PSI - Issue 78

Angelo Masi et al. / Procedia Structural Integrity 78 (2026) 686–693

688

predictions with observed structural behavior under dynamic loading conditions (Ponzo et al., 2024). Additionally, the use of shake-table experiments and full-scale component testing is increasingly recognized as an essential step toward the experimental validation of retrofit strategies and the refinement of computational models. This study investigates SPEAD, a local, non-invasive, dissipative retrofit technique developed within the framework of the SAFER-REBUILT project, founded by the Extended Partnership “Multi-Risk sciEnce for resilienT commUnities undeR a changiNg climate” (PE RETURN), with the aim to enhance the seismic performance of RC joints while complying with the Life Cycle Thinking principles (Passoni et al., 2021). To assess its effectiveness, a proper methodology including numerical simulations and experimental tests has been defined. After a brief description of the main objectives of the SAFER-REBUILT project and the main features of the SPEAD device, the paper summarizes the main phases of the methodology, describes the experimental tests on standalone devices and analyses the obtained results. 2. The SAFER – REBUILT project The SAFER-REBUILT project, aligned with the scientific objectives of PE RETURN and the VS3 – Earthquakes and Volcanoes spoke (https://www.fondazionereturn.it/), is the symbiotic integration of such goals into a broader multiobjective strategy that, thanks to life cycle thinking and life cycle approaches, goes beyond the current state of the art and produce solutions that maximize a) seismic and energy performance, b) efficient use of materials, c) use of renewable natural-based materials, d) reversibility, and e) durability of the intervention, while simultaneously minimizing i) costs, ii) intervention time, iii) downtime and invasiveness, and iv) environmental impacts. A multidisciplinary group of 5 Research Units (University of Basilicata; University of Bergamo; University of Brescia; University of Cassino; University of Trento) joined their experience in national and international collaborations, fund management capability and expertise, consistent with the RETURN research program, to suitably address the above described objectives. The research activities of SAFER_REBUILT have the main objective of defining innovative and sustainable solutions for reducing the vulnerability of constructions focusing on residential buildings, constituting the majority in medium to large urban areas. The proposed solutions will be conceived and tested in the framework of the Life Cycle Thinking principles (LCT, Passoni et al., 2021) following the entire cycle of retrofitted building’s life, from design (using renewable materials and low-impact solutions) to construction phase (using easy-to-install precast systems with modular components), maintenance program (effective procedure to reintegrate or substitute the degraded/damaged components) and, considering the reuse/recycle of the waste in the case of damaging earthquakes. In this framework, the research unit of the University of Basilicata proposed the SPEAD (Steel Plate Energy Absorption Device, Santarsiero et al., 2020) as an innovative seismic upgrading method for RC frames. As better described in Section 2.1, SPEAD strengthens beam-column joints, reducing earthquake-induced damage while using recycled steel, minimizing demolitions, reducing costs and impacts. 2.1. The SPEAD device SPEAD (Steel Plate Energy Absorption Device) is a patented technical solution (application no. 102019000006567 of the Italian Patent and Trademark Office) conceived to improve local performance of RC joints beam-columns (Fig. 1), which are one of the most vulnerable resisting elements in pre-code existing RC buildings, due to the complete absence or insufficient quantity amount of stirrups. SPEAD is a pre-formed steel plate with circular holes forming hourglasses that deforms under shear, providing a fixed threshold force and dissipation capacity due to steel hysteresis. The device is essentially made up of two parts (see Fig. 1). The first one must be connected to the column and the second one is connected to the beam. The SPEAD system exploits the relative deformations between the beam and column that occur during seismic events. In fact, the borders between the two parts of the device are made in such a way that plastic deformations can easily occur at predefined force thresholds. This deformation provides a fixed limit force and a dissipation capacity, exploiting the hysteretic behavior of steel. As shown in Fig 1, the forces acting on the device include the horizontal force Fp applied to the lever arm B, the moment Mp, and the shear force Vp that develops along the interface between parts 1 and 2 of the device.