PSI - Issue 78

Roberto Nascimbene et al. / Procedia Structural Integrity 78 (2026) 193–198

194

Keywords: Precast; Connections; energy dissipation; seismic performace; beam-column connections.

1. Introduction Precast concrete buildings in Europe are commonly characterized by a high degree of structural flexibility, primarily due to the widespread use of slender cantilever columns and beam-to-column connections that are either pinned or semi-rigid. These connections often rely on frictional resistance or embedded mechanical systems, which have shown susceptibility to failure during recent seismic events in Italy (Belleri et al. (2015), Nascimbene (2024), Savoia et al. (2017)). In several documented cases, such failures have resulted in the loss of beam support, raising serious concerns about the seismic adequacy of these structures. The observed vulnerabilities have emphasized the urgent need for large-scale assessment and retrofit initiatives targeting existing precast industrial buildings across Europe. The overarching goal of such initiatives is to mitigate seismic risk and improve the resilience of these critical facilities. A fundamental preliminary step in this process involves the development of a comprehensive taxonomy of structural typologies, tailored to the regional or national construction context as done by Bellotti et al. (2025). Typically, European precast industrial buildings are composed of single-storey, multi-bay frames spanning the transverse direction. These systems often include slender columns founded in individual socket bases, paired with long-span main beams, generally prestressed, with spans ranging from 14 meters up to over 20 meters. The beam-to column joints are usually designed as semi-rigid, though for design simplicity they are often treated as pinned. In the longitudinal direction, secondary beams or girders, if present, do not usually contribute to lateral resistance, resulting in a seismic force distribution that depends largely on the flexural capacity of the columns and the diaphragm stiffness of the roof system. A significant portion of Italy’s industrial precast building stock, constructed over the past six decades, was designed and erected prior to the seismic classification of their respective municipalities. Consequently, many of these structures lacked adequate seismic detailing and design considerations. The impact of recent earthquakes in Italy, including the 2009 L’Aquila earthquake, the 2012 Emilia-Romagna sequence, and the 2016–2017 Central Italy events, has led to widespread damage among these buildings (Fischinger et al. (2014); Magliulo et al. (2014); Bournas et al. (2014); Belleri et al. (2015); Savoia et al. (2017); Nascimbene (2024)). The final objective of this study is to propose an optimized frame configuration that can ensure adequate energy dissipation and displacement control during seismic events, outperforming conventional pendulum-type precast systems. Based on the simulation results obtained thus far (Bosio et al. (2023); Cavalieri et al. (2023a); Cavalieri et al. (2023b); Deyanova et al. (2023); Nascimbene et al. (2024); Nascimbene and Bianco (2021)), a thorough evaluation has been conducted in terms of structural effectiveness, practical feasibility, cost implications, and post-earthquake reparability. Guided by these evaluations, and prioritizing construction methods that align with current industrial practices, the study has focused on the most commonly adopted typologies. Accordingly, a novel frame design has been developed, integrating both hinged and partially restrained connections. This solution offers a viable compromise between enhanced seismic performance and ease of execution. Moreover, the system enables dry assembly of components, a feature that aligns well with the standard preferences of the precast industry, promoting rapid construction and simplified maintenance. 2. Description of the Beam-to-Column Subsystem A key feature of the proposed structural solution lies in the partially restrained beam-to-column connection, which is engineered to improve both stiffness and energy dissipation under seismic loading. This connection system involves threaded steel bars protruding from the beam and anchored into the column via a grouted sleeve technique. The anchorage zone consists of a narrow cavity, less than or equal to 10 cm, between the beam end and the column face, which is filled with high-strength cementitious grout.