Structural performance assessment of full-scale masonry wall systems using operational modal analysis: Laboratory testing and numerical simulations

Operational Modal Analysis (OMA) is a powerful approach to be used in structural performance assessment of historical masonry buildings during their service life. OMA is effective for detecting global damage to masonry buildings, although in some conditions it may exhibit poor sensitivity in detecting local/slight structural damage. Additionally, establishing robust correlations between changes in modal features and the residual load -bearing capacity of monitored buildings is an unresolved task in most of real -world applications. To deepen into these aspects, this paper presents an experimental and numerical program involving two full-scale masonry wall specimens tested under controlled laboratory conditions. Progressive damage was induced in diverse structural settings, and OMA was used to identify the modal features of the wall systems at increasing damage levels. Damage -induced decays in modal features were correlated with performance limit states related to the structures' residual load -bearing capacity, while non-linear Finite Element (FE) models were defined to replicate the tests. The obtained results contribute to filling current research gaps by demonstrating that natural frequencies and mode shapes can be sensitive to local and slight structural damage, also proposing correlations between damage -induced decays in modal features and performance limit states, hence corroborating the use of FE models for replicating damage -induced decays in both vibration frequencies and mode shapes.