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  • 1.
    Bagge, Niklas
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. 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 University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. 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 failure2019In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 15, no 1, p. 27-53Article in journal (Refereed)
    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 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.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Failure tests on concrete bridges: Have we learnt the lessons?2018In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 14, no 3, p. 292-319Article in journal (Refereed)
    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.
    Bayoglu Flener, Esra
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Design and Bridges.
    Karoumi, Raid
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Design and Bridges.
    Sundquist, Håkan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Design and Bridges.
    Field testing of a long-span arch steel culvert during backfilling and in service2005In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 1, no 3, p. 181-188Article in journal (Refereed)
    Abstract [en]

    The paper presents the first part of the in-situ measurements and data analyses for the tests conducted during backfilling and during service of a long-span corrugated steel culvert railway bridge over Skivarpsan, Rydsgard, Sweden. Static and dynamic tests were carried out measuring strains and displacements. Temperature readings were taken along with the measurements. Comparisons of moments during compaction showed that there is good agreement between test results and theoretical values. The theoretical calculation of the rise of the crown during compaction and the crown moments due to live load seem to be conservative, while the theoretical axial forces agree reasonably with the measured axial forces.

  • 4.
    Bennitz, Anders
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Täljsten, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Danielsson, Georg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    CFRP strengthening of a railway concrete trough bridge: a case study2012In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 8, no 9, p. 801-816Article in journal (Refereed)
    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.

  • 5. Blazkova, S
    et al.
    Beven, Keith J.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Uncertainty in flood estimation2009In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 5, no 4, p. 325-332Article in journal (Refereed)
    Abstract [en]

    The objective of this contribution is to form a clear picture of uncertainties we encounter in flood estimation, including both real-time flood forecasting and simulation for flood risk estimation. In simulation, we prefer the thesis of equifinality to obtain global optima. Many models producing acceptable simulations can be considered as multiple working hypotheses about the system process representations. Some of those hypotheses might later be confirmed or rejected, given additional data. In GLUE (Generalized Likelihood Uncertainty Estimation) the parameter sets are sampled randomly from physically reasonable ranges, often using uniform sampling where there is no strong information about prior expectations of parameter values. The parameter sets are then used to generate different realizations of the model outputs, which are then evaluated using some criteria (measures of likelihood) to provide a weight associated with each parameter set. Likelihood here is used in a much broader sense than in statistical inference. If some limits of effective observation error can be specified prior to running any simulations, models predicting outside of those limits can then be rejected as non-behavioural. Thus, any model evaluation of this type needs to take account of the multiple sources of model error more explicitly. This, however, is difficult for realistic cases. The procedure for the GLUE methodology is illustrated in examples. Usability for practical problems is suggested and future development is outlined.

  • 6.
    Bornet, Lucie
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Engineering and Bridges.
    Andersson, Andreas
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Engineering and Bridges.
    Zwolski, Jaroslaw
    Wroclaw University of Technology, Department of Civil Engineering.
    Battini, Jean-Marc
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Engineering and Bridges.
    Influence of the ballasted track on the dynamic properties of a truss railway bridge2015In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 11, no 6, p. 796-803Article in journal (Refereed)
    Abstract [en]

    This article presents numerical and experimental analyses of a steel truss railway bridge. The main interest of this work is that dynamic experiments have been performed before and after the ballasted track was placed on the bridge. Consequently, it has been possible to quantify the effect of the ballast and the rails on the dynamic properties of the bridge. For that, two finite element models, with and without the ballasted track, have been implemented and calibrated using the experimental results. It appears that the ballast gives an additional stiffness of about 25-30% for the lowest three eigenmodes. This additional stiffness can be only partly explained by the stiffness of the ballast. In fact, it seems that this additional stiffness is also due to a change of the support conditions.

  • 7.
    Butt, Ali Azhar
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Highway and Railway Engineering.
    Birgisson, Björn
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Highway and Railway Engineering.
    Assessment of the attributes based life cycle assessment framework for road projects2015In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980Article in journal (Refereed)
    Abstract [en]

    Number of life cycle assessment (LCA) tools has been suggested for pavements. However, very few have been adopted by the road authorities. Key reasons for this lack of implementation have been the tendency for very broad LCA analyses that include system boundaries considerably beyond the more natural system boundaries associated with road design, construction and maintenance as well as the lack of available LCA tools that have attributes that reflect key road properties. In this paper, a new attributesbased pavement LCA framework is evaluated for use on real road materials. Aggregates from two different sources and the effect of using a warm mix asphalt additive (WMAA) in asphalt mixtures were investigated in the laboratory. Different pavement design alternatives were generated using the laboratory data and analyzed using the road LCA framework. Asphalt production and material transportation were found to be the most energy consuming processes. The results presented showed that having actual pavement material properties as the key attributes in LCA enables a pavement focused assessment of environmental impacts associated with different design options and, LCA can help in decision support by evaluating environmental impacts of different design alternatives in a project planning/design stage.

  • 8.
    Cantero, Daniel
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Engineering and Bridges. Roughan & O’Donovan Innovative Solutions, Dublin, Ireland.
    Arvidsson, Therese
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Engineering and Bridges.
    O'Brien, Eugene
    Karoumi, Raid
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Engineering and Bridges.
    Train–track–bridge modelling and review of parameters2016In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 12, no 9, p. 1051-1064Article in journal (Refereed)
    Abstract [en]

    This study gathers all necessary information to construct a model to calculate the coupled dynamic response of train–track–bridge systems. Each component of the model is presented in detail together with a review of possible sources for the parameter values, including a collection of vehicle models, a variety of track configurations and general railway bridge properties. Descriptions of the most important track irregularity representations are also included. The presented model is implemented in MATLAB and validated against a commercially available finite element package for a range of speeds, paying particular attention to a resonant speed. Finally, the potential of the described model is illustrated with two numerical studies that address interesting aspects of train and bridge dynamic responses. In particular, the effect of the presence of a vehicle on the bridge’s fundamental frequency is studied, as well as the influence of the wavelength of the rail irregularities on the dynamic effects of the bridge and the vehicle.

  • 9.
    Du, Guangli
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Design and Bridges (name changed 20110630).
    Karoumi, Raid
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Design and Bridges (name changed 20110630).
    LCA of Railway Bridge: a comparison between two superstructure designs2013In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 9, no 11, p. 1149-1160Article in journal (Refereed)
    Abstract [en]

    Railway bridges currently encounter the challenges of increasing the load capacity while the environmental sustainability should be achieved. However, it has been realised that the environmental assessment of railway bridges has not been integrated into the decision-making process, the standard guideline and criterion is still missing in this field. Therefore, the implementation of life cycle assessment (LCA) method is introduced into railway bridges. This article provides a systematic bridge LCA model as a guideline to quantify the environmental burdens for the railway bridge structures. A comparison case study between two alternative designs of Banafjäl Bridge is further carried out through the whole life cycle, with the consideration of several key maintenance and end-of-life scenarios. Six impact categories are investigated by using the LCA CML 2001 method and the known life cycle inventory database. Results show that the fixed-slab bridge option has a better environmental performance than the ballasted design due to the ease of maintenances. The initial material manufacture stage is responsible for the largest environmental burden, while the impacts from the construction machinery and material transportations are ignorable. Sensitivity analysis illustrates the maintenance scenario planning and steel recycling have the significant influence on the final results other than the traffic disturbances.

  • 10.
    Du, Guangli
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Engineering and Bridges.
    Karoumi, Raid
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Engineering and Bridges.
    Life cycle assessment framework for railway bridges: literature survey and critical issues2014In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 10, no 3, p. 277-294Article in journal (Refereed)
    Abstract [en]

    Currently, the whole world is confronted with great challenges related to environmental issues. As a fundamental infrastructure in transport networks, railway bridges are responsible for numerous material and energy consumption through their life cycle, which in turn leads to significant environmental burdens. However, present management of railway bridge infrastructures is mainly focused on the technical and financial aspects, whereas the environmental assessment is rarely integrated. Life cycle assessment (LCA) is deemed as a systematic method for also assessing the environmental impact of products and systems, but its application in railway bridge infrastructures is rare. Very limited literature and research studies are available in this area. In order to incorporate the implementation of LCA into railway bridges and set new design criteria, this article performs an elaborate literature survey and presents current developments regarding the LCA implementation for railway bridges. Several critical issues are discussed and highlighted in detail. The discussion is focused on the methodology, practical operational issues and data collections. Finally, a systematic LCA framework for quantifying environmental impacts for railway bridges is introduced and interpreted as a potential guideline.

  • 11.
    Famurewa, Stephen Mayowa
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Asplund, Matthias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Rantatalo, Matti
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Parida, Aditya
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Kumar, Uday
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Maintenance analysis for continuous improvement of railway infrastructure performance2015In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 11, no 7, p. 957-969Article in journal (Refereed)
    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.

  • 12.
    Garmabaki, Amir Soleimani
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Marklund, Stefan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Thaduri, Adithya
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Hedström, Annelie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Kumar, Uday
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Underground pipelines and railway infrastructure: failure consequences and restrictions2019In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980Article in journal (Refereed)
    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.

  • 13.
    Hallberg, Daniel
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Buildning science - material science.
    Stojanovic, Bojan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Buildning science - material science.
    Akander, Jan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Building engineering.
    Status, needs and possibilities for service life prediction and estimation of district heating distribution networks2012In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 8, no 1, p. 41-54Article, review/survey (Refereed)
    Abstract [en]

    An optimised and proactive maintenance strategy aims to maximise the economical profit, minimise environmental impacts and keep the risk of failure to a low level. Implementation of such strategy in the context of district heating requires efforts and abilities for predicting future performances and estimating service life of district heating components. A literature review on failures (damages and performance reductions) occurring on district heating pipes, reveals that failures in district heating pipes are mainly leaks due to corrosion or mechanical impacts and reduced thermal insulation performance: leaks being the more serious damage type. A feasible service life estimation method for this type of damage is the Factor Method. Since the application of this method within the context of DH pipes has not been found in other publications, this paper focuses on describing the method and discusses the possibilities on how to apply it in two specific cases with respect to leakage: service life estimation of repaired district heating pipe sections (i.e. maintenance of district heating network) and of district heating pipes in new or extended district heating networks. A particular attention is paid on which modifying factors to consider and how to quantify them.

  • 14.
    Hallberg, Daniel
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering.
    Stojanovic, Bojan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering.
    Akander, Jan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering.
    Status, needs and possibilities for servicelife prediction and estimation of district heating distribution networks2012In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 8, no 1, p. 41-54Article in journal (Refereed)
    Abstract [en]

    An optimised and proactive maintenance strategy aims to maximise the economical profit, minimise environmental impacts and keep the risk of failure to a low level. Implementation of such a strategy in the context of district heating requires efforts and abilities for predicting future performances and estimating service life of district heating components. A literature review on failures (damages and performance reductions) occurring on district heating pipes, reveals that failures in district heating pipes are mainly leaks due to corrosion or mechanical impacts and reduced thermal insulation performance: leaks being the more serious damage type. A feasible service life estimation method for this type of damage is the Factor Method. Since the application of this method within the context of DH pipes has not been found in other publications, this paper focuses on describing the method and discusses the possibilities on how to apply it in two specific cases with respect to leakage: service life estimation of repaired district heating pipe sections (i.e. maintenance of district heating network) and of district heating pipes in new or extended district heating networks. Particular attention is paid to which modifying factors should be considered and how to quantify them.

  • 15.
    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 University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sas, Gabriel
    Infrastructure, Materials and Structures, Norut, Narvik.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Finite element analysis of shear deformation in reinforced concrete shear-critical beams2018In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 14, no 6, p. 791-806Article in journal (Refereed)
    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.

  • 16.
    Khajehei, Hamid
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Ahmadi, Alireza
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Soleimanmeigouni, Iman
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Nissen, Arne
    Trafikverket, Luleå, Sweden.
    Allocation of effective maintenance limit for railway track geometry2019In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 15, no 12, p. 1597-1612Article in journal (Refereed)
    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.

  • 17.
    Larsson Ivanov, Oskar
    et al.
    Lund University, Sweden.
    Honfi, Daniel
    RISE - Research Institutes of Sweden, Built Environment, Building Technology.
    Santandrea, Fabio
    RISE - Research Institutes of Sweden, Safety and Transport, Safety.
    Stripple, Håkan
    IVL, Sweden.
    Consideration of uncertainties in LCA for infrastructure using probabilistic methods2019In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 15, no 6, p. 711-724Article in journal (Refereed)
    Abstract [en]

    The construction and usage of transport infrastructure are major causes of greenhouse gas emissions and energy consumption. The effects of resource consumption and pollutant emissions are often quantified through Life Cycle Assessment (LCA) models. All decisions made in infrastructure projects during the whole life cycle are afflicted by uncertainty, e.g. physical properties of materials or amount of pollutants emitted by certain processes. The pervasive role of uncertainty is reflected in LCA models, which therefore should consider uncertainty from various sources and provide a sound quantification of their effects. The aim of the work presented in this paper is to give an overview of different sources of uncertainty in LCA of infrastructure projects and to describe systematic methods to evaluate their influence on the results. The possibility of including uncertainty in a LCA-tool for infrastructure is presented, studying the sensitivity of the model output to the input parameters and two alternative approaches for propagation of uncertainty using two case studies. It is shown that, besides the influence of uncertainty in emission factors, other inputs such as material amounts and service life could contribute significantly to the variability of model output and has to be considered if reliable results are sought. © 2019, © 2019 The Author(s).

  • 18.
    Liljencrantz, Axel
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Design and Bridges.
    Karoumi, Raid
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Design and Bridges.
    Twim, A MATLAB toolbox for real-time evaluation and monitoring of traffic loads on railway bridges2009In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 5, no 5, p. 407-417Article in journal (Refereed)
    Abstract [en]

    This paper describes Twim, a toolbox written in the MATLAB computer language. Twim is designed for monitoring bridge behaviour during train passages as well as for performing Bridge Weigh-In-Motion of railway traffic, both in real-time and offline. The algorithms calculate the static bogie loads and bogie distances, as well as the speed and acceleration of the train. Twim also includes visualization functions, automatic identification of known locomotives and an auto-calibration that uses locomotives with known bogie loads. The algorithms used place specific requirements on both the bridge type and the instrumentation of the bridge. These requirements are explained in the paper. The instrumentation of several bridges is described, and some of the interesting results gained through this instrumentation are presented.

  • 19. Lundgren, K
    et al.
    Kettil, P
    Analytical model for the bond-slip behaviour of corroded ribbed reinforcement2012In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 8, no 2, p. 157-169Article in journal (Refereed)
    Abstract [en]

    Corrosion of reinforcement affects the bond mechanism between reinforcement and concrete, and thus the anchorage. Reliable models describing this are needed especially for assessment of the load-carrying capacity of existing structures. This paper presents an analytical one-dimensional model for bond-slip response of corroded reinforcement. The proposed model is an extension of the bond-slip model given in the CEB-FIP Model Code 1990, and is practically applicable for structural analyses to determine the load-carrying capacity of corroded structures. Furthermore, the anchorage length needed to anchor the yield force is calculated from the bond slip, using the one-dimensional bond-slip differential equation. Results of the proposed model are compared with experimental results as well as results from an advanced three-dimensional finite element model. The suggested model is shown to give results that are consistent with the physical behaviour.

  • 20.
    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 University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Improved design of tubular wind tower foundations using steel micropiles2016In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 12, no 9, p. 1038-1050Article in journal (Refereed)
    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.

  • 21.
    Mirzadeh, Iman
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Highway and Railway Engineering.
    Butt, Ali Azhar
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Highway and Railway Engineering.
    Toller, Susanna
    Swedish Transport Administration, Sweden.
    Birgisson, Björn
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Highway and Railway Engineering.
    Life cycle cost analysis based on the fundamental cost contributors for asphalt pavements2014In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 10, no 12, p. 1638-1647Article in journal (Refereed)
    Abstract [en]

    A life cycle costing system should include the key variables that drive future costs in order to provide a framework for reducing the risk of under- or overestimating the future costs for maintenance and rehabilitation activities. In Sweden, price of oil products is mostly affected by the global economy rather than by the national economy. Whereas the price index of oil products has had a high fluctuation in different time periods, the cost fluctuation related to labour and equipment has been steady and followed the consumer price index (CPI). Contribution of the oil products was shown to be more than 50% of the total costs regarding construction and rehabilitation of asphalt pavements in Sweden. Consequently, it was observed that neither Swedish road construction price index (Vagindex) nor CPI has properly reflected the price trend regarding the asphalt pavement construction at the project level. Therefore, in this study, a framework is suggested in which energy- and time-related costs are treated with different inflation indices in order to perform a better financial risk assessment regarding future costs.

  • 22.
    Nasr, Amro
    et al.
    Lund University, Sweden.
    Kjellström, Erik
    SMHI Swedish Meteorological and Hydrological Institute, Sweden.
    Björnsson, Ivar
    Lund University, Sweden.
    Honfi, Daniel
    RISE - Research Institutes of Sweden, Built Environment, Building Technology.
    Ivanov, Oskar
    Lund University, Sweden.
    Johansson, Jonas
    Lund University, Sweden.
    Bridges in a changing climate: a study of the potential impacts of climate change on bridges and their possible adaptations2019In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980Article in journal (Refereed)
    Abstract [en]

    Climate change may have multifaceted impacts on the safety and performance of infrastructure. Accounting for the different ways in which potential climate change scenarios can affect our infrastructure is paramount in determining appropriate adaptation and risk management strategies. Despite gaining some attention among researchers in recent years, this research area is still largely uninvestigated. Several studies have indicated bridges to be especially susceptible to the effects of climate change. This article presents the potential impacts of climate change on bridges and combines the findings of close to 70 research articles to construct a broad list of their possible adaptation techniques. Although this study focuses on bridges, many of the presented climate change impacts and their adaptations are of relevance also to other types of infrastructure.

  • 23. Nyström, Birre
    et al.
    Söderholm, Peter
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Selection of maintenance actions using the analytic hierarchy process (AHP): decision-making in railway infrastructure2010In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 6, no 4, p. 467-479Article in journal (Refereed)
    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.

  • 24.
    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 University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    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"2005In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 1, no 2, p. 93-100Article in journal (Refereed)
    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

  • 25.
    Peñaloza, Diego
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Materials. RISE - Research Institutes of Sweden.
    Erlandsson, Martin
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Materials.
    Pousette, Anna
    Climate impacts from road bridges: effects of introducing concrete carbonation and biogenic carbon storage in wood2018In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 14, no 1, p. 56-67Article in journal (Refereed)
    Abstract [en]

    The construction sector faces the challenge of mitigating climate change with urgency. Life cycle assessment(LCA), a widely used tool to assess the climate impacts of buildings, is seldom used for bridges. Materialspecificphenomena such as concrete carbonation and biogenic carbon storage are usually unaccountedfor when assessing the climate impacts from infrastructure. The purpose of this article is to explore theeffects these phenomena could have on climate impact assessment of road bridges and comparisonsbetween bridge designs. For this, a case study is used of two functionally equivalent design alternativesfor a small road bridge in Sweden. Dynamic LCA is used to calculate the effects of biogenic carbon storage,while the Lagerblad method and literature values are used to estimate concrete carbonation. The resultsshow that the climate impact of the bridge is influenced by both phenomena, and that the gap betweenthe impacts from both designs increases if the phenomena are accounted for. The outcome is influencedby the time occurrence assumed for the forest carbon uptake and the end-of-life scenario for the concrete.An equilibrium or 50/50 approach for accounting for the forest carbon uptake is proposed as a middlevalue compromise to handle this issue.

  • 26.
    Plos, Mario
    et al.
    Chalmers University of Technology, Sweden.
    Shu, Jiangpeng
    Chalmers University of Technology, Sweden.
    Zandi, Kamyab
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute. Chalmers University of Technology, Sweden.
    Lundgren, Karin
    Chalmers University of Technology, Sweden.
    A multi-level structural assessment strategy for reinforced concrete bridge deck slabs2017In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 13, no 2, p. 223-241Article in journal (Refereed)
    Abstract [en]

    This paper proposes a multi-level assessment strategy for reinforced concrete bridge deck slabs. The strategy is based on the principle of successively improved evaluation in structural assessment. It provides a structured approach to the use of simplified as well as advanced non-linear analysis methods. Such advanced methods have proven to possess great possibilities of achieving better understanding of the structural response and of revealing higher load-carrying capacity of existing structures. The proposed methods were used for the analysis of previously tested two-way slabs subjected to bending failure and a cantilever slab subjected to a shear type of failure, in both cases loaded with concentrated loads. As expected, the results show that more advanced methods yield an improved understanding of the structural response and are capable of demonstrating higher, yet conservative, predictions of the load-carrying capacity. Nevertheless, the proposed strategy clearly provides the engineering community a framework for using successively improved structural analysis methods for enhanced assessment in a straightforward manner.

  • 27.
    Popescu, Cosmin
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. Northern Research Institute - NORUT, Narvik, Norway.
    Täljsten, Björn
    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.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    3D reconstruction of existing concrete bridges using optical methods2019In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 15, no 7, p. 912-924Article in journal (Refereed)
    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.

  • 28.
    Puurula, Arto
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Enochsson, Ola
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Blanksvärd, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Ohlsson, Ulf
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Bernspång, Lars
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Täljsten, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Loading to failure and 3D nonlinear FE modelling of a strengthened RC bridge.2014In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 10, no 12, p. 1606-1619Article in journal (Refereed)
    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.

  • 29.
    Safi, Mohammed
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Engineering and Bridges.
    Sundquist, Håkan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Engineering and Bridges.
    Karoumi, Raid
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Engineering and Bridges.
    Racutanu, George
    The Swedish Transport Administration, Trafikverket, Eskilstuna, Sweden.
    Development of the Swedish Bridge Management System by Upgrading and Expanding the Use of LCC2013In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 9, no 12, p. 1240-1250Article in journal (Refereed)
    Abstract [en]

    Although many bridge management systems (BMSs) contain some forms of life-cycle costing (LCC), the use of LCC in bridge engineering is scarce. LCC in many BMSs has mainly been applied within the bridge operation phase to support decisions related to existing bridges. LCC has several useful applications within the bridge entire life, from cradle to grave. This paper introduces the Swedish Bridge and Tunnel Management System (BaTMan). A comprehensive integrated LCC implementation schema will be illustrated, taking into account the bridge investment and management process in Sweden. The basic economic analytical tools as well as other helpful LCC techniques are addressed. A real case study is presented to demonstrate the recent improvement of BaTMan practically in the function of whether to repair or to replace a bridge.  Cost records for 2,508 bridges are used as input data in the presented case study. Considering the same records, the average real and anticipated initial costs of different bridge types in Sweden will be schematically presented.

  • 30.
    Soleimanmeigouni, Iman
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Ahmadi, Alireza
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Khajehei, Hamid
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Nissen, Arne
    Trafikverket, Luleå, Sverige.
    Investigation of the effect of the inspection intervals on the track geometry condition2019In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980Article in journal (Refereed)
    Abstract [en]

    In order to evaluate the railway track geometry condition and plan maintenance activities, track inspection cars run over the track at specific times to monitor it and record geometry measurements. Applying an adequate inspection interval is vital to ensure the availability, safety and quality of the railway track, at the lowest possible cost. The aim of this study has been to investigate the effect of different inspection intervals on the track geometry condition. To achieve this, an integrated statistical model was developed to predict the track geometry condition given different inspection intervals. In order to model the evolution of the track geometry condition, a piecewise exponential model was used which considers break points at the maintenance times. Ordinal logistic regression was applied to model the probability of the occurrence of severe isolated defects. The Monte Carlo technique was used to simulate the track geometry behaviour given different inspection intervals. The results of the proposed model support the decision-making process regarding the selection of the most adequate inspection interval. The applicability of the model was tested in a case study on the Main Western Line in Sweden.

  • 31.
    Soleimanmeigouni, Iman
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Ahmadi, Alireza
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Nissen, Arne
    Trafikverket.
    Xiao, Xun
    School of Fundamental Sciences, Massey University, Palmerston North, New Zealand.
    Prediction of railway track geometry defects: a case study2019In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980Article in journal (Refereed)
    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.

  • 32.
    Soleimanmeigouni, Iman
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Xiao, Xun
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Ahmadi, Alireza
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Xie, Min
    Department of Systems Engineering and Engineering Management, City University of Hong Kong, Kowloon.
    Nissen, Arne
    Trafikverket, Luleå.
    Kumar, Uday
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Modelling the evolution of ballasted railway track geometry by a two-level piecewise model2018In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 14, no 1, p. 33-45Article in journal (Refereed)
    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

  • 33.
    Stenström, Christer
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Norrbin, Per
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Parida, Aditya
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Kumar, Uday
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Preventive and corrective maintenance: cost comparison and cost–benefit analysis2016In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 12, no 5, p. 603-617Article in journal (Refereed)
    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.

  • 34.
    Tahershamsi, M.
    et al.
    Chalmers University of Technology, Sweden.
    Fernandez, I.
    Chalmers University of Technology, Sweden.
    Lundgren, K.
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute. Chalmers University of Technology, Sweden.
    Zandi, Kamyab
    RISE, SP – Sveriges Tekniska Forskningsinstitut, CBI Betonginstitutet AB, Betong & Berg. Chalmers University of Technology, Sweden.
    Investigating correlations between crack width, corrosion level and anchorage capacity2017In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 13, no 10, p. 1294-1307Article in journal (Refereed)
    Abstract [en]

    In assessing existing structures, inspection results need to be linked to the effects on load-carrying capacity; to provide such information, this study has investigated the correlation between splitting crack width, corrosion level and anchorage capacity. The study was based on 13 reinforced concrete beams that had been exposed to natural corrosion for 32 years, 11 beams with splitting cracks and 2 without. The crack pattern and widths were documented before undergoing structural testing of anchorage capacity. Thereafter, the reinforcement bars were extracted and their corrosion levels measured using two methods, gravimetric weight loss and 3D scanning. The corrosion level from the weight loss method was approximately twice as large; possible reasons are horizontal or subsurface corrosion pits, and the cleaning method. Further, for the same corrosion level, the specimens in this study had much larger crack widths and slightly lower bond capacity than the artificially corroded tests in the literature; a possible reason is that these specimens had been subjected to combined corrosion and freezing. However, the corrosion level and reduction in bond capacity related to crack width were both lower in the present than in previous studies in the literature. Thus, by formulating a damage indicator from the damage visible in the form of crack widths from artificial test data, the structural capacity is estimated to be on the safe side.

  • 35.
    Veganzones Muñoz, José Javier
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Engineering and Bridges.
    Pettersson, Lars
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Engineering and Bridges. Skanska Sweden.
    Sundqvist, Håkan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Engineering and Bridges.
    Karoumi, Raid
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Engineering and Bridges.
    Life-cycle cost analysis as a tool in the developing process for new bridge edge beam solutions2016In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 12, no 9, p. 1185-1201Article in journal (Refereed)
    Abstract [en]

    Currently in Sweden, the life-cycle measures applied on bridge edge beams may take up to 60% of the total costs incurred along the road bridges’ life span. Moreover, significant disturbances for the road users are caused. Therefore, the Swedish Transport Administration has started a project to develop alternative edge beam design solutions that are better for society in terms of cost. The purpose of this article is to investigate whether these proposals can qualify for more detailed studies through an evaluation and comparison based on a comprehensive life-cycle cost analysis. The alternatives including the standard design are applied to typical Swedish bridges. The impact of the values of the parameters with the largest influence is investigated by sensitivity analyses. Results with different life-cycle strategies are shown. The positive influences in the total life-cycle cost of a stainless steel reinforced solution and of the enhanced construction technique are estimated. The concrete edge beam integrated with the deck seems to be favourable, which is in line with international experience observed. Different designs may be appropriate depending on the bridge case and the life-cycle strategy. The Swedish Transport Administration will carry out a demonstration project in a bridge with one of the proposals.

  • 36.
    Wang, Chao
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. South East University, Nanjing, China.
    Zhang, JIwen
    South East University, Nanjing, China.
    Tu, Yongming
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. South East University, Nanjing, China.
    Sabourova, Natalia
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Grip, Niklas
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mathematical Science.
    Blanksvärd, Thomas
    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.
    Fatigue Assessment of Reinforced Concrete Railway Bridge based on a Coupled Dynamic System2020In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980Article in journal (Refereed)
    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.

  • 37.
    Wennström, Jonas
    et al.
    Kungliga Tekniska Högskolan.
    Sundquist, Håkan
    Kungliga Tekniska Högskolan.
    Karlsson, Robert
    Swedish National Road and Transport Research Institute, Infrastructure.
    Life cycle cost considerations in project appraisals of collision-free roads2016In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 12, no 2, p. 275-287Article in journal (Refereed)
    Abstract [en]

    In the last decade, many single carriageway roads in Sweden have been converted to collision-free roads as a cost-effective alternative to conventional motorways. Investigations have concluded that the road type has been successful in reducing the number of fatal accidents, despite increased operation and maintenance costs. In recent years, the focus has shifted to converting narrower roads which are anticipated to further increase operation and maintenance cost but also complicate traffic management during road works.

    There are concerns that when life cycle cost is considered in the investment assessment the socioeconomic profitability could be reduced. This article examines this issue by first assessing changes in costs for operation and maintenance using a life cycle cost analysis approach applied on a case study. The results from the analysis were thereafter integrated into a cost–benefit analysis to assess changes in costs in relation to benefits in improved traffic safety and travel time. The analysis indicated profitability even with substantial increase in operation, maintenance and road user work zone costs. Results are discussed from project implementation and road management perspectives.

  • 38.
    Wennström, Jonas
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Engineering and Bridges.
    Sundquist, Håkan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Engineering and Bridges.
    Karlsson, Robert
    Life cycle cost considerations in project appraisals of collision-free roads2016In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 12, no 2, p. 275-287Article in journal (Refereed)
    Abstract [en]

    In the last decade, many single carriageway roads in Sweden have been converted to collision-free roads as a cost-effective alternative to conventional motorways. Investigations have concluded that the road type has been successful in reducing the number of fatal accidents, despite increased operation and maintenance costs. In recent years, the focus has shifted to converting narrower roads which are anticipated to further increase operation and maintenance cost but also complicate traffic management during road works. There are concerns that when life cycle cost is considered in the investment assessment the socioeconomic profitability could be reduced. This article examines this issue by first assessing changes in costs for operation and maintenance using a life cycle cost analysis approach applied on a case study. The results from the analysis were thereafter integrated into a cost-benefit analysis to assess changes in costs in relation to benefits in improved traffic safety and travel time. The analysis indicated profitability even with substantial increase in operation, maintenance and road user work zone costs. Results are discussed from project implementation and road management perspectives.

  • 39.
    Wiberg, Johan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Design and Bridges.
    Karoumi, Raid
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Design and Bridges.
    Monitoring dynamic behaviour of a long-span railway bridge2009In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 5, no 5, p. 419-433Article in journal (Refereed)
    Abstract [en]

    A new long-span prestressed railway bridge was instrumented to better understand and monitor its dynamic behaviour. The bridge is a unique and geometrically complex concrete structure with a very slender box girder section and a slab track system. This paper briefly describes the instrumentation used for monitoring the structural behaviour and focuses on investigating the dynamic characteristics of the bridge. The bridge’s dynamic properties were estimated using the output only stochastic subspace identification technique – for which the theory and analysis technique are briefly described – together with more traditional peak picking methods. Natural frequencies of the bridge were identified and verified from a previous study. The obtained frequencies and damping ratios are to be used in updating the developed finite element model. In addition, extreme bridge acceleration values from different train passages were collected and compared with the recommended limit value in bridge design codes.

  • 40.
    Zandi, Kamyab
    RISE, SP – Sveriges Tekniska Forskningsinstitut, CBI Betonginstitutet AB. Chalmers University of Technology, Sweden.
    Corrosion-induced cover spalling and anchorage capacity2015In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 11, no 12, p. 1547-1564Article in journal (Refereed)
    Abstract [en]

    The aim of this study is to enhance our understanding of anchorage capacity in reinforced concrete structures with corrosion-induced cover spalling. Our objectives were to study the influence of corrosion-induced cover spalling on bond strength, and to validate an existing one-dimensional (1D) analysis for anchorage capacity in such cases. Thus, earlier developed bond and corrosion models suited for detailed three-dimensional (3D) finite element (FE) analysis were first combined with a new computation scheme to simulate corrosion-induced cover spalling. The 1D and 3D FE analyses were validated through two types of experiments, i.e. eccentric pull-out tests and beam tests, as well as a comparison with an existing empirical model. The application of 3D FE analysis showed that the corrosion of stirrups advances the emergence of cracking and spalling, while bond strength is only slightly influenced by the corrosion of stirrups after cover spalling if yielding of stirrups has not taken place. Moreover, it was shown that stresses in the stirrups due to corrosion in adjacent bars rapidly diminished within a short distance from the main bar, and that the corrosion of stirrups influenced the shear capacity more prominently than the induced stresses in stirrups due to the corrosion of main bars.

  • 41.
    Zandi, Kamyab
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, CBI Betonginstitutet AB.
    Kettil, P
    Modelling the structural behaviour of frost-damaged reinforced concrete structures2013In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 9, no 5, p. 416-431Article in journal (Refereed)
    Abstract [en]

    A methodology is introduced to predict the mechanical behaviour of reinforced concrete structures with an observed amount of frost damage at a given time. It is proposed that the effects of internal frost damage and surface scaling can be modelled as changes of material and bond properties, and geometry, respectively. These effects were studied and suggestions were made to relate the compressive strength and dynamic modulus of elasticity, as the indicators of damage, to the response of the damaged concrete in compression and tension, and to the bond behaviour. The methodology was applied to concrete beams affected by internal frost damage, using non-linear finite element analyses. A comparison of the results with available experimental data indicated that the changes in failure mode and, to a rather large extent, the effect on failure load caused by internal frost damage can be predicted. However, an uncertainty was the extension and distribution of the damaged region which affected the prediction of the load capacity.

  • 42.
    Zandi, Kamyab
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, CBI Betonginstitutet AB.
    Lundgren, Karin
    Three-dimensional modelling of structural effects of corroding steel reinforcement in concrete2013In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 9, no 7, p. 702-718Article in journal (Refereed)
    Abstract [en]

    The effect of corrosion products flowing through cracks becomes significant when large corrosion penetrations take place in reinforced concrete structures and wide cracks develop; this is favourable, as it decreases the splitting stress around the bar. The effect becomes more important when the corrosion rate is low, such as for natural corrosion. Acorrosion model describing the expansion due to voluminous corrosive products was previously developed. The model is here extended to include the flow of corrosion products through cracks. The volume flow of corrosion products through a crack is assumed to depend on the splitting stress and the crack width. The splitting stress is evaluated from the strain in the corrosion products, and the crack width is computed from the displacements across the crack. A one-dimensional flow model is used to formulate the flow phenomenon and to estimate the volume flow of corrosion products. The extended corrosion model, applied in detailed three-dimensional non-linear finite element analyses of highly corroded eccentric pull-out specimens, resulted in more corrosion cracks with smaller crack openings, which better corresponded to measurements of the tested specimens. Moreover, the results indicated the important effect of the flow phenomenon on the bond strength.

1 - 42 of 42
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