Dynamic analysis of a historical monumental structure due to acoustic and anthropic vibrations during large concert events

Historical monumental structures are a fundamental component of cultural identity, yet they are highly vulnerable to structural degradation driven by human activities. Among these, crowd-induced vibrations have emerged as a critical concern, particularly in historical venues that host large public events. This study investigates the structural impact of acoustic and anthropic loads on the historical Moletta Tower, located in the Circus Maximus archaeological site in Rome, Italy. A detailed three-dimensional finite element model of the tower was developed and calibrated using experimental data from a structural health monitoring campaign. The acoustic load was modeled as a periodic pressure load, while the anthropic load through a half sinusoidal model representing jumping motion of the crowd. A three-dimensional finite element model of the soil was also implemented to simulate the propagation of the crowd jumping load from the concert attendance area to the tower. A series of simulations was performed, in which the crowd size was progressively increased to assess the tower dynamic response. Structural safety was evaluated by tracking the formation of plastic hinges and comparing simulation results in terms of maximum accelerations and peak particle velocity with limits established by national regulations. Results indicate that while the effect of acoustic loads is negligible, the jumping motion of the audience can potentially pose a risk of damage for the tower. It is observed that once a certain crowd size is exceeded, localized plastic hinges begin to form, highlighting the need for proactive management strategies. By integrating analytical, experimental, and numerical methods, this research offers framework for supporting decision-makers with evidence-based policies that balance entertainment events with preservation of historical monumental structures.