An Automatic Algorithm for the Execution and Elaboration of Sonic Pulse Velocity Tests in Direct and Tomographic Arrangements

Abstract

The use of non-destructive tests (NDT) in the investigation phase of existing constructions plays a relevant role for the quick evaluation of the masonry quality during the survey phase and for the extension of results obtained from more punctual minor-destructive (MDT) or destructive tests (DT). As confirmed by last earthquakes occurred in the centre of Italy in 2016 and by previous phenomena already well described in literature, a weak masonry (e.g., with internal voids and poor core) is prone to early collapse even under medium-magnitude seismic events. In this framework, objective, quick and user-friendly tools aimed at the mechanical surveying of buildings may help in recognizing critical situations, e.g., vulnerable structural elements, poor masonry requiring consolidation, etc. Sonic pulse velocity method demonstrated to be effective in detection of different conditions inside masonry elements; nevertheless, the procedure is quite time-consuming, especially in case of tomographic test configuration. The paper describes an automatic algorithm, which significantly decrease the execution and elaboration time of sonic tests. It provides results directly on-site, so that the quality of the acquired signals can be checked in real-time. The comparison of those outcomes with the manual detection clearly shows the higher reliability and the lower dispersion of data. This tool also operates in the tomographic arrangement, thanks to an elaboration tool designed on purpose. The effectiveness of the new system is demonstrated by examples of application on masonry assemblages.