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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For this purpose, a case study building is selected and modelled in OpenSees . The building has been subjected to non-linear dynamic analyses. Eigen analyses are performed before and after each non-linear dynamic analysis for the estimation of the vibration period before and after the ground shaking. Numerical analyses also provide the maximum interstorey drift ratio for each storey (IDR max ) experienced by the structure during the analysis. Through the IDR max , the local damage level of each column is evaluated according to the relationships derived by Lubrano Lobianco et al. (2021) and reported in Table 1. Knowing the local damage level of each column, the global damage level (DL global ) is then estimated as: (i) the peak damage level experienced by the columns (DL peak ), representing the highest DL among all columns, and (ii) the average DL (DL average ), evaluated as the weighted average damage level of the whole building. In detail, the average damage is obtained by the following expression: = ∑ ∙ 4 =1 1) where is the i-th level of damage that changes from 1 to 4 and is the ratio between the number of columns in each and the total number of the columns. If μ d is lower or equal to 0.5, the average global damage level is classified as DL0, for 0.5< μ d ≤1.5 the average global damage level is classified as DL1, a 1.5< μ d ≤1.5 corresponds to a DL2, a 2.5< μ d ≤3.5 corresponds to a DL3 and μ d >3.5 is classified as a DL4. Finally, the variation of vibration period (ΔT global ) of the structure is correlated to the DL global , and compared with the ranges of variation of vibration period derived by the authors for the single columns. This preliminary study focuses on structural damage only and the effect of non-structural components (i.e., masonry infill walls) has not been considered. Future studies will also include the damage to non-structural components in the global damage level assessment. Table 1 – Correlation between IDR and damage level for RC columns (Lubrano Lobianco et al., 2021) IDR [%] Damage Level <0.5 0.5-1.2 DL0 DL1

1.2-1.9 1.9-3.8 3.8-4.8

DL2 DL3 DL4

2 Case study building The chosen case study is an existing building, located in the L'Aquila municipality, heavily damaged during the 2009 earthquake (Fig. 2). The building has a rectangular plan with dimensions 15.60x10.00m and each floor is 3.20 meters high (Del Vecchio et al., 2019). The building has columns of size 40x40cm for the entire height of the building and, in one direction, ordinary beams of size 40x55cm, while in the other direction wide beams of size 40x20cm, embedded in the floor slab, are used.