Dynamic evaluation of the top-down construction of the Belfiore high-speed railway station

The construction phase of underground railway stations executed with top-down method is often susceptible to a considerable number of interferences. The interference between the excavation of the Florence high-speed station and tunnels' execution is a critical element of the Florence underpass project, which foresees the simultaneous construction of the two infrastructures. The project's complexities and the interference between the various construction phases have been studied and resolved by developing the entire project in a Building Information Modeling (BIM) environment. In particular, the implemented four-dimensional (4D) BIM model managed to simulate the possible macrophases and identify an optimal construction solution or, at least, the crucial actions to be taken to ensure the simultaneous construction of the station and tunnels. The 4D BIM model allowed an accurate simulation of the specific critical construction phases by identifying spatial interferences between completed works, temporary structures, and overlapping interventions. Consequently, it was possible to adopt appropriate technical solutions and develop a reliable work plan. In addition, it was possible to verify the potential scenarios of the TBM passage through the excavated station, which allowed to foresee some specific interventions needed to ensure works' continuity. The BIM methodology also allowed to find optimal solutions in a reasonable time, preventing a significant use of resources.