GNGTS 2022 - Atti del 40° Convegno Nazionale

GNGTS 2022 Sessione 2.2 337 (2) Another IM used is the Pseudo Spectral Velocity (PSV), calculated as the SRSS combination of horizontal direction components, derived from the components of Spectral Displacement S d , which is given by the ESM flat-file, multiplied for the frequency of the reference structure in both directions, as expressed in eq.(3) and eq.(4): (3) (4) One IM most referred in literature is the Housner Intensity, calculated as the integral of the response spectrum in terms of pseudo-velocity, in the interval between 1s and 2.5s, as expressed in eq.(5). This IM is correlated to the potential damage provided by the reference record, and it is structure independent: (5) The last IM used in this work is the Modified Acceleration Spectrum Intensity (MASI), calculated as the integral of the response spectrum in terms of pseudo-acceleration, derived by the spectral displacement multiplied for the square of the frequency of the reference structure, expressed by eq.(6) and eq.(7): (6) (7) Each IM is represented by the RotD100 parameter, that is the RotD at the 100th percentile. Engineering Demand Parameters selection. Generally, structural damage as dynamic response is correlated with inter-storey drift ratio (IDR) occurring at each floor. To use a unique directionless value, the resultant inter-storey drift is calculated via SRSS combination of the IDR in the two orthogonal directions. Finally, the maximum inter-storey drift (MIDR) observed in the building is adopted as a single EDP to define the level damage reached in the structures. In this work, a more sophisticated EDP is used and compared with the maximum IDR. It is the Chord-rotation Capacity- demand Ratio (CRC), calculated for each local axis of horizontal elements ends defined by the Italian Building Code (C.S.LL.PP 2018) at C8.7.2.1, as the following eq. (8): (8) Finally, the maximum chord-rotation capacity demand ratio (MCRC) observed in the building is adopted as a single EDP.