Technical note on the use of visual grading codes for the appraisal of individual in situ structural timber elements



Bather, Mike ORCID: 0000-0002-6725-6815
(2022) Technical note on the use of visual grading codes for the appraisal of individual in situ structural timber elements. [Report]

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Abstract

It is common practice in the UK, the continent of Europe and in the USA for structural engineers to use visual grading codes when carrying out an appraisal of individual structural timber elements in an existing structure. The purpose of this technical note is to present the findings of a limited study into the background and efficacy of this process. Following a literature review of visual grading, three codes are used to visually grade a sample of new timber joists (n=527) of four lesser used species and the results are compared with the results of the laboratory testing of the same joists. It is concluded that the three visual grading codes reviewed are poor predictors of the mechanical and physical properties of individual timber joists. This outcome was expected and reflects the inappropriate use of the codes in this context rather than a fault in their use as intended (grading large numbers of timber elements from known sources for commercial purposes). Some aspects of visual grading could be used in the creation of a more appropriate model to predict the key mechanical properties of in situ structural timber.

Item Type: Report
Uncontrolled Keywords: visual grading, in situ timber, mechanical properties, physical properties, code of practice
Divisions: Faculty of Science and Engineering > School of Engineering
Depositing User: Symplectic Admin
Date Deposited: 14 Jan 2022 10:59
Last Modified: 18 Jan 2023 21:16
URI: https://livrepository.liverpool.ac.uk/id/eprint/3146806