Verifica secondo norma degli elementi strutturali per limitare il danno alle tamponature non strutturali

Nonstructural damage to the masonry infills of framed buildings under relatively weak earthquakes is quite usual. In this regard, the codes for building design prescribe to limit the inter-story drift ratios. However, the drift demand may be estimated by analysis of bare frames. The correlation between drift ratios of bare and infilled frames is studied herein by multivariate statistical methods, that of canonical correlation in particular. Nonlinear time-history analyses are carried out to compare statistics of the drift demands to frames with and without infills. Frames differing in number of stories, stiffness of infills, ductility class, and ground type are considered. The correlation appears to be significant with variation in seismic intensity. However, the intensity being fixed at the level proper to code’s verification, the correlation is quite weak. So much so that the null hypothesis of statistical independence of the drifts of the bare and infilled frames cannot be rejected at usual significance levels. The drift demand to an infilled frame cannot be predicted from that to the bare counterpart, and this result contradicts the code assumption for the damage verification. Modelling the structural members and masonry infills as well should be mandatory to compute the drift demand.