Structural evaluation of historical masonry walls utilizing non-destructive techniques – Comprehensive analysis

Abstract Assessment of structural capacity in the case of historical masonry walls is a complex task. Mathematical description is strongly hindered by the orthotropic or even anisotropic nature of masonry. Specifically, historical walls are characterized by the irregularity of texture and the variety of materials used. Furthermore, masonry is a composite consisting of two brittle materials – mortar and blocks. Phenomena like creep and deterioration impose other difficulties. Also, frequently, the central part of the walls is erected differently from the outer layers. The level of interlocking between these parts is another factor for consideration. Furthermore, over time, such walls might be modified or reshaped without any documentation. Hence, an unequivocal structural description of such walls is a challenging task, even with access to all the possible destructive tests. However, given the significant cultural value of such objects, frequently only non-destructive methods are allowed. This study provides a critical review and discussion regarding engineering applications of non-destructive methods (non-destructive testing [NDT] considering the available calculation methods and code requirements). It shows the possibilities and limitations of NDT, and the gaps and differences between the scientific, legislative, and engineering fields. Based on the gathered and processed data, proposals for the elimination of identified issues are provided.