ANSI ASC O5 O5.2-2012 Structural Glued Laminated Timber for Utility Structures.pdf

1、 ANSI O5.2-2012 Structural Glued Laminated Timber for Utility Structures AMERICAN NATIONAL STANDARD FOR WOOD PRODUCTS Accredited Standards Committee O5 was first organized in 1924 by the Bell Telephone System and the U.S. Independent Telephone Associations American Standards Association (ASA) Teleph

2、one Group. The Exchange Carrier Standards Association (ECSA), which later became the Alliance for Telecommunications Industry Solutions (ATIS), accepted sponsorship and Secretariat responsibility for ASC O5 in 1985. The American Wood Protection Association (AWPA) then assumed the role of Secretariat

3、, effective January 1, 2011. ASC O5 is jointly accredited with its Secretariat by the American National Standards Institute. This committee develops standards for wood poles, crossarms, braces, and glue laminated timber for utility structures. For more information, visit the ASC O5 website at www.as

4、co5.org. Founded in 1904, the American Wood Protection Association (AWPA) is a non-profit organization that promulgates voluntary standards for technologies which protect wood from degradation. AWPA Standards are developed by its technical committees in an open, consensus-based process that involves

5、 individuals from all facets of wood preservation: Producers of preservatives and preservative components; producers of treated and untreated wood products; end users of treated wood; engineers, architects and building code officials; government entities, academia, and other groups with a general in

6、terest in wood preservation. AWPAs Standards are universally specified for wood protection in the USA, and are recognized worldwide. For more information visit the AWPA website at . AMERICAN NATIONAL STANDARD Approval of an American National Standard requires review by ANSI that the requirements for

7、 due process, consensus, and other criteria for approval have been met by the standards developer. Consensus is established when, in the judgment of the ANSI Board of Standards Review, substantial agreement has been reached by directly and materially affected interests. Substantial agreement means m

8、uch more than a simple majority, but not necessarily unanimity. Consensus requires that all views and objections be considered, and that a concerted effort be made towards their resolution. The use of American National Standards is completely voluntary; their existence does not in any respect preclu

9、de anyone, whether he has approved the standards or not, from manufacturing, marketing, purchasing, or using products, processes, or procedures not conforming to the standards. The American National Standards Institute does not develop standards and will in no circumstances give an interpretation of

10、 any American National Standard. Moreover, no person shall have the right or authority to issue an interpretation of an American National Standard in the name of the American National Standards Institute. Requests for interpretations should be addressed to the secretariat or sponsor whose name appea

11、rs on the title page of this standard. CAUTION NOTICE: This American National Standard may be revised or withdrawn at any time. The procedures of the American National Standards Institute require that action be taken periodically to reaffirm, revise, or withdraw this standard. Purchasers of American

12、 National Standards may receive current information on all standards by calling or writing the American National Standards Institute. Notice of Disclaimer except that the needles shall be inserted to only a maximum of 1/4 the thickness of the piece of lumber. 4.3.3.3 If the moisture content of any o

13、ne piece of lumber does not fall within the minimum and maximum equilibrium moisture content specified by the purchaser (see Table 1), or if more than 5% of the pieces have a moisture content range greater than five percentage points, then each piece of lumber in the lot shall be checked for moistur

14、e content. All pieces not within the minimum and maximum values of Table 1 shall be rejected. 4.4 Designated fiber strength values The designated ultimate fiber strength values for structural glued laminated timber shall be determined according to either 4.4.1 or 4.4.2. 4.4.1 Fiber strength values b

15、ased on AITC designated combinations or their equivalents developed in accordance with ASTM D3737 Fiber strengths for various laminating combinations listed in AITC 117, or their equivalents developed in accordance with ASTM D3737, may be determined by multiplying the design strength, adjusted for a

16、ll end use conditions, by the actual beam volume factors, the loading condition coefficients as given in AITC 117 and by the values shown in table 2. The actual volume factors shall be permitted to exceed 1.0. Table 2 Stress adjustment factor K For laminated timber 2-5/8“ (67 mm) to 6-3/4“ (171 mm)

17、in width 3“ (76 mm) to 15“ (381 mm) in depth For laminated timber greater than 6-3/4“ (171 mm) in width or greater than 15“ (381 mm) in depth K = 2.9 or use the procedure outlined in 4.4.2 K = 2.7 or use the procedure outlined in 4.4.2 ANSI O5.2-2012 - 6 - 4.4.2 Fiber strength values for a specific

18、combination Fiber strength for a specific combination may be determined by testing a representative sample and determining the 75% one sided lower confidence level of the mean. Sampling and testing shall follow ASTM D2915, ASTM D1036 or other acceptable test procedures. An example of how to calculat

19、e fiber strength values based on test data is shown in Annex B. An acceptable test setup for evaluation of crossarm bending MOR is provided in Annex C. 5 Manufacturing requirements 5.1 Humidity The relative humidity of the manufacturing area shall be maintained at such a level that the moisture cont

20、ent will not change substantially during the manufacturing process. All bonding shall be performed as soon as practical after checking moisture content. 5.2 Adhesives Adhesives for structural laminating shall conform to all applicable requirements of ANSI/AITC A190.1 to comply with wet conditions of

21、 use and be compatible with the selected preservative solution to be used. Adhesives containing urea shall not be used. 5.3 Manufacture The selection, preparation, assembly, and bonding of the laminations shall be in accordance with ANSI/AITC A190.1 and as specified herein. 5.3.1 Edge joints Unglued

22、 edge joints shall be permitted for multiple width lamination lay-up as permitted by ANSI/AITC A190.1. Un-bonded edge joints shall not be permitted on the top lamination of horizontally or diagonally mounted members. 5.3.2 End joints End joints of laminations shall be pre-glued and cured before asse

23、mbly of the face joint into structural members. Spacing of the end joints shall be as specified in ANSI/AITC A190.1 5.3.3 Repairs Structural repairs as defined in ANSI/AITC A190.1 are allowed. End blocks as defined in ANSI/AITC A190.1 are prohibited. 5.3.4 Second stage gluing When two or more lamina

24、ted members that are over 2 inches (51 mm) in net thickness are glued together, a gap-filling adhesive shall be used in accordance with ANSI/AITC A190.1. 5.4 Proof-loading If performed, proof-loading shall be in accordance with ANSI/AITC A190.1. 5.4.1 End joint spacing When proof loading is performe

25、d in accordance with ANSI/AITC A190.1, end joint spacing is not required. 5.5 Dimensions and tolerances 5.5.1 Sizes and tolerances for crossarms, crossarm braces and x-braces shall be in accordance with ANSI/AITC A190.1. Sizes and tolerances for poles shall be in accordance with the following: a) De

26、pth 1/2“ (13 mm) b) Width 1/4“ (6 mm) ANSI O5.2-2012 - 7 - c) Squareness 3/8“ per foot (31 mm per meter) of depth d) Length of poles under fifty feet (15.24 meters), +6“ (+152 mm), -3“ (-76 mm), poles fifty feet or more in length (15.24 meters), +12“ (+305 mm), -6“ (-152 mm). 5.5.2 Unless specified

27、otherwise on the plans, drawings, or purchase orders, bolt holes 8 inches (203 mm) or less in length shall have hole diameters 1/32 inch (0.8 mm) to 1/16 inch (1.6 mm) larger than the bolt diameter. Bolt holes greater than 8 inches (203 mm) in length shall have hole diameters 1/16 inch (1.6 mm) to 1

28、/8 inch (3.2 mm) larger than the bolt diameter. 5.5.3 The tolerance of dimensions for hole locations when the dimensions are associated with the assembly of a given piece of hardware shall be +/- 1/32 inch (0.8 mm), unless some other tolerance is specified on the plans or drawings. The tolerance on

29、dimensions for hole locations when the dimensions are not associated with the assembly of hardware shall be +/- 1/8 inch (3.2 mm). 5.5.4 The purchaser shall specify whether or not a test assembly of each structure type or part thereof is required before shipment. 5.5.5 The camber or straightness tol

30、erance for crossarms, crossarm braces, and x-braces is 1/4 inch (6.4 mm) for members up to 20 feet (6.1 meters). For members over 20 feet (6.1 meters), the tolerance is increased by 1/8 inch (3.2 mm) per each additional 20 feet (6.1 meters), or fraction thereof, but should not exceed 3/4 inch (19 mm

31、). The camber or straightness tolerance for poles is 1/2 inch (13 mm) for members up to 20 feet (6.1 meters). For members over 20 feet (6.1 meters), the tolerance is increased by 1/2 inch (13 mm) per each additional 20 feet (6.1 meters), or fraction thereof, but should not exceed 2 inches (51 mm). T

32、hese tolerances are at the time of manufacture without allowance for dead load deflection and should be used for straight or slightly cambered members and are not applicable to more sharply curved members. 5.6 Appearance Glued laminated structural members shall be manufactured in accordance with the

33、 industrial appearance grade as defined in AITC 110 and as required in 5.6.1 through 5.6.6. 5.6.1 Eased edges shall be obtained by rounding or chamfering all edges. Crossarms, crossarm braces, and x-braces shall be eased to a minimum of 1/4 inch (6.4 mm) and a maximum of 1/2 inch (13 mm). Poles shal

34、l be eased to a minimum of 3/4 inch (19 mm) and a maximum of 1 inch (25 mm). 5.6.2 After gluing, all members shall be surfaced, at least on the two sides where glue lines are exposed. 5.6.3 Splintering around the holes caused by drilling, shall be kept to a minimum. Holes shall be drilled perpendicu

35、lar to the starting and finishing faces of members with a uniform cross section unless otherwise specified, or as specified on the plans and drawings of members with a variable cross section. 5.6.4 Occasional laminations may contain wane, may be scant of the specified width, or both. These condition

36、s in a lamination shall not be more than 3/16 inch (4.8 mm) in width. 5.6.5 The following defects that occur at the laminating plant after gluing are permitted: medium splits in the outside laminations of vertically mounted members, and short splits in the top laminations of horizontally and diagona

37、lly mounted members. 5.6.6 Open knot holes or voids in the butt and sides of poles need not be filled. Open knot holes or voids larger than 1/2 inch (13 mm) in diameter in crossarms, crossarm braces, and x-braces and all voids in the roof of poles shall be repaired with a void-filling compound unles

38、s otherwise specified. The compound shall be sanded or scraped smooth after patching. Wood dowels may be used to repair improperly drilled holes, as long as the holes do not affect the structural integrity of the member. 5.6.6.1 Filler compounds shall be similar in appearance to the wood surrounding

39、 the filled area. The compound shall be durable, in that it will remain intact with changes in the moisture content of the wood; will not be affected by the pressure or temperature of the treating cycle; will withstand incising, when required; and will not be physically or chemically affected by the

40、 wood preservative, preservative carrier, or ultraviolet radiation. The compound shall have a service life equal to or greater than that of the treated member. (See 7.3 for testing of filler compounds.) ANSI O5.2-2012 - 8 - 5.6.6.2 If the filler compound is to be used only for filling holes to impro

41、ve appearance, then it need not have physical properties equal to those of the wood in the member. If the compound is to be used to repair wood adjacent to timber connectors or for a similar end use, then it shall have equal or better bearing design values than the wood in the member. 6 Marking and

42、coding 6.1 All finished structural glued laminated timber shall be legibly and permanently marked or branded in letters and figures not less than 5/8 inch (16 mm) in height with the following information: a) Manufacturers or laminators designation; b) Buyers identification symbol (to be specified on

43、 plans, drawings, and purchaser order); c) Species (use species code in AWPA M6); d) Year of manufacture (use last two digits, e.g. 12, 13, etc.); e) Type of preservative (use preservative code in AWPA M6); f) Amount of preservative (as specified in AWPA U1). 6.2 All straight or slightly cambered me

44、mbers shall be permanently marked or branded as specified on the plans and drawings at both ends of one face to identify the orientation of the member. All letters of the brand shall be at least 5/8 inch (16 mm) in height. Those members that are fabricated in such a manner that they cannot be instal

45、led incorrectly need not be marked as to their orientation. 6.3 Poles: The following information shall be burn branded legibly or affixed to a metal tag and permanently fixed to the face and the butt of each pole (see note below). a) The suppliers code or trademark; b) The plant location and the yea

46、r of treatment; c) Code letters denoting the poles species and preservative used; d) The size designation and/or equivalent class and the length of the pole. If metal tags are used, they shall be corrosion-resistant and securely attached to the pole. NOTE The suppliers code or trademark, the plant l

47、ocation, the year of treatment and code letters denoting the poles species and preservative used (see above) may be omitted from the butt by agreement between supplier and purchaser. Information included in (d) may be then die-stamped or hammer-stamped. The code letters shall not be less than 5/8 in

48、ch (16 mm) high if burn branded and not less than 1/8 inch (3.2 mm) high if on a metal tag. The bottom of the brand or mark shall be placed squarely on the face of the pole and at 10 feet (3.05 meters) 2 inches (51 mm) from the butt of poles 50 feet (15.24 meters) or less in length and at 14 feet (4

49、.27 meters) 2 inches (51 mm) from the butt of poles 55 feet (16.76 meters) or more in length or as otherwise specified in the purchase order. 7 Testing and inspection 7.1 Requirements Testing and inspection shall be in accordance with ANSI/AITC A190.1 and AITC 200. 7.2 Material Testing and inspection shall be performed on the material and from the production that is supplied on the purchase order and produced in accordance with this standard. Samples for physical testing shall be at random. ANSI O5.2-2012 - 9 - 7.3 Void-filling compounds Physica