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  • 1.
    Bagge, Niklas
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand. Department of Bridge & Hydraulic Design, WSP Sverige AB, Gothenburg, Sweden.
    Plos, M.
    Department of Civil and Environmental Engineering, Chalmers University of Technology, Gothenburg, Sweden.
    Popescu, Cosmin
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand. Norut Northern Research Institute, Narvik, Norway.
    A multi-level strategy for successively improved structural analysis of existing concrete bridges: examination using a prestressed concrete bridge tested to failure2019Inngår i: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 15, nr 1, s. 27-53Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper describes a multi-level strategy with increased complexity through four levels of structural analysis of concrete bridges. The concept was developed to provide a procedure that supports enhanced assessments with better understanding of the structure and more precise predictions of the load-carrying capacity. In order to demonstrate and examine the multi-level strategy, a continuous multi-span prestressed concrete girder bridge, tested until shear failure, was investigated. Calculations of the load-carrying capacity at the initial level of the multi-level strategy consistently resulted in underestimated capacities, with the predicted load ranging from 25% to 78% of the tested failure load, depending on the local resistance model applied. The initial assessment was also associated with issues of localising the shear failure accurately and, consequently, refined structural analysis at an enhanced level was recommended. Enhanced assessment using nonlinear finite element (FE) analysis precisely reproduced the behaviour observed in the experimental test, capturing the actual failure mechanism and the load-carrying capacity with less than 4% deviation to the test. Thus, the enhanced level of assessment, using the proposed multi-level strategy, can be considered to be accurate, but the study also shows the importance of using guidelines for nonlinear FE analysis and bridge-specific information. 

  • 2.
    Bagge, Niklas
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Popescu, Cosmin
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Elfgren, Lennart
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Failure tests on concrete bridges: Have we learnt the lessons?2018Inngår i: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 14, nr 3, s. 292-319Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Full-scale failure tests of bridges are important for improving understanding of bridges’ behaviour and refining assessment methods. However, such experiments are challenging, often expensive, and thus rare. This paper provides a review of failure tests on concrete bridges, focusing on lessons from them. In total, 40 tests to failure of 30 bridges have been identified. These include various types of bridges, with reinforced concrete or prestressed concrete superstructures, composed of slabs, girders and combinations thereof. Generally, the tests indicated that theoretical calculations of the load-carrying capacity based on methods traditionally used for design and assessment provide conservative estimates. It can also be concluded that almost a third of the experiments resulted in unexpected types of failures, mainly shear instead of flexure. In addition, differences between theoretical and tested capacities are often apparently due to inaccurate representation of geometry, boundary conditions and materials

  • 3.
    Bennitz, Anders
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Täljsten, Björn
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Danielsson, Georg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    CFRP strengthening of a railway concrete trough bridge: a case study2012Inngår i: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 8, nr 9, s. 801-816Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents an upgrading and monitoring of a Swedish concrete railway bridge. The methods used for the upgrading as well as for the monitoring are innovative and new. Carbon fibre tubes are inserted in holes in the bridge deck, drilled in the transverse direction of the slab at a location ca. 40 mm from the top. Carbon fibre NSMR bars are bonded in transverse grooves in the soffit of the slab. Both methods are intended to increase the transverse bending moment capacity of the troughs' bottom slab in the ultimate limit state. Monitoring is performed to verify the effectiveness of the strengthening and to understand the behaviour of the bridge. However, for obvious reasons, monitoring is only carried out in the SLS (service limit state). Even though only marginal effects of strengthening could be recorded in the SLS, both the strengthening and monitoring were considered successful at a cost of approximately 8% of the total cost of a new bridge replacement.

  • 4.
    Famurewa, Stephen Mayowa
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Asplund, Matthias
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Rantatalo, Matti
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Parida, Aditya
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Kumar, Uday
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Maintenance analysis for continuous improvement of railway infrastructure performance2015Inngår i: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 11, nr 7, s. 957-969Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Railway transport system is massive and complex, and as such it requires effective maintenance to achieve the business goal of safe, economic and sustainable transportation of passengers and goods. The growing demand for improved service quality and capacity target by railway infrastructure managers requires appropriate maintenance analysis to facilitate continuous improvement of infrastructure performance. This paper presents the application of risk matrix as a maintenance analysis method for the identification of track zones that are bottlenecks that limit operational capacity and quality. Furthermore, an adapted analysis method is proposed to create a hierarchical improvement list for addressing the problem of train mission interruption and reduced operational capacity. A case study of a line section of the Swedish network is presented. The result classifies the zones on the line section into different risk categories based on their contribution to loss of capacity and punctuality. In addition, an improvement list for the lower-level system is presented to facilitate maintenance decisions and continuous improvement at both operational and strategic levels.

  • 5.
    Garmabaki, Amir Soleimani
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Marklund, Stefan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Arkitektur och vatten.
    Thaduri, Adithya
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Hedström, Annelie
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Arkitektur och vatten.
    Kumar, Uday
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Underground pipelines and railway infrastructure: failure consequences and restrictions2019Inngår i: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Underground pipelines are an essential part of the transportation infrastructure. The structural deterioration of pipelines crossing railways and their subsequent failures can entail critical consequences for society and industry, resulting in direct and indirect costs for all the stakeholders involved. Therefore, continuous and accurate condition assessment is critical for the effective management and maintenance of pipeline networks within the transportation infrastructure. The aim of this study has been to identify failure modes and consequences related to pipelines crossing railway corridors. Expert opinions have been collected through interviews and two sets of questionnaires have been distributed to the 291 municipalities in Sweden, with 137 responses in total. The failure analysis has revealed that pipe deformation has the highest impact, followed by pipe rupture at locations where pipelines cross railway infrastructure. For underground pipelines under railway infrastructure, ageing and the external load were awarded a higher ranking than other potential causes of pipeline failure.

  • 6.
    Garmabaki, Amir Soleimani
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Marklund, Stefan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Arkitektur och vatten.
    Thaduri, Adithya
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Hedström, Annelie
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Arkitektur och vatten.
    Kumar, Uday
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Underground pipelines and railway infrastructure: failure consequences and restrictions2019Inngår i: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Underground pipelines are an essential part of the transportation infrastructure. The structural deterioration of pipelines crossing railways and their subsequent failures can entail critical consequences for society and industry, resulting in direct and indirect costs for all the stakeholders involved. Therefore, continuous and accurate condition assessment is critical for the effective management and maintenance of pipeline networks within the transportation infrastructure. The aim of this study has been to identify failure modes and consequences related to pipelines crossing railway corridors. Expert opinions have been collected through interviews and two sets of questionnaires have been distributed to the 291 municipalities in Sweden, with 137 responses in total. The failure analysis has revealed that pipe deformation has the highest impact, followed by pipe rupture at locations where pipelines cross railway infrastructure. For underground pipelines under railway infrastructure, ageing and the external load were awarded a higher ranking than other potential causes of pipeline failure.

    Authors gratefully acknowledge the funding provided by Sweden’sinnovation agency, Vinnova, through the strategic innovation programmeInfraSweden2030. The funding was granted in a competitiveapplication process that assessed replies to an open call for proposalsconcerning “Condition Assessment and Maintenance of TransportInfrastructure (Grant No. 2016-033113)”.

    Authors gratefully acknowledge the technical support and collaboration(In-kind support) of Arrsleff R€orteknik at Sweden, Luleå RailwayResearch Center (JVTC), Stormwater&Sewers and the SwedishTransport Administration (Trafikverket). In addition, the authors arethankful to the anonymous referees for their constructive commentsand Dr Matthias Asplund and Dr Masoud Naseri for their support andsuggestions.

  • 7.
    Huang, Zheng
    et al.
    School of Civil Engineering, Southeast University, Nanjing.
    Lu, Zhitao
    School of Civil Engineering, Southeast University, Nanjing.
    Song, Shoutang
    School of Civil Engineering, Southeast University, Nanjing.
    Tu, Yongming
    School of Civil Engineering, Southeast University, Nanjing.
    Blanksvärd, Thomas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Sas, Gabriel
    Infrastructure, Materials and Structures, Norut, Narvik.
    Elfgren, Lennart
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Finite element analysis of shear deformation in reinforced concrete shear-critical beams2018Inngår i: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 14, nr 6, s. 791-806Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The objective of this paper was to study the contribution of shear deformation in reinforced concrete (RC) shear-critical beams. A 2D concrete material model based on smeared fixed crack was presented and incorporated into a commercial finite element (FE) software. A method of calculating shear and flexure deformation separately out of total deformation in the shear span was presented and implemented into the FE analysis. Several experiments of RC shear-critical beams were simulated and good agreement between the experimental and numerical results was obtained in terms of total deformation, flexure deformation, shear deformation and crack patterns. The results show that after shear cracking, the contribution of shear deformation to total deformation increases rapidly. The shear span-to-depth ratio, the longitudinal reinforcement, the shear reinforcement and the load level could be the critical factor to influence the contribution of shear deformation. It appears that for RC shear-critical beams without shear reinforcement, the deformational behaviour is governed by flexure deformation. However, for RC beams with shear reinforcement, the contribution of shear deformation is not negligible after shear cracks develop. Moreover, the measuring method could also affect the measured shear deformation. Finally, future work on experimental investigation into this topic is recommended.

  • 8.
    Khajehei, Hamid
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Ahmadi, Alireza
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Soleimanmeigouni, Iman
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Nissen, Arne
    Trafikverket, Luleå, Sweden.
    Allocation of effective maintenance limit for railway track geometry2019Inngår i: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The objective of this study has been to develop an approach to the allocation of an effective maintenancelimit for track geometry maintenance that leads to a minimisation of the total annual maintenancecost. A cost model was developed by considering the cost associated with inspection, preventivemaintenance, normal corrective maintenance and emergency corrective maintenance. The standarddeviation and extreme values of isolated defects of the longitudinal level were used as quality indicatorsfor preventive and corrective maintenance activities. The Monte Carlo technique was used tosimulate the track geometry behaviour under different maintenance limit scenarios and the effectivelimit was determined which minimises the total maintenance cost. The applicability of the model wastested in a case study on the Main Western Line in Sweden. Finally, a sensitivity analysis was carriedout on the inspection intervals, the emergency corrective maintenance cost and the maintenanceresponse time. The results show that there is an optimal region for selecting an effective limit.However, by considering the safety aspects in track geometry maintenance planning, it is suggestedthat the lower bound of the optimal region should be selected.

  • 9.
    Matos, Rui
    et al.
    ISISE, Department of Civil Engineering, University of Coimbra, Faculdade de Ciências e Tecnologia da Universidade de Coimbra.
    Pinto, Paolo L.
    University of Coimbra, Department of Civil Engineering.
    Rebelo, Carlos
    University of Coimbra, ISISE, Department of Civil Engineering, University of Coimbra.
    Gervásio, Helena
    University of Coimbra, Faculty of Science and Technology, Coimbra, Portugal, Universidade de Coimbra.
    Veljkovic, Milan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Improved design of tubular wind tower foundations using steel micropiles2016Inngår i: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 12, nr 9, s. 1038-1050Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The constant increase in the wind power production leads to the need of higher wind towers, which brings up some questions regarding the effectiveness of tubular towers and respective foundations. This work focuses on the comparative structural design, life cycle behaviour and costs of onshore concrete shallow foundations for tubular wind towers (WT) when steel micropiles are used to improve resistance of the soil–structure interface (hybrid foundation). Typical wind loading for Turbine Class II and moderate seismicity (.25 g peak ground acceleration) is used to design and analyse 18 WT foundation case studies. This allows the comparison between shallow and hybrid foundations designed for three different hub heights and respective turbine rated power (80 m/2 MW, 100 m/3.6 MW and 150 m/5 MW) and for three different tubular tower solutions (steel, concrete and hybrid steel–concrete). The possible benefits of the solution using steel grouted micropiles are discussed in terms of potential environmental and economic impacts using life cycle analysis. The use of micropiles reveals to be an interesting solution to improve common shallow WT foundations since it allows the reduction of the dimensions of the foundation leading to significant environmental and cost benefits.

  • 10. Nyström, Birre
    et al.
    Söderholm, Peter
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Selection of maintenance actions using the analytic hierarchy process (AHP): decision-making in railway infrastructure2010Inngår i: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 6, nr 4, s. 467-479Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A methodology for prioritising between different maintenance actions in the railway infrastructure is presented. The consistency of the prioritisation and the feasibility of the applied methodology are investigated. Criteria describing the diverse effects of maintenance are developed and presented to track managers, together with a set of maintenance actions that are specific for each track manager. Then, the analytical hierarchy process (AHP) is used to obtain preferences for the criteria and for the different actions. The track managers roughly agree on the prioritisation of criteria. However, the discrepancies between the results of the two ways employed to elicit the preferences for the actions are rather large. The track managers consider it easy to understand the rationale of the AHP and to enter their preferences. It is proposed that preferences are recorded as they are in this paper, in order to document the rationale of the decisions and to facilitate mutual learning among decision-makers and over time.

  • 11.
    Olofsson, Ingvar
    et al.
    Skanska Teknik, Göteborg.
    Elfgren, Lennart
    Bell, Brian
    Network Rail, London.
    Paulsson, Björn
    Banverket, Borlänge.
    Niederleithinger, Ernst
    BAM, Berlin.
    Jensen, Jens Sandager
    COWI A/S, Lyngby.
    Feltrin, Glauco
    EMPA, Zurich.
    Täljsten, Björn
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Cremona, Christian
    LCPC, Paris.
    Kiviluoma, Risto
    North Finnish Building Cluster, Helsinki.
    Bien, Jan
    Wroclaw University of Technology.
    Assessment of European railway bridges for future traffic demands and longer lives: EC project "sustainable bridges"2005Inngår i: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 1, nr 2, s. 93-100Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A European Integrated Research Project has recently been started within the 6th Framework Program of the European Commission. The project aims at improved methods for the upgrading of existing railway bridges within the European railway network. The main objectives of the project are to increase the transport capacity by allowing higher axle loads and by increasing the maximum speeds. Other objectives are to increase the residual lifetime of existing bridges and to enhance management, strengthening and repair systems. The overall goal is to enable the delivery of improved capacity without compromising the safety and economy of the working railway. A consortium consisting of railway bridge owners, consultants, contractors, research institutes and universities carry out the project, having a gross budget of more than 10 million Euros. Funding from the European Commission covers a major portion of the four-year project costs

  • 12.
    Popescu, Cosmin
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand. Northern Research Institute - NORUT, Narvik, Norway.
    Täljsten, Björn
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Blanksvärd, Thomas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Elfgren, Lennart
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    3D reconstruction of existing concrete bridges using optical methods2019Inngår i: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 15, nr 7, s. 912-924Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Routine bridge inspections usually consist of visual observations. These inspections are time-consum-ing and subjective. There is a need to identify new inspection techniques for infrastructure that reducetraffic disturbance, and improve the efficiency and reliability of the acquired data. This study comparedthe performance of three different imaging technologies for the three-dimensional (3D) geometricmodeling of existing structures: terrestrial laser scanning, close-range photogrammetry, and infraredscanning. Each technology was used to assess six existing concrete railway bridges. The technologieswere compared in terms of geometric deviations, visualization capabilities, the level of the inspector’sexperience, and degree of automation. The results suggest that all methods investigated can be usedto create 3D models, however, with different level of completeness. Measurements such as spanlength, deck widths, etc. can be extracted with good accuracy. Although promising, a full off-siteinspection is currently not feasible as some areas of the bridges were difficult to capture mainly dueto restricted access and narrow spaces. Measurements based on terrestrial laser scanning were closerto the reality compared to photogrammetry and infrared scanning. The study indicates the no specialtraining is needed for photogrammetry and infrared scanning to generate a 3D geometric model.

  • 13.
    Puurula, Arto
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Enochsson, Ola
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Sas, Gabriel
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Blanksvärd, Thomas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Ohlsson, Ulf
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Bernspång, Lars
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Täljsten, Björn
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Elfgren, Lennart
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Loading to failure and 3D nonlinear FE modelling of a strengthened RC bridge.2014Inngår i: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 10, nr 12, s. 1606-1619Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A reinforced concrete railway trough bridge in Örnsköldsvik, Sweden, was strengthened in bending with rods of carbon-fibre-reinforced polymer and loaded to failure. The aim was to test and calibrate methods developed in the European Research Project ‘Sustainable Bridges’ regarding assessment and strengthening of existing bridges. A steel beam was placed in the middle of one of the two spans and was pulled downwards. Failure was reached at an applied load of 11.7 MN. It was initiated by a bond failure caused by a combined action of shear, torsion as well as bending after yielding in the longitudinal steel reinforcement and the stirrups. The bond failure led to a redistribution of the internal forces from the tensile reinforcement to the stirrups, causing the final failure. The computer models developed to simulate the loading process were improved step by step from linear shell models to more detailed models. The most developed model, a three-dimensional nonlinear finite element model with discrete reinforcement, gave accurate accounts of the response of the bridge.

  • 14.
    Soleimanmeigouni, Iman
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Ahmadi, Alireza
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Nissen, Arne
    Trafikverket.
    Xiao, Xun
    School of Fundamental Sciences, Massey University, Palmerston North, New Zealand.
    Prediction of railway track geometry defects: a case study2019Inngår i: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The aim of this study has been to develop a data-driven analytical methodology for prediction of isolated track geometry defects, based on the measurement data obtained from a field study. Within the study, a defect-based model has been proposed to identify the degradation pattern of isolated longitudinal level defects. The proposed model considered the occurrence of shock events in the degradation path. Furthermore, the effectiveness of tamping intervention in rectifying the longitudinal level defects was analysed. The results show that the linear model is an appropriate choice for modelling the degradation pattern of longitudinal level defects. In addition, a section-based model has been developed using binary logistic regression to predict the probability of occurrence of isolated defects associated with track sections. The model considered the standard deviation and kurtosis of longitudinal level as explanatory variables. It has been found that the kurtosis of the longitudinal level is a statistically significant predictor of the occurrence of isolated longitudinal level defects in a given track section. The validation results show that the proposed binary logistic regression model can be used to predict the occurrence of isolated defects in a track section.

  • 15.
    Soleimanmeigouni, Iman
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Xiao, Xun
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Ahmadi, Alireza
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Xie, Min
    Department of Systems Engineering and Engineering Management, City University of Hong Kong, Kowloon.
    Nissen, Arne
    Trafikverket, Luleå.
    Kumar, Uday
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Modelling the evolution of ballasted railway track geometry by a two-level piecewise model2018Inngår i: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 14, nr 1, s. 33-45Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Accurate prediction and efficient simulation of the evolution of track geometry condition is a prerequisite for planning effective railway track maintenance. In this regard, the degradation and tamping effect should be equipped with proper and efficient probabilistic models. The possible correlation induced by the spatial structure also needs to be taken into account when modelling the track geometry degradation. To address these issues, a two-level piecewise linear model is proposed to model the degradation path. At the first level, the degradation characteristic of each track section is modelled by a piecewise linear model with known break points at the tamping times. At the second level, Autoregressive Moving Average models are used to capture the spatial dependences between the parameters of the regression lines indexed by their locations. To illustrate the model, a comprehensive case study is presented using data from the Main Western Line in Sweden

  • 16.
    Stenström, Christer
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Norrbin, Per
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Parida, Aditya
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Kumar, Uday
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Preventive and corrective maintenance: cost comparison and cost–benefit analysis2016Inngår i: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 12, nr 5, s. 603-617Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Maintenance can represent a significant portion of the cost in asset intensive organisations, as breakdowns have an impact on the capacity, quality and cost of operation. However, the formulation of a maintenance strategy depends on a number of factors, including the cost of down time, reliability characteristics and redundancy of assets. Consequently, the balance between preventive maintenance (PM) and corrective maintenance (CM) for minimising costs varies between organisations and assets. Nevertheless, there are some rules of thumb on the balance between PM and CM, such as the 80/20 rule. Studies on the relationship between PM and CM in practice are rare. Therefore, PM and CM costs are studied in this article by analysing historical maintenance data. A case study of rail infrastructure historical data is carried out to determine the shares of PM and CM, together with a cost–benefit analysis (CBA) to assess the value of PM. The results show that the PM represents 10% to 30% of the total maintenance cost when user costs, i.e. train delays, are included as a CM cost. The CBA shows the benefit of PM is positive with a benefit–cost ratio at 3.3. However, the results depend on the inclusion/exclusion of user costs, besides individual organisational parameters.

  • 17.
    Wang, Chao
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand. South East University, Nanjing, China.
    Zhang, JIwen
    South East University, Nanjing, China.
    Tu, Yongming
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand. South East University, Nanjing, China.
    Sabourova, Natalia
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Grip, Niklas
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Matematiska vetenskaper.
    Blanksvärd, Thomas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Elfgren, Lennart
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Fatigue Assessment of Reinforced Concrete Railway Bridge based on a Coupled Dynamic System2020Inngår i: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper proposes a fatigue damage assessment methodology of a reinforced concrete bridge based on a train bridge coupled dynamic analysis system. This coupling system is composed of a vehicle a ballasted track and a bridge structure to realize a coupled vibration analysis during train passages. This methodology adopts the Palmgren Miner rule to linearly accumulate fatigue damage, and accomplishes fatigue assessment based on recommended SN relationships for reinforced concrete from various criteria. In this paper, the dynamic performances of a bridge structure are analyzed with two different vehicle models, a moving load model (and a moving spring mass damper model). Calculated dynamic stresses areused to evaluate the fatigue damage of critical positions in a reinforced concrete bridge. A case study is carried out of a railway arch bridge with a span of 89 m, Långforsen Bridge. It runs over Kalix River on the railway between Kalix and Morjärv in northern Sweden The fatigue assessment is made by combining the presented methodology with measurements. Furthermore, the effects of train speed and axle load on fatigue damage are investigated. The results indicate that good estimations of the fatigue damage assessment are made for four measured cases based on a train-bridge coupled dynamic analysis. For low speeds and light loads no difference could be seen in the cumulative fatigue damage for the two vehicle models. But high speeds and/or heavy load ssignificantly affect the fatigue damage.

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