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A bridge failure can result in significant social, economic, and environmental problems; therefore, its reliability and risk management are essential. Bridges’ system reliability and risks are governed mainly by their redundancy and robustness, which currently are not adequately included in most design code specifications. Thus, in this study, a comprehensive comparison between relevant importance, redundancy, and robustness indicators found in the literature with different levels of complexity is carried out. The indicators under analysis have been used separately in different studies but have never been addressed together. Therefore, this study presents a joint evaluation of deterministic, reliability- and risk-based indicators to evaluate the differences in interpretation and information provided by the indicators. The approach is exemplified by analyzing a prestressed concrete bridge subjected to continuous degradation due to chloride ingress. A procedure is implemented to couple a metamodel-based reliability approach with a Nonlinear Finite Element Analysis (NLFEA). Based on the analysis performed, the comparison between indicators showed how different interpretations can be obtained depending on the implemented approach. Thus, creating more uniform formulations and agreeing on target values is necessary to help with redundancy and robustness interpretation., Validerad;2024;Nivå 1;2024-08-14 (signyg);Fulltext license: CC BY-NC ND

Prestressed concrete bridges experience complex load scenarios throughout their lifespan, which impacts their load capacity and overall performance. To ensure opyimal functionality and safety it is crucial to understand the diverse responses from the structure under varying load. By deploying sensors in strategically placed locations, a numerical representation of varying responses can be attained during operation. Variation in temperature can affect the reading of a sensor. This can lead to false positive structural damage responses. Thus, it is important to differentiate between variations in structural properties induced by temperature fluctuations, and variations from structural damage. This paper presents a novel approach for mapping the temperature effect in structural responses. By employing an artificial neural network (ANN) and measurement data from a prestressed concrete bridge located in northern Sweden, a correlation between temperature and the sensor values is achieved., Full text license: CC BY-NC-ND;ISBN for host publication: 978-1-032-77040-6, 978-1-032-77560-9, 978-1-003-48375-5, Sustainable Construction and Build Environment in Arctic Climate project

Railway bridges with masonry abutments represent a significant portion of aging infrastructure in north Sweden. The assessment of their structural integrity is crucial to ensure safe and efficient railway operations. This paper presents the development of a proof loading method tailored specifically for railway bridges with masonry abuments. Before conducting the tests, the bridge condition was assessed through visual inspections using ground-based photogrammetry and Ground Penetration Radar (GPR). Realistic loads were simulated using a carefully chosen train fleet during the tests to evaluate load-carrying capacity and structural integrity. Comprehensive data, including strains, displacements, temperature, and acceleration measurements, were collected to gain insights into the bridges' behavior under real-life loading conditions. This data played a crucial role in making predictions and guiding maintenance decisions for targeted rehabilitation efforts. To enhance capacity assessments, finite element models were calibrated using test results, enabling predictions of how the bridges would respond to varioius loads., Full text license: CC BY-NC-ND;ISBN for host publication: 978-1-032-77040-6, 978-1-032-77560-9, 978-1-003-48375-5

Noise barriers built parallel to the railway to reduce noise pollution, will be subjected to strong aerodynamic pressure from high-speed trains and have significant dynamic responses under such pressure. Based on computational fluid dynamics (CFD), a numerical simulation of train-induce aerodynamic pressure on noise barriers was performed. Time-varying pressure and its distribution along height direction of noise barriers were analysed, and the effect of different factors on results, i.e., the distance from noise barriers to track centre and the height of noise barrier, were discussed. Results show that the geometric changes in train nose and tail cause the obvious transient pressure pulse, and the pressure magnitude from nose is higher than that from tail. When the measuring height increases, the pressure gradually decreases, which can be well characterized by a height coefficient equation from Germany DB code. The pressure magnitude increases non-linearly when the distance to track centre decreases. Importantly, the height of noise barrier is also an important factor affecting pressure magnitude on noise barriers and when the height of noise barrier increases, the pressure magnitude gradually increases but tends to be stable at higher heights. An exponential equation can well characterize such effect of height of noise barrier on train-induced aerodynamic pressure., Full text license: CC BY 4.0

Bridge load testing is one of the tools engineers are using for the assessment of existing bridges, which is becoming increasingly important to manage the existing bridge stock in a sustainable manner. Over the past years, various research groups have worked on theoretical and practical research regarding load testing. Moreover, various international committee work on load testing recommendations. This paper provides an overview of recent research efforts in Denmark, the Netherlands, and Sweden. The way in which recent research efforts are implemented in new committee reports and guidelines is highlighted. Overall, the efforts have focused on combining load testing with insights in structural behavior, applying improved instrumentation techniques, combining with numerical analyses, and providing a probabilistic substantiation. In conclusion: bridge load testing is a dynamic field of research that benefits from international collaboration. Further improvements to existing codes and guidelines will be forthcoming in the next years., Funder: Italian High Council of Public Works;ISBN for host publication: 9781003483755;Full text license: CC BY-NC-ND

Railway noise barriers should provide excellent sound insulation and sufficient load-bearing capacity. High-speed railway noise barriers experience significant and transient aerodynamic loads from passing trains, resulting in noticeable dynamic responses. In this study, three simplified load models were applied to a noise barrier to compare the dynamic responses to those obtained under a reference load from computational fluid dynamics (CFD) simulations, Results show that the natural frequency of target noise barriers exceeds 10 Hz, significantly surpassing the excitation frequency of the train-induced areodynamic load, thereby minimizing the likelhood of resonance. The displacement or stress evolution closely correlatesd with the variation of pressure over time. Along the longitudinal direction of the noise barrier, the stress range initially increases, stabilizes, and eventually decreases, reaching its maximum at the penultimate post. Compared to the two simplified rectangular load models, the triangular load model with a distribution load length of 12 m better represents the detailed time-varying aerodynamic load., Full text license: CC BY-NC-ND;ISBN for host publication: 978-1-032-77040-6, 978-1-032-77560-9, 978-1-003-48375-5