Correlation between NDT results and mechanical strength of structural timber

The refurbishment of ancient timber structures requires the assessment of the residual capacity of structural members in order to design reliable repairing interventions. Many times, such information cannot be got by means of destructive tests on sacrificial elements extracted from existing structures. This difficulty can be overcome by using in-situ non-destructive tests (NDTs). In this paper, a methodology based on resistographic NDTs is analyzed. In particular, an experimental campaign carried out on ancient chestnut elements has been developed for determining a correlation between NDT results and the mechanical strength of the basic wooden material, which could be obtained by means of destructive tests according to the procedure provided in the companion paper. In addition, as in normal conditions in situ NDTs can be easily performed only throughout the direction transversal to the growth rings, a correlation between longitudinal and transversal NDTs is also presented. Finally, in order to validate the proposed correlations, the procedure defined by this experimental campaign is compared with those of the existing literature.