NONLINEAR ANALYSIS OF A LARGE RC CANTILEVER GRANDSTAND OF SAN SIRO MEAZZA STADIUM IN MILAN USING THE APPLIED ELEMENT METHOD

Stadiums may suffer from vibration serviceability problems when a large group of individuals in a crowd are involved in a coordinated motion due to their common light weight and adopted line of sight. Considering old stadium structures may have been designed without considering the dynamic effects associated to people jumping up and down or moving in synchro to a played song, it is of relevant interest to assess their safety usually conducted using Finite Element models. In this work, the Applied Element Method, a low-cost computational approach based on the mechanical interaction between rigid bodies and zero-thickness nonlinear interface springs, is used to assess the nonlinear structural performance of a sector of the reinforced concrete San Siro Meazza stadium in Milan, characterized by a large RC cantilever. Once the numerical model has been validated using available experimental data and results obtained through traditional FE models, nonlinear static analyses have been performed to evaluate the vertical capacity and the potential collapse mechanism. Thereafter, dynamic analyses have been conducted with a view to assess the structural response using a possible dynamic jumping load model. Displacement and acceleration time-histories have highlighted the nonlinear structural response of the analyzed portion when subjected to periodic dynamic loadings with frequencies resonant with those of the structure. Finally, a theoretical collapse mechanism has been numerically obtained.