A Real-Time Monitoring Strategy for the Assessment of Vibration Levels on Stadium Grandstands During Events

Stadiums represent a class of civil structures that deserve major concern, mainly because they are frequently subject to the dynamic loads of thousands of people that participate in live events. Their slender and long-span grandstands may reach critical limits, which are dangerous for both the comfort of the participants and the structural safety. This work describes the strategy adopted for the case of the Giuseppe Meazza Stadium in Milan to guarantee the vibration serviceability of grandstands during real events. The existing vibration monitoring system was originally designed for a different purpose, that is to evaluate the dynamic behaviour of the grandstands over the long-term period. For this reason, the collected data were postprocessed offline, so as to extract some relevant indicators (e.g. modal parameters) to assess the structural health. More recently, the system has been updated to include an online component that checks in real-time the vibration levels achieved during concerts or football matches. This allows to evaluate the grandstand behaviour also in case of short-term and extreme events. This paper focuses on the latter aspect, with particular emphasis on the challenges related to the data acquisition strategies, distributed processing, data synchronization and transfer. The monitoring system in use today can be considered a unique example either for the complexity of the implementation and for the innovation of the adopted solutions.