Abstract Summary
The dynamic response of high-speed railway bridges is a key performance parameter, both for designing new bridges (1, 2) and for evaluating existing bridges (3). In order to establish long-term continuous monitoring based on vibration measures, it is required to develop an efficient and realistic numerical model -or digital twin- with which to compare dynamic measurements. Long viaducts with continuous decks are efficient and often used solutions for new high-speed lines, exhibiting a marked redundant structural behaviour. Regarding their dynamic response, a key feature is that several vibration modes significantly influence the transient response for any single point in the viaduct. This influence differs from simpler structures that exhibit a fundamental mode for the dynamic response. In this work, La Marota viaduct is studied to demonstrate the feasibility of using suitable structural beam-type finite element (FE) models. This structure is located in Cordoba (Spain) and belongs to the Spanish high-speed railway. It has a 381 m length distributed in nine reinforced concrete spans. First, a detailed 3D continuum FE model was built and calibrated based on the performed operational modal analyses, here twenty vibration modes were experimentally obtained and the first ten used for calibration. The good agreement between the experimental and numerical results in frequency and modal shape guaranteed the procedure. Then, a novel beam-type FE model was built and calibrated to have the same dynamic response as the 3D FEM, considering also the first ten vibration modes. The advantage of this beam-type model was its low number of elements and low computational time cost concerning the 3D model. Finally, transient dynamic analyses were performed in the simplified beam-type model under the action of different high-speed trains. The results were compared with acceleration data recorded at each span during the experimental tests. The comparison in terms of the peak acceleration, root-mean-square (RMS) and moving RMS of accelerations between the real and numerical results confirmed the accuracy of the structural beam-type model that could also be used for further predictions. References 1 EN 1991-2:2003. 2003. Eurocode 1: Actions on structures – Part 2: Traffic loads on bridges. European Committee for Standardization. 2 EN 1990:2002+A1. 2005. Eurocode – Basic of structural design. European Committee for Standardization. 3 TSI Infraestructure: Technical Specifications for Interoperability. 2016. European Parliament and Council. Directive (EU) 2016/797.
