L’INFLUENZA DELLE TAMPONATURE SUL PERIODO ELASTICO DI TELAI ESISTENTI IN C.A.

The damage observed in past earthquakes, has shown as the presence of infills significantly influences the seismic performance of RC moment resisting frames. The reduction of the elastic period related with the increase of stiffness due to infills causes a different seismic behaviour and in particular a variation in the seismic demand. In this work the elastic period of infilled RC frames designed only for gravity loads and according to the Italian code available before the introduction of seismic design has been evaluated. A parametric analysis has been carried out, including the influence of the infills mechanical properties. Obtained results allowed to calibrate a relationship able to furnish the first elastic period of the frames taking into account all the parameters investigated. Finally, the comparison between the proposed relationship and that provided by the Italian Code evidences in some cases significant scatters in terms of seismic demand, suggesting the need of further investigations and validations.