Mitigation of Crowd-Induced Vibrations in Historic Masonry Towers: The Moletta Tower Case Study

Historic structures near large public gathering areas are increasingly exposed to dynamic loads from human activities, particularly during concerts and similar events. This study presents a numerical investigation of three mitigation strategies to protect the Moletta Tower from crowd-induced vibrations during large-scale events. A detailed finite element model of the Circus Maximus and the tower was developed to incorporate soil–structure interaction, realistic boundary conditions, and dynamic loading scenarios. The proposed strategies are: (1) installation of a Tuned Mass Damper Inerter (TMDI) within the tower to reduce structural vibrations; (2) deployment of a temporary foam-based vibration-damping mat to attenuate crowd-induced excitation at the source; and (3) implementation of subsoil barriers to dissipate ground-borne waves reaching the structure. Results indicate that the damping mat achieved the greatest reduction, lowering peak acceleration by up to 60%. Subsoil barriers provided variable performance, reducing vibrations by 15–45% depending on configuration, while the TMDI offered moderate attenuation, decreasing displacement by 10–40%. Each solution presents distinct advantages and limitations regarding feasibility, cost, and effectiveness. These findings provide valuable insights for safeguarding cultural heritage sites against anthropogenic dynamic loads.