PSI - Issue 64

Alessandra De Angelis et al. / Procedia Structural Integrity 64 (2024) 327–334 De Angelis et al./ Structural Integrity Procedia 00 (2019) 000 – 000

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Table 4: Correlation between experimental and numerical modes.

AVT n. 1

AVT n. 2

AVT n. 3

Mode

f num [Hz]

f exp [Hz]

D f [%] 4.59 4.87 0.72

f num [Hz] 2.47 3.11 4.07

f exp [Hz] 2.47 3.30 3.83

D f [%] 0.16 5.98 5.82

f num [Hz] 2.01 2.87 3.14

f exp [Hz] 2.10 2.91 3.03

D f [%] 4.48 1.50 3.60

1 2 3

3.05 3.19 4.09 3.89 4.19 4.16

4. Conclusions In this paper the influence of masonry infill walls and partitions on the dynamics of infilled frame buildings was investigated. The experimental campaign was carried out with reference to a specific case study where redevelopment and improvement of the energy and structural performance are in progress. In particular, three ambient vibration tests were carried out on the building during some key stages of the rehabilitation works: an AVT n. 1 referred to the as-built structure; an AVT n.2 after the emptying of the structure by all the furniture and the removal of internal masonry partitions, both in the longitudinal and transverse direction, and the removal of the floors. A final AVT n. 3 was performed to investigate the influence of the removal of external infill walls along the staircase and in some frames of the semi-basement and the removal of the inner layer of some double infills. The experimental comparison of the three different AVTs and the calibration of the numerical models related to these three stages allowed to identify the effects of masonry infills and partitions on the dynamic behavior of the r.c. frame building under consideration. In particular, it was found that the removal of the internal partitions (AVT n. 2) has led to a regularization of the mode shapes eliminating the rotational components coupled to the translational modes. Whereas following the removal of the infill only along the staircase (AVT n.3), irregularities in the stiffness distribution are again introduced leading to the presence of rotational components. References Ventura, C.E., Schuster, N.D., 2011. Structural dynamic properties of a reinforced concrete high - rise building during construction. Canad J Civil Eng 23(4):950–972. Bovo, M., Tondi, M., Savoia, M., 2020. Infill modelling influence on dynamic identification and model updating of reinforced concrete framed buildings. Adv Civ Eng. https:// doi. org/ 10. 1155/ 2020/ 93840 80 De Angelis, A., Pecce, M.R., 2020. The Role of Infill Walls in the Dynamic Behavior and Seismic Upgrade of a Reinforced Concrete Framed Building. Frontiers in Built Environment 2020; 6:590114, ISSN:2297 - 3362 Yun, Z., Yilin, P., Yi, Z., Hwang, H.J., Weijian, Y., 2020. Field measurements for calibration of simplified models of the stiffening effect of infill masonry walls in high - rise RC framed and shearwall buildings. Earthq Eng Eng Vib 19:87–104 Zhou, Y., Zhou, Y., Yi, W., Chen, T., Tan, D., Mi, S., 2017. Operational modal analysis and rational finite - element model selection for ten high rise buildings based on on - site ambient vibration measurements. J Perform Constr Facil 31(5):04017043 Nicoletti, V., Arezzo, D., Carbonari, S., Gara, F., 2022. Dynamic monitoring of buildings as a diagnostic tool during construction phases. Journal of Building Engineering, Volume 46,103764. De Angelis, A., Pecce, M.R., 2019. The structural identification of the infill walls contribution in the dynamic response of framed buildings. Structural Control and Health Monitoring 2019; 26(9): e2405. Pan, T.C., You, X., Brownjohn, M.W., 2006. Effects of infill walls and floor diaphragms on the dynamic characteristics of a narrow rectangle building. Earthq Eng Struct Dyn 35:637–651 MATLAB R2022b. The MathWorks, Inc ARTeMIS Modal, 2019. Ambient Response Testing and Modal Identification Software. Ver - sion: 6.0.2.0 – x64. Developed by: Structural Vibration Solutions A/S. Novi Science Park, Niels Jernes Vej 10, DK - 9220 Aalborg East, Denmark. Brincker, R., Zhang, L., Andersen, P., 2001. Modal Identification of Output - Only Systems us - ing Frequency Domain Decomposition. Smart Materials and Structures, 10(3), 441 - 445. Computers and Structures, 2016. SAP2000 version 18., Walnut Creek, CA. Dolsek, M., Fajfar, P., 2008. The effect of masonry infills on the seismic response of a four - storey reinforced concrete frame—a deterministic assessment. Eng Struct 30(7):1991–200142. Asteris, P.G., Antoniou, S.T., Sophianopoulos, D.S., Chrysostomou, C.Z., 2011. Mathematical macromodeling of infilled frame: State of art. J. Struct. Eng. 137(12):1508 - 1517.