New methodologies for the representation and assessment of the structural condition of historical bridges

Resumo

Bridges have always been one of the most important assets in transportation infrastructure. Their main function is to allow the passage of goods and people over rugged terrain, thus having a significant social and economic value. Many of the bridges currently in use were built at the beginning of the last century, so they have exceeded their service life and exhibits significant damage due to their degradation over the years. In addition, the traffic volume and the vehicle loads have been constantly increasing since then. All these nuances lead to the current situation, where there is a steady increase in the number of structural failures of historical bridges. The hypothetical collapse of one of these bridges would entail significant costs in terms of heritage, economics, environment, and even human life. To prevent their collapse, it would be necessary to invest in regular inspections, and maintenance and refurbishment works to mitigate the damage they present. However, due to the large number of historical bridges currently in use, carrying out such works would require a significant investment of time and resources. The main objective of this thesis is to investigate the implementation of several modelling and numerical calculus techniques for the development of new structural assessment methodologies. Therefore, by creating synergies between these techniques, it will be possible to generate databases that accurately characterize the current state of historical bridges, as well as calculate their actual load carrying capacity. Throughout this thesis, two different methodologies have been developed. The first one, based on the conjunction of HBIM technology and numerical calibration, allows for the generation of calibrated architectural and structural models at different bridge control phases. Each of these phases corresponds to a moment in the service life of the bridge when experimental information was collected. This methodology enables both, the generation of a database that compiles all changes in the structure, and the calculation and observation of the mechanical behavior of the bridge over the control phases. The second developed methodology links all the steps corresponding to structural evaluations to increase the robustness of the reliability analysis of historical bridges. On the one hand, to increase the accuracy of the obtained results, a thorough treatment of experimental and bibliographical data is performed to maintain a flow of updated information between the steps of the methodology. On the other hand, sensitivity analysis and surrogate modeling are implemented to reduce the computational requirements related to the model updating and structural analysis steps. Both methodologies, along with the work undertaken to develop them, have been disseminated to contribute to the state-of-the-art. As a result of this dissemination three peer-reviewed scientific articles were published in journals indexed in the Journal Citation Report (JCR) and two articles were presented at international conferences.