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  • 1.
    Blanksvärd, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Mätprogram för broarna över Åby älv och Rautasjokk: FAS 22013Report (Other academic)
  • 2.
    Blanksvärd, Thomas
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Häggström, Jens
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Nilimaa, Jonny
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Sabourova, Natalia
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Grip, Niklas
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mathematical Science.
    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.
    Carolin, Anders
    Trafikverket, Luleå & Borlänge, Sweden.
    Paulsson, Björn
    Trafikverket, Luleå & Borlänge, Sweden.
    Tu, Yongming
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering. Southeast University, Nanjing, PR China.
    Test to failure of a steel truss bridge – Calibration of assessment methods2014In: Bridge Maintenance, Safety, Management and Life Extension: proceedings of the Seventh International Conference of Bridge Maintenance, Safety and Management, 7-11 July 2014, Shanghai, China / [ed] Airong Chen; Dan M. Frangopol; Xin Ruan, London: CRC Press, Taylor & Francis Group , 2014, p. 1076-1081Conference paper (Refereed)
    Abstract [en]

    The steel truss railway bridge at Åby River was built in 1957 with a span of 32 m (105 feet). In 2012 it was replaced by a new steel beam bridge and the old bridge was placed beside the river. It was tested to failure to study its remaining load-carrying capacity in September 2013. The test was carried out by Luleå University of Technology by commission from Trafikverket as a part of the European Research Project MAINLINE (www.mainline-project.eu). In this paper some preliminary results are given. Two hydraulic jacks, anchored by cables to the bedrock, pulled the bridge downwards. The bridge remained elastic up to about three times the original design load and the load could then be almost doubled with substantial yielding deformations before a buckling failure appeared in the top girders for a load of ca. 11 MN (1000 short tons) for a midpoint deflection of ca. 0, 2 m (8 inches). No brittle or fatigue failure in any of the joints appeared and the bridge proved to behave in a ductile way with a substantial hidden capacity.

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  • 3.
    Collin, Peter
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Häggström, Jens
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Hällmark, Robert
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    International workshop on strengthening of steel/composite bridges2015Report (Other academic)
    Abstract [en]

    The European infrastructure is rapidly aging, and steel/composite bridges are noexception to the rule. With thousands of older steel/composite bridges, there is ademand of rational methods to strengthen the older bridges to compensate not onlyfor their age, but also for higher loads and new codes, of which perhaps the newfatigue rules for highway bridges in EC3-2 will be the hardest to meet.Within the frames of the European R&D project Prolife (RFCS-CT-2015-00025) aworkshop was arranged in Stockholm September 28th 2015. Bridge owners,designers and researchers from 12 countries participated, and the similaritiesbetween the countries as well as the variety of technical solutions were highlighted.The contributions are presented in this report and the organizers want to thank allparticipants for making this seminar successful.

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  • 4.
    Elfgren, Lennart
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Bell, Brian
    UIC, Network Rail, London.
    Nilimaa, Jonny
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Häggström, Jens
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Tu, Yongming
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering. College of Civil Engineering, Southeast University, Nanjing.
    Lundgren, Karin
    Chalmers University of Technology, Department of Civil and Environmental Engineering.
    Plos, Mario
    Chalmers University of Technology, Department of Civil and Environmental Engineering.
    Larsson, Oskar
    Faculty of Engineering, LTH, Department of Constructional Sciences, Lund University.
    Casas, Joan Ramon
    Universitat Politècnica de Catalunya.
    New technologies to extend the life of elderly rail infrastructure: Deliverable 1.3 in MAINLINE - a project within the EC 7th Framework Programme2015Report (Refereed)
    Abstract [en]

    There are many traditional technologies available to extend the life of elderly rail infrastructure, some of which are being improved or developed, whilst new technologies continue to emerge.In two earlier reports a benchmark of new technologies was given and assessment methods were presented, ML-D1.1 (2013) and ML-D1.2 (2013). In this report, ML-D1.3, an overview is given of some of the most promising new or updated technologies. Based on the findings, work in the Mainline project has focused on the following two areas for bridges, tunnels and track:- Assessment methods- Repair and Strengthening methodsSome of the methods are still under development and may not yet be available commercially. Hence these are presented on a “for information” basis and as something that may be introduced on a broader scale in a near future.In the report assessment and strengthening of bridges are treated in Chapter 4 and Chapter 5.Tunnels are treated in Chapter 6 and track and earthwork in Chapter 7.The report also includes with five appendices with details of important work that has been donein the MAINLINE project. Appendix A presents results from the assessment and full scale testing to failure of a 50 year old metallic truss bridge. Appendix B presents results from the strengthening by post-tensioning of a concrete trough bridge. Appendix C presents methods to extend life for tunnels. Appendix D proposes methods for the assessment of fatigue andAppendix E, finally, gives a fairly comprehensive list of references on how to extend the life of structures.A Guideline for application of the new technologies is given in ML-D1.4 (2014).

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  • 5.
    Eriksson, Kjell
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Materialteknisk provning av konstruktionsstål från järnvägsbro över Åby älv2014Report (Other academic)
    Abstract [sv]

    Brottmekanisk provning, dragprovning och slagprovning av konstruktionsstål från undre ramstång i huvudfackverk, från långbalk och från tvärbalk i den nedmonterade järnvägsbron över Åby älv, uppförd 1951.

  • 6.
    Häggström, Jens
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Bärighetsberäkning: Bro över södra Rautasjokk KM 1432+8832015Report (Other academic)
    Abstract [sv]

    Beräkningarna visar på att bron med avseende på brott och nedböjning klarar axellaster upp till 34,2 ton. Den mest kritiska punkten är nitförbandet som förbinder långbalkarna genom tvärbalkarna. Dessutom finns  detaljer som är kritiska med avseende på utmattning.

    Beräkningsmässigt kan det konstateras att detaljen där horisontalfackverkets infästning till långbalkens överfläns är den detalj som är mest kritisk för brons överlevnad, då denna (teoretiskt) redan är uttjänt. Brons fortsatta livslängd kan dock säkerställas genom regelbundna inspektioner av dessa knutpunkter. Det är värt att notera att denna detalj utsätts för tryckspänningar och att sprickor som uppstår rimligtvis ej propagerar i samma takt som en dragen spricka.

    Utmattningskontrollen har skett i tre steg.  Beräkningen förfinas om kapaciteten visats otillräcklig.

    1) Maximal spänningsvidd från typiserat spänningskollektiv där TLM3 används som fordon i LK:C.

    2) Delskadeberäkning baserad på uppskattad trafikmängd som belastat bron.

    3) Samma som steg 2 men baserad på influenslinjer och Rainflow‐summerin

    Steg 1 och 2, är traditionellt vedertagna metoder för att utvärdera utmattiningskapaciteten men kan i många fall ge något oprecisa resultat. För traditionella delskadeberäkningar  förväntas konstruktören bedöma om det är antalet axlar, vagnar eller tågpassager som är avgörande för en detalj. Utöver detta används kollektivparameterar för att beskriva variationen av dessa. Dessa val är ofta något trubbiga, då antaganden görs på "säker" sida.  Det förväntade resultatet är ofta en kombination av axlar/vagnar och tågset. Genom att använda sig av rainflow summering av spänningsvidderna som uppstår vid en tågpassage kan ett mer nyanserat resultat uppnås.

    För bron i fråga används denna metod för att utvärdera kritiska detaljer, där steg 1 och steg 2 ej uppfyller kraven. Metoden och resultaten beskrivs närmare under kapittel 8. De detaljer som ej uppfyller kraven för en "traditionell" delskadeberäkning men vars säkethet kunde säkerställas med hjälp av steg 3 är:

    * Horsisontalfackverkets infästning mot långbalkarna vid tvärbalk

    * Tvärbalkarna i böjning

    * Nitförbandet som förbinder långbalk mot tvärbalk

    Huruvida denna typ av analys beaktar dynamiskt tillskott på ett tillfredställande sätt är dock osäkert, då dynamiken inte enbart ökar de största spänningarna utan även minskar de minsta spänningarna ‐ vilket teoretiskt ger en ökad spänningsvidd.  Det kan även konstateras att metoden generellt ger mer gynnsamma resultat, jämfört med traditionella beräkningar och således även minskar på säkerheten. Denna är dock  fortfarande är inom ramen för vad som är ok. Genom användandet av metoden kan det konstateras att det huvudsakligen är antalet tågpassager snarare än antalet vagnar/axlar som är avgörande för de flesta detaljer.

    Skulle tågsetet bestå av flertalet tomvagnar skulle fler "stora" spänninscykler uppstå vilket har negativ inverkan på brons beräknde livslängd varför dessa detaljer också bör inspekteras extra noga.

    Urspårningslasten är i sammanhanget relativt liten. Då bron är försedd med skyddsräl begränsas excentrisiteten och lasteffekten är således relativt liten.

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  • 7.
    Häggström, Jens
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Evaluation of the Load Carrying Capacity of a Steel Truss Railway Bridge: Testing, Theory and Evaluation2016Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    A good deal of resources has been invested in building and maintaining existing infrastructure.Many structures are now becoming old and do not meet the requirements of an increasingtraffic load, or are reaching the end of their lifecycle. It is not possible or sustainable to replaceall those structures that have been judged to be obsolete or nearly obsolete. However, in manycases, their specified load carrying capacities are understated, so there is an urgent need toobtain more robust knowledge of their true status. In the design of new structures, a numberof assumptions relating to loading and structural behaviour have to be made, a number that canbe reduced by finding out more about the actual behaviour of the structure.

    This licentiate thesis describes the structural behaviour of existing unballasted open steel trussrailway bridges in general and methods for assessment in particular, with the aim of keepingthese structures in service for longer.

    An extensive program, divided into three phases of experimental studies, was carried out toincrease the understanding of existing unballasted steel truss railway bridges.

    Phase I consisted of instrumentation and monitoring of a 60 year-old railway bridge (ÅbyBridge) while it was still in service. A description of the object and the monitoring in thisphase of measurements is presented in Chapter 3 with some results and analysis in Chapter 4.Some of the findings from Phase I are described in Paper A, from which it was concluded thatthe stringer beams were subjected to large stresses originating from torsion and out-of-planebending. These effects are not normally considered yet may have significant consequences inrelation to fatigue.

    In Phase II, the former bridge over the Åby River was replaced and put beside the railwaytracks, where the instrumentation from Phase I was extended. The bridge was statically testedin 18 pre-defined load series before reaching failure. Phase II is described in Chapter 3 andsummarized in Paper B. It was found that the bridge could withstand loading corresponding tofour times the highest permitted axle-loading, or twice the design load for new bridges, beforeexhibiting an obvious non-linear behaviour with regard to vertical displacement in the midspan.The peak load was achieved at loading approximately 50% higher than the initial nonlinearbehaviour, where lateral buckling of the top chord limited the structure from carryingmore load. The failure can be concluded as being redundant without brittle failure of any ofthe connections.

    In Phase III, a different bridge was fitted with instrumentation and monitored while subjectedto live loading: the bridge over the river Rautasjokk. The Rautasjokk Bridge was constructedfive years later than the Åby Bridge, using the same drawings thus making it theoreticallyidentical in terms of geometry and material. It is situated along the “Ore line”, meaning that itis subjected to higher loads compared to the Åby Bridge which was located along the “Mainline”. The program for measurements originated from a code-based assessment which ruled thebridge unsafe to use with regard to fatigue of the stringers due to the gusset plates welded tothe top flange of the stringers. Paper C describes the measurement of local fatigue strains (hotspot)and comparison with nominal strains. In that paper, it was concluded that the hot-spotapproach was only favourable for one out of three studied positions, with regard to fatiguelifespan.

    This thesis ends with conclusions and suggestions for further research.

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  • 8.
    Häggström, Jens
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Nilsson, Martin (Editor)
    International Workshop on Eurocode 4-2, Composite Bridges2011Report (Other academic)
    Abstract [sv]

    Under de senaste åren har ingenjörer och designers i Europa börjat att använda Eurokod 4-2 – Samverkansbroar. Tillämpningen är nästan densamma i de olika länderna, fast med vissa skillnader, som det kan vara i början. Man har funnit en del svårigheter, problem och fördelar. Den 17 mars 2001 hölls en workshop om Eurokod 4-2 – Samverkansbroar på Ramböll i Stockholm och som lockade omkring 55 personer från tio olika länder. Workshopen fokuserade på bakgrunden till reglerna, på erfarenheter från Frankrike, Storbritannien, Sverige och Italien och avrundades med lite innovativa utveckling av samverkansbroar och en diskussion om möjlig forskning och utveckling för vidare utveckling av Eurokod 4-2.

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  • 9.
    Häggström, Jens
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Bagge, Niklas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Nilimaa, Jonny
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Blanksvärd, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Täljsten, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Puurula, Arto
    Savonia University of applied Sciences, Kuopia, Finland.
    Rydberg-Forssbeck, Lahja
    Trafikverket, Stockholm.
    Carolin, Anders
    Trafikverket, Luleå.
    Testing Bridges to Failure: Experiences2017In: IABSE Symposium, Vancouver, 2017: Engineering the Future, Zürich, Switzerland: IABSE - International Association for Bridges and Structural Engineering , 2017, p. 2832-2839Conference paper (Refereed)
    Abstract [en]

    Four bridges of different types have been tested to failure and the results have been compared to the load-carrying capacity calculated using standard code models and advanced numerical methods. The results may help to make accurate assessments of similar existing bridges. Here it is necessary to know the real behaviour, weak points, and to be able to model the load-carrying capacity in a correct way.

    The four bridges were: (1) a one span steel truss railway bridge; (2) a two span strengthened concrete trough railway bridge; (3) a one span concrete trough bridge tested in fatigue; and (4) a five span prestressed concrete road bridge.

    The unique results in the paper are the experiences of the real failure types, the robustness/weakness of the bridges, and the accuracy of different codes and models.

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  • 10.
    Häggström, Jens
    et al.
    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.
    Assessment and full scale failure test of a steel truss bridge2015In: IABSE Workshop Helsinki 2015: Safety, Robustness and Condition Assessments of Structures, Zürich: International Association for Bridge and Structural Engineering, 2015, p. 288-295Conference paper (Refereed)
    Abstract [en]

    Large amount of resources has been invested in maintaining existing infrastructure. Several of thesestructures are now becoming old and do not meet the requirements of today or are reaching the endof their lifecycle. It is not possible to replace all of these structures that are deemed or are about tobe deemed obsolete, due to high cost and environmental impacts.One way to keep these structures in use for a longer time is innovative and intelligent assessment ofthe actual state of stress and behaviour. In such cases, using structural health monitoring to assessthe structure might be an efficient way to extend the life of the structure.This paper will describe a unique monitoring program over two similar 33 m long steel trussbridges situated in Sweden. One of these bridges, Aby River, had a regulated axle load of 25 tonsand was tested to failure in 2013. The other bridge, Rautasjokk, has a regulated axle load of 30 tonswhich will be upgraded to 32.5 tons and will be in use for the coming years.The monitoring program was performed as; monitoring of the bridge over Aby river when it wasstill in service. After replacement the old bridge was moved and tested under static loads to assessboundary conditions and state of stress. Parts of this bridge were then disassembled to be tested formaterial properties and fatigue capacity. A theoretical assessment of the Rautasjokk bridge was thenperformed based on the conclusions from the measurements on the Aby bridge. Finally the plan isto verify findings by performing measurements on live loading for the Rautasjokk bridge in servicelimit state.The aim for this project is to verify the continuous safety for the Rautasjokk bridge by using inputfrom tests performed at both bridges.

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  • 11.
    Häggström, Jens
    et al.
    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.
    Collin, Peter
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Fatigue assessment of stringer beams using structural healthmonitoring2016In: 19th IABSE Congress Strockholm 21-23 September 2016: Challenges in Design and Construction of an Innovative ans Sustainable Built Environment / [ed] ennart Elfgren, Johan Jonsson, Mats Karlsson, Lahja Rydberg-Forssbeck and Britt Sigfrid, CH - 8093 Zürich, Switzerland, 2016, p. 1455-1462Conference paper (Refereed)
    Abstract [en]

    Fatigue assessment of existing bridges is often carried out through simple calculations where the nominalstress range is compared with the fatigue strength based on a number of detail categories specified incodes. Presented in this paper, is the stepwise fatigue assessment through measurements of the 60 yearold bridge over Rautasjokk located in northern Sweden. According to the code‐based assessment of thestringers, it has already exceeded its lifetime about four times; however no cracks have been identified. Bymeasuring strains the real state of stress was identified, where both nominal stresses and local approacheshave been evaluated and compared. Even though the local approach should provide a better accuracy incomparison with the nominal stresses, this approach was only favorable for one out of the three studiedlocations.

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    Fatigue assessment of stringer beams using structural health monitoring
  • 12.
    Häggström, Jens
    et al.
    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.
    Collin, Peter
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Tu, Yongming
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. Southeast University, School of Civil Engineering, Nanjing.
    Full-scale testing to failure of a steel truss railway bridge2017In: Proceedings of the Institution of Civil Engineers: Engineering Sustainability, ISSN 1478-4637, E-ISSN 1751-7664, Vol. 170, no 2, p. 93-101Article in journal (Refereed)
    Abstract [en]

    Significant resources have been invested in maintaining existing infrastructure. Many structures are becoming old, do not meet current requirements, or are reaching the end of their life cycle. It is not feasible or sustainable to replace all of those that may be deemed obsolete; however, often their specified capacities are very conservative. So there is an urgent need to obtain more robust knowledge of their true status. This paper describes a unique project, in which a 33 m long steel truss railway bridge (over the Åby River) was tested to failure. The findings can be used to identify optimal solutions for other bridges of the same design that are still in use, notably the bridge over Rautasjokk (a river in Sweden). These two bridges were tested in three stages. This paper focuses on the second stage, wherein Åby Bridge was subjected to static full-scale testing to failure, by pulling it downwards. The global failure mode consisted of buckling of the top chord with yielding of the steel starting at a total load of 8 MN and the peak load being reached at around 11 MN, corresponding to a load approximately four to five times higher than the characteristic design load.

  • 13.
    Häggström, Jens
    et al.
    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. Skanska Teknik, Göteborg.
    Collin, Peter
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering. Ramböll Sverige AB, Luleå.
    Täljsten, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Assessment and full scale failure test of a steel truss bridge2015In: IABSE symposium Madrid 2014: Engineering for progress, nature and people, Zürich: International Association for Bridge and Structural Engineering, 2015, p. 2757-2764Conference paper (Refereed)
    Abstract [en]

    Large amount of resources has been invested in maintaining existing infrastructure. Several of these structures are now becoming old and do not meet the requirements of today or are reaching the end of their lifecycle. It is not possible to replace all of these structures that are deemed or are about to be deemed obsolete, due to high cost and environmental impacts.One way to keep these structures in use for a longer time is innovative and intelligent assessment of the actual state of stress and behaviour. In such cases, using structural health monitoring to assess the structure might be an efficient way to extend the life of the structure.This paper will describe a unique monitoring program over two similar 33 m long steel truss bridges situated in Sweden. One of these bridges, Aby River, has a regulated axle load of 25 tons and is deemed to have reached is end of life due to fatigue. The other bridge, Rautasjokk, has a regulated axle load of 30 tons but will be in use for the coming years.The monitoring program has the following outline; monitoring of the bridge over Aby river when it is in service, after replacement this bridge will be moved and tested under static loads to assess boundary conditions and state of stress, then parts of this bridge will be disassembled and these parts will be tested in laboratory environment for fatigue life assessment, all of these results will then be controlled by monitoring of the bridge over Rautasjokk in service limit state.The outline of this project will give input for the fatigue life models that are used today and probably upgrade the fatigue life of the bridge over Rautasjokk.

  • 14.
    Häggström, Jens
    et al.
    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 Fire Engineering.
    Täljsten, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Bridge over Åby River: Evaluation of full scale testing2017Report (Other academic)
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  • 15.
    Nilimaa, Jonny
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Bagge, Niklas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Häggström, Jens
    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.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Täljsten, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    More Realistic Codes for Existing Bridges2016In: IABSE CONGRESS, STOCKHOLM, 2016: Challenges in Design and Construction of an Innovativeand Sustainable Built Environment / [ed] Elfgren, Lennart; Jonsson, Johan; Karlsson, Mats; Rydberg-Forssbeck, Laja; Sigfrid, Britt, CH - 8093 Zürich, Switzerland, 2016, p. 399-407Conference paper (Refereed)
    Abstract [en]

    Examples are given from comparisons of analyses based on (1) code models, (2) finite element models and (3) full scale tests to failure of three bridges. The analyses based on the code models gave very conservative results, while the finite element models could better predict the real behaviour.

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  • 16.
    Nilimaa, Jonny
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Häggström, Jens
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Bagge, Niklas
    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.
    Sas, Gabriel
    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.
    Carolin, Anders
    Trafikverket, Borlänge, Sweden.
    Paulsson, Björn
    Trafikverket, Borlänge, Sweden.
    Maintenance and Renewal of Concrete Rail Bridges - Results from EC project MAINLINE2014In: Nordic Concrete Research, ISSN 0800-6377, Vol. 50, p. 25-28Article in journal (Refereed)
    Abstract [en]

    There is a need to extend the life and capacity of many existing railway bridges. One of the objects of the EC-FP7-Project MAINLINE, 2011-2014, is to facilitate this. Guidelines for assessment and strengthening methods are presented as well as case studies in which existing bridges are being studied in order to extend their life length. Case studies on bridges tested to failure in order to calibrate assessment methods are also presented. Fatigue is often a vital question. A Life Cycle Assessment Tool (LCAT) is being prepared to enable Infrastructure Managers to choose optimal maintenance strategies.

  • 17.
    Nilimaa, Jonny
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Häggström, Jens
    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.
    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.
    Tu, Yongming
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Carolin, Anders
    Trafikverket, Trafikverket, Luleå.
    Paulsson, Björn
    Trafikverket, UIC, Banverket.
    Extend the life of existing railway bridges: Results from EU FP7 project MAINLINE2015In: IABSE Conference Geneva 2015: Structural Engineering: Providing Solutions to Global Challenges, Geneva: International Association for Bridge and Structural Engineering, 2015, p. 1219-1226Conference paper (Other academic)
    Abstract [en]

    There is a need to extend the life and capacity of many existing bridges. One of the objects of the EU FP7 Project MAINLINE, 2011-2014, was to facilitate this. Guidelines for assessment and strengthening methods are presented as well as case studies in which existing bridges are studied in order to extend their life length. One example is the prestressing of the slab in a one-span concrete trough bridge in order to increase its load-carrying capacity. Horizontal holes were drilled trough the slab and in them steel bars were placed and post-tensioned. In this way a compressive stress was introduced into the concrete section so that it’s bending and shear capacity was increased.In another study a metal truss bridge was monitored in order to check strain and stress ranges in critical connections to enable an enhanced evaluation of the remaining fatigue resistance. The studied bridge was then replaced and loaded to failure to study its robustness and the reliability of applied assessment methods. The results could then be applied to prolong the life of an identical twin bridge located in the northern part of Sweden. A Life Cycle Assessment Tool (LCAT) has been developed to enable Infrastructure Managers to choose optimal maintenance strategies.

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    fulltext
  • 18.
    Sas, Gabriel
    et al.
    Norut Northern Research Institute, Narvik.
    Bagge, Niklas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Häggström, Jens
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Nilimaa, Jonny
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Puurula, Arto
    Blanksvärd, Thomas
    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.
    Carolin, Anders
    Trafikverket, Trafikverket, Luleå.
    Paulsson, Björn
    Trafikverket, UIC, Banverket.
    Tested versus code capacity of existing bridges: Three examples2015In: IABSE Conference Geneva 2015: Structural Engineering: Providing Solutions to Global Challenges, Geneva: International Association for Bridge and Structural Engineering, 2015, p. 727-734Conference paper (Other academic)
    Abstract [en]

    This paper presents the results from three tests to failure of different types of bridges: a two span reinforced concrete railway trough bridge; a five-span prestessed concrete beam bridge; and a one span metal railway truss bridge. The results show that the capacity of the structures are underestimated by current standards, while numerical analysis combined with material testing can provide more accurate results. Some examples are also presented on how deficiencies incapacity can be mitigated using fiber reinforced polymer strengthening systems.

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    FULLTEXT01
  • 19.
    Täljsten, Björn
    et al.
    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.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Bagge, Niklas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Nilimaa, Jonny
    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.
    Carolin, Anders
    Trafikverket, Luleå, Sweden.
    Häggström, Jens
    Trafikverket, Luleå, Sweden.
    Bridges tested to failure in Sweden2018In: IABSE Conference Copenhagen 2018: Engineering the Past, to Meet the Needs of the Future, International Association for Bridge and Structural Engineering (IABSE) , 2018, p. 64-70Conference paper (Refereed)
    Abstract [en]

    Five bridges of different types have been tested to failure and the results have been compared to analyses of the load-carrying capacity using standard code models and advanced numerical methods. The results may help to make accurate assessments of similar existing bridges. There it is necessary to know the real behaviour, weak points, and to be able to model the load-carrying capacity in a correct way.The five bridges were: (1) a strengthened one span concrete road bridge - Stora Höga ; (2) a one span concrete rail trough bridge loaded in fatigue – Lautajokk; (3) a two span strengthened concrete trough railway bridge - Övik; (4) a one span railway steel truss bridge -Åby; and (5) a five span prestressed concrete road bridge - Kiruna. The unique results in the paper are the experiences of the real failure types, the robustness/weakness of the bridges, and the accuracy and shortcomings/potentials of different codes and models for safety assessment of existing structures

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    fulltext
  • 20.
    Vestman, Victor
    et al.
    Ramböll, Luleå.
    Collin, Peter
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Häggström, Jens
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Improvement of fatigue resistance through box-action for I-girder composite bridges2016In: IABSE CONGRESS, STOCKHOLM, 2016: Challenges in Design and Construction of an Innovativeand Sustainable Built Environment / [ed] ennart Elfgren, Johan Jonsson, Mats Karlsson, Lahja Rydberg-Forssbeck and Britt Sigfrid, CH - 8093 Zürich, Switzerland, 2016, p. 1988-1994Conference paper (Refereed)
    Abstract [en]

    When strengthening existing I-girder composite bridges one idea is to make the cross section act like a box section, by adding a horizontal truss between the bottom flanges. This means that eccentric loads produce a torque that is transferred by shear forces around the section. The magnitude of the effects coming from introducing such a framework between girders is addressed in this article. The fatigue resistance will be improved by the reduced stress ranges and increased amount of tolerated load cycles and extend the lifetime of the details, and by so the lifetime for the bridge.

1 - 20 of 20
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