American Institute of Timber Construction 7012 South Revere Parkway Suite 140 Centennial, CO Phone: 303/ Fax: 303/

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1 7012 South Revere Parkway Suite 140 Centennial, CO form per section/change. All information is mandatory, failure to include all information may result in your ballot being excluded from consideration by the Panel of Directors Voter s Name: Kevin Cheung Voter s Organization: Western Wood Products Association Section: 1.2 and 3.1 Vote: Negative Affirmative with Comment Explanation: Section 1.2 Species ES is the official species mark for Engelmann Spruce (see Standard Grading Rules for Western Lumber). The use of ES for Eastern Spruce in AITC 117 will create confusion in the marketplace. Section 3.1 Lumber Grade The 2008 edition of the AITC Grading Handbook for Laminating Lumber deviates from the grading rules for Structural Laminations in the Standard Grading Rules for Western Lumber as follows: - Twist provision is not included in AITC Grading Handbook - Timber Break described in the AITC Grading Handbook is inconsistent/incorrect. ALSC s NGR Interpretation provides the proper description of Timber Break. - The Slope of Grain provision in the AITC Grading Handbook Table for Hem-Fir L1 and LID grades are different from the Standard Grading Rules for Western Lumber. Proposed Revision:

2 7012 South Revere Parkway Suite 140 Centennial, CO form per section/change. All information is mandatory, failure to include all information may result in your ballot being excluded from consideration by the Panel of Directors Voter s Name: Brian K. Tolley Voter s Organization: AkzoNobel / Casco Adhesives Section: 1.2 Vote: Negative X Affirmative with Comment Explanation: I don t understand the need for the ES (Eastern Spruce) category when all 3 species are grouped in both SW (Softwood) and SFP (Spruce Pine Fir). Wouldn t this triple classification just add confusion to designers? Should any species be in multiple groupings? Proposed Revision: Remove the species grouping or remove those species from the other 2 classifications. Make sure each species is represented in only one species group.

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4 7012 South Revere Parkway Suite 140 Centennial, CO form per section/change. All information is mandatory, failure to include all information may result in your ballot being excluded from consideration by the Panel of Directors Voter s Name: Marc Mullins Voter s Organization: APA Section: 1.7 Vote: Negative Affirmative with Comment Explanation: The last paragraph still references Western Species. I thought the intent of this standard is to avoid using such a term Proposed Revision: Replace it by laminations of other softwood species.

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6 7012 South Revere Parkway Suite 140 Centennial, CO form per section/change. All information is mandatory, failure to include all information may result in your ballot being excluded from consideration by the Panel of Directors Voter s Name: Marc Mullins Voter s Organization: APA Section: 1.9 Vote: Negative Affirmative with Comment Explanation: The use of Appearance Grades may be confusing with the mechanical property requirements. Proposed Revision: Suggest changing it to Appearance Classifications, as used by APA Y110. This change shall be also applied to Section 3.4 (a couple of places).

7 7012 South Revere Parkway Suite 140 Centennial, CO form per section/change. All information is mandatory, failure to include all information may result in your ballot being excluded from consideration by the Panel of Directors Voter s Name: Jeff Linville Voter s Organization: AITC Section: 2.1 Vote: Negative Affirmative with Comment Explanation: Add a drawing showing x-x and y-y axes. Proposed Revision: Design values for structural glued laminated timber are dependent on the orientation of the member relative to the applied loads. Values designated with a subscript x are based on transverse loads applied perpendicular to the wide faces of the laminations, causing bending about the x-x axis (Figure 2.1-1). Values designated with a subscript y are based on transverse loads applied parallel to the wide faces of the laminations, causing bending about the y-y axis (Figure 2.1-1).

8 Figure Axis Orientations.

9 7012 South Revere Parkway Suite 140 Centennial, CO form per section/change. All information is mandatory, failure to include all information may result in your ballot being excluded from consideration by the Panel of Directors Voter s Name: Larry Beineke Voter s Organization: PFS Corporation Section: 2.4 Vote: Negative X Affirmative with Comment Explanation: Reference to AITC Technical Note 18 (3) should not be deleted. It is still in the References and presumably still provides guidance in the evaluation of the effects of checks and splits. Proposed Revision: Add to the end of the fourth paragraph of the section, See AITC Technical Note 18 (3) for additional assistance.

10 AITC x 5 2. Reference Design Values 2.1. General Design values for structural glued laminated timber are dependent on the orientation of the member relative to the applied loads. Values designated with a subscript x are based on transverse loads applied perpendicular to the wide faces of the laminations, causing bending about the x-x axis. Values designated with a subscript y are based on transverse loads applied parallel to the wide faces of the laminations, causing bending about the y-y axis. Design values are tabulated for bending (F + bx, F - bx, F by ), compression perpendicular to grain (F c x, F c y ), shear (F vx, F vy ), modulus of elasticity (E x, E y ), tension parallel to grain (F t ), and compression parallel to grain (F c ). Also tabulated are specific gravity values and species groups for use in connection design. Values are not tabulated for torsion, for modulus of rigidity, or for radial stresses in curved bending members, because these values can be determined from other tabulated design values Bending Design Values, F bx +, F bx -, F by Tabulated design values are provided for positive bending of horizontally laminated timbers (F bx + ), negative bending of horizontally laminated timbers (F bx - ), and bending of vertically laminated members (F by ). Horizontally laminated members have bending loads applied perpendicular to the wide faces of the laminations. Vertically laminated members have bending loads applied parallel to the wide faces of the laminations. Positive bending causes tensile stresses at the bottom of a beam. Negative bending causes compressive stresses at the bottom of a beam Compression Perpendicular to Grain Design Values, F c x, F c y The use of multiple laminating grades results in different design values in compression perpendicular to grain for the top and bottom and for the side faces of a beam. One value is tabulated for use in bearing on the top or bottom of the beam and one value is tabulated for side bearing to simplify design. The tabulated compression perpendicular to grain design values are based on a deformation limit of 0.04 in. (1 mm) obtained when tested in accordance with ASTM D143 (7). A compression perpendicular to grain design value based on a 0.02 in. (.5 mm) deformation limit can be estimated as 73% of the tabulated value Shear Design Values, F vx, F vy The tabulated shear design values, F vx and F vy, are permitted to be used for prismatic members subjected to most load conditions. For non-prismatic members and for all members subject to impact or cyclic loads, the reference shear values shall be 72% of the tabulated values. The reduced value shall also apply to the design of members to resist shear from mechanical fasteners. Prismatic members shall be defined as straight (or cambered) members with constant cross section. Non-prismatic members include, but are not limited to: arches, tapered beams, curved beams, and notched members. The tabulated shear design values, F vy, are applicable to members with four or more laminations. For members with three laminations, the reference design value shall be 95% of the tabulated value. For members with two laminations the reference design value shall be 84% of the tabulated value. The tabulated shear design values permit minor amounts of checking ( 15% of beam width) without explicit consideration by the designer. Accredited Inspection and Testing Agencies typically provide guidelines for the analysis of severely checked beams Modulus of Elasticity Design Values, E x, E y, E x min, E y min, E axial Deleted: AITC Technical Note 18 (3) Deleted: s Comment [RHS1]: Also see AITC Technical Note 18. Design values for modulus of elasticity are tabulated for bending about either axis. In general, E x and E y are used for calculation of deflection of members and E x min and E y min are used for stability calculations for columns and beams (2005 NDS (6) and later). For the calculation of extensional deformations, the axial modulus of elasticity, can be estimated as E axial = 1.05E y, such as for use in calculating deflection of trusses.

11 7012 South Revere Parkway Suite 140 Centennial, CO form per section/change. All information is mandatory, failure to include all information may result in your ballot being excluded from consideration by the Panel of Directors Voter s Name: Kurt Stochlia Voter s Organization: ICC-ES Section: 2.4 Vote: xx Affirmative with Comment Explanation: The last paragraph notes Accredited Inspection and Testing Agencies. There are several definitions and requirements that could apply to these agencies. It might be helpful to provide a clarification as to the intent. Proposed Revision: Since there are several ways to resolve this, I am not proposing any specific solution since I am not sure of your intent.

12 7012 South Revere Parkway Suite 140 Centennial, CO form per section/change. All information is mandatory, failure to include all information may result in your ballot being excluded from consideration by the Panel of Directors Voter s Name: Marc Mullins Voter s Organization: APA Section: 2.5 Vote: Negative Affirmative with Comment Explanation: The reference to 2006 NDS (6) and later is not appropriate for a national consensus standard. Proposed Revision: Suggest deleting and later. Section: 2.5 Vote: Negative Affirmative with Comment Explanation: In the paragraph after Equation 1.2.4, it states that For span to depth ratios of 15 or less, deflections due to shear stresses should be considered. The ratio of 15 is inconsistent with Section 8.9 of ASTM D3737. Proposed Revision: with ASTM D3737. Suggest the ratio be changed to less than 14 to avoid confusion

13 7012 South Revere Parkway Suite 140 Centennial, CO form per section/change. All information is mandatory, failure to include all information may result in your ballot being excluded from consideration by the Panel of Directors Voter s Name: Marc Mullins Voter s Organization: APA Section: 2.9 Vote: Negative Affirmative with Comment Explanation: The section is confusing. Proposed Revision: Suggest tabulate the radial tension values as follows: (a) Softwood species other Loading type Southern pine than Southern pine 1/3 of F Wind or seismic vx for non-prismatic 1/3 of F vx for non-prismatic members members Other loading 15 psi (a) 1/3 of F vx for non-prismatic members If the calculated radial tension stress (due to loads or load combinations not including wind or seismic loads) exceeds 15 psi (100 kpa) multiplied by appropriate adjustment factors, radial reinforcement shall be required. Design values for radial tension for radially-reinforced members shall be limited to 1/3 of the shear design value for nonprismatic members. Radial reinforcement shall be designed in accordance with the Timber Construction Manual (4).

14 7012 South Revere Parkway Suite 140 Centennial, CO form per section/change. All information is mandatory, failure to include all information may result in your ballot being excluded from consideration by the Panel of Directors Voter s Name: Jeff Linville Voter s Organization: AITC Section: 2.12 Vote: Negative Affirmative with Comment Explanation: In Section 2.1, we defined x-x axis and y-y axis. We should use this language here, rather than loads applied perpendicular to the wide faces of the lamination and loads applied parallel to the wide faces of the laminations, which can be confusing. Proposed Revision: The design values in Table A1 and Table A1-Expanded are applicable to members with 4 or more laminations and are intended primarily for members stressed in bending about the x-x axis. Design values are included, however, for axial stresses and stresses from bending about the y-y axis. The values in Table A1 are for the industry recommended stress classes. Each stress class is representative of a group of combinations with similar design values. Design values for individual combinations are shown in Table A1-Expanded. Table A2 contains design values for timbers with uniform grade lay-ups. These combinations are intended primarily for timbers loaded axially or in bending about the y-y axis. Design values are included, however, for bending about the x-x axis. Deleted: due to loads applied perpendicular to the wide faces of the laminations. Deleted: loads Deleted: loads applied parallel to the wide faces of the laminations. Deleted: due to loads applied parallel to the wide faces of the laminations. Deleted: due to loads applied perpendicular to the wide face of the laminations.

15 7012 South Revere Parkway Suite 140 Centennial, CO form per section/change. All information is mandatory, failure to include all information may result in your ballot being excluded from consideration by the Panel of Directors Voter s Name: Marc Mullins Voter s Organization: APA Section: 3.1 Vote: Negative Affirmative with Comment Explanation: The wording used in 3.1 should be consistent with Sections and of ANSI/AITC A Proposed Revision: Lumber used for laminations shall be graded according to the standard grading rules approved by the Board of Review of the American Lumber Standard Committee and/or special laminating rules.

16 8 AITC x 3. Lay-up Requirements 3.1. Lumber Grades Lumber grades shall be in accordance with Section 4.3 Lumber for Laminating of ANSI/AITC A AITC Grading Handbook for Laminating Lumber (1) summarizes the requirements for laminating grades of approved species and references approved grading rules Substitutions Lumber of higher grades of the same species is permitted to be substituted in all lay-ups with some restrictions. Visually graded lumber shall not be permitted to be substituted for E-rated lumber. Substitutions of E-rated lumber grades for visual grades of lumber shall be approved by the laminator s accredited inspection agency prior to making the substitution. Full or partial length substitutions are permitted Determining Number of Laminations in Each Zone The number of laminations to use in each zone in the lay-up shall be calculated based on the percentages shown in Tables B1 and B2. Percent values shall be multiplied by the total depth of the member. The required number of laminations shall be determined starting with the outer zones and working inward. When the calculated number of laminations results in a fractional number, the fractional number of laminations shall be rounded upward to the next whole number. For the inner zones, the resulting excess of percentage resulting from rounding upward of the outer zone is permitted to be subtracted from the next inner zone requirements. Example: The tension zone of a hypothetical 16 lamination beam requires 5% , 15% L1, and 10% L2. The number of laminations is determined by: 16 x 0.05 = 0.8 (rounded up to 1). The number of L1 laminations is: 16 x 0.15 (1 0.8) = = 2.2 lams (round up to 3). The number of L2 lams is 16 x 0.1 (3 2.2) = = 0.8 (rounded up to 1). Where more than one thickness is used within a member and those lamination thicknesses vary by more than 3/16 in., the total thickness of each grade of lumber required in the inner and outer tension and compression zones shall be determined by using the thickest lamination in the member as the basic lamination thickness. Example: When the thickest lamination used is 1-3/8 in. (35 mm) and 1.6 in. (41 mm) of L1 grade is required in a zone (based on multiplying the percentage required for that zone in the table by the depth of the member in inches), then a total thickness of at least 2-3/4 in. (70 mm) of L1 grade is required in that zone Wane Deleted: 5 Comment [RHS2]: I suggest the following calculations instead of those in the preceding 2 sentences: The number of L1 laminations is : 16( ) 1 = 2.2 lams (round up to 3). The number of L2 lams is: 16 ( ) (1 + 3) = = 0.8 (round up to 1). Comment [RHS3]: Least 2 1 3/8 lams = 2 ¾ Certain combinations are permitted to contain wane. These combinations are for dry conditions of use only, except as allowed in ANSI/AITC A190.1 (5). These combinations allow wane up to 1/6 the width of the member on each side of the member. When this is the case, the basic shear design value shall be reduced by 1/3. When wane is restricted to just one side of the member, the basic design shear value shall be reduced by 1/6. When wane material is used in these combinations, members shall be for industrial or framing appearance grades and for prismatic members only. Selectively placed wane is permitted for use in glued laminated timber combinations without a corresponding reduction in shear design values based on the following set of rules. Combinations meeting these requirements are for dry conditions of use only, except as allowed in ANSI/AITC A190.1 (5). When wane material is used in these combinations, members shall be for industrial or framing appearance grades and for prismatic members only. 1. Lumber with wane up to 1/6 of the finished member width and 1/2 of the lamination thickness shall be permitted on only one side of the member. 2. No wane shall be permitted within the central 40% of the depth of the cross section. 3. No wane shall be permitted in the outer laminations (top & bottom). 4. No wane shall be permitted in the 302 grade tension laminations. 5. No wane shall be permitted at the glue lines adjacent to the top or bottom laminations or at glue lines adjacent to 302 grade tension laminations.

17 7012 South Revere Parkway Suite 140 Centennial, CO form per section/change. All information is mandatory, failure to include all information may result in your ballot being excluded from consideration by the Panel of Directors Voter s Name: Jeff Linville Voter s Organization: AITC Section: 3.7 Vote: Negative Affirmative with Comment Explanation: ANSI/AITC A190.1 already requires TOP to be marked on all beams. Do we need to repeat that requirement for this particular case? Proposed Revision: Lay-ups modified to meet these requirements shall be marked with 1-HOUR FIRE RATING if one additional tension lamination is used or 2-HOUR FIRE RATING if two additional tension laminations are used. Deleted: Additionally, balanced layups designed and manufactured for three-sided fire exposure shall be marked with TOP on the appropriate face to ensure proper orientation in the structure.

18 7012 South Revere Parkway Suite 140 Centennial, CO form per section/change. All information is mandatory, failure to include all information may result in your ballot being excluded from consideration by the Panel of Directors Voter s Name: Marc Mullins Voter s Organization: APA Section: 3.8 Vote: Negative Affirmative with Comment Explanation: This section shall permit the option that the design value is adjusted in accordance with Table A3. Proposed Revision: Suggest change the wording as follows: Beams manufactured with a bevel cut (or cuts) on the compression face shall be laid up so that the grade of laminations in the outer compression zone is maintained through the entire depth of the bevel cut. Where necessary, core laminations shall be removed and additional compression laminations shall be added to meet this requirement. Otherwise, the beam design values shall be adjusted in accordance with Table A3.

19 7012 South Revere Parkway Suite 140 Centennial, CO form per section/change. All information is mandatory, failure to include all information may result in your ballot being excluded from consideration by the Panel of Directors Voter s Name: Jeff Linville Voter s Organization: AITC Section: All Tables Vote: Negative Affirmative with Comment Explanation: Do we need to create metric versions of the tables? Can we just include a footnote with the conversion factor? If we have to convert the table values do we create duplicate tables or place the metric values in parentheses alongside the inch-pound values? Proposed Revision: Place metric conversion factor in a footnote in the table (first preference) If a footnote isn t adequate, create separate metric versions of the larger tables. The smaller tables could possibly just have metric units added after the inch-pound units.

20 7012 South Revere Parkway Suite 140 Centennial, CO form per section/change. All information is mandatory, failure to include all information may result in your ballot being excluded from consideration by the Panel of Directors Voter s Name: Jeff Linville Voter s Organization: AITC Section: Table A1 and A1-Expanded Vote: Negative Affirmative with Comment Explanation: The headings for the flexure values should be changed to reflect the text in 2.2, which states, Positive bending causes tensile stresses at the bottom of the beam. Negative bending causes compressive stresses at the bottom of the beam. Proposed Revision: Revise Table Headings: Bottom of Beam Stressed in Tension (Positive Bending) Top of Beam Stressed in Tension (Negative Bending) Deleted: Tension Zone Deleted: Tension Zone Deleted: Bottom Deleted: Compression

21 7012 South Revere Parkway Suite 140 Centennial, CO form per section/change. All information is mandatory, failure to include all information may result in your ballot being excluded from consideration by the Panel of Directors Voter s Name: Marc Mullins Voter s Organization: APA Section: Table A1 Vote: Negative Affirmative with Comment Explanation: Footnote 8 to Table A1 is inconsistent with Footnote 6 to Table A1- Expanded. There is no reason these 2 footnotes should be different. Footnote 6 to Table A1-Expanded reflects more accurately on the current industry practice. Proposed Revision: Replace Footnote 8 to Table A1 by Footnote 6 to Table A1- Expanded.

22 7012 South Revere Parkway Suite 140 Centennial, CO form per section/change. All information is mandatory, failure to include all information may result in your ballot being excluded from consideration by the Panel of Directors Voter s Name: Marc Mullins Voter s Organization: APA Section: Table A3 Vote: Negative Affirmative with Comment Explanation: It is unclear why the reduced design values for the stress classes are so conservative, as compared to the reduced design values for individual layup combinations within the stress class. For example the reduced F + bx for 16F-1.3E is tabulated at 1,050 psi. However, the minimum F + bx for all layup combinations within this stress class is 1,350 psi. Suggest the reduced values for the stress classes be double- Proposed Revision: checked.

23 7012 South Revere Parkway Suite 140 Centennial, CO form per section/change. All information is mandatory, failure to include all information may result in your ballot being excluded from consideration by the Panel of Directors Voter s Name: Jon Howard Voter s Organization: Rosboro, LLC Section: Appendix B, Table B1 Vote: Negative X Affirmative with Comment Explanation: There is no reference to a 6 nominal width limitation for 30F-E1 SP and 30F- E2 Sp. Proposed Revision: Include a footnote with the same wording as footnote 6 for Table A1- Expanded.

24 7012 South Revere Parkway Suite 140 Centennial, CO form per section/change. All information is mandatory, failure to include all information may result in your ballot being excluded from consideration by the Panel of Directors Voter s Name: Marc Mullins Voter s Organization: APA Section: Appendix B Vote: Negative Affirmative with Comment Explanation: The width limitation of 6 inches or less on 30F-E1/SP and 30F-E2/SP is not included in the layup table. Even though Footnote 6 to Table A1-Expanded has such a limitation, this could be easily overlooked. Proposed Revision: those 2 layups. Add a footnote similar to Footnote 6 to Table A1-Expanded to