ABSTRACT Existing timber structures often present elements with different levels of decay and the choice to maintain them comes from the structural assessment, made by a civil engineer on the basis of the results coming from the on-site survey. The choice may also rely on visual inspection combined non-destructive tests. In that case, the choice to maintain an element will greatly depend on the accuracy and reliability of the results obtained through these tests. This work aims to assess the properties of timber elements through non-destructive tests, using resistance drilling, pin penetration, ultrasound, and acoustic emission tests. The tests were carried out on three timber elements from two old timber roof trusses. The results are analysed regarding the specimen size and the use of multiple non-destructive test parameters. Decay was initially identified by means of visual inspection and different levels of decay were identified taking into account their influence on the non-destructive test results and on the predictability of models based on single and multiple regression analysis. Moreover, the obtained classification was found to increase the reliability on the prediction of density.

中文翻译：

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用于评估现有木材构件腐烂程度的无损测试组合

摘要 现有的木结构通常存在不同程度的腐烂元素，维护它们的选择来自于土木工程师根据现场调查结果做出的结构评估。选择也可能依赖于目视检查和无损检测。在这种情况下，维护元素的选择将在很大程度上取决于通过这些测试获得的结果的准确性和可靠性。这项工作旨在通过无损测试，使用电阻钻孔、针穿透、超声波和声发射测试来评估木材元素的特性。测试是在来自两个旧木屋架的三个木构件上进行的。分析了关于试样尺寸和多个无损测试参数的使用的结果。衰减最初是通过目视检查来识别的，并且考虑到它们对无损检测结果的影响以及基于单一和多元回归分析的模型的可预测性，确定了不同程度的衰减。此外，发现获得的分类增加了密度预测的可靠性。