismic areas.
I. Fastening Deck Units:
1. Fasten floor deck units to steel supporting members by not less than 16 mm (5/8 inch) diameter puddle welds or elongated welds of equal strength, spaced not more than 305 mm (12 inches) o.c. with a minimum of two welds per unit at each support. Where two units abut, fasten each unit individually to the supporting steel framework.
2. Tack weld or use self-tapping No. 8 or larger machine screws at 915 mm (3 feet) o.c. for fastening end closures. Only use welds to attach longitudinal end closures.
3. Weld side laps of adjacent floor deck units that span more than 1524 mm (5 feet). Fasten at midspan or 915 mm (3 feet) o.c., whichever is smaller.
J. Welding conform to AWS D1.3 and done by competent experienced welding mechanics.
K. Areas scarred during erection and welds shall be thoroughly cleaned and touched-up with zinc rich galvanizing repair paint. Paint touch-up is not required for welds or scars that are to be in direct contact with concrete.
L. Provide metal concrete stops at edges of deck as required.
M. Cutting and Fitting:
1. Cut all metal deck units to proper length in the shop prior to shipping.
2. Field cutting by the metal deck erector is restricted to bevel cuts, notching to fit around columns and similar items, and cutting openings that are located and dimensioned on the structural drawings.
3. Other penetrations shown on the approved metal deck shop drawings but not shown on the structural drawings are to be located, cut and reinforced by the trade requiring the opening.
4. Make all cuts neat and trim using a metal saw, drill or punchout device; cutting with torches is expressly prohibited.
5. Do not make any cuts in the metal deck that are not shown on the approved metal deck drawings. If an additional opening not shown on the approved shop drawings is required, submit a sketch, to scale, locating the required new opening and any other openings and supports in the immediate area. Do not cut the opening until the sketch has been reviewed and accepted by the Resident Engineer. Provide any additional reinforcing or framing required for the opening at no cost to the Government. Failure to comply with these requirements is cause for rejection of the work and removal and replacement of the affected metal deck.
6. Reinforcement at Openings: Provide additional metal reinforcement and closure pieces as required for strength, continuity of decking and support of other work shown.
N. Installation of shear connector studs through previously installed metal deck conform to AWS D1.1, Section 7, except all studs will be installed with automatically timed welding equipment and as specified below:
1. Do not place reinforcing steel temperature mesh or other materials and equipment which will interfere with stud installation on steel deck until shear connector studs are installed.
2. Steel deck sheets shall be free of oil, rust, dirt, and paint. Release water in decks valley so that it does not become entrapped between deck and beam. Surface to which stud is to be welded shall be clean and dry.
3. Rest metal deck tightly upon top flange of structural member with bottom of deck rib in full contact with top of beam flange.
4. Weld studs only through a single thickness of deck. Place decking so that a butt joint is obtained. Place studs directly over beam web, where one row of studs are required.
5. Ferrules specially developed for the weld-through technique must be used. Ferrules shall be appropriate for size of studs used and be removed after welding.
6. Submit report of successful test program for stud base qualification as required by AWS D1.1, Appendix K.
Clean deck in accordance with manufacturer's recommendation before concrete placement.
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