05120_structural_steel_DF.doc

SECTION 05120 - STRUCTURAL STEEL

PART 1 - GENERAL

1.1 SUMMARY

A. This Section includes structural steel.

1.2 SUBMITTALS

A. Product Data: For each type of product indicated.

B. Shop Drawings: Show fabrication of structural-steel components.

Retain first paragraph below if procedures for welder certification are retained in "Quality Assurance" Article.

C. Welding certificates.

1.3 QUALITY ASSURANCE

Retain first paragraph below if AISC certification of fabricator is required. Category Sbd is for conventional steel-building structures.

A. Welding: Qualify procedures and personnel according to AWS D1.1, "Structural Welding Code--Steel."

B. Comply with applicable provisions of AISC's "Code of Standard Practice for Steel Buildings and Bridges."

1.4 PROJECT CONDITIONS

If possible, design railings so that they do not have to fit other construction, and delete this Article.

A. Field Measurements: Verify actual locations of walls, floors, mounting posts, and other construction affecting structural steel placement by field measurements before fabrication and indicate measurements on Shop Drawings.

Delete first subparagraph below if not allowed.

1. Established Dimensions: Where field measurements cannot be made without delaying the Work, establish dimensions from plans and accessible work and proceed with fabricating railings without field measurements. Verify dimensions as work allows.

2. Where dimensions rely on incomplete Work, provide allowance for trimming and fitting at site.

1.5 MEASUREMENT AND PAYMENT

This item shall include all structural steel shown on the plans for installation inside the Tower, and on the exterior platform to support the roof, and center support for removable cover. Work shall include fabrication, installation, painting, finishing, cleanup, and all associated work for a complete and functional installation as shown on the drawings.

Measurement for this item will be one lump sum for the completed work. Payment will be made at the contract unit price as shown on the Schedule of Item.

PART 2 - PRODUCTS

2.1 STRUCTURAL-STEEL MATERIALS

A. Channels, Angles, Plate and Bar: ASTM A 36/A 36M B. Steel Pipe: ASTM A 53/A 53M, Type E or S, Grade B.

C. Welding Electrodes: Comply with AWS requirements.

2.2 PERFORATED STEEL SHEETING

Plain steel 11 gauge sheet, ½” hex opening, 1/16” divider, 80% open area with 1” unpunched margin on edge. Material as manufactured by McNichols Co, mcnichols.com, 1-800-237-3820 or equivalent.

2.3 BOLTS, CONNECTORS, AND ANCHORS

A. High-Strength Bolts, Nuts, and Washers: ASTM A 325 (ASTM A 325M), Type 1, heavy hex steel structural bolts; ASTM A 563 (ASTM A 563M) heavy hex carbon-steel nuts; and ASTM F 436 (ASTM F 436M) hardened carbon-steel washers.

Select one finish from options in subparagraph below.

1. Finish: Galvanized Tension-control (twist-off) bolt assemblies in paragraph below correspond to strength of ASTM A 325 (ASTM A 325M) bolts. If corrosion-resisting (weathering) steel is used, change Type 1 assemblies to Type 3 below and delete "Finish" Subparagraph.

B. Threaded Rods: ASTM A 36/A 36M.

Select one finish from options below.

1. Finish: Galvanized

2.4 PRIMER

Delete this Article if shop painting is not required. Add proprietary primers if required as part of special coating or painting system. Coordinate primer selection with surface preparation and topcoats, requirements for slip-critical joints, and limitations of sprayed fire-resistive materials. Add color if required.

A. Primer: Fabricator's standard lead- and chromate-free, nonasphaltic, rust-inhibiting primer.

2.5 GROUT

Delete this Article if grouting is specified elsewhere.

A. Nonmetallic, Shrinkage-Resistant Grout: ASTM C 1107, factory-packaged, nonmetallic aggregate grout, noncorrosive, nonstaining, mixed with water to consistency suitable for application and a 30-minute working time.

2.6 FABRICATION

A. Structural Steel: Fabricate and assemble in shop to greatest extent possible. Fabricate according to AISC's "Code of Standard Practice for Steel Buildings and Bridges" and AISC's

2.7 SHOP CONNECTIONS

Retain first paragraph and subparagraph below for high-strength bolts.

A. High-Strength Bolts: Shop install high-strength bolts according to RCSC's "Specification for Structural Joints Using ASTM A 325 or A 490 Bolts" for type of bolt and type of joint specified.

RCSC requires that joint types be specified in the Contract Documents for most loading conditions.

1. Joint Type: Snug tightened B. Weld Connections: Comply with AWS D1.1 for welding procedure specifications, tolerances, appearance, and quality of welds and for methods used in correcting welding work.

2.8 PREPARING PERFORATED SHEETS

A. Sandblast, debur, chamfer, and smooth edges, corners, and surfaces of sheets. Sheets shall be free of all projections, burs and sharp corners and edges so as to not to cut or abrade skin that contacts sheets.

B. Degrease, clean and shop prime immediately after sandblasting and preparation before surface oxidation and rust is able to form.

C. Paint sheets before delivery, and wrap to prevent scratching and finish damage during transportation.

D. Field touch up paint after installation.

2.9 SHOP PRIMING

Retain this Article if shop priming is required.

A. Shop prime steel surfaces except the following:

Retain, revise, or delete five subparagraphs below to suit Project.

1. Surfaces embedded in concrete or mortar. Extend priming of partially embedded members to a depth of 2 inches (50 mm).

2. Surfaces to be field welded.

3. Galvanized surfaces.

B. Surface Preparation: Clean surfaces to be painted. Remove loose rust and mill scale and spatter, slag, or flux deposits. Prepare surfaces according to the following specifications and standards:

1. SSPC-SP 2, "Hand Tool Cleaning."

Cleaning in subparagraph above and below removes loose rust, mill scale, and paint. Cleaning above is minimum surface preparation accepted by AISC for painted steel.

2. SSPC-SP 3, "Power Tool Cleaning."

C. Priming: Immediately after surface preparation, apply primer according to manufacturer's written instructions and at rate recommended by SSPC to provide a dry film thickness of not less than 1.5 mils (0.038 mm). Use priming methods that result in full coverage of joints, corners, edges, and exposed surfaces.

2.10 SOURCE QUALITY CONTROL

Retain this Article if fabricator's shop testing is required and revise to suit local practices and requirements of authorities having jurisdiction. Consider deleting if requiring AISC-certified fabricators and if authorities having jurisdiction approve fabrication work without special inspections. Coordinate with "Fabricator Qualifications" Paragraph in Part 1 "Quality Assurance" Article.

A. Owner will engage an independent testing and inspecting agency to perform shop tests and inspections and prepare test reports. Comply with testing and inspection requirements of Part 3, Article "Field Quality Control."

B. Correct deficiencies in Work that test reports and inspections indicate does not comply with the Contract Documents.

Retain below if shop-welded shear connectors are required.

PART 3 - EXECUTION

3.1 ERECTION

A. Examination: Verify elevations of concrete- and masonry-bearing surfaces and locations of anchor rods, bearing plates, and other embedments.

1. Proceed with installation only after unsatisfactory conditions have been corrected.

B. Set structural steel accurately in locations and to elevations indicated.

C. Base Plates: Clean concrete- and masonry-bearing surfaces of bond-reducing materials, and roughen surfaces prior to setting base plates. Clean bottom surface of base plates.

Revise requirements in subparagraphs below to suit Project.

1. Set base plates for structural members on wedges, shims, or setting nuts as required.

2. Weld plate washers to top of base plate.

3. Snug tighten anchor rods after supported members have been positioned and plumbed. Do not remove wedges or shims but, if protruding, cut off flush with edge of base plate before packing with grout.

4. Promptly pack grout solidly between bearing surfaces and base plates so no voids remain. Neatly finish exposed surfaces; protect grout and allow to cure.

D. Maintain erection tolerances of structural steel within AISC's "Code of Standard Practice for Steel Buildings and Bridges."

3.2 FIELD CONNECTIONS

A. High-Strength Bolts: Install high-strength bolts according to RCSC's "Specification for Structural Joints Using ASTM A 325 or A 490 Bolts" for snug tightened joints.

B. Weld Connections: Comply with AWS D1.1 for welding procedure specifications, tolerances, appearance, and quality of welds and for methods used in correcting welding work.

C. Comply with AISC's "Code of Standard Practice for Steel Buildings and Bridges" and for bearing, adequacy of temporary connections, alignment, and removal of paint on surfaces adjacent to field welds

D. Position edges of perforated sheets to align both horizontally and vertically.

1. Adjust spacing nuts on mounting bolts to position sheet edges to align.

2. Clamp or brace sheets so that corners of adjacent sheets meet straight and true.

3. Field drill and attach stitch plates to fasten adjacent sheets flat and square as shown on drawings.

3.3 Field Painting and Touchup.

A. Wire brush, sand, and otherwise clean areas that are to be field painted. Feather sanded areas into adjacent finish to allow for seamless touchup painting.

B. All areas that are scratched, scuffed, welded or otherwise damaged during installation shall be primed and color painted to match shop painting.

C. Feather and blend edges of touchup painting to match adjacent finish.

3.4 FIELD QUALITY CONTROL

Delete this Article if not required.

A. Testing Agency: Owner will inspect field welds and bolted connections.

RCSC prescribes inspection for snug-tightened joints and testing and inspection for each method of pretensioning joints.

B. Bolted Connections: Shop-bolted connections will be inspected according to RCSC's "Specification for Structural Joints Using ASTM A 325 or A 490 Bolts."

C. Welded Connections: Field welds will be visually inspected according to AWS D1.1.

Retain subparagraph and applicable associated subparagraphs below if required.

D. Correct deficiencies in Work that test reports and inspections indicate does not comply with the Contract Documents.

END OF SECTION 05120

STRUCTURAL STEEL

SECTION 05120-2