05120 Structural Steel.pdf

Standard Drawings for Doppler (VHF)

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STRUCTURAL STEEL 05120-1

SECTION 05120

STRUCTURAL STEEL

PART 1 - GENERAL

1.1 Work Included: Provide fabrication and erection of structural steel and other items as shown on the drawings or required by other divisions of these specifications. Provide inspector to inspect bolts and welds during steel erection.

1.2 Applicable Publications: Industry publications controlling the work of this division include:

A. American Institute of Steel Construction (AISC):

Manual of Steel Construction, Allowable Stress Design (ASD).

B. American Society for Testing and Materials (ASTM):

ASTM A36-90 Structural Steel.

ASTM A53-90a Pipe, Steel, Black and Hot Dipped, Zinc Coated Welded and Seamless.

ASTM A108-90a Steel Bars, Carbon, Cold Finished, Standard Quality.

ASTM A123-89a Zinc (Hot-Dip Galvanized) Coatings on Iron and Steel Products.

ASTM A307-90 Carbon Steel Bolts and Studs, 60,000 psi Tensile Strength.

ASTM A325-90 High-Strength Bolts for Structural Steel Joints.

ASTM A490-90 Heat-Treated, Structural Steel Bolts, 150 (KSI) (1035MPa) Tensile

Strength.

ASTM A500-90 Cold-Formed Welded and Seamless Carbon Steel Structural Tubing in

Rounds and Shapes.

ASTM A563-90 Carbon and Alloy Steel Nuts.

ASTM A780-80 Standard Practice for Repair of Damaged Hot-Dip Galvanized Coatings.

ASTM B695-91 Coatings of Zinc Mechanically Deposited on Iron and Steel.

ASTM F436-90 Hardened Steel Washers.

ASTM F959-90 Compressible-Washer-Type Direct Tension Indicator for Use with

Structural Fasteners.

C. American Welding Society (AWS):

AWS A5.1: Covered Carbon Steel Arc Welding Electrodes1.

AWS A5.5: Low Alloy Steel Covered Arc Welding Electrodes.

AWS C2.2-67: Recommended Practices for Metalizing with Aluminum and Zinc for

Protection of Iron and Steel.

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AWS D1.1: Structural Welding Code - Steel.

D. Research Council on Structural Connections (RCSC):

"Specifications for Structural Joints Using ASTM A325 Bolts or ASTM A490 Bolts," as endorsed by AISC.

E. Steel Structures Painting Council (SSPC):

SSPC-SP3: Power Tool Cleaning.

SSPC-Paint 11: Red Iron Oxide, Zinc Chromate, Raw Linseed Oil and Alkyd Paint.

1.3 Submittals: Submit Fabrication and erection drawings showing all details, connections, material designations, and all top of steel elevations.

1.4 Quality Assurance: Welders shall be qualified as prescribed in AWS D1.1.

PART 2 - PRODUCTS

2.1 Structural Steel - Structural shapes, plates, bars, tubing and steel pipe shall conform to the following specifications:

A. Shapes, plates and bars: conform to ASTM A36.

B. Structural tubing: conform to ASTM A500, Grade B.

C. Steel pipe: conform to ASTM A53, Type E or S, Grade B.

2.2 Anchor Bolts: conform to ASTM A307 with heavy hexagonal nuts.

2.3 Bolts: Bolts shall be in accordance with the following:

A. Common (machine) bolts shall conform to ASTM A307 Grade A and nuts to ASTM A563. One common bolt assembly shall consist of a bolt, a heavy hex nut, a lock nut and a hardened washer.

B. High strength bolts shall conform to ASTM A325. One high strength bolt assembly shall consist of a heavy hex head structural bolt, a heavy hex nut, a hardened washer conforming with ASTM F436 and a direct tension indicator conforming with ASTM F959. The hardened washer shall be installed against the element turned in tightening.

2.4 Welding Electrodes: Welding electrodes shall comply with AWS D1.1 using AWS A5.1 or AWS A5.5

E70XX and shall be compatible with the welding process selected.

2.5 Headed Welded Studs: Headed welded studs shall be manufactured of cold rolled steel conforming to

ASTM A108. Yield strength shall be 50,000 psi minimum; ultimate tensile strength shall be 60,000 psi minimum.

2.6 Locknut: For use with other than high strength bolts.

A. Alternate 1: “Palnuts” as manufactured by Palnut Company of Irvington, NJ, or approved equal.

B. Alternate 2: “Anco Lock Nut” as manufactured by Automatic Nut Co. of Lebanon, PA, or approved equal, in lieu of the regular hex nut and the locknut.

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2.7 Primer: Primer shall be a red oxide-chromate primer complying with SSPC Paint Specification No. 11.

PART 3 - EXECUTION

3.1 Fabrication: Shop fabricate and assemble materials as specified herein.

3.1.1 Fabricate items of structural steel in accordance with the AISC-ASD Specifications, and as indicated on the approved shop drawings.

3.1.2 Properly mark and match-mark materials for field assembly and for identification as to location for which intended.

3.1.3 Fabricate and deliver in a sequence which will expedite erection and minimize field handling of materials.

3.1.4 Where finishing is required, complete the assembly, including welding of units, before start of finishing operations.

3.1.5 Provide finish surfaces of members exposed in the final structure free from markings, burrs, and other defects.

3.1.6 Provide connections as specified herein.

3.1.6.1 Provide bolts and washers of types and sizes required for completion of field erection.

3.1.6.2 Install high strength threaded fasteners in accordance with RCSC "Specifications for

Structural Joints Using ASTM A325 or ASTM A490 Bolts."

3.1.6.3 Welded construction shall comply with AWS D1.1 for procedures, appearance, quality of welds, and methods used in correcting welded work.

3.1.6.4 Assemble and weld built-up sections by methods which will produce true alignment of axes without warp.

3.1.6.5 All connections which are not detailed or otherwise noted on the design drawings shall be shop welded and field bolted in accordance with AISC Framed Beam Connections, Tables

II and III as shown in the AISC-ASD Manual of Steel Construction. Use the maximum number (n) rows of field bolts compatible with a beam T dimension and flange cope for each beam depth under consideration. Use a 1/4-inch shop weld "A" shown in Table III for the required number of field bolts. All bolted connections shall be designed for the full capacity of the connecting members.

3.1.6.6 The fabricator shall furnish and install erection clips for fit-up of welded connections.

3.1.6.7 Double angle members shall have welded fillers spaced in accordance with Chapter E4 of the AISC-ASD Specification.

3.2 Plates: Gusset and stiffener plates shall be 3/8-inch thick minimum.

3.3 Columns: Columns shall have full bearing at splices and at end plates.

3.4 Camber: All members shall be fabricated with natural camber up.

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3.5 Shop Priming: Structural steel shall be shop primed as specified herein, unless shown otherwise on the drawings.

3.5.1 Structural steel surface preparation shall conform to SSPC-SP3, "Power Tool Cleaning."

3.5.2 Surface preparation and primer application shall be in accordance with AISC Code of Standard

Practice as included in the ASD Manual of Steel Construction.

3.5.3 Storing, thinning, mixing, handling, and application of paint materials shall be in accordance with manufacturer's instructions. Containers shall remain closed until required for use. Manufacturer's pot-life requirements shall be strictly adhered to.

3.5.4 Primer shall be applied to dry, clean, prepared surfaces and under favorable conditions in accordance with manufacturer's instructions. Unless otherwise recommended by manufacturer, priming shall not be done when the ambient temperature is less than 50°F, the relative humidity is more than

90 percent, or the surface temperature is less than 5°F above the dew point.

3.5.5 Generally, all primer shall be spray applied. Brush or roller application shall be restricted to touch-up and to areas not accessible by spray gun.

3.5.6 Primer shall be uniformly applied without runs, sags, solvent blisters, dry spray or other blemishes.

All blemishes and other irregularities shall be repaired or removed and the area recoated. Special attention shall be paid to crevices, weld lines, bolt heads, corners, edges, etc., to obtain the required nominal film thickness.

3.5.7 The dry film thickness of the primer shall be 2.0 mils.

3.5.8 If primer is damaged by welding or physical abuse, the area shall be touched-up and repaired. The touch-up paint shall be compatible with the applied primer with minimum dry film thickness of

1.5 mils.

3.5.9 All primers and touch-up paint shall be applied in strict accordance with the manufacturer's instructions and these specifications.

3.6 Galvanizing: All galvanizing shall be as specified herein.

3.6.1 When indicated on the drawings, structural steel including handrail, ladder, stairway, treads, grating, checkered plate, bolts, nuts and washers shall be galvanized in accordance with this Section and the applicable ASTM Standards.

3.6.2 Galvanizing of structural steel shapes, plates, bars and strips shall be in accordance with ASTM

A123. Minimum weight of zinc coating shall be 2.0 oz/ft² for individual specimen and minimum thickness of 3.4 mils.

3.6.3 When specified on drawings, all bolts, nuts and washers shall be mechanically zinc coated in accordance with ASTM B695, Type I. Nuts shall be tapped oversize in accordance with ASTM

A563 prior to zinc coating and need not be retapped after coating.

3.6.4 The fabricator shall be responsible to safeguard against embrittlement and warpage.

3.6.5 Whenever practical, cutting, drilling and welding shall be performed prior to galvanizing.

3.7 Erection: Erection of structural steel shall be as specified herein.

3.7.1 Erection of structural steel shall comply with AISC "Code of Standard Practice."

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3.7.2 Structural field welding shall be done by the electric submerged or shielded metal arc process.

Welded construction shall comply with AWS D1.1.

3.7.3 Headed welded studs shall be automatically end welded in accordance with the manufacturer's recommendations in such a manner as to provide complete fusion between the end of the stud and the plate. There shall be no porosity or evidence of lack of fusion between the welded end of the stud and the plate. The stud shall decrease in length during welding approximately 1/8-inch for studs 5/8-inch diameter and under, and 3/16-inch for studs over 5/8-inch diameter.

3.7.4 Provide anchor bolts and other connectors required for securing structural steel to foundations and other in-place work. Provide templates and other devices necessary for presetting bolts and anchors to accurate locations.

3.7.5 Splice members only where indicated on the drawings.

3.7.6 Gas cutting torches shall not be used for correcting fabricating errors in the structural framing. Gas cutting is permitted only in secondary members. Finish gas cut sections to a sheared appearance.

3.7.8 Provide temporary shoring and bracing members with connections of sufficient strength to bear imposed loads. Provide temporary guy lines to achieve proper alignments of the structure as erection proceeds. Remove temporary connections and members when permanent members are in place and the final connections have been made.

3.7.9 Provide and set bases and bearing plates as specified herein. Clean concrete bearing surfaces free from bond-reducing materials, and then roughen to improve bond to the surface. Clean the bottom surface of base and bearing plates. Set loose and attached base plates and bearing plates for structural members in wedges or other adjusting devices. Tighten anchor bolts after the supported members have been positioned and plumbed. Do not remove wedges or shims but, if protruding, cut off flush with the edge of the base or bearing plate prior to packing with grout. Dry pack grout solidly between bearing surfaces and bases or plates to assure that no voids remain. Finish exposed surfaces, protect installed materials, and allow to cure in strict compliance with the manufacturer's recommendations.

3.7.10 Set structural frames accurately to the lines and elevations indicated.

3.7.11 Align and adjust members forming part of a complete frame or structure before fastening permanently.

3.7.12 Clean bearing surfaces, and other surfaces which will be in permanent contact, before assembly.

3.7.13 Level and plumb individual members of the structure within AISC tolerances in accordance with the

AISC Code of Standard Practice as included in the ASD Manual of Steel Construction.

3.7.15 Establish required leveling and plumbing measurements on the mean operating temperature of the structure, making allowances for the difference between temperature at time of erection and the mean temperature at which the structure will be when completed and in service.

3.7.16 Install and fully tension high strength threaded fasteners in accordance with RCSC, "Specifications for Structural Joints Using ASTM A325 or ASTM A490 Bolts."

3.8 Repairing Damaged Hot-Dip Galvanized Coatings: When approved by the WRPE Designee, hot-dip galvanized coatings shall be repaired as follows:

3.8.1 All damaged hot-dip galvanized coatings of reamed or field-drilled holes shall be repaired using a zinc-rich paint.

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3.8.1.1 As a minimum, the zinc-rich paint dried film shall contain 94% zinc dust by weight, and shall conform to ASTM A780-80.

3.8.1.2 Minimum dry film thickness is 3 mils.

3.8.1.3 Acceptable products include Z.R.C. liquid cold galvanizing compound with shiny finish, by

ZRC Products Company, or previously approved alternate.

3.8.2 All other damaged galvanized coatings shall be repaired using a metalizing/thermal spray coating process per AWS C2.2-67.

3.8.2.1 Use a metalizing alloy composed of 85% zinc and 15% aluminum.

3.8.2.2 Minimum coat thickness shall be 6 mils. Dry film thickness shall be measured by using a magnetic or electromagnetic gage. Measurements shall be taken in the presence of the

WRPE Designee at locations selected by him.

3.8.3 Surface Preparation:

3.8.3.1 Surfaces to be reconditioned shall be clean, dry, and free of oil, grease, and corrosive products.

3.83.2 Surface preparation shall be in accordance with ASTM A870 and AWS C2.2-67.

3.8.3.3 To ensure a smooth coating, surface preparation shall extend into the undamaged galvanized coating. The method and extent of surface preparation shall be approved by the WRPE Designee.

END OF SECTION