Seismic and Sonic applications on artifacts and historical buildings

Historic buildings, no matter whether they are famous monuments or socalled "minor," or even vernacular, architecture, represent an important part of our cultural heritage. This patrimony, which is the living memory of the country history and development, must be preserved as much as possible as an historic document of our past. Unfortunately, wars and dramatic events (earthquakes, floods, slides, fires, etc.), but also abandonment and lack of maintenance, are constant menaces to the cultural heritage in every country of the world. Difficulties exist when is necessary to evaluate the degree of the degradation process inside the heritage buildings. The degradation processes affect many structural levels (cracks, fissures, detachments, displacements...) as much as the aesthetic values (dirt, crusts, efflorescence...) of the historical buildings. The knowledge of this reality is important for the valuation of its stability conditions and also for a restoration planning environment. The main pathologies that can result in the breakdown of historical buildings are humidity damage caused by capillarity ascent, breeze, or high humidity environments, successive freeze-thaw cycles that result in crystallization, broken mortar joints, and loss of the most exposed material, and finally erosion damage caused by lack of vegetation. Centering on structural pathologies (cracks, fissures ...), the detection and characterization of the aforementioned problems are important to estimate the status and to plan the possible repair. This chapter describes the possible applications of a nondestructive testing (NDT) method related to the study of the propagation of sonic and ultrasonic waves to analyze the conservation state of heritage buildings. Some tests for masonry investigations and the conditions for applicability are here reported, providing necessary information and decision criteria for the planned application of the methods to historic masonry buildings. The chapter comprises a short summary of the basic technical principles of the method and describes the required equipment, measurement setup,application, and relevant limits and site conditions, data analysis and interpretation, and the required safety cautions.