PSI - Issue 78

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

1979

3.4. Alternative strategies for overturning reduction: dampers and tuned masses Beyond base isolation and active control systems, numerous studies have explored strategies that allow for controlled rocking motion while limiting overturning. Among these, devices based on the Tuned Mass Damper (TMD) principle have shown particular promise. In particular, de Leo et al. (2016) and Di Egidio et al. (2019) investigated the use of pendulum-type TMDs, where a concentrated mass is suspended via a pivot on the top of the rocking block. This setup uses the relative movement of the mass to dampen the oscillations of the main block, thus reducing accelerations and internal forces. An alternative is provided by SDOF TMDs, such as those analyzed by Simoneschi et al. (2017), in which the mass is connected via linear viscoelastic elements. More recent research (Di Egidio et al., 2023) has also proposed active control methods to intelligently actuate the TMD mass, further enhancing the system’s capacity to mitigate seismic responses (Fig. 2). These solutions represent a valid complement or alternative to isolation systems, especially for rigid elements with specific architectural or functional constraints.

Fig. 2. Representative example of the effectiveness of the active control method developed by Di Egidio et al. (2023), based on the implementation of active mass damper optimized according to the Pole placement (PP) method algorithm. (a) Rocking maps related to NAC (no active control) and TAC (top active control) under Kobe earthquake and (b) rocking angle (θ) and control force (F c histories associated with poi nt C depicted in (a). 4. Anchorage devices and restraints systems: overturning prevention Anchorage devices represent a well-established solution for limiting or preventing the overturning movement of NSEs during seismic events. These systems include mechanical anchors, tie rods, cables, and springs specifically designed to resist the dynamic forces generated by earthquakes. The main objective is to ensure that the element remains stable without excessive deformation or detachment from the main structure, thereby avoiding significant damage or safety hazards. The installation of anchors requires careful assessment of connection points, the selection of appropriate materials, and integration with the structural system. Standards such as FEMA 412 and FEMA 413 provide guidelines for the design and sizing of these devices. Their effectiveness heavily depends on the quality of installation and the ability to absorb or transfer loads without damaging the anchored element. Although anchorage significantly improves stability, poorly designed systems can introduce negative effects, such as excessive stress concentrations or restraining forces that could compromise the integrity of the element. Studies such as those by Dimitrakopoulos and DeJong (2012) have suggested the use of complementary damping systems, such as linear viscous dampers placed at the element’s corners, which help dissipate energy and reduce the forces transmitted through the anchors. In recent years, research has focused on developing semi-active anchorage systems, which combine the robustness of passive devices with the ability to adapt in real time to dynamic structural and seismic conditions. These systems