fluid dynamic interaction between train and noise barriers on high speed lines

Abstract Noise barriers are lineside structures next to the railway track, subject to vibrations due to fluid-dynamic excitation induced by the train passage in High-Speed-Lines (HSLs). The train, travelling along the railway track, is immersed in a fluid, which increases its resistance as the speed of the train increases; the generated pressure field, with sinusoidal trend, is orthogonal to the barrier and excites its dynamic response, testing strength and fatigue resistance. This phenomenon becomes particularly significant for the HSLs trains, travelling at 300 kph speed, and should be evaluated to ensure the transport safety. The aim of the study is to focus on the dynamic response of existing noise barriers, with special regard to fatigue aspects, and proposes the introduction of special devices, Tuned-Mass-Dampers (TMDs), to place on the top of each column in order to reduce structural vibrations. The noise barrier is modeled as a generalized single-degree-of-freedom (SDOF) system. The pressure field induced by the train passage is modeled by a dynamic action function of the barrier height and geometry, of the railway geometry and the train speed. Two case studies are illustrated with columns 4 and 5 m high and concrete noise panels. The design of the auxiliary system, the TMD, is carried out as first tentative solution for reducing the structural vibrations and dynamic analysis on the barriers with and without the TMD shows the effectiveness of the control system to reduce the amplitude of motion and the number of cycles of vibration