GB/T 26899-2022Structural glued laminated timber (English PDF)

Foreword

This document is in accordance with the provisions of GB/T 1.1-2020 "Guidelines for Standardization Work Part 1: Structure and Drafting Rules of Standardization Documents" drafted.

This document replaces GB/T 26899-2011 "Structural Glulam". Compared with GB/T 26899-2011, except for structural adjustment and editing In addition to the sexual changes, the main technical changes are as follows.

a) Changed the definition of "visual grade" (see 3.1.27, 3.1.27 of the 2011 edition);

b) the term "characteristic strength" was deleted (see 3.1.37 of the 2011 edition);

c) Changed the thickness and deviation requirements of laminates (see 4.1.2, 4.2.2 of the 2011 edition);

d) The requirements for discoloration, vortex lines and cracks have been changed (see Table 1, Table 1 of the 2011 edition);

e) Added the very minor and minor requirement descriptions for other defects (see Table 1);

f) Changed the difference in moisture content of the same structural laminate (see 4.2.1, 4.3.1 of the 2011 edition);

g) Changed the tree population classification (see Table 3, Table 4 of the 2011 edition);

h) Added the description of requirements for cracking, discoloration and reverse texture (see Table 5);

i) Changed the content of the longitudinal spacing of adjacent laminates (see 4.2.3.2, 4.3.3.2 of the 2011 edition);

j) Changed the symbol of strength grade of glulam for structure (see Table 9, Table 13, Table 14, Table 21, Table 22 and Table 23, Table 9, Table 13, Table 14, Table 21, Table 22 and Table 23);

k) Changed the selection and use principles of adhesives (see 4.3.1, 4.1.1 of the 2011 edition);

l) Added the content of polyurethane adhesive (see 4.3.2);

m) Added the content of glulam for secondary gluing structure (see 4.3.3);

n) Changed the requirements for warping and twisting (see 4.4.3, 4.4.3 of the 2011 edition);

o) Added the description of the non-obvious requirements in the surface quality grades and requirements of glulam for structural use (see Table 20);

p) Changed the description of the peel test under the conditions of use environment 1, 2 and 3 (see 4.5.2.1, 4.5.2.1 of the 2011 edition);

q) Changed the requirements for moisture content (see 4.5.3, 4.5.3 of the 2011 edition);

r) Changed the content and grade symbols of formaldehyde emission (see 4.5.4, Table 25, 4.5.4 and Table 25 of the 2011 edition);

s) Added the requirements and inspection methods for the anti-corrosion and insect-proof performance of the glulam for structures (see 4.6, 5.7, 6.1.2, 6.2, Table 28, Table 29);

t) The inspection method of "dimensional deviation and appearance quality" of laminated wood for structure is added (see 5.1);

u) Changed the content of peel test specimen production (see 5.2.1.1, 5.1.1.1 of the 2011 edition);

v) Changed the drying range of the test piece (see 5.2.1.2, 5.1.1.2 of the 2011 edition);

w) Changed the shear strength test method (see 5.2.2.2, 5.1.2.2 of the 2011 edition);

x) Modified the test piece fabrication method of bending test method A (see 5.4.1.1, 5.3.1.1 of the 2011 edition);

y) Modified the reference standard for the calibration of sodium thiosulfate solution (0.1mol/L) (see 5.6.2.2.2, 5.5.2.2.2 of the 2011 edition);

z) Added "Sampling Plan for Dimensional Deviation and Appearance Quality Inspection of Structural Glulam" (see 6.1.1).

1 Scope

This document defines the terms, definitions and symbols for structural glulam, and specifies the requirements, inspection methods and inspection rules for structural glulam and product identification, etc.

This document applies to structural glulam.

2 Normative references

The contents of the following documents constitute essential provisions of this document through normative references in the text. Among them, dated citations documents, only the version corresponding to that date applies to this document; for undated references, the latest edition (including all amendments) applies to this document.

Preparation of GB/T 601 Standard Titration Solutions for Chemical Reagents

GB/T 23229 Analysis method of waterborne wood preservatives

GB/T 27651 Use classification and requirements of preservative wood

GB/T 27654 Wood preservative

GB/T 37315 Basic requirements for bonding properties of wood structure adhesives

ISO 20152-2 Bonding properties of wood structural adhesives - Part 2: Additional requirements

3 Terms, Definitions and Symbols