1、 ANSI/ASAE EP559.1 W/Corr. 1 AUG2010 (R2014) Design Requirements and Bending Properties for Mechanically Laminated Wood Assemblies American Society of Agricultural and Biological Engineers ASABE is a professional and technical organization, of members worldwide, who are dedicated to advancement of e
2、ngineering applicable to agricultural, food, and biological systems. ASABE Standards are consensus documents developed and adopted by the American Society of Agricultural and Biological Engineers to meet standardization needs within the scope of the Society; principally agricultural field equipment,
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7、 that the requirements for due process, consensus, and other criteria for approval have been met by ASABE. 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
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9、res of ASABE require that action be taken periodically to reaffirm, revise, or withdraw each standard. Copyright American Society of Agricultural and Biological Engineers. All rights reserved. ASABE, 2950 Niles Road, St. Joseph, Ml 49085-9659, USA, phone 269-429-0300, fax 269-429-3852, hqasabe.org A
10、NSI/ASAE EP559.1 W/Corr. 1 AUG2010 (R2014) Copyright American Society of Agricultural and Biological Engineers 1 ANSI/ASAE EP559.1 W/Corr. 1 AUG2010 (R2014) Revision approved August 2010; reaffirmed January 2015 as an American National Standard Design Requirements and Bending Properties for Mechanic
11、ally Laminated Wood Assemblies Developed by the ASAE Mechanically Laminated Post Design Subcommittee of the Structures Group; approved by the Structures and Environment Division Standards Committee; adopted by ASAE December 1996; approved as an American National Standard February 1997; reaffirmed by
12、 ANSI February 2003; reaffirmed by ASAE February 2003; reaffirmed by ASABE and ANSI February 2008; revised and approved by ANSI August 2010; corrigenda 1 issued March 2011; reaffirmed by ASABE December 2014; reaffirmed by ANSI January 2015. Corrigenda 1 corrected publication errors in equation 3 (7.
13、3.1). Keywords: Beams, Columns, Girders, Laminated Lumber, Laminating, Lumber, Wood Design, Wood Structures 1 Purpose and Scope 1.1 The purpose of this Engineering Practice is to establish guidelines for designing and calculating allowable bending properties of mechanically laminated wood assemblies
14、 used as structural members. 1.2 The scope of this Engineering Practice is limited to mechanically laminated assemblies with three or four wood laminations that have the following characteristics: 1.2.1 The actual thickness of each lamination is between 38 and 51 mm (1.5 and 2.0 in.). 1.2.2 All lami
15、nations have the same depth (face width), d. 1.2.3 Faces of adjacent laminations are in contact. 1.2.4 The centroid of each lamination is located on the centroidal axis of the assembly (axis Y-Y in Figure 1a), that is, no laminations are offset. 1.2.5 Concentrated loads are distributed to the indivi
16、dual laminations by a load distributing element. 1.2.6 All laminations are of the same grade and species of lumber or structural composite lumber. 1.2.7 There is no more than one common end joint per lamination within a splice region. 1.3 The provisions of this Engineering Practice do not apply to a
17、ssemblies designed for biaxial bending. The design requirements in clause 4, and allowable bending properties in clauses 5 and 6, are only for uniaxial bending about axis Y-Y (Figure 1a). Spliced assemblies with butt joints shall have sufficient lateral support to prevent out-of-plane (lateral) move
18、ment or buckling, and/or delamination in the splice region. 1.4 This Engineering Practice does not preclude the use of assembly designs not meeting the criteria in clauses 1.2 and 1.3. ANSI/ASAE EP559.1 W/Corr. 1 AUG2010 (R2014) Copyright American Society of Agricultural and Biological Engineers 2 F
19、igure 1 (a) Vertically laminated, (b) horizontal laminated assemblies 2 Normative References The following standards contain provisions which, through reference in this text, constitute provisions of this Engineering Practice. At the time of publication, the editions were valid. All standards are su
20、bject to revision, and parties to agreements based on this Engineering Practice are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Standards organizations maintain registers of currently valid standards. AF or the use of the preservat
21、ive/species combination has been proven ineffective ANSI/ASAE EP559.1 W/Corr. 1 AUG2010 (R2014) Copyright American Society of Agricultural and Biological Engineers 6 4.5.2.2 Delamination Requirement. Delamination after one complete cycle shall not exceed 5% for softwoods or 8% for hardwoods. If dela
22、mination exceeds these values after one cycle, a second cycle shall be performed on the same specimens, in which case the delamination shall not exceed 10%. 4.5.3 Daily Quality Control. All glued end joints produced during a work shift shall qualify as certified structural glued end joints if all en
23、d joints sampled in accordance with clause 4.5.3.1 meet the strength requirements of clause 4.5.3.2 and the delamination requirements of 4.5.3.3. 4.5.3.1 Sampling. The number of end joints to be tested for strength and delamination shall be a minimum of 1 per 200 manufactured joints, but no less tha
24、n 2 end joints per work shift, with one of these joints being the first produced during the work shift and the other being the last produced during the work shift. In addition, the first production joint produced following a change of end joint cutter heads shall be tested, and the first joint produ
25、ced following any major change in end joint production variables shall be tested. Major changes include, but are not limited to, changes in lumber dimension, lumber grade, lumber species, lumber treatment, and curing procedure. 4.5.3.2 Strength. A glued end joint must not fail when subjected to the
26、appropriate qualifying proof load (QPL). The QPL is an edge-wise bending load applied in accordance with the requirements of ASTM D7469 with the end joint located midway between load points. The magnitude of the QPL is the load that induces a maximum wood bending stress in the sample equal to 2.1 ti
27、mes the adjusted bending design value, Fb, calculated in accordance with the National Design Specifications (NDS) for Wood Construction for normal load duration and dry-service conditions. When the end joint connects lumber with different Fb values, the QPL shall be based on the lesser of the two Fb
28、 values. 4.5.3.2.1 End joint failure. Is any failure that is initiated by the joint. This does not include wood fractures that originate at locations away from the joint and extend to the joint where they may then initiate a glue bond failure or wood fracture in the end joint. 4.5.3.2.2 Non joint fa
29、ilure. Is any failure that is not classified as an end joint failure. If a non joint failure occurs prior to full application of the QPL, the test is inconclusive with respect to end joint strength and another end joint specimen must be tested. Where possible, this replacement specimen should be the
30、 end joint manufactured immediately before or after the end joint associated with the inconclusive test. 4.5.3.2.3 Documentation of test. A record shall be kept of each test that includes: date and time of test; lumber size, species and grade; qualifying proof load; load rate; and details of any fai
31、lure that occurs prior to reaching the QPL. 4.5.3.2.4 Use of test specimens. Test specimens that meet the strength requirements of clause 4.5.3.2 without visible or audible signs of failure can be used in the production of laminated assemblies. 4.5.3.3 Cyclic delamination. Tests shall be conducted i
32、n accordance with AITC Test T110. Delamination after one complete cycle shall not exceed 5% for softwoods or 8% for hardwoods. If delamination exceeds these values after one cycle, a second cycle shall be performed on the same specimens, in which case the delamination shall not exceed 10%. 4.5.3.3.1
33、 Documentation of test. A record shall be kept of each test that includes: date and time of test, identifying information for batch of end joints being tested, and the required report from AITC Test T110. 4.5.4 Periodic Auditing. All certified structural glued end joints shall be manufactured in fac
34、ilities that are subject to periodic, unannounced audits by an accredited inspection agency. All processes and records relevant to the production of such end joints shall be subject to audit. 4.5.4.1 Accredited Inspection Agency. An accredited inspection agency is defined as an entity that: (a) Oper
35、ates an inspection system which audits the quality control systems for certified structural end joints. (b) Provides the facilities and personnel to perform the audit and to verify the required testing. ANSI/ASAE EP559.1 W/Corr. 1 AUG2010 (R2014) Copyright American Society of Agricultural and Biolog
36、ical Engineers 7 (c) Determines the individual facilitys ability to produce certified structural end joints in accordance with this standard. (d) Provides periodic auditing of the plants production operations and production quality to ensure compliance with this standard. (e) Enforces the proper use
37、 of the inspection agency quality marks and certificates (f) Has no financial interest in, or is not financially dependent upon, any single company manufacturing any portion of the product being inspected or tested. (g) Is not owned, operated, or controlled by any single company manufacturing any po
38、rtion of the product being inspected or tested. (h) Provides an arbitration review board to arbitrate disputes between the agency and the laminator. Such a board shall include, but not be limited to, three persons: 1. A recognized independent authority in the field of engineered timber construction
39、to serve as chairman 2. At least one registered professional engineer knowledgeable in the design and use of the final product. 3. At least one person knowledgeable in the manufacture and quality control of certified structural glued end joints. (i) Is accredited under ISO/IEC Standard 17020 as an I
40、nspection Agency. 4.6 Metal connector plates. Metal connector plates used to reinforce common end joints shall meet all applicable requirements specified in ANSI/TPI 1 except that no specific structural design evaluation is required beyond that given in clause 5.4 of this EP. 5 Nail- and Screw-Lamin
41、ated Assembly Design Requirements 5.1 End joint arrangement. End joint arrangement is dependent on the number of layers, type of end joints, and presence (or absence) of joint reinforcement. End joint arrangements described in Table 2 and shown in Figure 3 shall be used for common end joints. 5.2 Ov
42、erall splice length. Wood stresses and fastener shear forces within the splice region can increase rapidly as overall splice length is reduced. For applications where the splice region is located at a point of high assembly bending moment, the minimum overall splice lengths in Table 3 are recommende
43、d. When the splice region is centered at a point of low assembly bending moment, overall splice lengths shorter than those in Table 3 may be more practical. Table 2 Recommended joint arrangements Number of Layers Common End Joint Type Outside Butt Joint Reinforcement1)Recommended Joint Arrangements2
44、)3 Butt joints No 3A Butt joints Yes 3A, 3B Glued end joints3)NA 3A, 3B 4 Butt joints No 4B, 4C Butt joints Yes 4A Glued end joints3)NA 4A, 4B, 4C 1)See clause 5.4. 2)See Figure 3. 3)Glued end joints that do not meet the requirements in clause 4.5 for certified structural glued end joints. ANSI/ASAE
45、 EP559.1 W/Corr. 1 AUG2010 (R2014) Copyright American Society of Agricultural and Biological Engineers 8 Figure 3 Joint arrangements for three- and four-layer spliced assemblies Table 3 Recommended minimum overall splice lengths Actual Face Width of Laminations, mm(in.) Minimum Overall Splice Length
46、, m (in.) Glued End Joints1) Butt Joints 140 (5.5) 0.61 (24) 1.22 (48) 184 (7.25) 0.91 (36) 1.52 (60) 235 (9.25) 0.91 (36) 1.83 (72) 286 (11.25) 1.22 (48) 2.44 (96) 1)See clause 4.5 5.3 Fastener requirements. The number of nails or screw fasteners required in an assembly is dependent on the amount o
47、f shear that must be transferred between layers (interlayer shear capacity). Fastener location is controlled by spacing requirements which reduce the likelihood of splitting, yet ensure a good distribution of fasteners. 5.3.1 Interlayer shear capacity. Minimum required interlayer shear capacities ar
48、e expressed on the basis of force per interface per unit length of assembly. There are two design levels. Level I values are listed in Table 4 and apply to: (1) unspliced assemblies, (2) unspliced regions of spliced assemblies, and (3) spliced assemblies with common glued end joints (i.e., glued joi
49、nts that do not meet the requirements of clause 4.5). Level II values apply to the splice region of all assemblies with butt joints even when the butt joints are reinforced. Use equation 1 to calculate level II values. This equation only applies to assemblies with overall splice lengths equal to or greater than the Table 3 minimums. ()BELdAdFISCb+=20024.0 (1) where: ISC is minimum required interlayer shear capacity per interface per unit length of assembly, N/mm (lbf/in.); ANSI/ASAE EP559.1 W/Corr. 1 AUG2010 (R2014) Copyright American Society of Agricult
