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1 2 3 4 5 6 7 8 3.28 GUIDE SPECIFICATION - SECTION 05 44 00 ## Some TrusSteel chord members are manufactured from ASTM A653M steel of a higher grade with minimum yield strength of 55 ksi (380 MPa) and minimum tensile strength of 65 ksi (448 MPa) a. Nominal 28 mil (22 GA) members: 1) Minimum bare metal thickness: 0.0284 inch (0.72 mm). 2) Maximum design thickness: 0.0299 inch (0.76 mm). b. Nominal 33 mil (20 GA) members: 1) Minimum bare metal thickness: 0.0329 inch (0.84 mm). 2) Maximum design thickness: 0.0346 inch (0.88 mm). c. Nominal 43 mil (18 GA) members: 1) Minimum bare metal thickness: 0.0428 inch (1.09 mm). 2) Maximum design thickness: 0.0451 inch (1.15 mm). d. Nominal 54 mil (16 GA) members: 1) Minimum bare metal thickness: 0.0538 inch (1.37 mm). 2) Maximum design thickness: 0.0566 inch (1.44 mm). e. Nominal 68 mil (14 GA) members: 1) Minimum bare metal thickness: 0.0677 inch (1.72 mm). 2) Maximum design thickness: 0.0713 inch (1.31 mm). f. Nominal 97 mil (12 GA) members: 1) Minimum bare metal thickness: 0.0966 inch (2.46 mm). 2) Maximum design thickness: 0.1017 inch (2.58 mm). 3. Tube Webs: Cold-formed ASTM A500 steel structural tubing; minimum yield strength of 45 ksi (310 MPa); minimum tensile strength of 55 ksi (380 MPa). a. Nominal 33 mil (20 GA) members: 1) Minimum bare metal thickness: 0.033 inch (0.84 mm). 2) Maximum design thickness: 0.035 inch (0.89 mm). b. Nominal 47 mil (18 GA) members: 1) Minimum bare metal thickness: 0.047 inch (1.19 mm). 2)Maximum design thickness: 0.049 inch (1.24 mm). c. Nominal 63 mil (16 GA) members: 1) Minimum bare metal thickness: 0.063 inch (1.6 mm). 2) Maximum design thickness: 0.065 inch (1.65 mm). 4. Rolled formed Webs: Cold-formed from ASTM A 653/A 653M galvanized steel sheet, minimum G90 coating; minimum yield strength of 40 ksi (276 MPa) for 20 and 18 GA components or 50 ksi (345 MPa) for 16 GA components; minimum tensile strength of 55 ksi (379 MPa) for 20 and 18 GA components or 65 ksi (448 MPa) for 16 GA components. a. Nominal 33 mil (20 GA) members: 1) Minimum bare metal thickness: 0.0329 inch (0.84 mm). 2) Maximum design thickness: 0.0346 inch (0.88 mm). b. Nominal 43 mil (18 GA) members: 1) Minimum bare metal thickness: 0.0428 inch (1.09 mm). 2) Maximum design thickness: 0.0451 inch (1.15 mm). c. Nominal 54 mil (16 GA) members: 1) Minimum bare metal thickness: 0.0538 inch (1.37 mm). 2) Maximum design thickness: 0.0566 inch (1.44 mm). C. Fasteners Used in Fabricating Trusses: Fasteners as recommended by Truss Component Manufacturer, bearing stamp of Truss Component Manufacturer for ready identification. PART 3 EXECUTION 3.1 EXAMINATION A. Verify that bearing surfaces and substrates are ready to receive steel trusses. ## The tolerances appropriate for truss bearings surfaces are dependent on required tolerances of subsequent construction; coordinate with other sections and modify as required. B. Verify that truss bearing surfaces are within the following tolerances: 1. Variation from Level or Specified Plane: Maximum 1/8 inch in 10 feet (6 mm in 3 m). 2. Variation from Specified Position: Maximum 1/4 inch (6 mm). C. Verify that rough-in utilities and chases that will penetrate plane of trusses are in correct locations and do not interfere with truss, bracing or bridging placement. D. Inspect conditions under which installation is to be performed and submit written notification if such conditions are unacceptable to installer. 1. Notify Architect/Engineer-of-Record within 24 hours of inspection. 2. Beginning construction activities of this section before unacceptable conditions have been corrected is prohibited. 3. Beginning construction activities of this section indicates installer's acceptance of conditions. 3.2 - INSTALLATION A. Install trusses in accordance with Truss Component Manufacturer's instructions and Truss Manufacturer's Truss Design Drawings. Use correct fasteners as previously described. B. Place components at spacings indicated on the Truss Design Drawings. C. Install all erection (temporary installation) bracing and permanent bracing and bridging before application of any loads; follow recommendations of the CFSBCSI - Cold-Formed Steel Building Components Safety Information. D. Install erection bracing -follow recommendations of CFSBCSI Cold-Formed Steel Building Components Safety Information. 1. Provide bracing that holds trusses straight and plumb and in safe condition until decking and permanent truss bracing has been fastened to form a structurally sound framing system. 2. All sub-contractors shall employ proper construction procedures to insure adequate distribution of temporary construction loads so that the carrying capacity of any single truss or group of trusses is not exceeded. E. Install permanent bracing and bridging as shown in the Architect/Engineer-of-Record's drawings and notes and as shown in the Truss Fabricator's shop drawings. F. Removal, cutting or alteration of any truss chord, web or bracing member in the field is prohibited unless approved in advance in writing by the Architect/Engineer-of-Record and the Truss Designer. G. Repair or replace damaged chords, webs, and completed trusses as previously directed and approved in writing by the Architect/Building Designer and the Truss Component Manufacturer. 3.3 FIELD QUALITY CONTROL ## This article is optional. A. Owner will provide inspection service to inspect field connections; see Section 01 40 00. ENGINEERED BY ALPINE S P E C I F Y I N G / D E S I G N I N G