PSI - Issue 78

Available online at www.sciencedirect.com

ScienceDirect

Procedia Structural Integrity 78 (2026) 9–16

© 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of XX ANIDIS Conference organizers Keywords: Vertical acceleration; Non-linear dynamics; Precast members; Earthquake response Abstract Past Italian earthquakes, such as the L'Aquila 2009 and Emilia 2012, were characterized by a strong combination of horizontal and vertical components of seismic acceleration, which highlighted the vulnerability of long-span precast structures. Nevertheless, common design practice neglects the effect of the vertical component, despite current codes prescribe specific checks for horizontal prestressed and long-span members in regions of high seismic hazard only. In such cases, simplified linear calculations based on simply supported uncoupled members are typically carried out. However, there is limited knowledge about the actual behaviour of such members under vertical acceleration. This study addresses the seismic performance of various configurations of a 25 m wing shaped roof element supported by a I-shaped beam, representative of a typical long-span deck grid for modern precast industrial buildings. Linear and non-linear analyses were carried out considering both uncoupled and coupled roof decks, encompassing Linear Static Analysis (LSA), Natural Frequency Analysis (NFA), Spectral Response Analysis (SRA), and Non-linear Time History Analysis (NLTHA). The comparison between different coupled and uncoupled configurations revealed critical insights into the realistic behaviour of long span precast elements under vertical seismic loading. The analysis of the data collected allowed also to critically assess the current design methodologies, and to highlight potential improvements. 1. Introduction Recent earthquakes in Italy have had a significant impact on precast concrete structures, particularly those occurred in regions hosting a high concentration of industrial buildings (L'Aquila 2009 and Emilia 2012). These earthquakes XX ANIDIS Conference Vulnerability of precast concrete decks to vertical earthquakes Riccardo Maurizio Ambrogio Baltrocchi a, *, Bruno Dal Lago b , Francesco Foti a a Dipartimento di Ingegneria Civile e Ambientale, Politecnico di Milano, piazza Leonardo da Vinci 32, 20133 Milano. b Dip artimento di Scienze Teoriche e Applicate, Università degli Studi dell’Insubria, via Dunant 3, 21100 Varese.

* Corresponding author. Tel.: 390341488725. E-mail address: riccardo.baltrocchi@polimi.it

2452-3216 © 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of XX ANIDIS Conference organizers 10.1016/j.prostr.2025.12.002