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  • 1.
    Agredo Chavez, Angelica Maria
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Gonzalez, Jaime
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Andersson, Kasper
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Leidzen, Jon
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Andersson, Erik
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Petersson, Mats
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Häggström, Jens
    Swedish Traffic Administration, Luleå, Sweden.
    Cracking and Fatigue of Heavy Loaded Prestressed Concrete Bridge in Sweden2022In: IABSE Symposium Prague 2022: Challenges for Existing and Oncoming Structures - Report, International Association for Bridge and Structural Engineering / [ed] František Wald; Pavel Ryjáček, Zürich: International Association for Bridge and Structural Engineering, 2022, p. 792-799Conference paper (Refereed)
    Abstract [en]

    A prestressed concrete bridge was built in 1963 with BBRV cables. It has three spans and a total length of 134.8 m. Due to mining activities the bridge was loaded with trucks with a total weight of 90 ton during 2012-2014 and from 2019. Crack development has been monitored manually and from 2020 with strain gauges and LVDTs.

    Cracks normally vary between 0.1 to 0.3 mm in width and grow in length with time. In November 2020 some of the strain gauges on the concrete showed alarming growth and the bridge was closed for traffic. Additional strain gauges were installed on vertical reinforcement bars and an assessment was carried out of the fatigue capacity of the bridge. It was found that the new strain gauges did not indicate any growth in strain and that the fatigue capacity was sufficient. The bridge could be opened again for traffic after being closed for five weeks. Monitoring drift in the strain gauges and fatigue are discussed.

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  • 2.
    Agredo Chavez, Angelica Maria
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Gonzalez, Jaime
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Capacci, L.
    Politecnico di Milano, Milan, Italy.
    Biondini, F.
    Politecnico di Milano, Milan, Italy.
    Structural model updating of an existing concrete bridge based on load testing and monitoring data2023In: Life-Cycle of Structures and Infrastructure Systems / [ed] Fabio Biondini, Dan M. Frangopol, Taylor & Francis Group, 2023, Vol. 1, p. 3999-4006Conference paper (Other academic)
    Abstract [en]

    The backbone of European infrastructure was built after the end of the second World War and has reached, or is near to, the end of its nominal design life. This issue urges the development of structural assessment procedures that can provide infrastructure managers the information to make decisions for repairing, upgrading, or replacement. In this paper, a methodology based on load testing and Structural Health Monitoring (SHM) for the assessment of a 65- year-old prestressed concrete bridge located in Northern Sweden is presented. The retrieved data is used to develop and calibrate structural models with different levels of data completeness. The SHM procedure includes the evaluation of material properties by diagnostics, definition of the layout and installation of the instrumentation, test execution, and data analysis. A preliminary structural model is developed based only on the original design parameters, and it is sequentially updated with monitoring data retrieved during a performed proof loading test of the bridge.

  • 3.
    Agredo Chavez, Angelica Maria
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Gonzalez, Jaime
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Bianchi, Silvia
    Politecnico di Milano, Milan, Italy.
    Biondini, Fabio
    Politecnico di Milano, Milan, Italy.
    Kukay, Brian
    Montana Technological University, Montana, United States.
    Available Tests to evaluate Residual Prestressing Forces in Concrete Bridges2022In: IABSE Symposium Prague 2022: Challenges for Existing and Oncoming Structures - Report, International Association for Bridge and Structural Engineering / [ed] František Wald; Pavel Ryjáček, International Association for Bridge and Structural Engineering, 2022, p. 1123-1131Conference paper (Refereed)
    Abstract [en]

    The reduction of the structural capacity and eventual collapse of existing concrete bridges is often related to the loss of the initial prestressing forces. This loss can be associated to immediate or time dependent factors such as elastic shortening, creep, relaxation, loading, and cracking, among others. In addition, environmental factors can lead to corrosion of the strands with the subsequent reduction of their area, loss of bond with the concrete and additional cracking which in turn will influence the value of the residual prestress force and the bridge capacity. Therefore, the evaluation of such losses is critical in the decision-making process of defining a financial and environmental cost optimized intervention strategies (e.g., strengthening or replacement). In this paper, a detailed literature review regarding destructive and non-destructive methods for measuring the residual force in prestressed concrete bridges is carried out and used to develop a database of existing experimental tests.

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  • 4.
    Agredo Chavez, Angelica Maria
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Ulfberg, Adrian
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Gonzalez-Libreros, Jaime
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Data Validation of Strain-Based Monitoring Systems in Low Temperature Conditions, Case Study: The Kalix Bridge2023In: Building for the Future: Durable, Sustainable, Resilient - Proceedings of the fib Symposium 2023 - Volume 2 / [ed] Alper Ilki; Derya Çavunt; Yavuz Selim Çavunt, Springer, 2023, Vol. 2, p. 986-995Conference paper (Refereed)
    Abstract [en]

    Over the last decades, economic growth and sustained development have enforced the need to ensure reliable and long-lasting infrastructure network to guarantee serviceability and safety. Nevertheless, detrimental effects can lead over time to insufficient structural performance under increasing service loadings and extreme events. Hence, Structural Health Monitoring (SHM) arises as a solution to cope with the need of having timely and continuous data to assess the state of crucial structural assets, such as prestressed concrete bridges. On this matter, the validation of the retrieved data becomes essential for the risk-based decision making in the assessment of bridges, where selecting the most suitable monitoring system could allow to addressed main causes to the right phenomena of deterioration during the service life of the bridge. Consistently with these efforts, this paper deals with a comparative study between the data acquired by different strain-based sensors such as Fiber optic systems (FOS) and strain gauges that were installed to monitor a proof loading test developed on a 65-year-old balanced cantilever prestressed concrete bridge located in Northern Sweden. The monitored data led to establish main differences between emerging types of monitoring systems such as FOS to the well-based strain gauges when exposed to low temperature conditions. Conclusions regarding the influencing parameters between both retrieved data are drawn when evaluating the structural response under serviceability loading conditions is performed, supporting decision makers when different levels of structural assessment are required.

  • 5.
    Agredo Chávez, Angélica
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Gonzalez-Libreros, Jaime
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Wang, Chao
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Capacci, Luca
    Department of Civil and Environmental Engineering, Politecnico di Milano, Milan, Italy.
    Biondini, Fabio
    Department of Civil and Environmental Engineering, Politecnico di Milano, Milan, Italy.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Assessment of residual prestress in existing concrete bridges: The Kalix bridge2024In: Engineering structures, ISSN 0141-0296, E-ISSN 1873-7323, Vol. 311, article id 118194Article in journal (Refereed)
    Abstract [en]

    The direct socio-economic consequences of the deterioration of aging infrastructure systems have triggered a continuous process of revising and updating current design standards and guidelines for critical network components. Specifically, long-term degradation processes demand the analysis and evaluation of vital structural assets such as prestressed concrete bridges. It is crucial to develop theoretically consistent, user-friendly, and non-destructive methodologies that engineering professionals can employ to prevent and mitigate potential catastrophic outcomes during the service life of these bridges. This study provides a thorough review of the available testing methods employed over the years for prestressed concrete bridges and introduces a comprehensive framework for evaluating existing methods for residual prestress force assessment. Through a multi-criteria selection process, the three most feasible tests were designed and carried out on an existing 66-year-old balanced cantilever box girder bridge exposed to freezing temperatures that affected the instrumentation plan and test execution. Finally, predictive models compliant with standard codes were calibrated based on the experimental results and the life cycle loss of prestress forces was evaluated to assess relevant bounding intervals. Findings reveal limited on-site testing and discrepancies between calculated residual forces and predictions by standard codes. The saw cut method showed a 18% difference from the initial applied prestress according to the prestress protocol, suggesting the use of a cover meter and concrete modulus evaluation for improved accuracy. The strand cutting method resulted in a 14% difference, emphasizing the need for stress redistribution assessment. The second-order deflection method showed a 6% difference, indicating a focus on enhanced boundary conditions and thorough sensitivity analysis for future investigations.

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  • 6.
    Al-Gburi, Majid
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Gonzalez-Libreros, Jaime
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Nilsson, Martin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Quantifying the Environmental Impact of Railway Bridges Using Life Cycle Assessment: A Case Study2022In: IABSE Symposium Prague 2022: Challenges for Existing and Oncoming Structures - Report, International Association for Bridge and Structural Engineering, 2022Conference paper (Refereed)
    Abstract [en]

    As emission regulations in the EU are becoming stricter, the reduction of greenhouse gas emissions from the construction industry has become a pressing need. As part of the efforts related to this issue, it has been found that Environmental Life Cycle Analysis (LCA) approaches are required to optimize the design, construction, operation, and maintenance of buildings and infrastructure assets. In this paper, The Institution of Structural Engineers guidance on how to calculate the embodied carbon in structures is used as LCA model and evaluated in a case study. The guidance divides the structure´s life cycle into five stages (A1-A3: Product, A4-A5: Construction process, B1-B7: Use, C1-C4: End of live and D: Benefits and loads beyond the system boundary) and the environmental impact is measured in terms of carbon dioxide equivalent emissions (kgCo2e) or global warming potential (GWP). The model was applied to an existing reinforced concrete trough bridge, which is a structure type commonly used in Swedish railways. Results show that that the model was effective and simple for investigating the environmental impact of the studied structure. 

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  • 7.
    Bagge, Niklas
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. WSP Bridge & Hydraulic Design, Göteborg, Sweden.
    Nilimaa, Jonny
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sarmiento, Silvia
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Puurula, Arto
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. Savonia University of Applied Sciences, Kuopio, Finland.
    Gonzalez-Libreros, Jaime
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Carolin, Anders
    Swedish Transport Administration, Luleå, Sweden.
    Häggström, Jens
    Swedish Transport Administration, Luleå, Sweden.
    Enoksson, Ola
    Swedish Transport Administration, Luleå, Sweden.
    Coric, Ibrahim
    Swedish Transport Administration, Luleå, Sweden.
    Full Scale Test of a PC Bridge to Calibrate Assessment Methods2021In: IABSE Congress Ghent 2021: Structural Engineering for Future Societal Needs / [ed] H.H. (Bert) Snijder, Bart De Pauw, Sander van Alphen, Movares, Pierre Mengeot, International Association for Bridge and Structural Engineering (IABSE) , 2021, p. 965-973Conference paper (Refereed)
    Abstract [en]

    In this paper, experiences on the development of an assessment method for existing bridges are presented. The method is calibrated using the results of full-scale testing to failure of a prestressed bridge in Sweden. To evaluate the key parameters for the structural response, measured by deflections, strains in tendons and stirrups and crack openings, a sensitivity study based on the concept of fractional factorial design is incorporated to the assessment. Results showed that the most significant parameters are related to the tensile properties of the concrete (tensile strength and fracture energy) and the boundary conditions. A finite element (FE) model in which the results of the sensitivity analysis were applied, was able to predict accurately the load-carrying capacity of the bridge and its failure mode. Two additional existing prestressed concrete bridges, that will be used to improve further the method, are also described, and discussed.

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  • 8.
    Bista, Dipen
    et al.
    Sintef Narvik AS, 8517 Narvik, Norway; Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway.
    Ulfberg, Adrian
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Lia, Leif
    Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway.
    Gonzalez-Libreros, Jaime
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Johansson, Fredrik
    KTH Royal Institute of Technology, 10044 Stockholm, Sweden.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Numerical parametric study on the influence of location and inclination of large-scale asperities on the shear strength of concrete-rock interfaces of small buttress dams2024In: Journal of Rock Mechanics and Geotechnical Engineering, ISSN 1674-7755Article in journal (Refereed)
    Abstract [en]

    When assessing the sliding stability of a concrete dam, the influence of large-scale asperities in the sliding plane is often ignored due to limitations of the analytical rigid body assessment methods provided by current dam assessment guidelines. However, these asperities can potentially improve the load capacity of a concrete dam in terms of sliding stability. Although their influence in a sliding plane has been thoroughly studied for direct shear, their influence under eccentric loading, as in the case of dams, is unknown. This paper presents the results of a parametric study that used finite element analysis (FEA) to investigate the influence of large-scale asperities on the load capacity of small buttress dams. By varying the inclination and location of an asperity located in the concrete-rock interface along with the strength of the rock foundation material, transitions between different failure modes and correlations between the load capacity and the varied parameters were observed. The results indicated that the inclination of the asperity had a significant impact on the failure mode. When the inclination was 30° and greater, interlocking occurred between the dam and foundation and the governing failure modes were either rupture of the dam body or asperity. When the asperity inclination was significant enough to provide interlocking, the load capacity of the dam was impacted by the strength of the rock in the foundation through influencing the load capacity of the asperity. The location of the asperity along the concrete-rock interface did not affect the failure mode, except for when the asperity was located at the toe of the dam, but had an influence on the load capacity when the failure occurred by rupture of the buttress or by sliding. By accounting for a single large-scale asperity in the concrete-rock interface of the analysed dam, a horizontal load capacity increase of 30%–160% was obtained, depending on the inclination and location of the asperity and the strength of the foundation material.

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  • 9.
    Caddemi, S.
    et al.
    Department of Civil Engineering and Architecture, University of Catania, Via Santa Sofia 64, 95125 Catania, Italy.
    Caliò, I.
    Department of Civil Engineering and Architecture, University of Catania, Via Santa Sofia 64, 95125 Catania, Italy.
    Cannizzaro, F.
    Department of Civil Engineering and Architecture, University of Catania, Via Santa Sofia 64, 95125 Catania, Italy.
    Rapicavoli, D.
    Department of Civil Engineering and Architecture, University of Catania, Via Santa Sofia 64, 95125 Catania, Italy.
    Simoncello, N.
    Department of Civil, Environmental and Architectural Engineering, University of Padua, Via Marzolo 9, 35131 Padua, Italy.
    Zampieri, P.
    Department of Civil, Environmental and Architectural Engineering, University of Padua, Via Marzolo 9, 35131 Padua, Italy.
    Gonzalez-Libreros, Jaime
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Pellegrino, C.
    Department of Civil, Environmental and Architectural Engineering, University of Padua, Via Marzolo 9, 35131 Padua, Italy.
    Numerical Modelling of Masonry Arches Strengthened with SFRM2021In: 12th International Conference on Structural Analysis of Historical Constructions (SAHC 2021) / [ed] P. Roca; L. Pelà; C. Molins, International Center for Numerical Methods in Engineering (CIMNE), 2021, p. 2612-2619Conference paper (Refereed)
    Abstract [en]

    The adoption of effective strengthening techniques of historical constructions is one of the most widely debated aspects in structural engineering. Within this topic, the application of steel fiber reinforced mortar (SFRM) has been recently proposed as a low invasive and effective way to obtain a considerable structural benefit in the safety of existing masonry structure. To this purpose, in this paper the experimental results obtained on a circular masonry arches are presented. The considered specimens, subjected to a vertical increasing static load, is tested in the unstrengthened and strengthened configurations, and is part of a wider experimental campaign. After presenting and discussing the experimental results, they are compared with those relative to numerical simulations conducted by means of a discrete macroelement (DME) strategy, based on a simple mechanical scheme, able to model the nonlinear behavior of masonry structures with a limited computational effort. Such an approach is here extended to model the SFRM strengthening technique accounting for the main failure mechanisms associated to the combined presence existing masonry and the additional strengthening layer applied at the intrados of the arch. Numerical and experimental results demonstrate the efficacy of the proposed retrofitting strategy both in terms of bearing capacity and increase of ductility.

  • 10.
    Cao, Jie
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Wang, Chao
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Wang, Tongfang
    Southeast University, Nanjing, China.
    Gonzalez-Libreros, Jaime
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Tu, Yongming
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. Southeast University, Nanjing, China.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Effects of Temperature and NaCl Concentration on the Adsorption of C-S-H Gel in Cement Paste: A Multi-fidelity Molecular Dynamics Simulation2023In: Building for the Future: Durable, Sustainable, Resilient - Proceedings of the fib Symposium 2023 - Volume 2 / [ed] Alper Ilki, Derya Çavunt, Yavuz Selim Çavunt, Springer, 2023, Vol. 2, p. 499-508Conference paper (Refereed)
    Abstract [en]

    The durability and compressive strength of concrete will vary with the material components, ambient temperature, external intrusion. Using molecular dynamics (MD) methods to study the dynamic behavior of particles in cement-based materials can help us understand the underlying mechanism of property changes in concrete caused by above factors at the atomic level. So far, MD methods have been widely used to analyze the physical and chemical properties of concrete materials and the interaction mechanism between different interfaces at the nanoscale. However, too much complexity in the models will reduce the result accuracy and increase the computational cost. A suitable neural network structure can not only ensure the accuracy of analysis results, but also reduce the computational cost. In this work, MD methods are applied to build the models to explore the diffusivity of Na+ and Cl− in the calcium silicate hydrate (C-S-H) gel pores at different concentration and temperatures. In the process of running models, part of the MD models’ fidelity is reduced to save the computational cost, then the trained multi-fidelity physics informed neural network framework was used to obtain more accurate analysis results. The combination of MD simulations and deep learning methods expands the application range of MD in the field of concrete structure, has good development prospect and application value.

  • 11.
    Coric, Vedad
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Wang, Chao
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Gonzalez, Jaime
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Modelling temperature impact on sensor data in prestressed concrete bridges2024In: Bridge Maintenance, Safety, Management, Digitalization and Sustainability / [ed] Jens S Jensen, Dan M Frangopol, Jacob W Schmidt, CRC Press, 2024, p. 921-928Conference paper (Refereed)
    Abstract [en]

    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.

  • 12.
    Daescu, Cosmin Al
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. Politehnica University Timisoara, Timisoara, Romania.
    Gonzalez-Libreros, Jaime
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Wang, Chao
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Demolition of a 65-year-old box-girder prestressed concrete bridge located in Northern Sweden2023In: EuroStruct 2023 European Association on Quality Control of  Bridges and Structures: Digital Transformation in Sustainability / [ed] Alfred Strauss; Konrad Bergmeister, John Wiley & Sons, 2023, p. 229-234Conference paper (Refereed)
    Abstract [en]

    A new bridge was built in Kalix, northern Sweden, to replace an existing prestressed concrete box-girder bridge that had been in service for over 60 years. The old bridge had a total length of 283.6 m divided into five spans: 43.9 m, 47.0 m, 94.0 m, 47.0 m, and 43.9 m. It was constructed using the balanced cantilever method with segments having lengths of around 3.0 m. The need for replacement arose from recommendations extracted from an assessment of the old bridge's state and capacity. In addition to the construction of the new bridge, its replacement necessitated the creation and evaluation of demolition procedure for the existing bridge. This procedure had to be carefully designed to avoid damaging the new bridge and stability-related issues but also to prevent debris from falling into the Kalix River, which is part of a Natura 2000 protected area. This paper discusses various issues considered while developing the demolition strategy, including the use of bed-rock anchored tendons, intermediate support fixing at specific locations, and proper evaluation of position of the demolition equipment supported by the bridge, among others. The problem of disposing of the demolished material is also discussed.

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  • 13.
    Daescu, Cosmin
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. Politehnica University of Timisoara, Timisoara, Romania.
    Lundin, Hanna
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sarmiento Nova, Silvia Juliana
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Gonzalez-Libreros, Jaime H.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Study of demolition strategies and preliminary plan for the case of the Kalix bridge2022In: Bridge Safety, Maintenance, Management, Life-Cycle, Resilience and Sustainability: Proceedings of the Eleventh International Conference on Bridge Maintenance, Safety and Management (IABMAS 2022), Barcelona, Spain, July 11-15, 2022 / [ed] Joan-Ramon Casas; Dan M. Frangopol; Jose Turmo, Taylor & Francis, 2022, p. 2396-2403Conference paper (Refereed)
  • 14.
    Das, Oisik
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Babu, Karthik
    Department of Mechanical Engineering, Assam Energy Institute, Centre of Rajiv Gandhi Institute of Petroleum Technology, Sivasagar, 785697, Assam, India.
    Shanmugam, Vigneshwaran
    Department of Mechanical Engineering, Saveetha School of Engineering, Saveetha Institute of Medical and Technical Sciences, Chennai, 602 105, Tamilnadu, India.
    Sykam, Kesavarao
    Polymers & Functional Materials Division, Indian Institute of Chemical Technology, Uppal Road, Tarnaka, Hyderabad, 500007, Telangana, India.
    Tebyetekerwa, Mike
    School of Chemical Engineering, The University of Queensland, St Lucia, Brisbane 4072, Australia.
    Neisiany, Rasoul Esmaeely
    Department of Materials and Polymer Engineering, Faculty of Engineering, Hakim Sabzevari University, Sabzevar, 9617976487, Iran.
    Försth, Michael
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Gonzalez-Libreros, Jaime
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Capezza, Antonio J.
    Department of Fibre and Polymer Technology, Polymeric Materials Division, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, Stockholm, 100 44, Sweden.
    Hedenqvist, Mikael S.
    Department of Fibre and Polymer Technology, Polymeric Materials Division, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, Stockholm, 100 44, Sweden.
    Berto, Filippo
    Department of Mechanical Engineering, Norwegian University of Science and Technology, Trondheim, 7491, Norway.
    Ramakrishna, Seeram
    Center for Nanofibres and Nanotechnology, Department of Mechanical Engineering, Faculty of Engineering, Singapore, 117576, Singapore.
    Natural and industrial wastes for sustainable and renewable polymer composites2022In: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 158, article id 112054Article in journal (Refereed)
    Abstract [en]

    By-products management from industrial and natural (agriculture, aviculture, and others) activities and products are critical for promoting sustainability, reducing pollution, increasing storage space, minimising landfills, reducing energy consumption, and facilitating a circular economy. One of the sustainable waste management approaches is utilising them in developing biocomposites. Biocomposites are eco-friendly materials because of their sustainability and environmental benefits that have comparable performance properties to the synthetic counterparts. Biocomposites can be developed from both renewable and industrial waste, making them both energy efficient and sustainable. Because of their low weight and high strength, biocomposite materials in applications such as automobiles can minimise fuel consumption and conserve energy. Furthermore, biocomposites in energy-based applications could lead to savings in both the economy and energy consumption. Herein, a review of biocomposites made from various wastes and their related key properties (e.g. mechanical and fire) are provided. The article systematically highlights the individual wastes/by-products from agriculture and materials processing industries for composites manufacturing in terms of their waste components (materials), modifications, resultant properties, applications and energy efficiency. Finally, a perspective for the future of biowastes and industrial wastes in polymer composites is discussed.

  • 15.
    Eriksson, Alex
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Ullrich, Anita
    The Fraunhofer-Chalmers Research Centre for Industrial Mathematics, Gothenburg, Sweden.
    Wang, Chao
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Gonzalez-Libreros, Jaime
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Johansson, Johan
    Trafikverket, Swedish Transport Administration, Gothenburg, Sweden.
    Enoksson, Ola
    Trafikverket, Swedish Transport Administration, Luleå, Sweden.
    Quist, Johannes
    The Fraunhofer-Chalmers Research Centre for Industrial Mathematics, Gothenburg, Sweden.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Numerical and Analytical Evaluation of Load Distribution Patterns on Ballasted Concrete Railway Bridges2023In: Building for the Future: Durable, Sustainable, Resilient - Proceedings of the fib Symposium 2023 - Volume 2 / [ed] Alper Ilki, Derya Çavunt, Yavuz Selim Çavunt, Springer, 2023, Vol. 2, p. 109-118Conference paper (Refereed)
    Abstract [en]

    A significant portion of the reinforced concrete railway bridges in Sweden is reaching its designed lifespan and is scheduled to be demolished and replaced in the upcoming years. To limit the economic and environmental impact related to the replacement of this existing railway infrastructure, a comprehensive evaluation of their capacity is required with the aim of extending its lifespan. Experimental evidence has shown that some of these bridges may have a higher capacity than previously determined due to the conservative assumptions used during their design. The proper stress distribution pattern at the ballast-concrete interface is among the factors that need to be studied, as research on the topic has shown that some of the available guidelines to calculate it can produce conservative results. In this paper, available analytical models for computing the forces in concrete bridges due to train axle loads are compared to numerical models calibrated using the experimental results obtained from the test of ballasted reinforced concrete trough bridge, a typical structural type found in Sweden. As a first step, a literature review of existing numerical modeling strategies for ballasted concrete railway structures (e.g., finite element models, discrete element models, and their combination) is conducted. Then, appropriate numerical modelling strategies are identified and used to develop the numerical model of the bridge, including the ballast. Finally, results of contact pressure and vertical stresses in the numerical models are compared to those obtained analytically.

  • 16.
    Gonzalez-Libreros, Jaime H.
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Wang, Chao
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Agredo, Angelica
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sarmiento, Silvia
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Tu, Yongming
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. School of Civil Engineering, Southeast University, Nanjing, P.R., China.
    Daescu, Cosmin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. Politehnica University of Timisoara, Timisoare, Romania.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Development of a bridge load test procedure for low temperature conditions2022In: Bridge Safety, Maintenance, Management, Life-Cycle, Resilience and Sustainability: Proceedings of the Eleventh International Conference on Bridge Maintenance, Safety and Management (IABMAS 2022), Barcelona, Spain, July 11-15, 2022 / [ed] Joan-Ramon Casas; Dan M. Frangopol; Jose Turmo, Taylor & Francis, 2022, p. 576-583Conference paper (Refereed)
  • 17.
    Gonzalez-Libreros, Jaime
    et al.
    Department of Civil, Environmental and Architectural Engineering, University of Padua, Italy.
    Sabau, Cristian
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sneed, Lesley H.
    Department of Civil, Architectural, and Environmental Engineering, Missouri University of Science and Technology, Rolla, MO, USA.
    Pellegrino, Carlo
    Department of Civil, Environmental and Architectural Engineering, University of Padua, Italy.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. Department of Infrastructure, Materials and Structural Engineering, Northern Research Institute (NORUT), Narvik, Norway.
    Confinement of concrete elements with FRCM composites: What do we know so far?2018In: SP-327: The 13th International Symposium on Fiber-Reinforced Polymer Reinforcement for Concrete Structures / [ed] Raafat El-Hacha; Maria Lopez de Murphy; William J. Gold; Lijuan Cheng, American Concrete Institute , 2018, p. 307-325, article id 327-19Conference paper (Other academic)
  • 18.
    Hermosilla Carrasco, Carlos
    et al.
    Acciona, Madrid, Spain.
    García Farré, Alfredo
    Acciona, Madrid, Spain.
    Gonzalez-Libreros, Jaime
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Wang, Chao
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Carolin, Anders
    Swedish Road Administration Trafikverket, Boden, Sweden.
    Kjellman, Jouko
    Finnish Traffic Information Agency, Oulu, Finland.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Shear strengthening of a concrete trough bridge using embedded through-section (ETS) FRP bars2023In: EuroStruct 2023 European Association on Quality Control of Bridges and Structures: Digital Transformation in Sustainability / [ed] Alfred Strauss; Konrad Bergmeister, John Wiley & Sons, 2023, p. 1006-1013Conference paper (Refereed)
    Abstract [en]

    As worldwide infrastructure is ageing, significant efforts have been paid to the development of strengthening techniques that will restore or increase the initial capacity of existing structures. Considering that it is expected that shear failure happens in a less ductile mode than that observed under bending actions, special attention has been devoted to shear strengthening methods. These methods included externally bonded fiber reinforced polymers (EB-FRP), near-surface mounted (NSM-FRP) method, and the embedded trough-section (ETS) technique, among others. In this paper, ETS method is used for the strengthening in shear of a reinforced concrete railway bridge located in Finland. The ETS method consists in the embedment of FRP or steel bars through predrilled holes into the concrete core. The bars are bonded to the concrete using adhesives. The paper includes a brief review of recent advances in the use of ETS and comparison with other available techniques, the description of the case study, instrumentation of the bars using fiber optic sensors (FOS) for strain monitoring, the procedure used for the installation of the bars in the field, and a preliminary analysis of the data collected. 

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  • 19.
    Liu, Dongyun
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Tu, Yongming
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. School of Civil Engineering, Southeast University, P.R. China.
    Wang, Chao
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Gonzalez-Libreros, Jaime
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Zhang, Yu
    School of Civil Engineering, Southeast University, P.R. China.
    Resistance to salt-corrosion of concrete with externally bonded FRP sheets in marine environment2022In: Bridge Safety, Maintenance, Management, Life-Cycle, Resilience and Sustainability: Proceedings of the Eleventh International Conference on Bridge Maintenance, Safety and Management (IABMAS 2022), Barcelona, Spain, July 11-15, 2022 / [ed] Joan Ramon Casas; Dan M. Frangopol; Jose Turmo, Taylor & Francis, 2022, p. 2495-2502Conference paper (Refereed)
  • 20.
    Liu, Dongyun
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Wang, Chao
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Gonzalez, Jaime
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Enoksson, Ola
    Trafikverket.
    Höjsten, Tommy
    Trafikverket.
    Tu, Yongming
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. School of Civil Engineering, Southeast University.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Numerical simulation of train-induced aerodynamic pressure on railway noise barriers2023In: XII International Conference on Structural Dynamics, Delft, Netherlands, July 2-5, 2023., 2023Conference paper (Refereed)
    Abstract [en]

    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.

  • 21.
    Liu, Dongyun
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Wang, Chao
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Gonzalez, Jaime
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Mensah, Rhoda Afriyie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Försth, Michael
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Das, Oisik
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Tu, Yongming
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. School of Civil Engineering, Southeast University, Nanjing, 211189, China.
    Correlation between early- and later-age performance indices of early frost-damaged concrete2022In: IABSE Symposium Prague 2022: Challenges for Existing and Oncoming Structures - Report, International Association for Bridge and Structural Engineering / [ed] František Wald, Pavel Ryjáček, International Association for Bridge and Structural Engineering, 2022, p. 934-941Conference paper (Refereed)
    Abstract [en]

    Freeze‐thaw cycles can lead to serious damage of early‐age concrete and influence its behaviour at later ages. In this study, the later‐age compressive strength, resistance to chloride penetration and resistance to freeze‐thaw of early frost‐damaged concrete were experimentally studied and the relationship between its early‐ (i.e., strength and resistivity) and later‐age (i.e., strength, chloride ion electric flux and freeze‐thaw durability factor) performance indices were analysed. Results show that the later‐age performance of the concrete subjected to freeze‐thaw cycles at early age was generally worse than that of the control samples, which had not undergone early frost damage. This was especially significant for the concrete subjected to freeze‐thaw cycles before the age of 24 h. The compressive strength after early frost action had a higher linear correlation with the later‐age indices of the concrete than the compressive strength before early frost action. Results also showed that the early‐age resistivity is a good indicator for the later‐age performance of early frost‐damaged concrete if the pre‐curing time before frosting is at least 24 h. 

  • 22.
    Liu, Dongyun
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Wang, Chao
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Gonzalez, Jaime
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Tu, Yongming
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Enoksson, Ola
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. Trafikverket.
    Höjsten, Tommy
    Trafikverket.
    FEM-based dynamic analysis of noise barriers under train-induced aerodynamic load2024In: Bridge Maintenance, Safety, Management and Sustainability / [ed] J S Jensen, D Frangopol, J W Schmidt, CRC Press, 2024, p. 3817-3824Conference paper (Refereed)
    Abstract [en]

    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.

  • 23.
    Liu, Dongyun
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Wang, Chao
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Gonzalez-Libreros, Jaime
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Enoksson, Ola
    Trafikverket, Luleå, Sweden.
    Hojsten, Tommy
    Trafikverket, Luleå, Sweden.
    Tu, Yongming
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. Southeast University, Nanjing, China.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Numerical Analysis of High-Speed Train Induced Aerodynamic Load on Noise Barrier Considering Wind Effect2023In: Building for the Future: Durable, Sustainable, Resilient - Proceedings of the fib Symposium 2023 - Volume 2 / [ed] Alper Ilki, Derya Çavunt, Yavuz Selim Çavunt, Springer, 2023, Vol. 2, p. 332-341Conference paper (Refereed)
    Abstract [en]

    Along the high-speed railway lines, the noise barriers need to be installed to protect nearby inhabitants from noise pollution caused by the running trains. When a high-speed train passes through the noise barriers, due to the blocking effect of noise barrier on air movement, transient train-induced aerodynamic pressure will increase significantly. Field measurement and computational fluid dynamics (CFD) simulation are main ways to study the train-induced aerodynamic pressure on the noise barriers. Due to the complexity of the environmental conditions in field test, however, it is difficult to take into account the wind effects on measurement results. Based on CFD simulation, in this paper, the aerodynamic effects on noise barrier from high-speed trains was simulated by applying the wind flow in the opposite direction to the train running. Influences of train speed and distance from noise barrier to track centre on such aerodynamic pressure were analysed. In addition, by applying the wind flow perpendicular to the longitudinal of train body, the effect of cross wind on the train-induced aerodynamic pressure was evaluated. Results show that pressure magnitude on the noise barriers increases non-linearly with the train speed. There is good nonlinear relationship between the pressure and the square of the distance to track centre. Cross wind increases the magnitude of positive pressure and makes the duration of high-pressure zone longer and absolute value of negative pressure peak decreases. There is a coupling effect of cross wind effect and train-induced aerodynamic effect on noise barriers. 

  • 24.
    Liu, Dongyun
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Wang, Chao
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Gonzalez-Libreros, Jaime
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Guo, Tong
    Key Laboratory of Concrete and Prestressed Concrete Structures of Ministry of Education, National Engineering Research Center for Prestressing Technology, School of Civil Engineering, Southeast University, 211189 Nanjing, P.R. China.
    Cao, Jie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Tu, Yongming
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. Key Laboratory of Concrete and Prestressed Concrete Structures of Ministry of Education, National Engineering Research Center for Prestressing Technology, School of Civil Engineering, Southeast University, 211189 Nanjing, P.R. China.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. SINTEF Narvik AS, Narvik 8517, Norway.
    A review of concrete properties under the combined effect of fatigue and corrosion from a material perspective2023In: Construction and Building Materials, ISSN 0950-0618, E-ISSN 1879-0526, Vol. 369, article id 130489Article, review/survey (Refereed)
    Abstract [en]

    When in use, reinforced concrete bridge structures not only experience high-frequency fatigue loading caused by passing vehicles, but also suffer from the effects of a corrosive environment. In addition to fatigue damage to reinforcement, long-term fatigue loading also causes concrete cracking and deterioration of pore structures, thereby accelerating the ingress of external corrosive substances and reducing concrete durability. Long-term exposure to a corrosive environment also reduces the performance of concrete and causes corrosion of reinforcement materials, affecting the fatigue performance of the structure. Therefore, there is a combined effect between fatigue loads and corrosion on concrete. This paper is a review of the current literature from a material perspective on the performance degradation of concrete under the combined action of fatigue loading and corrosion, that is, carbonation, chloride ion attack, freeze–thaw cycles, and sulphate attack. The paper includes (1) a description of a test method for examining the combined action of fatigue loading and corrosion, (2) a summary of performance degradation of concrete under the combined effect of fatigue loading and corrosion, and (3) an introduction to durability deterioration models considering fatigue damage, and fatigue models that can account for corrosion. Finally, potential future research on concrete under the combined effect of fatigue loading and corrosion is described.

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  • 25.
    Liu, Dongyun
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Wang, Chao
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Gonzalez-Libreros, Jaime
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Tu, Yongming
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. Key Laboratory of Concrete and Prestressed Concrete Structures of Ministry of Education, National Engineering Research Center for Prestressing Technology, School of Civil Engineering, Southeast University, 211189, Nanjing, PR China.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    A review on aerodynamic load and dynamic behavior of railway noise barriers when high-speed trains pass2023In: Journal of Wind Engineering and Industrial Aerodynamics, ISSN 0167-6105, E-ISSN 1872-8197, Vol. 239, article id 105458Article in journal (Refereed)
    Abstract [en]

    Noise barriers need to be installed along high-speed railway lines to protect nearby inhabitants from the noise pollution caused by the running of high-speed trains (HSTs). The vertical noise barrier is the main structural type. However, when an HST passes through the noise barriers sited along the track, significant and transient aerodynamic pressure will act on the surface of the noise barriers, resulting in strong dynamic responses and even fatigue damage. Therefore, it is important to determine the train-induced aerodynamic load on the barrier surface and analyze the dynamic behaviors of the noise barriers under such a load for its structural design and to guarantee its safety and durability. This paper is a systematic review of the current literature on the aerodynamic load and dynamic behavior of vertical noise barriers; it includes (1) a summary and analysis of characteristics of such aerodynamic pressure and relevant influencing factors, (2) an introduction to measurement methods of aerodynamic load and relevant pressure models on the surface of noise barriers, and (3) a description of the dynamic response and fatigue analysis of noise barriers under such loads. Finally, potential further studies on this topic are discussed, and conclusions are drawn.

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  • 26.
    Liu, Dongyun
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Wang, Chao
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Gonzalez-Libreros, Jaime
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Tu, Yongming
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. Key Laboratory of Concrete and Prestressed Concrete Structures of Ministry of Education, National Engineering Research Center for Prestressing Technology, School of Civil Engineering, Southeast University, 211189, Nanjing, PR China.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Modified calculation model of train-induced aerodynamic pressure on vertical noise barriers considering the train geometry effect2024In: Journal of Wind Engineering and Industrial Aerodynamics, ISSN 0167-6105, E-ISSN 1872-8197, Vol. 249, article id 105750Article in journal (Refereed)
    Abstract [en]

    High-speed trains (HSTs) generate air disturbance, leading to significant aerodynamic pressure on the noise barriers. Differences in train geometry result in variations in the aerodynamic pressure on noise barriers, implying that existing European standard calculation models may not necessarily be suitable for all types of HSTs. In this paper, the influence of the width, height, and nose length of the train on the aerodynamic pressure on vertical noise barriers was studied using computational fluid dynamics (CFD) simulations. Results showed that taller and wider trains result in greater aerodynamic loads on noise barriers. Conversely, an increase in the nose length of a train leads to a reduction in such pressure. Using grey relational analysis, correlation of various factors with the train-induced aerodynamic pressure is, from strong to weak: distance to the track center, width, height, and nose length of the train. Building upon the EN 14067-4 calculation model, the shape coefficients of trains with varying geometric characteristics were derived using the simulation data obtained in this study. A modified pressure calculation model was established accounting for the differences in geometric features of HSTs and pressure distribution in the vertical direction of noise barriers and validated using relevant data from the literature.

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  • 27.
    Liu, Dongyun
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. Key Laboratory of Concrete and Prestressed Concrete Structures of Ministry of Education, National Engineering Research Center for Prestressing Technology, School of Civil Engineering, Southeast University, Nanjing, PR China.
    Wang, Chao
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Guo, Tong
    Key Laboratory of Concrete and Prestressed Concrete Structures of Ministry of Education, National Engineering Research Center for Prestressing Technology, School of Civil Engineering, Southeast University, Nanjing, PR China.
    Gonzalez-Libreros, Jaime
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Ge, Yuanfei
    Key Laboratory of Concrete and Prestressed Concrete Structures of Ministry of Education, National Engineering Research Center for Prestressing Technology, School of Civil Engineering, Southeast University, Nanjing, PR China.
    Tu, Yongming
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. Key Laboratory of Concrete and Prestressed Concrete Structures of Ministry of Education, National Engineering Research Center for Prestressing Technology, School of Civil Engineering, Southeast University, Nanjing, PR China.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Time–depth dependent chloride diffusion coefficient of self-compacting concrete2024In: Magazine of Concrete Research, ISSN 0024-9831, E-ISSN 1751-763X, Vol. 76, no 12, p. 600-616Article in journal (Refereed)
  • 28.
    Mirzazade, Ali
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Popescu, Cosmin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. SINTEF Narvik AS, 8517 Narvik, Norway.
    Gonzalez-Libreros, Jaime
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Blanksvärd, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Täljsten, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Semi-autonomous inspection for concrete structures using digital models and a hybrid approach based on deep learning and photogrammetry2023In: Journal of Civil Structural Health Monitoring, ISSN 2190-5452, Vol. 13, no 8, p. 1633-1652Article in journal (Refereed)
    Abstract [en]

    Bridge inspections are relied heavily on visual inspection, and usually conducted within limited time windows, typically at night, to minimize their impact on traffic. This makes it difficult to inspect every meter of the structure, especially for large-scale bridges with hard-to-access areas, which creates a risk of missing serious defects or even safety hazards. This paper presents a new technique for the semi-automated damage detection in tunnel linings and bridges using a hybrid approach based on photogrammetry and deep learning. The first approach involves using photogrammetry to reconstruct a 3D model. It is shown that a model with sub-centimeter accuracy can be obtained after noise removal. However, noise removal also reduces the point cloud density, making the 3D point cloud unsuitable for quantification of small-scale damages such as fine cracks. Therefore, the captured images are also analyzed using deep convolutional neural network (CNN) models to enable crack detection and segmentation. For this aim, in the second approach, the 3D model is generated by the output of CNN models to enable crack localization and quantification on 3D digital model. These two approaches were evaluated in separate case studies, showing that the proposed technique could be a valuable tool to assist human inspectors in detecting, localizing, and quantifying defects on concrete structures.

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  • 29.
    Saback, Vanessa
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Gonzalez‐Libreros, Jaime
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Daescu, Cosmin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. Politehnica University of Timisoara, Romania.
    Hojsten, Tommy
    Swedish Road Administration Trafikverket, Sweden.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Evaluation of the snow loads on the snow galleries on the Iron Ore Line in Northern Sweden2023In: ce/papers, ISSN 2509-7075, Vol. 6, no 5, p. 221-228Article in journal (Refereed)
    Abstract [en]

    The Iron Ore Line is a railway in northern Sweden and Norway, crucial for iron oretransportation. Snow galleries safeguard this route, ensuring uninterrupted trafficfor efficient operations. A snow gallery is a protective structure that shields roadsand railways from heavy snowfall and avalanches. Reported damages to these structures caused by excessive snow loads have prompted an investigation to preventfurther issues. This paper presents an analysis of the evolution of snow load calculations over time, though a comparison of Swedish design standards. The designsnow loads required by current standards have increased up to 60% from the initialregulations, depending on the location of the structure. Besides, climate change ispredicted to further increase snow loads due to more frequent winter precipitation,higher snow density, and extreme snowfall events. This analysis is part of a broaderresearch project involving numerical simulations, live monitoring, and a digital twinmonitoring system of some snow galleries in the Iron Ore Line. 

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  • 30.
    Saback, Vanessa
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Gonzalez-Libreros, Jaime
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Daescu, Cosmin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. Department of Civil Engineering and Installations (CCI), Politehnica University of Timisoara, Timisoara, Romania.
    Popescu, Cosmin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. SINTEF Narvik AS, Narvik, Norway.
    Garmabaki, Amir Soleimani
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Adapting to climate change: snow load assessment of snow galleries on the Iron Ore Line in Northern Sweden2024In: Frontiers in Built Environment, E-ISSN 2297-3362, Vol. 9Article in journal (Refereed)
    Abstract [en]

    The snow galleries along the Iron Ore railway line in northern Sweden have facedproblems in recent years due to increasingly large snow loads, and several gallerieshave been damaged. These incidents motivated an evaluation of the maximumload supported by the galleries before collapse, which is presented in this study. In2021, a monitoring system was installed in one of the main frames of two snowgalleries built in the 1950s to follow up with temperature and displacements,including a trigger that sends out a warning message when a critical load isreached. A literature review on snow loads was performed, followed bycalculations on snow distribution on the galleries based on the Eurocodes andNational Swedish Standards. Finite element 2D and 3D models were created usingAxisVM to accurately assess the efforts in the structural elements. Analysis anddiscussion are complemented by observations from site visits. It was concludedthat the critical loads supported by the galleries are lower than the requirements oftoday’s standards, but since secondary construction elements were damagedbefore the main frames reached their full capacity, no major collapse has yet takenplace. The cobweb effect (load re-distribution between the neighboring elementsin a 3D structure) influenced the behavior of the galleries in the 3D analysis and thecapacity of the main frames proved to be significantly increased compared to the2D assessment.

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  • 31.
    Saback, Vanessa
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Mirzazade, Ali
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Gonzalez, Jaime
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Blanksvärd, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Popescu, Cosmin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. SINTEF Narvik AS, Narvik, 8517, Norway.
    Täljsten, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Daescu, Cosmin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. Politehnica University of Timisoara, Romania.
    Petersson, Mats
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Crack monitoring by fibre optics and image correlation: a pilot study2022In: IABSE Symposium Prague, 2022: Challenges for Existing and Oncoming Structures, Report, International Association for Bridge and Structural Engineering, 2022, p. 437-444, article id O-048Conference paper (Refereed)
    Abstract [en]

    As reinforced concrete structures reach the end of their design lives, technology for improving accuracy and efficiency of inspections and structural health monitoring rapidly progresses. Concrete cracking and reinforcement strains are two relevant parameters in assessing damage and safety ofthese structures. The use of Digital Image Correlation (DIC) systems and distributed Fibre Optic Sensors (FOS) to evaluate these parameters are two of the technologies that have been gaining momentum due to their advantages over other approaches. This study presents an experimental investigation of crack propagation of a reinforced concrete beam specimen through FOS and DIC.The FOS were positioned inside a groove carved in the rebar and in the concrete immediately outside the bar for comparison. The results showed a significant difference between both positions, with more reliable data coming from inside the bar. The addition of the DIC crack propagation images to the FOS analysis complemented the results, and good visual correlation was identified between both methods. This study is part of a broader research program, which aims at applying DIC and FOS for structural health monitoring of a real scale bridge structure.

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  • 32.
    Sarmiento Nova, Silvia J.
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Gonzalez-Libreros, Jaime
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. SINTEF Narvik AS, Narvik, Norway.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Coric, Ibrahim
    Trafikverket, Luleå, Sweden.
    Enoksson, Ola
    Trafikverket, Luleå, Sweden.
    Metamodel-Based Reliability Assessment of Reinforced Concrete Beams Under Fatigue Loads2021In: Proceedings of the 1st Conference of the European Association on Quality Control of Bridges and Structures / [ed] Carlo Pellegrino, Flora Faleschini, Mariano Angelo Zanini, José C. Matos, Joan R. Casas, Alfred Strauss, Springer, 2021, Vol. 200, p. 84-92Conference paper (Refereed)
    Abstract [en]

    It is well-known that highway bridges are frequently under cyclic load; therefore, deterioration due to fatigue is one of the most important phenomena to be analyzed when determining a bridge safety margin. This paper studies how uncertainties related to fatigue models for concrete structures affect reinforced concrete element’s reliability, and the critical parameters in fatigue damage are investigated. To this end, a metamodel-based method is described and used to calculate the probability of failure and reliability index values of an application example. Metamodel-based methods have become an essential and efficient tool to determine structural safety as the possibility to decrease the computational cost and couple the reliability approach with nonlinear finite element analysis (NLFEA) allows a better estimation of structural reliability. Results show how the proposed method can reduce the computational cost of traditional reliability simulation methods, maintaining a good accuracy. 

  • 33.
    Sarmiento Nova, Silvia J.
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Gonzalez-Libreros, Jaime
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. SINTEF Narvik AS, Rombaksveien E6-47, N-8517 Narvik, Norway.
    Sanabria Díaz, Rafael A.
    University of Campinas, Campinas, Brazil.
    Texeira da Silva, Maria C. A.
    University of Campinas, Campinas, Brazil.
    Trautwein, Leandro M.
    University of Campinas, Campinas, Brazil.
    Response Surface Method strategies coupled with NLFEA for structural reliability analysis of prestressed bridges2021In: IABSE Congress Ghent 2021: Structural Engineering for Future Societal Needs / [ed] H. H. (Bert) Snijder; Bart De Pauw; Sander van Alphen; Pierre Mengeot, International Association for Bridge and Structural Engineering (IABSE) , 2021, p. 1813-1822Conference paper (Refereed)
    Abstract [en]

    The Response Surface Method (RSM) has become an essential tool to solve structural reliability problems due to its accuracy, efficacy, and facility for coupling with Nonlinear Finite Element Analysis (NLFEA). In this paper, some strategies to improve the RSM efficacy without compromising its accuracy are tested. Initially, each strategy is implemented to assess the safety level of a highly nonlinear explicit limit state function. The strategy with the best results is then identified and used to carry out a reliability analysis of a prestressed concrete bridge, considering the nonlinear material behavior through NLFEA simulation. The calculated value of 𝛽 is compared with the target value established in Eurocode for ULS. The results showed how RSM can be a practical methodology and how the improvements presented can reduce the computational cost of a traditional RSM giving a good alternative to simulation methods such as Monte Carlo. 

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  • 34.
    Sarmiento Nova, Silvia J.
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Gustafsson, Jacob
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Åkergren, David
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Gonzalez-Libreros, Jaime H.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Coric, Ibrahim
    Trafikverket, Luleå, Sweden.
    Enoksson, Ola
    Trafikverket, Luleå, Sweden.
    Pressure Distribution Patterns Between the Ballast and the Concrete Slab in Railway Trough Bridges2021In: Proceedings of the 31st European Safety and Reliability Conference and (ESREL 2021) / [ed] Bruno Castanier; Marko Cepin; David Bigaud; Christophe Berenguer, Research Publishing (S) Pte Ltd. , 2021, p. 1093-1100Conference paper (Refereed)
    Abstract [en]

    In Sweden, a substantial amount of railway bridges is approaching their intended lifespans and are planned to be replaced. However, it is not sustainable neither from a financial nor an environmental perspective to replace these bridges if they are still sound and safe. Thus, an evaluation of their actual capacity is required with the aim of extending their lifespans. A way to obtain a more accurate capacity is to determine the loads that are acting on them. Available literature points out the lack of experimental investigations on sleeper-ballast contact pressure, as well as on the stress distribution along and across the ballast. Consequently, railway bridge design has been based on traditional rather than rational assumptions, which can be quite conservative. In this paper, a review of models is carried out for evaluating stress patterns on the surface of the slab on ballasted concrete bridges. Then, a simplified finite element model of a concrete trough bridge, a common type of structure in Sweden, is used in a parametric analysis aimed to understand how the identified pressure distribution patterns affect the performance of this type of structure. Finally, with the purpose of studying how some parameters influence the bridge safety, a probabilistic reliability analysis is used. The reliability index beta (b) is obtained using the polynomial response surface method and its value is compared for different boundary condition scenarios. Also, the sensitivity factors for the considered random variables are compared and analyzed. Results show that the assumption of support condition and pressure pattern has a significant impact on the capacity, failure mode and probability of failure of this type of structure.

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  • 35.
    Sarmiento Nova, Silvia Juliana
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Gonzalez-Libreros, Jaime H.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Thöns, S.
    Lund University, Lund, Sweden.
    Björnsson, I.
    Lund University, Lund, Sweden.
    Díaz, R. S.
    University of Campinas, Campinas, Brazil.
    A risk-based robustness evaluation of a prestressed concrete bridge2022In: Bridge Safety, Maintenance, Management, Life-Cycle, Resilience and Sustainability: Proceedings of the Eleventh International Conference on Bridge Maintenance, Safety and Management (IABMAS 2022), Barcelona, Spain, July 11-15, 2022 / [ed] Joan-Ramon Casas; Dan M. Frangopol; Jose Turmo, Taylor & Francis, 2022, p. 2045-2052Conference paper (Other academic)
  • 36.
    Sarmiento, Silvia
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Gonzalez-Libreros, Jaime
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    An improved metamodel-based algorithm to assess reliability analysis of existing structures using FEM2023In: Article in journal (Other academic)
  • 37.
    Sarmiento, Silvia
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    González-Libreros, Jaime
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Andersson, Erik
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Petersson, Mats
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Validation of an Experimental Methodology for Measuring Concrete Fracture Energy in Existing Structures2023In: Building for the Future: Durable, Sustainable, Resilient - Proceedings of the Symposium 2023 - Volume 1 / [ed] Alper Ilki, Derya Çavunt, Yavuz Selim Çavunt, Springer Science and Business Media Deutschland GmbH , 2023, Vol. 1, p. 936-945Conference paper (Refereed)
    Abstract [en]

    Numerical modeling is often used to assess the load-carrying capacity of existing structures, especially for complex structural systems such as bridges. These numerical models are always sensitive to certain parameters, such as the mechanical properties of the materials. In the case of concrete structures, the tensile strength and fracture energy of concrete have demonstrated great influence in the numerical evaluation of deformations and capacity. However, for existing structures, the fracture energy value is mainly estimated using empirical formulae based on the concrete compressive strength, as there is no methodology to evaluate it experimentally. This issue leads to uncertainty regarding the obtained values and subsequently influences the results of finite element models (FEM) and capacity prediction. With the aim of reducing this uncertainty, an experimental methodology for the evaluation of the fracture energy in existing structures is validated in this paper. First, uniaxial tensile loading tests were carried out on notched standard cylinders and drilled cores specimens cast under laboratory conditions. Then, crack opening versus load curves and fracture energy values were compared to those obtained from three-point bending tests in notched beams and Finite Element Modeling. The results showed that the proposed methodology can be a potential method to estimate the fracture energy of existing structures, and the notch depth have an influence on the fracture energy value obtained.

  • 38.
    Sarmiento, Silvia
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Thöns, Sebastian
    Lund University, Sweden.
    Sanabria Díaz, Rafael Andrés
    University of Campinas.
    Björnsson, Ivar
    Lund University, Sweden.
    Gonzalez, Jaime
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    COMPARISON AND JOINT EVALUATION OF IMPORTANCE, REDUNDANCY AND ROBUSTNESS INDICATORS APPLIED TO AGING PRESTRESSED CONCRETE BRIDGES2024Article in journal (Other academic)
    Abstract [en]

    The use of an adequate approach to assess and design large-scale structures, such as bridges, may prevent early structure failures and provide economical solutions throughout the service life. 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 properly 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; however, they 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. This points out the necessity to create more uniform formulations and to agree on target values that can help with the redundancy and robustness interpretation.

  • 39.
    Sarmiento, Silvia
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Åkergren, David
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Gustafsson, Jacob
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Gonzalez, Jaime
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Coric, Ibrahim
    Trafikverket, Luleå, Sweden.
    Enoksson, Ola
    Trafikverket, Luleå, Sweden.
    A Parametric Study of an old Concrete Trough Bridge using non-linear Finite Element analysis2022In: IABSE Symposium Prague 2022: Challenges for Existing and Oncoming Structures - Report, International Association for Bridge and Structural Engineering, International Association for Bridge and Structural Engineering, 2022, p. 1652-1659Conference paper (Refereed)
    Abstract [en]

    At least 20% of existing railway bridges in Sweden are reinforced concrete (RC) trough bridge that consist in a slab carried by two longitudinal main beams. As these bridges are getting old, there is an urging need to assess their remaining capacity with the aim of prolonging their service lives. The limited literature on the topic has pointed out that there is a significant difference between the capacity predicted by available codes and that obtained experimentally. In this paper, a review of the Bridge and Tunnel Management database (BaTMan) of railway infrastructure in Sweden, is carried out to gain an overview of the current state of the Swedish railway bridge, with focus on trough bridges. Then, a non-linear finite element model is calibrated using the experimental results of the previous testing of a decommissioned trough bridge. The model is used in a parametric study where the effect of key mechanical parameters on the capacity of trough bridges is studied. 

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  • 40.
    Sas, Gabriel
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Gonzalez, Jaime
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Gamla bron över Kalix Älv – Kalibrering av mät- och analysmetoder2022In: Bygg & Teknik, ISSN 0281-658X, no 4Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    För att optimera underhållet av befintliga broar är det viktigt att kalibrera de mät- och analysmetoder som används för att värdera broarnas kondition och bärighet. I samband byggandet av en ny bro för E4 över Kalix älv har ett tillfälle givits att utvärdera och kalibrera mät- och analysmetoder på den gamla bron från 1957 innan den rivs. I projektet deltar Trafikverket, entreprenören NCC och forskare från Danmark, Norge, Finland och från Sveriges Bygguniversitet (LTH, Chalmers, KTH och LTU).

    The full text will be freely available from 2027-06-09 18:15
  • 41.
    Ulfberg, Adrian
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Gonzalez, Jaime
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Das, Oisik
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Malm, Richard
    Swedish Defence Research Agency, Stockholm, Sweden.
    Johansson, Fredrik
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Westberg Wilde, Marie
    AFRY, Stockholm, Sweden.
    On the applicability of scale model tests for concrete dams: A Review2023Conference paper (Other academic)
  • 42.
    Ulfberg, Adrian
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Gonzalez-Libreros, Jaime
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Das, Oisik
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Bista, Dipen
    Norwegian University of Science and Technology, Trondheim, Norway; SINTEF Narvik, Narvik, Norway.
    Westberg Wilde, Marie
    Division of Soil- and Rock Mechanics, KTH Royal Institute of Technology, Stockholm, Sweden; AFRY, Stockholm, Sweden.
    Johansson, Fredrik
    Division of Soil- and Rock Mechanics, KTH Royal Institute of Technology, Stockholm, Sweden.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Probabilistic finite element analysis of failures in concrete dams with large asperities in the rock–concrete interface2023In: Archives of Civil and Mechanical Engineering, E-ISSN 1644-9665, Vol. 23, no 2, article id 109Article in journal (Refereed)
    Abstract [en]

    Common analytical assessment methods for concrete dams are unlikely to predict material fracture in the dam body because of the assumption of rigid body behavior and uniform- or linear stress distribution along a predetermined failure surface. Hence, probabilistic non-linear finite element analysis, calibrated from scale model tests, was implemented in this study to investigate the impact of concrete material parameters (modulus of elasticity, tensile strength, compressive strength, fracture energy) on the ultimate capacity of scaled model dams. The investigated dam section has two types of large asperities, located near the downstream and/or upstream end of the rock–concrete interface. These large-scale asperities significantly increased the interface roughness. Post-processing of the numerical simulations showed interlocking between the buttress and the downstream asperity leading to fracture of the buttress with the capacity being determined mainly by the tensile strength of the buttress material. The capacity of a model with an asperity near the upstream side, with lower inclination, was less dependent on the material parameters of the buttress as failure occurred by sliding along the interface, even with inferior material parameters. Results of this study show that material parameters of the concrete in a dam body can govern the load capacity of the dam granted that significant geometrical variations in the rock–concrete interface exists. The material parameters of the dam body and their impact on the capacity with respect to the failure mechanism that developed for some of the studied models are not commonly considered to be decisive for the load capacity. Also, no analytical assessment method for this type of failure exists. This implies that common assessment methods may misjudge the capacity and important parameters for certain failure types that may develop in dams.

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  • 43.
    Ulfberg, Adrian
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Gonzalez-Libreros, Jaime
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Das, Oisik
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Andersson, Erik
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Bista, Dipen
    Norwegian University of science and technology, Trondheim, Norway; SINTEF Narvik, Narvik, Norway.
    Arntsen, Bård
    SINTEF Narvik, Narvik, Norway.
    Seger, Andreas
    SINTEF Narvik, Narvik, Norway; The Arctic University of Norway, Tromsø, Norway.
    Influence of large-scale asperities on the stability of concrete dams2022In: IABSE Symposium Prague, 2022: Challenges for Existing and Oncoming Structures - Report, International Association for Bridge and Structural Engineering (IABSE) , 2022, p. 1358-1365Conference paper (Refereed)
    Abstract [en]

    For concrete dams founded on rock, there are only a few options in the common analysis methods to account for large‐scale asperities. However, previous research alludes that they have a significant impact on the behaviour of interfaces under shear. This study investigates the behaviour of concrete dam scale models with varying interface geometries, under a realistic set of eccentric loads. The outcome of the scale model tests shows that not only the capacity of the scale models was significantly impacted by the asperities, but also the type of failure in the scale models.

  • 44.
    Wang, Chao
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Gonzalez, Jaime
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Daescu, Cosmin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. Politechnica University Timisoara, Romania.
    Enochsson, Ola
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. Trafikverket.
    Höjsten, Tommy
    Trafikverket.
    Development of proof loading method for railway bridges with masonry abutments2024In: Bridge Maintenance, Safety, Management, Digitalization and Sustainability / [ed] Jens S Jensen, Dan M Frangopol, Jacob W Schmidt, CRC Press, 2024, p. 399-408Conference paper (Refereed)
    Abstract [en]

    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. 

  • 45.
    Wang, Chao
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Gonzalez, Jaime
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Lu, Senlu
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. School of Civil Engineering, Southeast University, Nanjing, P.R, China.
    Tu, Yongming
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. School of Civil Engineering, Southeast University, Nanjing, P.R, China.
    Damage detection of steel truss bridge based on stacked auto-encoder2022In: Bridge Safety, Maintenance, Management, Life-Cycle, Resilience and Sustainability: Proceedings of the Eleventh International Conference on Bridge Maintenance, Safety and Management (IABMAS 2022), Barcelona, Spain, July 11-15, 2022 / [ed] Joan Ramon Casas; Dan M. Frangopol; Jose Turmo, Taylor & Francis, 2022, p. 1994-2001Conference paper (Refereed)
  • 46.
    Wang, Chao
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Zhang, Jiwen
    School of Civil Engineering, Southeast University, Nanjing, China; Key Laboratory of Concrete and Prestressed Concrete Structures of Ministry of Education, National Engineering Research Center for Prestressing Technology, School of Civil Engineering, Southeast University, Nanjing, China.
    Gonzalez-Libreros, Jaime
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Tu, Yongming
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. School of Civil Engineering, Southeast University, Nanjing, China; Key Laboratory of Concrete and Prestressed Concrete Structures of Ministry of Education, National Engineering Research Center for Prestressing Technology, School of Civil Engineering, Southeast University, Nanjing, China..
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    A quantitative residual stiffness model for carbon fiber reinforced polymer tendons2024In: Fatigue & Fracture of Engineering Materials & Structures, ISSN 8756-758X, E-ISSN 1460-2695, Vol. 47, no 6, p. 2068-2084Article in journal (Refereed)
    Abstract [en]

    In this study, tension-tension fatigue tests were conducted to investigate the residual stiffness degradation of carbon fiber-reinforced polymer (CFRP) tendons. Different stress levels were used in the tests, and measurements of residual stiffness and the number of loading cycles were taken. Based on experimental data for CFRP tendons, a quantitative residual stiffness model was developed by modifying Yao's model. This model is applicable to various stress levels. To assess its accuracy and applicability, the predicted results of this model were compared with those of cited models from other researchers. The findings revealed a three-stage degradation of residual stiffness in CFRP tendons under different stress levels. Furthermore, it was observed that the proportion of fatigue life accounted for by Stage III decreased with smaller stress ranges, while the proportion accounted for by Stage II increased. The proposed quantitative residual stiffness model was verified using both experimental and cited data. Tension-tension fatigue tests of CFRP tendons were conducted at various stress levels. A quantitative model was proposed based on the residual stiffness of the CFRP tendon. Stress level influence on stiffness degradation of composite material was discussed. Model accuracy was verified against experimental and cited data.

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    fulltext
  • 47.
    Sas, Gabriel (Editor)
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Gonzalez-Libreros, Jaime (Editor)
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Wang, Chao (Editor)
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Pinar, Mert (Editor)
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Condition Assessment of Existing Bridges: A Case Study of The Kalix Bridge2024Report (Other academic)
    Abstract [en]

    This document is the final report for project BBT 2020-013 (Trafikverket). It presents the results for the development and testing of a loading system based on realistic convoy loads for serviceability limit state (SLS) applied to the Kalix Bridge. It also includes a determination of the bridge condition through non-destructive testing (NDT) and assessment of non-destructive methods for the determination of residual prestressing forces. The work carried out included the development of linear and non-linear finite element models and their calibration, based on the information collected in the experimental part. Digital twin models intended for the prediction of bridge response were also created, and novel AI-based methods for crack detection were evaluated. In addition, a framework for condition management based on reliability and robustness parameters was developed within the scope of the project. As the Kalix Bridge was replaced by a new structure in 2022, the report summarizes a comprehensive review of methods for demolition of prestressed bridges and presents a methodology for demolition based on numerical analysis of the structure, considering the specific characteristics of the project and existing information about the bridge.

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    fulltext
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