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Short-span railway bridges subjected to high-speed traffic are structures where dynamic effects are mandatory. Additionally, the variability associated with materials and geometric characteristics introduces uncertainty to the safety assessment of railway traffic. This work discusses the current norms limit for vertical deck acceleration regarding the evaluation of stability on ballasted tracks, as stated on Annex A2 of EN1990. A probabilistic methodology to define a partial safety factor is presented, employing dynamic analyses and Monte Carlo simulations. The evaluation of a case study is presented for a single-span filler-beam bridge of the Portuguese Railways Network. The results allow the definition of deterministic design scenarios that are compared to the simulations outcome. Conclusions show consistent partial safety factors with the norms limit, contributing to further discussion of this factor. (c) 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG.

A management system is a decision-making tool that uses mathematical models to predict the future condition of the infrastructures as well as to make recommendations to the project managers. Generally, an infrastructure management system shall include a system for processing and analysing data, predicting deterioration, proposing maintenance actions, forecasting costs, obtaining optimal solutions and defining strategies that considers the political and economic constraints. The focus on this paper will be the module regarding the definition of cost-models. During its life cycle, bridges are exposed to several issues that can compromise their functionality. In this way, performing maintenance and rehabilitation actions and establishing cost models are very important tasks to keep the bridge functions according to the demands of the society. In the field of bridge engineering, the cost models can be used for different purposes such as the definition of optimum maintenance policies and project investment alternatives. Also, they are very important for the decision-making process once they cover several aspects related to the decisions about the system’s performance and decisions that are influenced by social-economic aspects. Hence, the idea of this paper is to discuss different approaches of how the cost-models are evaluated over a life cycle of a bridge due different scenarios of maintenance and rehabilitation with an application to a case study., The authors would like to thank to ISISE – Institute for Sustainability and Innovation in Structural Engineering and FCT – Portuguese Scientific Foundation under the iRail PhD program. The last author also like to thank to CONSTRUCT – Institute of R&D in Structures and Construction. Also, authors would like to thank to GEG- Engineering Structures for Life by providing the case study.

In this paper a probabilistic methodology for the safety assessment of short span railway bridges for high-speed traffic is presented. The proposed methodology combines simulation techniques with the extreme value theory in order to minimize the required computational time and guarantee accurate results. Stochastic simulation is employed as it enables reflecting the real variability of the parameters that characterize the dynamic response of the train-bridge system. The variability of the bridge, the track and the train was accounted for, as well as the existence of track irregularities. As a case study the safety of a short span filler beam railway bridge crossed by a TGV double train is analysed. The safety of the train-bridge system is assessed for the two most critical aspects of the dynamic response: the deck accelerations and the wheel-rail contact forces. Two stopping criteria for the simulation analysis were defined in order to direct the computational effort to the critical train speeds. For cases where the probability of failure is one order of magnitude apart from the safety threshold proved the efficiency of these criteria, as ruling them out as critical required a reduced number of simulations. Moreover, it was concluded that the track instability due to excessive deck accelerations is the governing aspect of the dynamic response and the Ÿ span the critical section, limiting the train speed over the bridge to 280 km/h. In terms of number of simulations it was observed that less than 25,000 simulations were needed to accurately estimate the probability of failure for the critical train speed for both safety criteria. Since the probability of failure threshold was set at 10-4 used, this is a good indicator of the efficiency of the proposed methodology.

The behavior of short span high speed railway bridges is known to be particularly difficult to predict due to the complex coupled train-track-bridge system, as well as for being particularly sensitive to resonant phenomena. The objective of this paper is to evaluate the influence of train-bridge interaction on the safety of short span bridges in high speed railway lines. This requires the definition of variables related to the structure, the train, the track and also the wheel-rail contact. As the bridge model had already been developed in previous works this paper focus its attention on the numerical models developed for both the train and the track. Track irregularities are also accounted for in the analysis and they proved to significantly affect the dy-namic behavior. Therefore, it is not certain that a significant increase of the allowable train speed on the bridge will be observed when train-bridge interaction is accounted for.