Overview
ISO/TR 19623:2019 is a technical report that reviews methodologies for assigning characteristic strength and stiffness values of glued laminated timber (glulam) from the measured properties of lumber laminations. The report compares analytical models and verification routes used in Europe, the USA, Australia/New Zealand and Canada, explaining differences in fundamental philosophies and noting that methodologies are not intended to be combined without clear understanding of their assumptions. The document supports harmonization and informed selection of methods for deriving glulam design values from laminate properties.
Key topics and technical requirements
- Scope and intent: Reviews approaches to derive glulam mechanical properties (strength, stiffness, density) from lamination properties and joint performance rather than prescribing new normative requirements.
- Regional methodologies: Summaries of European, US, Australian/New Zealand and Canadian methods, illustrating differing philosophies and accepted practices.
- EN 14080 routes (European example): Three verification routes are described - classification from standardized beam lay-ups, calculation from cross-sectional lay-up and board/joint properties, or full-scale testing.
- Material inputs: Emphasis on lamination strength and stiffness, finger-joint strength, lay-up geometry and nominal moisture content (document references 12 % as nominal, with 12 ± 3 % allowed in tests).
- Verification techniques: Includes mechanics-based models, statistical analysis of test data, and full-scale tests used to establish characteristic values.
- Limitations and assumptions: The report stresses that detailed model assumptions and numerical parameters are available in the cited standards and bibliography, and that mixing routes requires careful understanding.
Practical applications
- Deriving declared characteristic bending strength and stiffness for glulam product certification and design.
- Developing glulam lay-ups and validating new combinations of laminations for production.
- Supporting manufacturers, testing laboratories and structural designers in converting board-level grading data into usable glulam design properties.
- Informing national standards bodies and conformity assessment schemes on method selection and harmonization.
Who should use ISO/TR 19623:2019
- Glulam manufacturers and R&D teams
- Structural engineers and designers using mass timber
- Standards developers and certification bodies
- Testing laboratories and quality assurance personnel
Related standards
- EN 14080 (glued laminated timber standard, Europe)
- EN 14081-1 (timber strength grading)
- ASTM D3737 (US glulam-related methods)
- AS/NZS 1328 (Australia/New Zealand)
- ANSI A190.1 (US industry standard)
For implementation details, consult the specific standards cited in the report and your national standards body.