A simple methodology for the infill masonry wall stiffness estimation

The importance of assessing the overall dynamic behavior of buildings considering the contribution of infills is nowadays widely recognized considering that they play an important role in the verifications at damageability limit states and, at ultimate limit states, they can trigger fragile mechanisms of structural members preventing the evolution of dissipative ones. In addition, in case of strategic structures, for which often high performance levels are required such as the full operativity condition (i.e. absence of damage to both structural and non-structural components) after severe earthquake, the contribution of non-structural members should be necessarily included in the seismic assessment. The paper proposes a simplified procedure for estimating the stiffness of masonry infill walls through expeditious dynamic impact tests. Stiffness can be adopted to model infills into conventional 3-D finite element models of buildings. The procedure is validated by means of an experimental campaign carried out on a laboratory real-scale mock-up and then applied to a real infilled reinforced concrete frame building. Experimental results are compared with those obtained from refined finite element models including infills, proving the methodology reliability.