PSI - Issue 44

Paola Sorrentino et al. / Procedia Structural Integrity 44 (2023) 1308–1315 Paola Sorrentino et al. / Structural Integrity Procedia 00 (2022) 000–000

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rotational with a period equal to 0.65s and the third is translational in y direction (transversal direction) with a period equal to 0.64s. The results of the modal analysis (in particular the values of periods of first and third mode that assume two significantly different values) show that the structure is characterized by different stiffness values in both orthogonal directions. Table 1. Dynamic characteristics of the structure: periods and participating mass ratios. Mode T M Ux /M x,TOT M Uy /M y,TOT M Rz /M Rz,TOT [-] [s] [%] [%] [%] 1 1.78 73.6% 0.0% 0.0% 2 0.65 0.0% 3.1% 73.0% 3 0.64 0.0% 73.8% 3.1% 4 0.52 14.1% 0.0% 0.0% 5 0.25 6.4% 0.0% 0.6% 6 0.25 0.3% 0.0% 12.2% 7 0.24 0.0% 12.7% 0.0% 8 0.15 0.5% 0.0% 4.4% 9 0.15 3.1% 0.0% 0.7% 10 0.14 0.0% 4.7% 0.0% 11 0.10 0.0% 0.1% 3.7% 12 0.09 0.0% 3.4% 0.1% Sum 98.0% 97.8% 97.8% The assessment of the seismic vulnerability of the analyzed structure has been carried out through linear and nonlinear static analysis. At first, the site seismicity has been evaluated. In compliance with the current Italian Building Code, the Acceleration Spectrum (AS) has been defined by assuming the following parameters: • V N ≥ 50 years; • 2 nd class of use; • reference period V R =50 years; • return period T R =475 years. The following seismic hazard parameters correspond to this return period for the Olympic Village site: • ag =0.104g; • F 0 =2.64; • T C *=0.32s. To the definition of inertial forces, the Response Spectrum has been scaled with two different behavioral factors q in x and y direction. The cases of dissipative behavior and low ductility class and the non-dissipative behavior have been considered in y and x direction, respectively. In particular, in the first case, it is defined as follows: = # % = 2.88 (1) where: # is a coefficient that depends on the Ductility Class and the structural typology and for frame structure with several floors and a single span is equal to 3.6; % is that for structure not regular in height is equal to 0.8. In the case of non-dissipative behavior, it is equal to 1.5. 4. Analysis