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  • 51.
    Cederwall, Krister
    et al.
    Luleå University of Technology.
    Elfgren, Lennart
    Luleå University of Technology.
    Shear and Torsion Design of Prestressed and Non-Prestressed Concrete Beams1981In: Journal - Prestressed Concrete Institute, ISSN 0032-793X, Vol. 26, no 6, p. 96-97Article in journal (Other academic)
  • 52.
    Cederwall, Krister
    et al.
    Chalmers University of Technology.
    Elfgren, Lennart
    Losberg, Anders
    Chalmers University of Technology.
    Prestressed concrete columns under long-time loading1970Conference paper (Refereed)
    Download full text (pdf)
    FULLTEXT01
  • 53. Cermona, Christian
    et al.
    Bien, Jan
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Field testing of old bridges2007In: Sustainable bridges: assessment for future traffic demands and longer lives / [ed] Jan Bien; Lennart Elfgren; Jan Olofsson, Wrocław: Dolnoslaskie Wydawnictwo Edukacyjne , 2007, p. 423-433Conference paper (Refereed)
  • 54.
    Collin, Peter
    et al.
    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.
    Lagerqvist, Ove
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Hoglund, Torsten
    Royal Institute of Technology, Stockholm, Sweden.
    Kuhlmann, Ulrike
    University of Stuttgart, Stuttgart, Germany.
    Veljkovic, Milan
    Delft University of Technology, Delft, Netherlands.
    In memoriam - Bernt Johansson2018In: Steel Construction, ISSN 1867-0520, Vol. 11, no 4, p. 315-315Article in journal (Other academic)
  • 55.
    Coric, Ibrahim
    et al.
    Swedish Transport Administration, The Business Area Maintenance, Bridge and Tunnel within Railway System, Luleå, Sweden.
    Enochsson, Ola
    Swedish Transport Administration, The Business Area Maintenance, Bridge and Tunnel within Railway System, Luleå, Sweden.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Eisenbahnbrücken auf der Erzbahnlinie in Nordschweden - Erhöhung der Achslasten von 14 auf 32.5 metrische Tonnen: [Railway bridges on the Iron Ore line in Northern Sweden  - From axle loads of 14 to 32.5 metric tons]2021In: Internationale Arbeitstagung Brücken- und Ingenieurbau 2021 / [ed] Gero Marzahn, Berlin: Bundesministerium für Verkehr und digitale Infrastruktur , 2021, p. 118-122Conference paper (Refereed)
    Abstract [en]

    The Iron Ore Railway Line was built around 1900 and has more than 100 bridges. It has a length of ca 500 km and runs from the mines in northern Sweden to harbours on the Atlantic and on the Baltic. The original axle load was 14 ton. In order to lower freight costs, the axle loads has gradually been increased to 25 ton in 1955, to 30 ton in 1998,  and to 32.5 ton in 2017-2019. The increases in axle loads have been proceeded by monitoring and assessment studies of the bridges. Many of the bridges could carry a higher load than what it was designed for. Experiences from studies are presented showing that much money can be saved by a well planned maintenance and retrofitting/replacement program.

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    fulltext
  • 56.
    Coric, Ibrahim
    et al.
    Trafikverket, Luleå, Sweden .
    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. Skanska Sverige.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. Norut, Norge.
    Ohlsson, Ulf
    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.
    Railway Bridges on the Iron Ore Line in Northern Sweden: From Axle Loads of 14 to 32,5 ton2018In: IABSE Conference Copenhagen 2018: Engineering the Past, to Meet the Needs of the Future, International Association for Bridge and Structural Engineering (IABSE) , 2018, p. 55-62Conference paper (Refereed)
    Abstract [en]

    The Iron Ore Railway Line was built around 1900 and has more than 100 bridges. It has a length of ca 500 km and runs from Kiruna and Malmberget in northern Sweden to the ice-free harbour in Narvik in Norway on the Atlantic and to Luleå in Sweden on the Baltic. The original axle load was 14 ton. The axle load has gradually been increased to 25 ton in 1955, to 30 ton in 1998 and to 32,5 ton in 2017.

    The increases in axle loads have been preceded by monitoring and assessment studies of the bridges. The capacity and need for strengthening or replacement of the bridges have been evaluated. Many of the bridges could carry a higher load than what it was designed for. Experiences from studies before the axle load was increased in 1998 and 2017 are presented and discussed.

    Download full text (pdf)
    fulltext
  • 57.
    Daerga, Per-Anders
    et al.
    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.
    Draghållfasthet hos högpresterande betong1991In: Bygg och Teknik, ISSN 0281-658X, E-ISSN 2002-8350, no 7, p. 25-26, 28Article in journal (Other (popular science, discussion, etc.))
  • 58.
    Daerga, Per-Anders
    et al.
    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.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Behaviour of concrete at low temperatures1989In: POAC '89: 10th International conference on port and ocean engineering under arctic conditions / [ed] Kenneth B.E. Axelsson; Lennart Å. Fransson, Luleå: Luleå tekniska universitet, 1989, Vol. 2, p. 808-819Conference paper (Other academic)
  • 59.
    Daescu, Cosmin Al
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. Politehnica University Timisoara, Timisoara, Romania.
    Gonzalez-Libreros, Jaime
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Wang, Chao
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Demolition of a 65-year-old box-girder prestressed concrete bridge located in Northern Sweden2023In: EuroStruct 2023 European Association on Quality Control of  Bridges and Structures: Digital Transformation in Sustainability / [ed] Alfred Strauss; Konrad Bergmeister, John Wiley & Sons, 2023, p. 229-234Conference paper (Refereed)
    Abstract [en]

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

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    fulltext
  • 60.
    Daescu, Cosmin
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. Politehnica University of Timisoara, Timisoara, Romania.
    Lundin, Hanna
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sarmiento Nova, Silvia Juliana
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Gonzalez-Libreros, Jaime H.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Study of demolition strategies and preliminary plan for the case of the Kalix bridge2022In: Bridge Safety, Maintenance, Management, Life-Cycle, Resilience and Sustainability: Proceedings of the Eleventh International Conference on Bridge Maintenance, Safety and Management (IABMAS 2022), Barcelona, Spain, July 11-15, 2022 / [ed] Joan-Ramon Casas; Dan M. Frangopol; Jose Turmo, Taylor & Francis, 2022, p. 2396-2403Conference paper (Refereed)
  • 61. Danielsson, Georg
    et al.
    Johansson, Håkan
    Thun, Håkan
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Töjningsmätning på järnvägsbro över Luossajokk i Kiruna2002Report (Other academic)
  • 62.
    Ditrani, Marco
    et al.
    Politecnico di Milano.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Eriksen, Jörgen
    Enochsson, Ola
    Veljkovic, Milan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Andersson, P.
    Vägverket.
    Eriksson, Per
    Vägverket.
    Improving transportation investment decision through life-cycle cost analysis: case study on some bridges in the north of Sweden2009In: Sustainability of Constructions - Integrated Approach to Life-time Structural Engineering: Proceedings of the Workshop Timişoara, 23-24 October 2009. COST Action C25, 2009, p. 266-275Conference paper (Refereed)
    Abstract [en]

    The scope of this project is to perform Life Cycle Cost Analysis (LCCA) on different types of bridges, in order to learn which is most cost-efficient in a particular situation. A second scope is to study the impact of different cost items on the whole Life Cycle Cost. The work is performed to enable optimal strategic decisions regarding future investments.Beam and Slab Bridges, Slab Bridges and Slab Frame Bridges are analyzed. The bridges are located in the north of Sweden, in the regions of Norrbotten and Västerbotten. All bridges have a total length of around 20 m, which is the most common length in Sweden and in Europe. Furthermore, the analysis includes Timber and Soil-Steel bridges in order to understand the prospects for this types of bridges in Sweden. The analysis does not focus on a particular bridge but, based on information from some Swedish producers, it studies different scenarios.The data collection covers initial investments, maintenance, repair and rehabilitation (MR&R) costs, user and demolition costs.

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    FULLTEXT01
  • 63.
    Du, Linpu
    et al.
    Key Laboratory of Concrete and Prestressed Concrete Structures of Ministry of Education, School of Civil Engineering, Southeast University, 211189, Nanjing, China.
    Zhang, Wei
    Key Laboratory of Concrete and Prestressed Concrete Structures of Ministry of Education, School of Civil Engineering, Southeast University, 211189, Nanjing, China.
    Tu, Yongming
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. Key Laboratory of Concrete and Prestressed Concrete Structures of Ministry of Education, School of Civil Engineering, Southeast University, 211189, Nanjing, China; National Engineering Research Center for Prestressing Technology, Southeast University, 211189, Nanjing, China.
    Song, Shoutan
    Key Laboratory of Concrete and Prestressed Concrete Structures of Ministry of Education, School of Civil Engineering, Southeast University, 211189, Nanjing, China; National Engineering Research Center for Prestressing Technology, Southeast University, 211189, Nanjing, China.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. SINTEF Narvik AS, Narvik 8517, Norway.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Shaking table test on a novel mega-frame suspended structural system2022In: Journal of Building Engineering, E-ISSN 2352-7102, Vol. 52, article id 104440Article in journal (Refereed)
    Abstract [en]

    This paper designed a 1/20 scaled two-segment 19-story mega-frame suspended structure. The seismic behaviors of the structure equipped with viscous dampers (named damping suspended structure, DSS) or rigid connecting rods (named normal suspended structure, NSS) were studied and evaluated by a series of shaking table tests, where three seismic ground motions with two intensities were selected as input motions. Both acceleration and displacement responses of the primary and suspended structures were recorded. The results revealed that the mega-frame suspended system showed good seismic behaviors and viscous dampers could effectively improve its energy dissipation capacities. For DSS, the maximal acceleration and displacement reduction of suspended structures were 75.4% and 39.8% while those of the primary structure were 29.4% and 35.3% respectively. White noise tests showed all models were at the elastic stage under all cases. Evident relative displacements between the primary and subordinate structures were observed for DSS, in this case, the suspended floors were considered as the additional mass of the primary structure and the energy could be dissipated by the swing of suspended floors. The energy dissipation mechanism of DSS was theoretically analyzed while the effect of connection forms on vibration reduction was discussed.

  • 64. Dury, Robin
    et al.
    Bernander, Stig
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Kullingsjö, Anders
    Skanska Teknik AB.
    Laue, Jan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Knutsson, Sven
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Pusch, Roland
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Progressive Landslide Analysis with Bernander Finite Difference Method2017In: / [ed] Vikas Thakur, Jean-Sébastien L’Heureux, Ariane Locat, 2017, p. 1-Conference paper (Other academic)
    Abstract [en]

    The poster presents a new Spreadsheet developed by Robin Dury (2017) to simplify the use of the Finite Difference Method developed by Stig Bernander et al (2011, 2016).

    It includes:

    - Material Properties

    - Finite Difference Method

    - Progressive failure process with five phses

    - Discussion

    - References

    Download full text (pdf)
    Poster
  • 65.
    Duvnjak, Ivan
    et al.
    University of Zagreb, Croatia.
    Bartolak, Marko
    University of Croatia.
    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.
    Lessons Learnt from Full-Scale Tests of Bridges in Croatia and Sweden2018In: IABSE Symposium, Nantes 2018: Tomorrow's Megastructures, International Association for Bridge and Structural Engineering , 2018, p. S23-127-S23-134Conference paper (Refereed)
    Abstract [en]

    Load testing is a way to control the capacity and function of a bridge. Methods and recommendations for load testing are described and examples are given form tests carried out in Croatia and Sweden. In order not to damage the bridge being tested, the load must be limited, often to be within the serviceability limit state (SLS). Numerical models can be calibrated by load tests and then be used to check the carrying capacity for higher loads than what has been tested. Need for further work and recommendations are discussed. By effective planning, costs can be saved and a more sustainable use of bridges can be obtained.

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    fulltext
  • 66.
    Duvnjak, Ivan
    et al.
    University of Zagreb, Croatia.
    Damjanović, Domagoj
    University of Zagreb, Croatia.
    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.
    Ohlsson, Ulf
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Tu, Yongming
    School of Civil Engineering, Southeast University, Nanjing, China.
    Damage Detection in Structures – Examples2019In: IABSE Symposium 2019: Towards a Resilent Built Environment - Risk and Asset Management, nternational Association for Bridge and Structural Engineering (IABSE) , 2019, p. 471-478Conference paper (Refereed)
    Abstract [en]

    Damage assessment of structures includes estimation of location and severity of damage. Quite often it is done by using changes of dynamic properties, such as natural frequencies, mode shapes and damping ratios, determined on undamaged and damaged structures. The basic principle is to use dynamic properties of a structure as indicators of any change of its stiffness and/or mass. In this paper, two new methods for damage detection are presented and compared. The first method is based on comparison of normalised modal shape vectors determined before and after damage. The second method uses so-called 𝑙1-norm regularized finite element model updating. Some important properties of these methods are demonstrated using simulations on a Kirchhoff plate. The pros and cons of the two methods are discussed. Unique aspects of the methods are highlighted.

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    Preprint
  • 67.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Activity: Bridge Design, K7005B2015Conference paper (Other (popular science, discussion, etc.))
  • 68.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Aktivitet: Högpresterande betong ger lättare konstruktioner1992Other (Other (popular science, discussion, etc.))
  • 69.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Aktivitet: Kompetenscentra behövs. Goda erfarenheter av tvärdisciplinär forskning i Luleå1992Other (Other (popular science, discussion, etc.))
  • 70.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    American Structural Engineering Research: A report form an academic year in the United States and Canada 1972-731975Report (Other (popular science, discussion, etc.))
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    FULLTEXT01
  • 71.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Analogy between anchor bolt failure and punching shear2000In: Proceedings: International Workshop on Punching Shear Capacity of RC Slabs, dedicated to professor Sven Kinnunen / [ed] J. Silfwerbrand; G. Hassanzadeh, Stockholm: Kungliga tekniska högskolan, 2000, p. 493-502Conference paper (Refereed)
    Abstract [en]

    Similarities in the behaviour, analysis and design of anchor bolts and punching shear are discussed. The treatment of size effects in codes is compared.

  • 72.
    Elfgren, Lennart
    Luleå University of Technology.
    Application of fracture mechanics to concrete structures1989In: Fracture Toughness and Fracture Energy: Test Methods for Concrete and Rock: Proceedings of the international workshop, Sendai, Japan, 12-14 October 1988 / [ed] H. Mihashi, H. Takahashi, F.H. Wittmann, Rotterdam: Balkema, 1989, p. 575-590Conference paper (Refereed)
    Abstract [en]

    Various examples are presented on how fracture mechanics can be used to get a better insight into the behaviour of structural concrete components. Special emphasis is given to the phenomenon of size dependence. Since dependence is shown to be a function of a brittleness number which is derived from a simple study of energy. The concept of brittleness has similar features as slenderness -  a well established parameter in the design of elements in compression

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    fulltext
  • 73.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Arne Hillerborg and Fracture Mechanics1991In: Analysis of Concrete Structures by Fracture Mechanics: Proceedings of the International RILEM Workshop dedicated to pofessor Arne Hillerborg / [ed] Lennart Elfgren; Surendra P Shah, London: Taylor and Francis Group , 1991, p. 1-16Conference paper (Refereed)
    Abstract [en]

    The paper gives an overview of Arne Hillerborg's contributions to Fracture Mechanics. Arne Hillerborg was born in 1923 and was a professor at Lund Institute of Technology 1968-1989.

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    FULLTEXT01
  • 74.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Assessment of structural concrete: results from a European research project Sustainable Bridges2008In: Proceedings, Nordic Concrete Research, Bålsta, Sweden: [ ... XXth Symposium on Nordic Concrete Research & Development ... The current proceedings contain 90 summaries of oral poster presentations] / [ed] Johan Silfwerbrand, Oslo: Norsk Betongforening , 2008, p. 140-141Conference paper (Refereed)
  • 75.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Avancerade cementbaserade material och konstruktioner1994In: Bygga framtid, Vol. 5, p. 72, 74-76Article in journal (Other (popular science, discussion, etc.))
  • 76.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Avdelningen för Konstruktionsteknik. Verksamhetsberättelse 1983/841984Report (Other (popular science, discussion, etc.))
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    FULLTEXT01
  • 77.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Avdelningen för Konstruktionsteknik. Verksamhetsberättelse 1984/851985Report (Other (popular science, discussion, etc.))
    Download full text (pdf)
    FULLTEXT01
  • 78.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Benchmark of new technologies to extend the life of elderly rail infrastructure: Deliverable D1.1 of the MAINLINE Project2013Report (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 this report an overview is given of some of the most promising new or updated technologies. Based on these findings further work in the Mainline project will mostly focus on the following areas: - Assessment methods - Monitoring methods- Repair and Strengthening methodsQuestionnaires on bridges, tunnels, earthworks and track were prepared and twelve Infrastructure Managers have responded to the bridge questionnaire; responses to the other questionnaires have been more limited. If the results from this bridge sample are extrapolated from the about 125 000 km of network and the about 150 000 railway bridges that these Infrastructure Managers oversee to the full European network, which is about 230 000 km, a rough estimate may be obtained of the needs for the next years. Such an extrapolation suggests that in the next ten years we may expect to strengthen some 1 500 bridges, to replace some 4 500 bridges and to replace the deck of some 3 000 bridges. Some of the bridges that are planned to be replaced may instead be strengthened, if the new technologies presented here would be used.Work is also going on to improve the life length of track, switches and crossings and other rail infrastructure as earthwork, tunnels, drainage and culverts.It can also be seen that not many Infrastructure Managers currently use Life Cycle Costing (i.e. financial) and/or Life Cycle Assessment (i.e. environmental) in the planning of maintenance and repair of their rail infrastructure. There is a lack of data and methods and here the Mainline Project is intending to give guidance. There is also often a lack of economic resources for maintenance which may lead to a shorter life length and less sustainability than would otherwise be the case; results from the Mainline Project are also intended to give advice that may help to improve this situation.Stakeholders in Europe will benefit from reduced costs, higher efficiency and reduced environmental impact for existing rail infrastructure by using the methods presented here. For upgrading of bridges some 150 million Euros per year may be saved compared to the cost of replacing existing bridges with new ones. For track and other rail infrastructure similar savings may be achieved adding up to a total possible saving of more than 300 million euros per year. In Eastern Europe savings may be proportionally larger as a larger part of the tracks and the structures is old and in need of upgrading or replacement.

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    FULLTEXT01
  • 79.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Betongforskning vid Luleå tekniska universitet2001In: Betong, ISSN 1101-9190, Vol. 11, no 3, p. 19-21Article in journal (Other (popular science, discussion, etc.))
  • 80.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Brottmekanik1989Report (Other academic)
    Abstract [sv]

    En grundläggande presentation av idéer och begrepp inom brottmekaniken.

    Download full text (pdf)
    fulltext
  • 81.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Bygga med betong - några utmaningar1993In: Bygga framtid, Vol. 4, p. 18-22Article in journal (Other (popular science, discussion, etc.))
  • 82.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    CHPC - Centrum för Högpresterande Cement: Slutrapport till EGs Strukturfonder, Mål 2, 1997-07-01--1999-12-312000Report (Other (popular science, discussion, etc.))
    Abstract [sv]

    Egenskaperna för ett nytt, miljövänligt, energimodifierat cement har utvecklats och modifierats på ett sätt som gör att det kan reducera utsläppne av koldioxid.

  • 83.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Defects in railway bridges and procedures for maintenance: UIC Code 778-4R2009Report (Other (popular science, discussion, etc.))
    Abstract [en]

    This leaflet gives guidelines and recommendations covering procedures for the maintenance and strengthening of railway bridges. Arrangements and methods for inspection are presented; defects are described; methods for monitoring and assessment are given; and procedures for maintenance, repair, strengthening and renewal are defined.The purpose is to update the 1989 edition of UIC Code 778-4R and to implement results from a European Integrated Research Project (2003-2007) on “Sustainable Bridges – Assessment for Future Traffic Demands and Longer Lives” (TIP3-CT-2003-001653) within the 6th Framework Programme.

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  • 84.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Development of models for torsion of concrete structures in northern Europe2009In: Thomas T.C. Hsu Symposium: Shear and Torsion in Concrete Structures / [ed] Abdeldjelil (DJ) Belarbi; Yi-Lung Mo; Ashraf S Ayoub, Farmington Hills, MI: American Concrete Institute, 2009, p. 309-325Conference paper (Refereed)
    Abstract [en]

    The paper describes the development of models for torsion in northern Europe. After an introduction with a few historical notes, early use of nonlinear methods in Scandinavia is presented. The development of failure models for combined torsion, bending and shear is then described as well as the use of truss models. Static and kinematic methods are treated and a discrepancy in the results from different approaches is discussed. A refined model is then presented which unifies the results. Finally, some recent contributions are presented regarding prestressed high strength circular column elements, hollow core slabs and curved bridges.

  • 85.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Discussion of “Failure Load Test of a CFRP Strengthened Railway Bridge in Örnsköldsvik, Sweden” by Marcus Bergström, Björn Täljsten, and Anders Carolin2011In: Journal of Bridge Engineering, ISSN 1084-0702, E-ISSN 1943-5592, Vol. 16, no 3, p. 490-Article in journal (Other academic)
    Abstract [en]

    The authors have written an interesting paper on the test to failure of a strengthened railway bridge. However, the failure mode analysis of the bridge as built is not correct. The failure mode is the same for the bridge as built as for the strengthened bridge, i.e., crushing of the compression concrete with yielding of the steel in tension. For the strengthened bridge, bond failure of the carbon-fiber-reinforced polymer (CFRP)reinforcement also played an important part in the initiation of the final collapse. Eq. (1) in the original paper underestimates the bending moment capacity M1 of the bridge as built almost by a factor of 2 as loading up to crushing of the concrete was not considered. Instead, Eq. (8) should have been used with a zero contribution from strengthening. In Eq. (8) there is also a printing error as the coefficient β2 is left out in the last parentheses (it should read “h - β2x2” instead of “h - 2”). The underestimation of the capacity of the bridge as built gives erroneous results in Table 2 and in Fig. 5. In Table 2 the height x1 of the compression zone for the bridge as built should be about half the given value of 291 mm. The value M1 corresponding to the bridge as built should be about twice the given value of 4.5 MN. The given flexural capacities M1 and M2, of the as built and strengthened bridges, respectively, refer to the corresponding applied vertical load P causing the flexural moments and not to the moments themselves. This explains why the unit MN is used instead of MN·m. Furthermore, the shear capacity V also refers to the corresponding applied vertical load P causing the shear and not to the shear capacity itself (which is about half the value of the applied load P). Furthermore, in Table 2 the comment to the shear capacity V should be referring to Eq. (11) instead of to Eq. (6). In Fig. 5, all the load values refer to the values of the applied load P causing the shear and flexure;  not to the moments M1 and M2 or to the shear force T. After the corrections mentioned previously, the values corresponding to the two moments M1 and M2 will be located much closer to each other. 

    The corrections do not change the main conclusions of the paper, and the discusser agrees with the authors that the tested bridge gives a good example of the complex interaction of bending and shear in concrete bridges. Additional information about the test and the different analysis of it and the European Research Project, which it was a part of, can be found in Elfgren et al. (2008), Puurula et al. (2008), Feltrin et al. (2008), Helmerich et al. (2008), Jensen et al. (2008), Täljsten et al. (2008), and Sustainable Bridges (2008).

  • 86.
    Elfgren, Lennart
    Institutionen för konstruktionsteknik, Chalmers tekniska högskola, Göteborg, Sweden.
    Elementmetoder i Styrkebergninger: Rapport från en studieresa i Norge i januari 19691969Report (Other (popular science, discussion, etc.))
    Abstract [sv]

    Rapport från en studieresa till Norge med deltagande i kursen "Elementmetoder i styrkeberegninger" - den första kursen on finit elementmetod (FEM) i Norden. Den ägde rum i Trondheim 1969-01-06--11. I Trondheim besöktes även Institutt for Betongkonstruksjober, Institutt for Statikk och Forskningsinstituttet for Cement og Betong. På hemresan besöktes Norges byggforskningsinstitutt och Norges Betongtekniske Institutt i Oslo 1969-01-13..

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  • 87.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Fatigue Capacity of Concrete Structures: Assessment of Railway Bridges2015Report (Other academic)
    Abstract [en]

    Present codes are mostly written for the design of new structures. When assessing existing structures it is possible to ascertain actual properties and to use them instead of using very conservative estimates. Possible reinforcement fatigue damage can e.g. be assessed with partial damage methods in the same way as is done for steel structures and with similar failure stresses.- The definition of a load cycle depends on the structure and what part of it that is studied. For ballasted bridges often two bogies for adjacent wagons can be identified as one load cycle. For the highest stress ranges often a whole train can be looked upon as one load cycle. The influence of earlier traffic can be checked with a damage hypothesis.- Material properties. The concrete capacity is often underestimated, especially its capacity to carry shear forces in slabs without stirrups. For stirrups usually no reduction normally needs to be considered of the stress range capacity due to bending of the bars. This is true as long as the cracks in concrete crossing the bars are not situated in the corners of the cross sections- Dynamic factors can often be reduced from the ones obtained from standard code values after an evaluations and/or measurement on the structure in question.- The need for closed stirrups and reductions of capacity due to splicing of reinforcement bars can be reduced if the reinforcement is fully bonded as e.g. when it is situated in compressed concrete.- More research is needed to calibrate design and assessment methods to real full scale tests on bridges. Here new measurement technology makes it possible to check real strain and stress ranges, which may be considerably smaller than the ones obtained from conservative design models.- Recommendations for assessment procedures are given in Appendix A. Examples of assessments of two concrete trough bridges are presented in Appendix B (Övre Bredån) and Appendix C (Kallkällan).

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  • 88.
    Elfgren, Lennart
    Luleå University of Technology.
    Fracture mechanics of concrete structures: From theory to applications: Report of the Technical Committee 90-FMA Fracture Mechanics to Concrete/Applications, RILEM (the International Union of Testing and Research Laboratories for Materials and Structures)1989Collection (editor) (Other academic)
    Abstract [en]

    Ductile and durable concrete structures are the goal of all designers. In order to achieve such goals it is necessarry to know the laws that govern the behaviour of materials and structures.This report explains how cracking, ductility and brittleness are influenced by dimensions (size effects) and material properties such as tensile strength, stiffness (modulus of elasticity) and fracture energy. This is done with the help of models of fracture mechanics. The different models that have emerged during the last ten years are first presented and accomodated inside a common frame. Practical applications are then presented in a variety of fields. The report should be of interest to persons engaged in design, development, research and teaching in the field of Concrete structures. It was prepared by RILEM Technical Committee 90-FMA 'Fracture Mechanics of Concrete - Applications' during 1986-1988.

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  • 89. Elfgren, Lennart
    Förstärkning av infrastrukturkonstruktioner, bedömning av livslängd och bärförmåga hos betongkonstruktioner: projektuppgifter i doktorandkurs anordnad av Lennart Elfgren, Göran Fagerlund, Håkan Sundqvist och Björn Täljsten för industrikonsortiet Väg-Bro-Tunnel2001Other (Other (popular science, discussion, etc.))
    Abstract [sv]

    I rapporten redovisas projektarbeten som utförts i en doktorandkurs som arrangerats av industrikonsortiet Väg-Bro-Tunnel under hösten 2000. Konsortiet stöds av Vinnova (NUTEK t o m 2000-12-31), Cementa, Elforsk, LKAB, NCC och Skanska. Doktorandkursen har arrangerats i samarbete mellan KTH, LTH och LTU. Vid tre samlingar på Kebnekaise fjällstation, på LTH och på KTH har föreläsningar och projektgenomgångar ägt rum. Rapporten innehåller följande delar: * Förstärkning av traversbalk med avancerade kompositmaterial. Dimensionering av förstärkning. Joakim Jeppsson och Håkan Nordin * Livslängdsberäkning och förslag på förstärkningsåtgärder för huvudbalkarna till Ölandsbrons lågbrodel. Jonas Carlswärd och Peter Harrysson* Förstärkning av parkeringsdäck i Malmö. Fredrik Carlsson och Mattias Wäppling* Förstärkning av spannmålssilo i Grästrorp. Daniel Eklund och Anders Rönneblad* Pelare 154 i Ölandsbron - Bedömning av bärförmåga, resterande livslängd och förstärkning. Martin Nilsson och Anders Wiber* Skadebedömning och reparationsåtgärder av mittpelare av bro i Eskilstuna. Ghassem Hassanzadeh och Lutfi Ay* Betongsliprar. Anders Carolin och Gerard James

  • 90.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    High performance concrete and tension softening1999In: Werkstoffe im Bauwesen: Theorie und Praxis. Festschrift zum 60. Geburtstag von Prof. Dr. Hans-Wolf Reinhardt, Stuttgart: Ibidem-Verlag, 1999, p. 85-93Chapter in book (Other academic)
    Abstract [en]

    Some results regarding Tension Stiffening of High Performance Concrete are presented. The results are based on a Swedish Research Program on High Performance Concrete Structures. The aim of the program is to develop (a) more efficient structures, (b) better production methods and (c) more durable materials.

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  • 91.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Hook anchors and adhesive anchors. Ch. 13.31989In: Fracture mechanics of concrete structures: from theory to applications, London & New York: Taylor and Francis Group , 1989, p. 300-309Chapter in book (Other academic)
  • 92.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Högpresterande betongkonstruktioner1996In: Byggforskning : Byggforskningsrådets tidning för en bättre byggd miljö, ISSN 1102-3686, no 3, p. 36-Article in journal (Other (popular science, discussion, etc.))
  • 93.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Högpresterande betongkonstruktioner: Vad kan vi? Vilka möjligheter finns?1998In: V-byggaren : väg- och vattenbyggaren, ISSN 0283-5363, no 2, p. 16-20Article in journal (Other academic)
  • 94.
    Elfgren, Lennart
    Chalmers tekniska högskola.
    Cederwall, Krister (Contributor)
    Chalmers tekniska högskola.
    Injekteringsförankrade kohesionsstag: Belastningsförsök med dragstag i lera1971Report (Other academic)
    Abstract [sv]

    Sedan tekniken att förankra provisoriska sponter med dragstag injekterade i berg eller friktionsjörd introducerades har tanken på att förankra sponter i lera av Göteborgskaraktär ständigt förekommit hos dem som brottas med problemet att få dessa sponter stabila. För att undersöka möjligheterna gjordes år 1966-1967 en serie belastningsförsök med tre stag injekterade i lera. Härvid studerades stagens last-deformationsegenskaper vid korttids- och långtidsförsök. Dessutom bestämdes stagens brottlaster (200, 240 och 260 kN). Försöksresultaten presenteras i denna rapport jämte en diskussion om stagens lastupptagande förmåga.

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  • 95.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Kan vi öka lasten på våra broar?2006In: Bygga framtid, Vol. 17, p. 14-15Article in journal (Other (popular science, discussion, etc.))
  • 96.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Konsten att bygga nätverk: en liten ordbok1997In: Bygga framtid, Vol. 8, p. 4-5Article in journal (Other (popular science, discussion, etc.))
  • 97.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Konstruktioner av högpresterande betong1994In: Betong, ISSN 1101-9190, no 1, p. 8-11Article in journal (Other (popular science, discussion, etc.))
  • 98.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Lars Nordström 1918-20002001In: Thule: Kungl. Skytteanska samfundets årsbok 2001, Umeå: Kungl. Skytteanska samfundet , 2001, p. 161-162Chapter in book (Other (popular science, discussion, etc.))
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  • 99.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Lättare, billigare och starkare med lite mindre vatten i betongen1992In: NCCnyheter, no 1, p. 4-5Article in journal (Other (popular science, discussion, etc.))
  • 100.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Långsiktig strategisk forskning1991In: Kaldt klima: teknologisk FoU på Nordkalotten : innstilling fra utvalg nedsatt av Nordkalottkomitéen, Nordkalottens utdannings- og forskningsråd , 1991, p. 49-53Conference paper (Other academic)
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