PSI - Issue 78

Riccardo Maurizio Ambrogio Baltrocchi et al. / Procedia Structural Integrity 78 (2026) 9–16

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4. Conclusions The vertical seismic response of precast structural components has been evaluated through both linear and non linear analytical methods using a FEM software, examining both coupled and uncoupled configurations of Ondal roof members and the supporting beam. From this research, the following conclusions can be drawn: • Significant variations in dynamic properties (NFA) arise between uncoupled and coupled configurations, particularly regarding frequencies, modal mass participation, and relevant modes. • SRA on uncoupled configurations show more vulnerability in beam members. • SRA on coupled configurations demonstrate that the limit accelerations associated with beam elements relevantly grow, while for roof elements they remain similar. • NLTHA yields to remarkably less conservative results than SRA for the Ondal member and to results only slightly less conservative for the I-shaped beam. • In coupled configurations under NLTHA, the Ondal members are subject to a 0.63 g decrease in failure acceleration, whereas the beam exhibits a 0.14 g increase. • The comparison of coupled and decoupled configurations confirms how there are non-negligible dynamic interaction effects. Thus, uncoupled configurations should be disregarded in case a realistic behaviour is targeted. • Nevertheless, SRA always resulted on the safe side when evaluating the seismic strength of prestressed members under vertical acceleration. • The more realistic analysis (IDA on coupled configurations) shows that the deck combining Ondal members with I-shaped beam is associated to a critical PGAv as high as 0.8 g (failure of beam element), which is remarkably high, suggesting that the risk associated with flexural collapse of the roof induced by vertical acceleration is low. It is however to be noted that the conclusions above are valid for the specific considered roof arrangement, and thus more work is needed to potentially generalize such conclusions to roof characterized by different elements and different spans. Future research will focus on both incorporating probabilistic approaches and extending the methodology presented in this study to additional structural elements, aiming to achieve a deeper understanding of the variability in dynamic interaction effects across different structural systems. References Bovo, M., Savoia, M., 2018. Numerical Simulation of Seismic-Induced Failure of a Precast Structure during the Emilia Earthquake. Journal of Performance of Constructed Facilities, 32(1). https://doi.org/10.1061/(asce)cf.1943-5509.0001086. Bovo, M., Savoia, M., 2019. Evaluation of force fluctuations induced by vertical seismic component on reinforced concrete precast structures. Engineering Structures, 178, 70 – 87. https://doi.org/10.1016/j.engstruct.2018.10.018. Buratti, N., Minghini, F., Ongaretto, E., Savoia, M., Tullini, N., 2017. Empirical seismic fragility for the precast RC industrial buildings damaged by the 2012 Emilia (Italy) earthquakes. Earthquake Engineering and Structural Dynamics, 46(14), 2317 – 2335. https://doi.org/10.1002/eqe.2906 Dal Lago, B., 2017. Experimental and Numerical Assessment of the Service Behaviour of an Innovative Long-Span Precast Roof Element. International Journal of Concrete Structures and Materials, 11(2), 261 – 273. https://doi.org/10.1007/s40069-017-0187-6. Dal Lago, B., Krelani, V., Visconti, D., 2024. Environmental impact of real precast and cast-in-situ supermarket building structures. Engineering Sustainability (Proceedings of the ICE), issued online. doi: 10.1680/jensu.23.00054. Di Sarno, L., Elnashai, A. S., Manfredi, G., 2011. Assessment of RC columns subjected to horizontal and vertical ground motions recorded during the 2009 L’Aquila (Italy) earthquake. Engineering Structures, 33(5), 1514– 1535. https://doi.org/10.1016/j.engstruct.2011.01.023. EN 1998-1:2004: Eurocode 8: Design of structures for earthquake resistance. Part 1: General rules, seismic actions and rules for buildings. (n.d.). Foti, F., Dal Lago, B., Capacci, L., 2023. Dynamics of Simply Supported Beam Members Subject to Vertical Seismic Acceleration. In E. Hajrizi (Ed.), 2th UBT International Conference on Civil Engineering, Infrastructure and Environment (IC-UBT) (pp. 132 – 138). G+D Computing, 2010. Introducing Strand7 finite element analysis system. Manoukas, G., Tsiggelis, V., 2024. Evaluation of Conventionally Designed Reinforced Concrete Beams Against Vertical Seismic Excitation. Iranian Journal of Science and Technology - Transactions of Civil Engineering. https://doi.org/10.1007/s40996-024-01641-0 Varevac, D., Draganić, H., Gazic, G. , 2010. Influence of the vertical component of earthquake on large span RC beams. Tehnicki Vjesnik-Technical Gazette, 3, 357 – 366.