Seismic risk evaluation aided by IR thermography

In order to evaluate the seismic risk of historical masonry buildings an ample level of knowledge based on the importance of structural geometry is required; this may include the damages, details of construction and properties of materials. For the identification and the classification of masonry it is necessary to find shape, type and size of the elements, wall texture characteristics, size of mortar joints, and information about the assemblage. The recognition of these characteristics can be done through a visual inspection of the surface of walls after removal of the plaster, but a more efficient and less damaging procedure can be achieved using non destructive techniques that can be proficiently used in heritage buildings. Infrared thermography is a non-destructive method that allows to recognize the structural damages, to detect the presence of discontinuity in masonry and to reveal the wall texture under the plaster layer. IR thermography is indeed an excellent tool for a fast but extensive survey in order to collect information for this purpose, but it is important to define a precise procedure for the inspection of a very heterogeneous class of buildings such as the historical ones. Furthermore, the fast identification of subsurface state allows to select areas where other methods either more penetrating or partially destructive have to be applied. The paper reports experimental results achieved in the mainframe of the European project RECES Modiquus and in the campaign of surveys carried out on historical buildings of the city of L'Aquila (Italy). The main aim of the project is to improve methods, techniques and instruments for facing anti seismic options.