Non-destructive Consolidation Assessment of Historical Camorcanna Ceilings by Scanning Laser Doppler Vibrometry

This paper presents a procedure for the evaluation of the conservation state and restoration efficiency of nineteenth century camorcanna vaults based on the analysis of objective features extrapolated from non-destructive vibration testing data. The camorcanna vault in “Salone Grande” of the ninteenth century Villa Greppi in Monticello Brianza, near Milan, Italy, was chosen as an application example. Non-contact scanning Laser Doppler Vibrometry was exploited for the evaluation of the dynamic behaviour of the vault before and after rehabilitation. In the first section, the frescoed structure in question, a reed ceiling spread with mortar, is described and possible related aging problems, e.g painting detachment, are highlighted. In Sects. 1 and 2, traditional and innovative non-invasive diagnostic techniques are illustrated, with particular attention to Laser Doppler Vibrometry. In Sect.3, the case study of Villa Greppi is illustrated, reporting on the restoration intervention, the equipment used on site and how the measurements were taken. While in Sect.4 the results are shown, objective feature indices are defined and conclusions are drawn.