PSI - Issue 44

Alessandro Lubrano Lobianco et al. / Procedia Structural Integrity 44 (2023) 910–917 A. Lubrano Lobianco et al./ Structural Integrity Procedia 00 (2022) 000 – 000

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0.30 X + 1.00 Z

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1.00 X + 0.30 Z where the X direction is the direction with the greatest number of spans while the Z direction is a direction with the least number of spans (see Fig. 3b). An eigen analysis is performed before and after each nonlinear dynamic analysis to detect the variation of modal properties of the structure. Analysis of results For each nonlinear dynamic analysis, the variation of vibration period (ΔT global ) of the structure is recorded, as well as the IDR max for each storey. These records are compatible with the output data obtained from a long-term SHM system with at least one accelerometer for each floor of the building. The results of the analyses are first discussed as a function of the direction of the ground shaking and of the seismic intensity, then overall results of all the considered scenarios are reported and discussed. Direction of the ground shaking Fig. 6 shows the IDR max reached by each column of the case-study building during the ground shaking for an earthquake intensity of 150% and under all the considered loading scenarios (i.e., 1.00X, 1.00Z, 1.00X+0.30Z, 0.30X+1.00Z). It can be noted that, for the case-study building, the IDR reaches maximum values at the lower levels of the structure. Indeed, columns at first and second storey experience a DL3 for all the loading cases, while columns at the third storey reach a DL1 or DL2, depending from the loading scenario. The global structural damage is then evaluated considering the peak and the weighted averaged IDR max , and the damage level is assigned following the relationships reported in Table 1. Results are summarized in Table 2 for the considered scenarios. 4.1

Fig. 3 – Interstorey drift of each column for analysis with 150% intensity of ground shaking