Out-of-plane structural identification of a masonry infill wall inside beam-column RC frames

Field observations after seismic events have shown that out-of-plane collapses are one of the predominant modes of infill masonry wall failure leading to life-safety hazards. This type of mechanism depends on the geometrical and mechanical features of the structure, but it is substantially affected by the constraints along the structural frame. However, the actual boundary conditions are very difficult to define, especially in the case of an existing building, for which information is lacking, a visual screening can be inefficient, and deterioration may have occurred due to the design conditions. In this paper, a procedure for the structural identification of the out-of-plane behaviour of infill masonry walls using a simple and cost effective innovative procedure based on an in situ experimental dynamic test and a consequent process of updating is proposed. The procedure, composed of the in situ test and the updating of the numerical model, was implemented for a case study to confirm that it is effective in defining the mechanical characteristics of the masonry, the absence of collaboration between the two brick leaves of the infill wall, and the out-of-plane constraints along the perimeter.