Recent Advances and Open Issues on the Use of Smart Bricks for Seismic Monitoring of Masonry Buildings: Experimental Tests and Numerical Simulations

Masonry buildings are particularly prone to structural pathologies and brittle failures, typically caused by excessive stresses/strains, differential foundation settlements, aging of materials, and natural hazards, such as seismic events. Monitoring the health state of this type of structures during their service life plays a fundamental role in the identification of incipient damages or critical conditions and the optimization of maintenance interventions. In light of that, the Authors recently developed a novel class of sensors, called smart bricks, for structural health monitoring of masonry constructions. These novel sensors consist of fired bricks made by doping fresh clay with conductive stainless steel micro fibers that enhance the piezoresistive capability of the composite. Smart bricks are equipped with copper plate electrodes and can be deployed within masonry constructions, as normal bricks, for monitoring changes in strain, modifications in load paths, and development of damages. This paper deals with an investigation on the effectiveness of smart bricks for the estimation of strain under increasing compression loads, in particular when sensors are deployed within a typical structural setting. With this aim, smart bricks’ strain measurements are compared with those of traditional strain gauges applied onto each tested sample. Furthermore, numerical simulations are carried out for reconstructing strain field maps of a masonry wall subjected to eccentric axial compression tests, by exploiting strain measurements outputted by smart bricks embedded within the load-bearing structure. Overall, results have confirmed the effectiveness of the novel sensors in strain measurements under increasing compression states.