PSI - Issue 78

Michele Morici et al. / Procedia Structural Integrity 78 (2026) 1673–1680

1674

1. Introduction

The seismic vulnerability of the built environment remains a critical challenge in earthquake-prone regions, where the need to ensure the safety, functionality, and resilience of essential infrastructure has driven significant advancements in structural engineering and seismic protection technologies. Among the available mitigation strategies, seismic base isolation has gained widespread recognition as one of the most effective solutions for reducing structural demands during strong ground motions. By introducing a flexible interface between the superstructure and the foundation, isolation systems can substantially reduce seismic accelerations and inter-storey drifts, thereby limiting both structural and non-structural damage. This makes them particularly suitable for facilities where post-earthquake operational continuity is crucial, such as research laboratories, hospitals, and emergency management centers. While the design and analytical modelling of base-isolated structures have reached a high level of sophistication, their actual in-service performance is influenced by several factors that cannot be fully captured during the design stage. Variations in material properties, manufacturing tolerances, installation conditions, environmental influences (such as temperature and humidity), and progressive aging can all contribute to deviations from predicted behavior (Van Engelen and Kelly 2015; Ragni et al. 2025). Furthermore, the interaction between the isolation devices and the superstructure under combined seismic, environmental, and operational loads remains a complex phenomenon, particularly in hybrid isolation systems that combine different device types. In this context, there is an increasing recognition of the need for long-term, in-situ performance evaluation to complement design stage analyses and to provide data for model updating and lifecycle management. Structural Health Monitoring (SHM) systems have emerged as a key enabling technology to address this need. By integrating an array of sensors capable of recording acceleration, displacement, strain, and other response parameters, SHM enables continuous or periodic evaluation of structural integrity (Bao et al. 2019). Such systems facilitate the detection of damage initiation, progressive deterioration, and changes in serviceability, while also allowing for the identification of trends that may signal the onset of performance degradation. In base-isolated structures, SHM plays an additional role: it provides direct feedback on the isolation system’s efficiency, verifies the validity of analytical models under actuals conditions, and supports the identification of any deviations from design assumptions following dynamic loading events. The use of SHM in seismically isolated buildings is not only valuable for post-event assessment but also for routine operational monitoring, model validation, and performance optimization. Despite these advantages, the literature still presents a relatively limited number of case studies involving permanent SHM installations in newly constructed base-isolated buildings, particularly where the system is integrated from the early construction phases. Such early integration allows for optimal sensor placement, comprehensive baseline data acquisition, and better alignment between monitoring objectives and structural characteristics. The present study addresses this gap by describing the implementation and initial results of a permanent SHM system installed in the Chemistry Interdisciplinary Project (ChIP) Research Centre at the University of Camerino. The Chemistry Interdisciplinary Project (ChIP) Research Centre of the University of Camerino is a strategic building designed to accommodate high-risk and very sensitive instruments of the chemistry and physics laboratories (Dall’Asta et al., 2020) . Given these critical roles, to achieve enhanced seismic performance, a base isolated structural system was adopted. The superstructure consists of a two-storey steel braced frame with pinned joints, supported by reinforced concrete substructures. The isolation interface comprises a hybrid system of 28 High Damping Rubber Bearings (HDRBs) and 36 low-friction Flat Sliding Bearings (FSBs). This hybrid approach was selected to provide a long isolation period and moderate damping (Ragni et al., 2019). Furthermore, two complementary strategies were implemented to guarantee structural integrity even under seismic demands exceeding design levels: (i) safety margins in the displacement capacities of the isolation system and seismic gaps, and (ii) the incorporation of over-strength elasto-plastic steel braces in the superstructure to manage extreme horizontal actions (Dall’Asta et al., 2021) . In addition, the structure is equipped with a specialized push-and-release mechanism designed to assess the global dynamic response of the building under displacement levels comparable to those expected during severe seismic events. This system allows the repetition of controlled tests throughout the building’s service life for evaluating long -term performance. An experimental campaign including both quasi-static push tests and dynamic push-and-release tests was described in detail in Dall’Asta et al. (2022) and Dall’Asta et al.