DYNAMIC IDENTIFICATION OF MASONRY PARTITION WALLS BY AMBIENT VIBRATION DATA

Masonry infill walls and partitions are commonly used in r.c. building and seismic events showed that out-of-plane collapse can be one of the predominant mode of failure for masonry infill walls and partitions leading to life-safety hazard. This type of mechanism is related to the geometrical and mechanical features of the masonry but it is substantially affected by the constraints along the structural frame; however, these actual boundary conditions are very difficult to be defined, especially in the case of an existing building, for which information are lack and deterioration can be occurred respect to the design conditions. Moreover, in order to conduct a more accurate seismic analysis or damage assessment of these components, it is necessary to establish reliable numerical models. In this paper the results of experimental ambient vibration tests carried out on two masonry partition walls with different constraints along the structural frame are reported. The dynamic properties extracted using Operational Modal Analysis (OMA) techniques have been used to update a preliminary finite element model implemented by SAP2000 software. The implemented procedure, including the in-situ test and the updating of the numerical model confirmed its effectiveness in defining the mechanical characteristics of the masonry and the out-of-plane constraints along the perimeter.