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• Deck acceleration measurement up to the train speed of 374 km/h were analyzed. • Global and local vibration modes up to 30 Hz were identified from field tests. • A highly accurate simulation model of deck acceleration was constructed. • High-order resonance of deck vibration is the dominant on the maximum acceleration. • Determination method to consider the track deformation is proposed. European design standards have established an upper limit on the deck acceleration of the high-speed railway bridges, however the influence of local vibrations of the deck members is rarely considered when modelling the vibrational responses of bridges. To evaluate how the inclusion of local deck vibrations might influence predictions of the maximum acceleration, detailed measurements were taken from a steel-concrete composite box-girder bridge on the Italian high-speed railway, and a numerical model of the system was developed. Deck vibrations were measured during high-speed train passages at the maximum train speed of 374 km/h, and compared against a numerical model of the vehicle-bridge system. This analysis revealed that the maximum deck acceleration is 1.3 times greater than the acceleration of the bridge girders, because of the sixth- and seventh-order resonance between the deck's local vibration modes and the structure with a train running at high speeds over 300 km/h. Moreover, when considering local deck vibrations in the numerical model, we found that the interaction between transient local rail deformations and the vehicle travelling on the rails can increase the acceleration of the deck through resonance. [ABSTRACT FROM AUTHOR]

[Display omitted] • New drive-by detection method for resonant bridges in high-speed railway proposed. • Difference in track irregularities for the first and last vehicles used. • Applicability of the proposed method verified numerically. • Proposed method applied to track irregularities in Japan's high-speed railways. • Resonant bridges verified by in-situ bridge response measurements. Resonance of railway bridges is a matter of major concern in high-speed railways because it reduces riding comfort, damages the attached structures, and decreases the strength of girder bodies. Although this abnormal behavior can be inspected using in situ displacement measurements taken from the ground, its investigation is tedious and, consequently, is very expensive. In this study, authors developed a novel drive-by system for high-speed railways to detect resonant bridges; the difference between two track irregularities at the same position using devices mounted on the first and last vehicles of a train was measured. This is based on the idea that the response of the last vehicle passing through the resonant bridge is attributed to the superposition of track irregularities and abnormal bridge displacement because of resonance mechanisms. However, the response of the first vehicle primarily arises from track irregularities since the resonance phenomenon is not yet sufficiently excited. The Resonance Detection Index (RDI), defined as the difference between the track irregularities measured by the devices mounted on the first and last vehicles, is used to emphasize the component excited by vehicle length to propose a methodology for detecting resonant bridges. Numerical simulations clarify that bridge span and track irregularity have greater effects on the RDI than either measurement noise or positioning error. Track irregularity may cause the RDI to vary by ± 2 mm depending on vehicle length wave component of the track irregularity. Consequently, this study demonstrates that resonant bridges with spans between 20 and 60 m can be detected using the proposed RDI. Finally, the proposed method was applied to track irregularity measurements using actual high-speed trains operating in Japan. More than ten bridges, out of more than 800 bridges, were detected as resonant bridges according to RDI. In situ displacement measurements were performed for three of these bridges, demonstrating the presence of resonance phenomenon and thereby validating the proposed method. [ABSTRACT FROM AUTHOR]

The recent development of high-speed trains over the last decade led to a growing interest in their aerodynamics. A train at full operational speed generates a strong induced airflow that may damage infrastructures near the trackside and endanger people near the rails. Nowadays the tests required for the train homologation are based on full scale measurements of the airspeed taken in specified positions close to the railway line. An important part of the work was initially dedicated to the data analysis of an extensive experimental campaign performed on the Italian high-speed line, in order to obtain reliable results to be used for comparison with CFD results. These ones have been performed on the full-scale train geometry using an URANS approach with a wall treatment based on wall functions, checking mesh and turbulence models dependencies. The full-scale simulations highlighted the great complexity of the problem being the comparison with the experimental measurements performed close to the shear layer of the train boundary layer. Encouraging results are obtained from the numerical analysis on the full-scale train geometry indicating the ability of the URANS coupled with the SST turbulence model in the prediction of both the train induced flow and the turbulent structures around it. • Flow statistics strongly influenced by crosswind. • CFD provide good estimation of the 3D flow around a full scale high speed train in operational conditions. • k-omega SST turbulence model showed a strong stability and versatility in reproducing high turbulence flow. [ABSTRACT FROM AUTHOR]