AN ANALYSIS METHODOLOGY FOR STUDYING THE STRUCTURAL VIBRATIONS CAUSED BY RAIL TRAFFIC: A CASE STUDY OF THE ARCHAEOLOGICAL AREA AROUND THE COLESSEUM IN ROME

The article presents a new methodology for analysing dynamic soilstructure interaction connected to rail traffic. The results can be used to monitor the weak vibrations caused by traffic and to improve the resistance of structures to earthquakes. The proposed methodology entails the use of two three-dimensional models functionally connected and comparable with experimental data. The first model, a “wagons-track” model, instantaneously provides the strengths in the rail-sleeper connections created by the transit of wagons/trains, which vary according to load and use. These strengths are the input for the second model which evaluates “soilstructure” interaction to evaluate the structural vibrations. This analysis methodology was applied to the archaeological zone of Rome comprising the Colosseum and the Arch of Constantine which is affected by the underground railway. The characteristics of motion s(t), v(t) and a(t) for all of the nodes, and the tensorial characteristics ε(t) e σ(t ) for all of the finite elements (EF) of the model are obtained for the unidirectional transit of a railway wagon running along this line at the end of the 1980’s. The results are discussed for a “sample pillar” of the Colosseum.