33_72_00_TND.pdf

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SECTION 33 72 00 – SUBSTATION STEEL STRUCTURES

PART 1 - GENERAL

1.01 RELATED DOCUMENTS:

A. Drawings and general provisions of the Contract, including General and Supplementary

Conditions Specification Sections, apply to this Section.

1.02 SUMMARY:

A. This Division covers the design, detailing, materials, fabrication, and labor necessary to furnish and deliver for the Owner all substation steel structures complete.

1.03 REFERENCE STANDARDS:

A. Design of the structures shall conform to the requirements of the following, as specified and as modified by provisions of this Specification:

1. American Institute of Steel Construction (AISC):

a. Manual of Steel Construction.

2. National Electrical Manufacturers Association (NEMA):

a. SG6 - Power Switching Equipment.

b. TT1 - Tapered Tubular Steel Structures.

3. American Society of Civil Engineers (ASCE):

a. Guide for the Design of Steel Transmission Towers, Manual No. 52.

4. American Concrete Institute (ACI):

a. 318-16 - Building Code Requirements for Reinforced Concrete.

5. International Conference of Building Officials:

a. Uniform Building Code.

B. Structures shall be fabricated, assembled, and tested in conformance with the latest revision of the following, as applicable.

1. American National Standards Institute (ANSI):

a. B18.2.1 - Square and Hex Bolts and Screws, Inch Series.

b. B18.2.2 - Square and Hex Nuts.

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

a. A6 - General Requirements for Rolled Steel Plates, Shapes, Sheet Piling, and Bars for Structural Use.

b. A36 - Structural Steel.

c. A90 - Test Method for Weight of Coating on Iron and Steel Articles with Zinc or

Zinc-Alloy Coatings.

d. A123 - Zinc (Hot-Dip Galvanized) Coatings on Iron and Steel Products.

e. A143 - Safeguarding Against Embrittlement of Hot-Dip Galvanized Structural Steel

Products and Procedure for Detecting Embrittlement.

f. A153 - Zinc Coating (Hot-Dip) on Iron and Steel Hardware.

g. A239 - Locating the Thinnest Spot in a Zinc (Galvanized) Coating on Iron or Steel

Articles by the Preece Test (Copper Sulfate Dip).

h. A307 - Carbon-Steel Bolts and Studs, 60,000 psi Tensile.

i. A325 - Structural Bolts, Steel, Heat Treated, Minimum Tensile Strength.

j. A370 - Test Method and Definitions for Mechanical Testing of Steel Products.

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k. A384 - Safeguarding Against Warpage and Distortion During Hot-Dip Galvanizing of Steel Assemblies.

l. A394 - Zinc-Coated and Bare Steel Transmission Tower Bolts and Nuts.

m. A449 - Quenched and Tempered Steel Bolts and Studs.

n. A490 - Heat-Treated Steel Structural Bolts, 150-ksi Minimum Tensile Strength.

o. A563 - Carbon- and Alloy-Steel Nuts.

p. A572 - High-Strength Low-Alloy Columbium - Vanadium Steels of Structural

Quality.

q. A678 - Quenched and Tempered Carbon-Steel and High-Strength Low-Alloy Plates for Structural Steel Applications.

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

s. E376 - Measuring Coating Thickness by Magnetic-Field or Eddy-Current

(Electromagnetic) Test Methods.

3. American Welding Society (AWS):

a. D.1.1. - Structural Welding Code: Steel.

C. Fabricators of steel structures supplied under this Division shall be subject to the approval of the Engineer and shall have the following qualifications:

1. They shall be regularly engaged in the fabrication of substation structures of the type furnished for this Contract.

2. They shall have previously designed and fabricated substation structures of the general types specified.

3. They shall have a qualified design staff regularly devoted to the design and detailing of substation structures.

1.04 SUBMITTALS:

A. Submittals shall be submitted as specified in SECI specifications.

B. A complete set of submittals shall be furnished for each individual substation. (No common drawings for different substations will be allowed.)

C. Photographic reproductions or copies of the Contract Documents or parts thereof will not be accepted as submittals.

D. Complete fabrication and erection drawings for each structure supplied shall be furnished including, but not limited to, the following:

1. A drawing to an exact scale showing the location and code marking (piece mark) of each piece in the structure, the location, size, grade, and number of bolts for all connections and the weight of the entire structure and major subassemblies.

2. Drawings showing each individual piece in sufficient detail for shop fabrication including shipping weight.

3. Anchor bolt or stub angle setting plans showing the number, location, projection, and size of all anchor bolts.

PART 2 - PRODUCTS

2.01 GENERAL:

A. All equipment structures, including rigid bus supports, shall be of wide flange or tubular construction. Combination of shapes except as specified shall not be permitted. Structure shapes are defined as follows:

1. Wide flange: A structure consisting principally of rolled "W" and "I" sections with loads carried in tension, compression, and bending and having all members carrying calculated stresses. Rolled angle sections may be used as truss components and bracing members.

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2. Tubular: A structure composed of closed sections (tubes) of circular, multi-sided, or elliptical cross sections and tapered or untapered; with loads carried in tension, compression, and bending; and having all members carrying calculated stresses.

B. All steel structures designed as frames shall also be designed to include a maximum differential movement of 1 inch in any direction between adjacent supports.

2.02 DESIGN:

A. Structures shall have the number of support points (legs) and general layout indicated.

B. All field connections shall use galvanized bolts and nuts as fasteners. No field welding shall be required. A lockwasher or Joslyn MF No. 1 locknut shall be provided for each structure bolt whether field or factory installed. Furnish at least 5% spares of each size bolt, nut, washer, lockwasher, locknut, etc., required in assembly. Self-locking type nuts shall not be used.

C. All bolted shear connections shall be designed as bearing connections with the bolts' threads in the shear plane or planes.

D. Arrange all structural members so that there are no pockets which can accumulate moisture without draining.

E. Provide all drilling, punching, mounting plates, brackets, etc., for addition of future equipment on the structures and for future extensions of the structures as indicated.

F. Provide all drilling, punching, mounting plates, brackets, etc., for all miscellaneous equipment to be mounted on the structures such as nameplates, fuse and terminal cabinets, phase identification tags, etc.

2.03 DETAILS:

A. Each member of a structure shall have identifying numbers and letters (piece marks), keyed to the fabrication and erection drawings for each substation, with characters a minimum of

1/2 inch high stamped into the steel prior to galvanizing. Piece marks shall be circled with black indelible ink after galvanizing.

B. Provide specific instructions and torque values required for each type of connection.

2.04 PROTECTIVE COATING:

A. All steel members shall be galvanized after all hole punching, drilling, bending, clipping, coping, welding, or other forming or fabricating operations have been completed.

B. Galvanizing shall be done in accordance with ASTM A123 and ASTM A143.

C. Bolts shall be galvanized in accordance with ASTM A153 except that a 1.65-ounce coating shall be provided. Alternately, a 1.65-ounce coating can be provided by mechanical galvanizing per ASTM B695, Class 50, Type I.

D. The Contractor shall be responsible for all field repair of damage to the galvanized coating occurring during shipping and erection. A minimum of two gallons of a suitable cold galvanizing compound shall be supplied for field repair.

2.05 ANCHOR BOLTS:

A. Anchor bolts with two zinc-coated nuts and flat washers per bolt shall be supplied for all structures specified.

B. The nuts and the threaded portion of anchor bolts plus a minimum of six additional inches shall be galvanized in accordance with ASTM A153 or B695, Class 50, Type I.

C. Anchor bolts shall either be shipped as preassembled clusters or shall have steel templates adequate to properly align the bolts for each individual base plate shipped with them.

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2.06 PACKING AND SHIPMENT: Shall be made as specified in DIVISION 01.

PART 3 - EXECUTION

3.01 Field services of representatives of the equipment and materials shall be provided in a timely manner to correct errors, discrepancies, or omissions in the structures furnished as required by the Owner or by the Engineer.

3.02 CORRECTIONS:

A. Correction of errors, discrepancies, or omissions shall be made immediately upon notification from the Owner or Engineer in order to prevent delay of construction. All corrections resulting from errors, discrepancies, shipping damage, etc., approved by the Owner or Engineer to avoid delay of construction and required for the installation and proper use of the structures shall be paid for by the Contractor.

B. The Contractor shall be contacted prior to field corrections. However, if time is critical, the

Owner reserves the right to decide whether to correct the member or have a replacement member furnished.

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