Experimental analysis of arroyo bracea II bridge in Madrid – Sevilla high-speed railway line: Dynamic response of the structure and effect of soil properties

Abstract

Traffic induced vibrations in railway bridges has become an issue of main concern among scientists and engineers due to the extensive construction of new High-Speed railway lines and the upgrading of existing lines for higher operating velocities [1, 2]. In this context, short to medium-span bridges (10–25 m) composed by simply-supported elements are especially critical, due to their usually associated low masses, and may experience considerably high vertical acceleration levels at the platform area [3]. As a result, the transverse acceleration in such structures is one of the most demanding Serviceability Limit States according to present regulations [4]. As a consequence, there is a need to realistically predict the behavior of railway structures in the design phase and along the bridge’s life. In this contribution the authors include results and conclusions from an experimental and numerical analysis of Arroyo Bracea II railway bridge, located in the Madrid-Sevilla High-Speed railway line in Spain. This structure is monitored due to its short length and typology, which make it susceptible to experience high transverse vibration levels. During the experimental campaign the soil properties at the site were obtained. Also, the response of the structure under the circulation of railway convoys travelling at speeds over 260 km/h was measured at several points of the deck and at the abutments. From the experimental measurements the modal parameters of the bridge are identified. Finally the experimental results are compared to those provided by a finite element numerical model in the time and frequency domains. Conclusions are extracted regarding the structure performance and the adequacy of the numerical model implemented for the particular soil and loading conditions.