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The moisture content variations in wood have a significant influence in wood’s physicochemical properties, as well as in its electromagnetic properties and to specific effects upon waves’ characteristics. In particular, this paper focuses on the analysis of the Ground-penetrating Radar’s (GPR) using an antenna of 1.6GHz central frequency capacity to register the velocity and the amplitude of the electromagnetic waves’ variation during the drying process of Pinus pinaster Ait timber joists. The results showed that when timber MC descends, the propagation velocity and amplitude of both the direct and the reflected wave increased. The high correlation found between the variables studied demonstrates GPR efficiency and the innovative application of this technique as a non-destructive evaluation tool for timber structures, particularly when studying its moisture content.

The moisture content (MC) has a significant influence in wood’s physicochemical properties and therefore in most types of wood pathologies. The MC variation leads to modifications of its electromagnetic properties and to specific effects upon waves’ characteristics. Given the advantages of the direct electromagnetic wave (DW) observation, the aim of this work is to asses the ability of this wave to provide access to timber MC characterization. For this purpose, GPR measurements were carried out on timber joists (1.6 GHz central frequency). The dielectric behaviour of wood varies according to the direction of the fiber. Therefore, it is necessary to distinguish between differences attributable to the wood anisotropy and those due to variations in MC. With this aim, prior to the MC analysis, assays were carried out in different directions regarding the fiber. The results of this study show very satisfactory correlations between DW amplitudes and MC in all fiber directions. These results showed, in agreement with theory, that a decrease of MC results in an increase of the DW amplitude. These results demonstrates the GPR efficiency and the innovative application of this technique as a non-destructive evaluation tool for the rapid sounding of timber structures.

This work analyzes the efficiency of the ground penetrating radar (GPR) technique for the evaluation of strength grading of structural sawn timber. For this end, tests were performed on pinus radiata timber samples using GPR and other common evaluation techniques: visual grading and ultrasound-based evaluation. In order to determine the level of reliability of the different grading methods for timber structures, the results obtained with each method are compared to the results obtained from experimental bending-strength tests undertaken in accordance with standard EN408. Finally, the level of reliability of the GPR technique is compared to that of the other methods analyzed in this paper. The results obtained in this work show that GPR can be a valuable tool for the evaluation of structural timber, since it is a non-destructive technique, fast and easy to use, and what is more important, more reliable than other current evaluation methods used for timber grading.

This work shows the geophysical study carried out at La Lonja de los Mercaderes of Valencia (15th c. Spain), which was declared a World Heritage site in 1996 by UNESCO. The main objective has been to determine the exact outline of the Moorish moat and map it by using two geophysical techniques: Gravimetry and GPR. The study has been carried out as part of the Project for the Restoration and Cleaning of the building. Gravimetric and GPR studies were conducted in two and three areas, respectively. The correlation and modelling of the results of these techniques has lead us to conclude that the moat is in fact beneath La Lonja, showing its outline and dimensions. Moreover, this study also allows us to assume that in some areas the moat is partially filled in. The results obtained in this survey are a good example of combining high resolution methods, i.e. GPR and microgravimetry, as an efficient and respectful tool in cultural Heritage. This combination of techniques could help to avoid destructive actions both in excavations works and in restoration projects as well as in the rehabilitation and cleaning of historical buildings, specially in World Heritage Sites.