PSI - Issue 78

Alessandro Contento et al. / Procedia Structural Integrity 78 (2026) 1975–1982

1981

5.2. Future outlook and research directions To address these gaps, future research must focus on several key areas. First, it is essential to develop more realistic and representative models of NSEs under actual conditions, incorporating geometric variability, material characteristics, and anchorage or interaction modes with the main structure. This requires a multidisciplinary approach that combines advanced numerical modeling, full-scale experimentation, and field monitoring. A second crucial aspect is the need for in-depth study of the dynamic interactions between NSEs and the supporting structure, to understand how forces are transferred, amplified, or attenuated during seismic events. This also involves the analysis of complex systems with multiple NSEs interacting both with each other and with the primary structure, in order to assess cumulative or amplification effects. Finally, it will be important to define design procedures and verification criteria for the integration of NSEs into technical codes, making methodologies more accessible to engineers and designers. This also includes the development of open-access technical databases collecting experimental and field data, along with practical guidelines for rapid and reliable assessments. 6. Conclusions This work presents a summary and discussion of the critical review conducted by the authors in D’Angela et al. (2025). For further information and detailed review assessment, the readers are encouraged to consult the comprehensive study referenced above. The analysis conducted in this work has highlighted that the seismic protection of NSEs subject to rocking mechanisms represents a complex and multidisciplinary challenge, involving theoretical, experimental, and practical aspects. Traditional methods, mainly based on rigidity and on containing the forces transmitted to structural systems, are evolving toward more sophisticated solutions. These aim not only to prevent overturning but also to actively control and manage the dynamic response. In particular, the use of base isolation systems, such as elastomeric bearings and innovative devices like rolling-ball isolators, has proven effective in dissipating seismic energy and significantly reducing the accelerations and forces transmitted to protected elements. These solutions, however, require careful design that considers the specific characteristics of the element being protected, the seismic hazard level of the site, and the desired performance in terms of isolation. Recent integrations of active control systems, such as control strategies based on pole placement (PP) and linear quadratic regulator (LQR), have opened new perspectives for the proactive management of seismic response. These strategies allow for real-time modulation of the forces and displacements of the isolated system, showing particular effectiveness in preventing the onset of rocking and providing superior protection compared to traditional passive systems. Alongside isolation and control devices, anchoring and restraint techniques are also valuable tools, especially when integrated with viscous or semi-active damping systems, to enhance resistance and stability under dynamic conditions. However, it is crucial to maintain a balance between limiting movement and avoiding the introduction of excessive concentrated loads that could damage the element itself. Despite these important advancements, research highlights several critical gaps, such as the need to develop more representative and generalizable models that consider the interaction between NSEs and supporting structures, and which can be validated on real-world cases rather than generic configurations. Moreover, the definition of specific design criteria and regulatory guidelines for NSEs remains in its early stages, limiting the widespread adoption of these technologies in everyday engineering practice. Looking ahead, research should be increasingly directed toward integrating theoretical modeling, advanced experimentation, and practical design applications. This includes developing design and verification procedures based on probabilistic approaches and energy-balance methods. The creation of shared databases, the dissemination of best practices, and the updating of technical codes are essential steps in translating scientific results into effective, concrete, and sustainable solutions. Finally, adopting a multi-technical approach, combining isolation, active control, anchoring, and damping, may represent the most effective strategy for ensuring the safety and preservation of elements with high historical, cultural, or technological value, particularly in high-seismicity regions. Through these coordinated efforts, it will be possible to significantly improve the seismic resilience of buildings and facilities, contributing to the protection of both heritage and human lives.