GNGTS 2022 - Atti del 40° Convegno Nazionale

GNGTS 2022 Sessione 2.2 335 Tab. 1 - TIR. RF NRF1 NRF2 TIR 1.1 1.15 1. Tab. 2 - Vibrational periods and masses. Regular Frame ‘RF’ Mode Period [s] [Ux] [Uy] [Rz] 1 0.956 0.00% 80.03% 0.00% 2 0.857 0.00% 0.00% 80.74% 3 0.745 82.17% 0.00% 0.00% 4 0.291 0.00% 11.70% 0.00% 5 0.263 0.02% 0.00% 11.47% 6 0.241 10.88% 0.00% 0.02% Non-Regular Frame 1 NRF1 Mode Period [s] [Ux] [Uy] [Rz] 1 0.986 0.01% 76.78% 1.13% 2 0.839 1.97% 1.08% 75.54% 3 0.730 78.70% 0.01% 1.40% 4 0.300 0.00% 12.85% 0.12% 5 0.266 0.08% 0.14% 13.23% 6 0.242 11.94% 0.00% 0.01% Non-Regular Frame 2 ‘NRF2’ Mode Period [s] [Ux] [Uy] [Rz] 1 1.014 0.33% 63.84% 5.16% 2 0.738 30.11% 1.88% 34.90% 3 0.658 40.84% 0.28% 15.41% 4 0.303 0.00% 16.41% 0.29% 5 0.236 6.89% 0.69% 6.95% 6 0.221 8.54% 0.38% 10.22% Using a response spectrum analysis to obtain the maximum stress values, beams and columns are designed according to the Italian Building Code (NTC18) considering a low ductility class (Class B) and adopting a behaviour factor equal to 3.9. The weak beam/strong column capacity design criteria are applied and shear forces in members are evaluated from the flexural capacity of their critical regions preventing any shear weak failure. Floors are considered as rigid diaphragms and a fixed support is applied at the base nodes. The Torsional Irregularity Ratio (TIR) (ASCE/SEI 7-16, 2014), which is the ratio of the maximum drift at building’s edge to the average drift. To obtain a suitable in plant and in height non-regularity, building parts were removed, i.e. beam elements and column elements. Thus, two more buildings were derived, characterized by different levels of regularity, called “Non-Regular Frame 1” (NRF1) and “Non-regular Frame 2” (NRF2). The TIR of the structures are shown in Table 1 – TIR : The three structures are shown in the Fig 1 – Frames. The vibrational modes properties and mass participation ratios (MPR) of the designed structures are summarized in the following Table 2 – Vibrational periods and masses :