Denver Museum of Nature and Science: Education and Collections Facility Project number 2009.104
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SECTION 05 1243 – ARCHITECTURALLY EXPOSED STRUCTURAL STEEL
PART 1 - GENERAL 1.1
SUMMARY A.
Section includes Architecturally Exposed Structural Steel. 1.
B.
Related Sections: 1. 2. 3. 4. 5.
1.2
Requirements in Division 05 Section "Structural Steel Framing" also apply to steel framing for curtain wall.
Division 01 Section "Quality Requirements" for independent testing agency procedures and istrative requirements. Division 03 Section "Cast-in-Place Concrete" for install anchor bolts, wedge-type inserts and other items indicated to be cast into concrete. Division 05 Section "Structural Steel Framing" for additional requirements applicable to steel framing for curtain wall. Division 05 Section "Metal Fabrications" for miscellaneous steel fabrications and other metal items not defined as structural steel. Division 09 Section "High-Performance Coatings" for surface preparation and priming requirements.
DEFINITIONS A.
Structural Steel: Elements of steel frame, as classified by AISC's "Code of Standard Practice for Steel Buildings and Bridges" that design loads.
B.
Architecturally Exposed Structural Steel: Structural steel designated as "architecturally exposed structural steel" or "AESS" in the Contract Documents.
C.
Category 1 AESS: All structural steel framing for curtain wall shall be designated as "Category 1 architecturally exposed structural steel" or "AESS-1".
1.3
ACTION SUBMITTALS A.
Shop Drawings: Show fabrication and installation details for Architecturally Exposed Structural Steel. 1. 2. 3. 4. 5.
Include plans, elevations, sections and details of Architecturally Exposed Structural Steels. Include anchorage and accessory items. Include details of cuts, connections, splices, holes, and other pertinent data. Include embedment drawings. Include templates for anchor installation.
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6.
7. 8. 9. B.
Indicate welds by standard AWS symbols, distinguishing between shop and field welds, and show size, length, and type of each weld. Show backing bars that are to be removed and supplemental fillet welds where backing bars are to remain. Indicate grinding, finish, and profile of welds. Indicate type, size, and length of bolts, distinguishing between shop and field bolts. Indicate orientation of bolt heads. Indicate exposed surfaces and edges and surface preparation being used. Indicate special tolerances and erection requirements.
Samples: Submit samples of AESS to set quality standards for exposed welds. 1.
1.4
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Steel plate, 3/8 by 8 by 8 inches, with one end of a short length of rectangular steel tube, 4 by 6 by 3/8 inches, welded to plate with a continuous fillet weld and with weld ground smooth and blended.
INFORMATIONAL SUBMITTALS A.
Qualification Data: For qualified Installer and Fabricator.
B.
Welding Certificates.
C.
Mill Test Reports: Signed by manufacturer certifying that the following products comply with requirements: 1. 2. 3.
Structural steel including chemical and physical properties. Bolts, nuts and washers including mechanical properties and chemical properties. Shear stud connectors.
D. LEED Submittals: 1.
Product Data for Recycled Content (MRc4) a. Submit product data or other published information indicating total weight of product to be provided for the Project, percent of post-consumer recycled material by weight and percent of post-industrial recycled material by weight. Include material costs (excluding costs of installation).
2.
Material Source (MRc5) a. Submit product data or other published information ing the location of manufacturing facility including name, address, and distance between manufacturing facility and the project site. Provide manufacturer’s documentation indicating location where the base materials were extracted, mined, quarried, harvested, etc. and the distance between this location and the project site. Also include material costs (excluding costs of installation). b. Include information on Material Tracking Worksheets.
3.
Low-Emitting Paints and Coatings (EQc4.2)
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a.
1.5
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Submit product data or other published information ing the VOC (Volatile Organic Compound) content is less than or equal to the allowable VOC content established by the governing standards
QUALITY ASSURANCE A.
Installer Qualifications: A qualified installer who participates in the AISC Quality Certification Program and is designated an AISC-Certified Erector, Category CSE.
B.
Fabricator Qualifications: A qualified fabricator that participates in the AISC Quality Certification Program and is designated an AISC-Certified Plant, Category SBD.
C.
Shop-Painting Applicators: Qualified according to AISC's Sophisticated Paint Endorsement P1 or SSPC-QP 3, "Standard Procedure for Evaluating Qualifications of Shop Painting Applicators".
D.
Welding: Qualify procedures and personnel according to AWS D1.1, "Structural Welding Code-Steel".
E.
Mockups: Build mockups of AESS to set quality standards for fabrication and installation. 1. 2.
F. 1.6
Build mockup of typical portion of steel framing for curtain wall as shown on Drawings. Coordinate finish painting requirements with Division 09 painting Sections.
Preinstallation Conference: Conduct conference at Project site. DELIVERY, STORAGE, AND HANDLING
A.
Use special care in handling to prevent twisting, warping, nicking, and other damage. Store materials to permit easy access for inspection and identification. Keep steel off ground and spaced by using pallets, dunnage, or other s and spacers. Protect steel and packaged materials from corrosion and deterioration. 1.
1.7
Do not store materials on structure in a manner that might cause distortion, damage, or overload to or ing structures. Repair or replace damaged materials or structures as directed.
PROJECT CONDITIONS A.
Field Measurements: Where AESS is indicated to fit against other construction, actual dimensions by field measurements before fabrication.
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Denver Museum of Nature and Science: Education and Collections Facility Project number 2009.104
1.8
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COORDINATION A.
Coordinate selection of shop primers with topcoats to be applied over them. Comply with paint and coating manufacturers' recommendations to ensure that shop primers and topcoats are compatible with one another.
B.
Furnish anchorage items to be embedded in or attached to other construction without delaying the Work. Provide setting diagrams, sheet metal templates, instructions and directions for installation.
PART 2 - PRODUCTS 2.1
STRUCTURAL-STEEL MATERIALS A.
Plate and Bar: ASTM A 36/A 36M.
B.
Angles: ASTM A 36/A 36M.
C.
Cold-Formed Hollow Structural Sections: ASTM A 500, Grade B, structural tubing.
D.
Welding Electrodes: Comply with AWS requirements; 70 Series.
E.
Submit product data or other published information indicating total weight of product to be provided for the Project, percent of post-consumer recycled material by weight and percent of post-industrial recycled material by weight. Include material costs (excluding costs of installation)
2.2
BOLTS, CONNECTORS, AND ANCHORS A.
Tension-Control, High-Strength Bolt-Nut-Washer Assemblies: ASTM F 1852, Type 1, roundhead assemblies, consisting of steel structural bolts with splined ends, heavy-hex carbon-steel nuts, and hardened carbon-steel washers. 1.
B.
2.3
Finish: Plain.
Expansion Anchors: Wedge type with current LADBS approval and published LADBS Research Report. Completed with required nuts, washers, and manufactures installation instructions. PRIMER
A.
Primer: Comply with Division 09 Section "High-Performance Coatings".
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Denver Museum of Nature and Science: Education and Collections Facility Project number 2009.104
2.4
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FABRICATION A.
Locate field ts at concealed locations if possible. Detail assemblies to minimize handling and to expedite erection.
B.
In addition to special care used to handle and fabricate steel framing ing curtain wall, comply with the following: 1. 2. 3. 4. 5. 6. 7. 8. 9.
Fabricate with exposed surfaces smooth, square, and free of surface blemishes including pitting, rust, scale, and roughness. Grind sheared, punched, and flame-cut edges of "AESS-1" to remove burrs and provide smooth surfaces and edges. Fabricate "AESS-1" with exposed surfaces free of mill marks, including rolled trade names and stamped or raised identification. Fabricate "AESS-1" with exposed surfaces free of seams to maximum extent possible. Remove blemishes by filling or grinding or by welding and grinding, before cleaning, treating, and shop priming. Fabricate with piece marks fully hidden in the completed structure or made with media that permits full removal after erection. Fabricate "AESS-1" to the tolerances specified in AISC 303 for steel that is designated AESS. Fabricate "AESS-1" to the tolerances specified in AISC 303 for steel that is not designated AESS. Seal-weld open ends of hollow structural sections with 3/8-inch closure plates for "AESS-1"
C.
Coping, Blocking, and t Gaps: Maintain uniform gaps of 1/8 inch with a tolerance of 1/32 inch for "AESS-1".
D.
Bolt Holes: Cut, drill, or punch standard bolt holes perpendicular to metal surfaces.
E.
Holes: Provide holes required for securing other work to structural steel and for other work to through steel framing . 1. 2. 3.
2.5
Cut, drill, or punch holes perpendicular to steel surfaces. Do not thermally cut bolt holes or enlarge holes by burning. Baseplate Holes: Cut, drill mechanically thermal cut, or punch holes perpendicular to steel surfaces. Weld threaded nuts to framing and other specialty items indicated to receive other work.
SHOP CONNECTIONS A.
High-Strength Bolts: Shop install high-strength bolts according to RCSC's "Specification for Structural ts Using ASTM A 325 or A 490 Bolts" for type of bolt and type of t specified. 1.
t Type: Snug tightened.
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Denver Museum of Nature and Science: Education and Collections Facility Project number 2009.104
B.
Weld Connections: Comply with AWS D1.1/D1.1M for tolerances, appearances, welding procedure specifications, weld quality, and methods used in correcting welding work, and comply with the following: 1. 2. 3. 4. 5.
6. 7.
8. 9.
2.6
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Assemble and weld built-up sections by methods that will maintain true alignment of axes without exceeding specified tolerances. Use weld sizes, fabrication sequence, and equipment for steel framing ing curtain wall that limit distortions to allowable tolerances. Provide continuous welds of uniform and profile where "AESS-1" is welded. Grind butt and groove welds flush to adjacent surfaces within tolerance of plus 1/16 inch, minus 0 inch for "AESS-1". Make butt and groove welds flush to adjacent surfaces within tolerance of plus 1/16 inch, minus 0 inch for "AESS-1". Do not grind unless required for clearances or for fitting other components, or unless directed to correct unacceptable work. Remove backing bars or runoff tabs; back-gouge and grind steel smooth for "AESS-1". At locations where welding on the far side of an exposed connection of "AESS-1" occurs, grind distortions and marking of the steel to a smooth profile aligned with adjacent material. Make fillet welds for "AESS-1" oversize and grind to uniform profile with smooth face and transition. Make fillet welds for "AESS-1" of uniform size and profile with exposed face smooth and slightly concave. Do not grind unless directed to correct unacceptable work.
SHOP PRIMING A.
Shop prime steel surfaces except the following: 1. 2.
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.
C.
Surfaces embedded in concrete or mortar. Extend priming of partially embedded to a depth of 2 inches. Surfaces to be field welded.
SSPC-SP 6/NACE No.3, "Commercial Blast Cleaning".
Priming: Immediately after surface preparation, apply primer according to manufacturer's written instructions and at rate recommended by SSPC to provide a minimum dry film thickness of 1.5 mils. Use priming methods that result in full coverage of ts, corners, edges, and exposed surfaces. 1. 2.
Stripe paint corners, crevices, bolts, welds, and sharp edges. Apply two coats of shop paint to surfaces that are inaccessible after assembly or erection. Change color of second coat to distinguish it from first.
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Denver Museum of Nature and Science: Education and Collections Facility Project number 2009.104
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PART 3 - EXECUTION 3.1
EXAMINATION A.
, with steel erector present, elevations of concrete and masonry bearing surfaces and locations of anchor rods, bearing plates, and other embedment's for compliance with requirements. 1.
Prepare a certified survey of bearing surfaces, anchor rods, bearing plates, and other embedment's showing dimensions, locations, angles, and elevations.
B.
Examine steel framing for twists, kinks, warping gouges, and other imperfections before erecting.
C.
Proceed with installation only after unsatisfactory conditions have been corrected.
3.2
PREPARATION A.
Provide temporary shores, guys, braces, and other s during erection to keep framing secure, plumb, and in alignment against temporary construction loads and loads equal in intensity to design loads. Remove temporary s when connections, and bracing are in place unless otherwise indicated. 1.
3.3
If possible, locate welded tabs for attaching temporary bracing and safety cabling where they will be concealed from view in the completed Work.
ERECTION A.
Set steel framing for Architecturally Exposed Structural Steel accurately in locations and to elevations indicated and according to AISC 303 and AISC 360. 1.
B. 3.4
Erect "AESS-1" to the tolerances specified in AISC 303 for steel that is designated AESS.
Do not use thermal cutting during erection. FIELD CONNECTIONS
A.
High-Strength Bolts: Install high-strength bolts according to RCSC's "Specification for Structural ts Using ASTM A 325 or A 490 Bolts" for type of bolt and type of t specified. 1. 2.
t Type: Snug tightened. Orient bolt heads in same direction for each connection and to maximum extent possible in same direction for similar connections.
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B.
Weld Connections: Comply with requirements in "Weld Connections" Paragraph in "Shop Connections" Article. 1. 2. 3.
3.5
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Remove backing bars or runoff tabs; back-gouge and grind steel smooth for "AESS-1". Remove erection bolts in "AESS-1" fill holes, and grind smooth. Fill weld access holes in "AESS-1" and grind smooth.
FIELD QUALITY CONTROL A.
Testing Agency: Engage a qualified independent testing and inspecting agency to inspect steel framing for curtain wall as specified in Division 05 Section "Structural Steel Framing". The testing agency will not be responsible for enforcing requirements relating to aesthetic effect.
B.
The Designer will observe AESS in place to determine acceptability relating to aesthetic effect.
3.6
REPAIRS AND PROTECTION A.
Touchup Painting: Immediately after erection, clean field welds, bolted connections, and abraded areas of shop paint, and paint exposed areas with the same material as used for shop painting to comply with SSPC-PA 1 for touching up shop-painted surfaces. 1.
Clean and prepare surfaces by SSPC-SP 2 hand-tool cleaning or SSPC-SP 3 power-tool cleaning.
END OF SECTION 05 1243
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