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  • 1.
    Elfgren, Lennart
    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.
    Danielsson, Georg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Åström, Lars
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Johansson, Håkan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Paulsson, Björn
    Trafikverket.
    Töyrä, Björn
    Trafikverket.
    30 ton på Malmbanan. Rapport 3.3 Infrastruktur.: Forsknings- och utvecklingsprojekt avseende betongbroars bärighet1996Report (Refereed)
    Abstract [sv]

    I rapporten redovisas fältmätningar på fyra broar och provbelastning I laboratoriet av en bro

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    FULLTEXT01
  • 2.
    Puurula, Arto
    et al.
    Savonia University of Applied Sciences, Kuopia, Finland.
    Enochsson, Ola
    Bodens kommun, Sverige.
    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.
    Ohlsson, Ulf
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Bernspång, Lars
    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.
    3D non-linear FE analysis of a full scale test to failure of a RC Railway Bridge strengthened with carbon fibre bars2016In: IABSE CONGRESS, STOCKHOLM, 2016: Challenges in Design and Construction of an Innovativeand Sustainable Built Environment / [ed] Lennart Elfgren, Johan Jonsson, Mats Karlsson, Lahja Rydberg-Forssbeck and Britt Sigfrid, CH - 8093 Zürich, Switzerland: International Association for Bridge and Structural Engineering, 2016, p. 2527-2535Conference paper (Refereed)
    Abstract [en]

    At a full scale loading test to failure a 50 year old concrete railway trough bridge in Örnsköldsvik, in northern Sweden was tested to failure. The test was a part of the European Research Project “Sustainable Bridges” regarding assessment and strengthening of existing bridges. In the projectnew calculation methods were developed to capture the behaviour of the bridge during increasing load. The bridge was strengthened in bending with rods of Carbon Fiber Reinforced Polymer (CFRP) before the loading test. Failure was reached for an applied load of 11.7 MN by pulling a steel beam placed in the middle of one of the two spans downwards. The achieved failure was a combination of bond, shear, torsion and bending. The developed model, a 3D -non-linear finiteelement (FE) model with discrete reinforcement, gave accurate accounts of the response of thebridge. The FE calculations show the effect of the strengthening with CFRP and even the effect of the epoxy when using the Near Surface Mounted Reinforcement (NSMR) strengthening method.

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    fulltext
  • 3.
    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.

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    fulltext
  • 4. Thun, Håkan
    et al.
    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.
    A deformation criterion for fatigue of concrete in tension2011In: Structural Concrete, ISSN 1464-4177, E-ISSN 1751-7648, Vol. 12, no 3, p. 187-197Article in journal (Refereed)
    Abstract [en]

    A deformation criterion is proposed for the fatigue failure of concrete in tension. According to the criterion, a fatigue failure is imminent when the total deformation approaches the deformation at maximum stress in a corresponding static test. This criterion was originally proposed for bond slip by Balázs in 1991. It is tested on two series of new and old concrete cylinders loaded in cyclic tension. How the criterion may be used to predict the number of load cycles to failure for existing structures under cyclic tensile loading is also shown

  • 5.
    Huang, Zheng
    et al.
    School of Civil Engineering, Southeast University,Nanjing, China.
    Tu, Yongming
    School of Civil Engineering, Southeast University,Nanjing, China.
    Meng, Shaoping
    School of Civil Engineering, Southeast University,Nanjing, China.
    Ohlsson, Ulf
    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.
    A practical method for predicting shear deformation of reinforced concrete beams2020In: Engineering structures, ISSN 0141-0296, E-ISSN 1873-7323, Vol. 206, article id 110116Article in journal (Refereed)
    Abstract [en]

    This paper presents a practical method for predicting the deflections, including both the flexure and shear contributions, of reinforced concrete (RC) beams. The shear force - shear strain (V-γ) curve of a section in the shear span of RC beams is represented by a piecewise model and the tangent shear stiffness after shear cracking, Kt,cr, is assumed to be constant. A 2D finite element model, which has been validated for predicting shear deformation of RC beams, was used to identify factors that may affect the shear reduction factor (the ratio of Kt,cr to the elastic shear stiffness) and establish methodology for predicting the V-γ curve. Two types of methods, integration-form and closed-form, for predicting the total deflection were developed, in which the flexure-induced deflection (FD) was predicted using the Bischoff model while the shear-induced deflection (SD) was predicted using the method proposed in this paper. Comparison of the predictions with experimental results confirms that the Bischoff model provides reliable predictions of FDs of RC beams with and without shrinkage. It also shows that the proposed method can provide accurate predictions for SD after shear cracking, provided the effect of shrinkage on the shear cracking load is adequately quantified.

    Support from: National Natural Science Foundation of China (No. 51378104) and A Project Funded by the Priority Academic Program Development ofJiangsu Higher Education Institutions. The Development Fund of the Swedish Construction Industry (SBUF), the Swedish Research Council Formas and Elsa and Sven Thysell Foundation

  • 6.
    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.))
  • 7.
    Elfgren, Lennart
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Anneling, Roger
    Eriksson, Anders
    Granlund, Stig-Ola
    Adhesive anchors: tests with cyclic and long-time loads1987Report (Other academic)
    Download full text (pdf)
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  • 8.
    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.))
  • 9.
    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.))
  • 10.
    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
  • 11.
    He, G.J.
    et al.
    Luleå tekniska universitet.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Yuan, M.
    Civil Engineering and Architecture College, Central South University of Forestry and Technology.
    An improved structural damage detection method based on modal strain energy2006In: Proceedings of the Eighth International Conference on Computational Structures Technology: Las Palmas de Gran Canaria - Spain 12 - 15 September 2006 / [ed] B.H.V. Topping, Klippen: Civil-Comp Press , 2006Conference paper (Refereed)
    Abstract [en]

    Structural damage detection methods based on modal strain energy usually require complete modes, however, only a small number of sensors are located on the structure in practice. In order to overcome this contradict, an improved structural damage detection algorithm based on modal strain energy is developed in this paper. By divided the contribution of higher modes into two parts, i.e., the static and dynamic contributions, the static term can be expressed by lower modes and dynamic term was approximately approached. It could be applied to detect structural damage location and quantity by using only first one or two modes. The three different simulated structures with the same damaged case are studied in present. The results illustrate that the present method is simple and effective with satisfying precision both in locating the place of damage and estimating the magnitude of damage

  • 12.
    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.

  • 13.
    Elfgren, Lennart
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Shah, Surendra P.
    Analysis of concrete structures by fracture mechanics: Proceedings of a RILEM Workshop dedicated to Professor Arne Hillerborg, Abisko, Sweden 19891991Collection (editor) (Other academic)
    Abstract [en]

    This book presents research findings of applications of fracture mechanics to concrete structures. Key papers from leading experts in the field describe existing and new modelling techniques in the analysis of materials and structures. The book explains the practical application of fracture mechanics to structural modelling, bending, shear, bond and anchorage. The proceedings of this RILEM Workshop is an important reference for those engaged in design, development, research and teaching in the field of concrete structures.

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    fulltext
  • 14.
    Song, Shoutan
    et al.
    Southeast University, Nanjing.
    Yang, Dong
    Southeast University, Nanjing.
    Tu, Yongming
    Southeast University, Nanjing.
    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.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Analysis of the shear strength of joints in segmental prestressed concrete bridges2016In: 19th IABSE Congress Strockholm 21-23 September 2016: Challenges in Design and Construction of an Innovative and Sustainable Built Environment / [ed] Lennart Elfgren, Johan Jonsson, Mats Karlsson, Lahja Rydberg-Forssbeck and Britt Sigfrid, CH - 8093 Zürich, Switzerland, 2016, p. 573-579Conference paper (Refereed)
    Abstract [en]

    Joints in segmental prestressed concrete bridge (SPCB) are weak links and shear failures are likely to take place under loads. Determining the shear strength is an important part in the design of a SPCB. The shear strength in the joint relates closely to the joint form (as dry joints, epoxy joints, flat joints and keyed joints). The strength can be divided into three main parts: (1) The strength of the dry plane connection, known mainly as concrete surface friction; (2) The strength of the epoxy plane connection; and (3) The strength of the shear key root. This paper analyzes the failure mechanism and shear strength of these three parts .It also considers the influences of the shear key size and the seam height to shear strength, and establishes calculation formulas of the joint section strength in a united form. This provides a guide for the joint design in precast segmental bridges

  • 15. Ohlsson, Ulf
    et al.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Anchor bolts analyzed with fracture mechanics1991In: Fracture Processes in Concrete, Rock and Ceramics: Proceedings of the International RILEM/ESIS Conference / [ed] J.G.M. van Mier; J.G. Rots; A. Bakker, London: Taylor and Francis Group , 1991, p. 887-897Conference paper (Refereed)
  • 16.
    Elfgren, Lennart
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Noghabai, Keivan
    Luleå tekniska universitet.
    Anchor bolts and tension stiffening of rebars: two RILEM round robin investigations on bond1998In: Fracture mechanics of concrete structures.: Numerical models and analysis / [ed] Hirozo Mihashi, AEDIFICATIO Publishers , 1998, Vol. Vol. 2, p. 1279-1290Conference paper (Refereed)
    Abstract [en]

    Results from two RILEM Round Robin Investigations are presented. The first one deals with anchor bolts and the second one with bond and tension stiffening of rebars. Some 30 groups of researches encompassing over 70 people have performed more than 350 tests and analyses in America, Asia, Australia and Europe

  • 17.
    Elfgren, Lennart
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Eligehausen, R
    Institut für Werkstoffe in Bauwesen, Universität Stuttgart.
    Rots, J.G.
    Faculty of Architectun, Delft University of Technology.
    Anchor bolts in concrete structures: summary of round robin tests and analysis arranged by RILEM TC 90-FMA ‘Fracture Mechanics of Concrete-Applications’2001In: Materials and Structures, ISSN 1359-5997, E-ISSN 1871-6873, Vol. 34, no 8, p. 451-457Article in journal (Refereed)
    Abstract [en]

    Results are presented from a RILEM Round Robin Investigation on tests and analyses of anchor bolts in concrete. About 60 researchers have performed more than 180 tests and 200 analyses in America, Asia, Australia and Europe. The investigation shows that it is possible to reasonably correctly analyse both plane and axi-symmetric anchor bolt problems. However, there are difficulties to overcome and correct boundary conditions are important both in analyses and tests.

  • 18.
    Broms, Carl Erik
    et al.
    Jacobson & Widmark AB.
    Johansson, Håkan E
    Rehnström, Arne
    Anchor bolts in reinforced concrete foundations: short time tests1980Report (Other academic)
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    FULLTEXT01
  • 19.
    Elfgren, Lennart
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Ohlsson, Ulf
    Anchor bolts modelled with fracture mechanics1992In: Applications of fracture mechanics to reinforced concrete: based on the papers presented at the International Workshop on the Applications of Fracture Mechanics to Reinforced Concrete, held in Turin, Italy, 6 October 1990, London: Elsevier, 1992, p. 267-283Chapter in book (Other academic)
  • 20.
    Ohlsson, Ulf
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Elfgren, Lennart
    Anchor bolts modelled with fracture mechanics1990In: Proceedings: Nordic Concrete Research Meeting : Trondheim 1990 / [ed] Jens Jacob Jensen, Oslo: Norsk Betongforening , 1990, p. 270-271Conference paper (Refereed)
  • 21.
    Olofsson, Thomas
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Noghabai, Keivan
    Ohlsson, Ulf
    Elfgren, Lennart
    Anchorage and bond properties in concrete1995In: Fracture of brittle, disordered materials: concrete, rock and ceramics : proceedings of the International Union of Theoretical and Applied Mechanics (IUTAM) Symposium on Fracture of Brittle, Disordered Materials: Concrete, Rock and Ceramics / [ed] G. Baker; B.L. Karihaloo, London: Taylor and Francis Group , 1995, p. 525-543Conference paper (Refereed)
  • 22.
    Elfgren, Lennart
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Noghabai, Keivan
    Ohlsson, Ulf
    Olofsson, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Applications of fracture mechanics to anchors and bond1995In: Fracture mechanics of concrete structures: proceedings / [ed] Folker H. Wittmann, AEDIFICATIO Publishers , 1995, p. 1685-1694Conference paper (Refereed)
  • 23.
    Fransson, Lennart
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Elfgren, Lennart
    Armerad is: fältförsök i full skala1983In: Väg- och Vattenbyggaren, ISSN 0042-2177, no 10, p. 24-25Article in journal (Other (popular science, discussion, etc.))
  • 24.
    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.

    Download full text (pdf)
    FULLTEXT01
  • 25. Enochsson, Ola
    et al.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Olofsson, 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.
    Töyrä, Björn
    Banverket, Luleå.
    Kronborg, Anders
    Banverket, Luleå.
    Paulsson, Björn
    Banverket, Luleå.
    Assessment and condition monitoring of a concrete railway bridge in Kiruna, Sweden2006In: Bridge maintenance, safety, management, life-cycle performance and cost: Proceedings of the third International Conference on Bridge Maintenance, Safety and Management. IABMAS'06 / [ed] Paulo J. da Sousa Cruz; Dan M Frangopol; Luis C Canhoto Neves, London: Taylor and Francis Group , 2006Conference paper (Refereed)
    Abstract [en]

    A two-span railway concrete trough bridge over Luossajokk in Kiruna in northern Sweden has been studied. The owner wanted to increase the axle loads from 250 to 300 kN in order to reduce freight costs for iron ore. Examples are given of methods used and results obtained from the assessment where bending, shear and fatigue were studied. Material properties, loads and load carrying capacity were evaluated using deterministic and probabilistic methods. It was shown that the bridge could carry the higher loads with a safety index β > 4.7 for reasonable assumptions of the load distributions. A measurement system was installed to check the actual level of critical strains and the worst positions of the train. Results are also given from a condition monitoring program 2001-2006, launched to periodically check the development of strains with time

  • 26.
    Bagge, Niklas
    et al.
    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.
    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.
    Sundquist, Håkan
    Royal Institute of Technology.
    Carolin, Anders
    Trafikverket, Luleå.
    Assessment and failure test of a prestressed concrete bridge2017In: Life-Cycle of Engineering Systems: Emphasis on Sustainable Civil Infrastructure / [ed] Jaap Bakker; Dan M Frangopol; Klaas van Breugel, Leiden: CRC Press/Balkema , 2017, p. 1058-1063Conference paper (Refereed)
    Abstract [en]

    Tests have been carried out at service- and ultimate load levels of a 55 year-old prestressed concrete girder bridge. The bridge, located in Kiruna, Sweden, was continuous in five spans with a total length of 121.5 m. The overall aim of the study was to determinate the accuracy of assessment methods for existing structures and to provide procedures for optimized assessment. Before the tests a 2D finite element (FE) analysis was performed to predict the behavior and load-carrying capacity of the bridge. In order to more accurately assess the bridge response a 3D FE model has now been developed. The actual loading history and material properties has been considered in the model. A Life Cycle Cost Assessment of the bridge has also been performed

  • 27.
    Nilimaa, Jonny
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sabau, Cristian
    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. WSP.
    Puurula, Arto
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. Savonia University.
    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. Skanska.
    Täljsten, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Carolin, Anders
    Trafikverket.
    Paulsson, Björn
    Charmec Railway Center.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Assessment and Loading to Failure of Three Swedish RC Bridges2018In: Evaluation of Concrete Bridge Behavior through Load Testing: International Perspectives / [ed] Eva Lantsoght and Pinar Okumus, Faarmington Hills, MI: American Concrete Institute, 2018, Vol. 323, p. 8.1-8.18, article id SP-323-8Chapter in book (Refereed)
    Abstract [en]

    Current codes often underestimate the capacity of existing bridges. The purpose of the tests presented here has been to assess the real behaviour and capacity of three types of bridges in order to be able to utilize them in a more efficient way.

    The three studied bridges are: (1) Lautajokk – A one-span trough bridge tested in fatigue to check the shear capacity of the section between the slab and the girders; (2) Övik – A two span trough bridge strengthened with Near Surface Mounted Reinforcement (NSMR) of Carbon Fibre Reinforced Polymers (CFRP) tested in bending, shear and torsion; and (3) Kiruna – A five-span prestressed three girder bridge tested to shear-bending failures in the girders and in the slab.

    The failure capacities were considerably higher than what the code methods indicated. With calibrated and stepwise refined finite element models, it was possible to capture the real behaviour of the bridges. The experiences and methods may be useful in assessment and better use of other bridges.

  • 28.
    Enochsson, Ola
    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.
    Kronborg, Anders
    Banverket.
    Paulsson, Björn
    Banverket.
    Assessment and monitoring of an old railway steel truss bridge in northern Sweden2008In: Bridge Maintenance, Safety Management, Health Monitoring and Informatics: Proceedings of the Fourth International Conference on Bridge Maintenance, Safety and Management, July 13-17 2008, Seoul, Korea - IABMAS '08 / [ed] Hyun-Moo Koh; Dan G Frangopol, Boca Raton, Fla: Taylor and Francis Group , 2008, p. 3617-3624Conference paper (Refereed)
  • 29.
    He, Guojing
    et al.
    Central South University of Science and Technology, Changsha, Hunan, PR China.
    Zou, Zhongquan
    Central South University of Science and Technology, Changsha, Hunan, PR China.
    Enochsson, Ola
    Bodens kommun, Sverige.
    Bennitz, Anders
    WSP, Luleå.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Kronborg, Anders
    Banverket, Luleå.
    Töyrä, Björn
    Banverket, Luleå.
    Paulsson, Björn
    Banverket.
    Assessment of a railway concrete arch bridge by numerical modelling and measurements2008In: Bridge Maintenance, Safety, Management, Health Monitoring and Informatics: Proceedings of the fourth International Conference on Bridge Maintenance, Safety and Management, Seoul, Korea, 13-17 July 2008. Leiden: CRC Press/Balkema, Taylor & Francis Group, ISBN 978-0-415-46844-2, 732 pp + CD with full versions of papers, 3699 pp. / [ed] Hyun-Moo Koh and Dan M. Frangopol, Leiden: CRC Press, 2008, p. 3733-3742Conference paper (Refereed)
    Abstract [en]

    Two main railway concrete arch bridges have been investigated in northern Sweden: the Vindel Bridge over the Vindel River with a span of 110 m and the Långforsen Bridge over the Kalix River with a span of 90 m. The bridges were constructed in the 1950s with similar designs. In order to investigate the possibility to increase the axle load from 225 kN to 250kN, two 3-D Finite Element models with shell elements were developed and two field tests were carried out with passing trains and ambient vibrations. The measurement frequencies and mode shapes were studied with the stochastic subspace identification method in the time domain. Based on a comparison of the predictions of the FE analyses and the results of the field tests, the FE models were updated. It was found that it was possible to make good predictions of the actual dynamic response with reasonable assumptions of material properties and joint stiffness in the structure.

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  • 30.
    Bagge, Niklas
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. WSP, Luleå, Sweden.
    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. Norut Teknik, Norut, Norge.
    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.
    Carolin, Anders
    Trafikverket, Luleå.
    Paulsson, Björn
    Trafikverket; UIC, Paris, France; Charmec, Chalmers tekn högskola.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Assessment of concrete bridges - Prestress forces: Experiences from full-scale testing to failure of a bridge in Kiruna2017In: Proceedings of the 23rd Nordic Concrete Research Symposium, Oslo, Norway: Nordic Concrete Federation, Oslo: Nordic Concrete Federation , 2017, p. 267-270Conference paper (Refereed)
    Abstract [en]

    To calibrate methods for condition assessment of prestressed concrete (PC) bridges, tests were carried out on a 55 year old five-span bridge with a length of 121 m in Kiruna in northern Sweden. Both non-destructive and destructive full-scale tests were performed. This paper presents results regarding the residual forces in the prestressed reinforcement.

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  • 31.
    Bagge, Niklas
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. WSP, Luleå, Sweden.
    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. Norut Teknik, Norut, Norge.
    Blanksvärd, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Bernspång, Lars
    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.
    Carolin, Anders
    Trafikverket, Luleå.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Assessment of concrete bridges - Structural capacity: Experiences from full-scale testing to failure of a bridge in Kiruna2017In: Proceedings of the 23rd Nordic Concrete Research Symposium, Oslo, Norway: Nordic Concrete Federation, Oslo: Nordic Concrete Federation , 2017, p. 263-266Conference paper (Refereed)
    Abstract [en]

    To calibrate methods for condition assessment of prestressed concrete (PC) bridges, tests were carried out on a 55 year old five-span bridge with a length of 121 m in Kiruna in northern Sweden. Both non-destructive and destructive full-scale tests were performed. This paper presents results regarding methods for assessment of the structural capacity of concrete bridges.

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  • 32.
    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

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  • 33.
    Elfgren, Lennart
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Nilforoush, Rasoul
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Nilsson, Martin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Ohlsson, Ulf
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Assessment of Fasteners to Concrete: A Tribute to Rolf Eligehausen2017In: Connections between Steel and Concrete: 3rd International Symposium / [ed] Akanshu Sharma and Jan Hofmann, Stuttgart, 2017, p. 1294-1302Conference paper (Refereed)
    Abstract [en]

    Some examples are given of assessment of fastenings to concrete structures and the work started by Rolf Eligehausen in fib Task Group 2.9 “Fastenings to structural concrete and masonry”. Studies have been made on e.g. the influence of creep on adhesive anchors and of surface reinforcement and size effects on headed anchors.

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  • 34.
    He, Goujing
    et al.
    CSUFT, Changsha, Hunan.
    Zou, Zhongquan
    CSUFT, Changsha, Hunan.
    Enochsson, Ola
    Bennitz, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Elfgren, Lennart
    Kronborg, Anders
    Banverket, Luleå.
    Töyrä, Björn
    Banverket, Luleå.
    Paulsson, Björn
    Banverket, Borlänge.
    Assessment of railway concrete arch bridge by numerical modelling and measurements2008In: Bridge Maintenance, Safety, Management, Health Monitoring and Informatics: Proceedings of the Fourth International Conference on Bridge Maintenance, Safety and Management, July 13-17 2008, Seoul, Korea - IABMAS '08 / [ed] Hyun-Moo Koh; Dan G Frangopol, Boca Raton: Taylor and Francis Group , 2008, p. 3733-3742Conference paper (Refereed)
  • 35.
    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)
  • 36.
    Puurula, Arto
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering. Savonia University of Applied Scinces, Kuopia, Finland.
    Enochsson, Ola
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering. Bodens kommun.
    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.
    Carolin, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering. Trafikverket.
    Paulsson, Björn
    Trafikverket.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Assessment of the Strengthening of an RC Railway Bridge with CFRP utilizing a Full-Scale Failure Test and Finite-Element Analysis2015In: Journal of Structural Engineering, ISSN 0733-9445, E-ISSN 1943-541X, Vol. 141, no 1 (Special Issue), p. D4014008-1-D4014008-11, article id D4014008Article in journal (Refereed)
    Abstract [en]

    A finite element (FE) model was calibrated using the data obtained from a full-scale test to failure of a 50 year old reinforced concrete (RC) railway bridge. The model was then used to assess the effectiveness of various strengthening schemes to increase the loadcarrying capacity of the bridge. The bridge was a two-span continuous single-track trough bridge with a total length of 30 m, situated in Örnsköldsvik in northern Sweden. It was tested in situ as the bridge had been closed following the construction of a new section of the Railway line. The test was planned to evaluate and calibrate models to predict the load-carrying capacity of the bridge and assess the strengthening schemes originally developed by the European research project called Sustainable bridges. The objective of the test was to investigate shear failure, rather than bending failure for which good calibrated models are already available. To that end, the bridge was strengthened in flexure before the test using near-surface mounted square section carbon fiber reinforced polymer (CFRP) bars. The ultimate failure mechanism turned into an interesting combination of bending, shear, torsion, and bond failures at an applied load of 11.7 MN (2,630 kips). A computer model was developed using specialized software to represent the response of the bridge during the test. It was calibrated using data from the test and was then used to calculate the actual capacity of the bridge in terms of train loading using the current Swedish load model which specifies a 330 kN (74 kips) axle weight. These calculations show that the unstrengthened bridge could sustain a load 4.7 times greater than the current load requirements (which is over six times the original design loading), whilst the strengthened bridge could sustain a load 6.5 times greater than currently required. Comparisons are also made with calculations using codes from Canada, Europe, and the United States.

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  • 37.
    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.))
  • 38.
    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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  • 39.
    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.))
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  • 40.
    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)
  • 41.
    Elfgren, Lennart
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Lundberg, Bengt
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Nilsson, Bruno
    Belastningsutrustning: En redogörelse över inköp av en servohydraulisk belastningsutrustning för provning av material och konstruktioner vid Högskolasn i Luleå1976Report (Refereed)
    Abstract [sv]

    Servohydraulisk belastningsutrustning för 2,3 miljoner kronor upphandlades under 1975 till Högskolan i Luleå. Utrustningen består av tre drag- och tryckprovningsmaskiner (30, 200 och 300 kN), sex belastningscylindrar (130, 265 och 1000 kN), en bergmekanisk press (4500 kN), en processdator (16 kioord) samt elektronikkonsoler för styrning och registrering.

    Upphandlingsarbetet beskrivs och utrustningen presenteras.

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  • 42.
    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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  • 43.
    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.))
  • 44. Thun, Håkan
    et al.
    Ohlsson, Ulf
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Elfgren, Lennart
    Betonghållfasthet i järnvägsbroar på Malmbanan: karakteristisk tryck- och draghållfasthet för 20 broar mellan Luleå och Gällivare1999Report (Other academic)
    Abstract [sv]

    Denna rapport redovisar provningsresultat från en utökad provning med hjälp av Capo-test och studsmätningar (Schmidthammare) för en bro över Lautajokki som tidigare har utmattningsprovats i LTUs testlaboratorium. Förutom resultaten från denna provning redovisas även provningsresultat som erhållits med hjälp av enaxiella dragförsök och provning av tryckhållfasthet i cylindrar, för broar (vägportar) på Malmbanan längs bansträckningen Luleå-Gällivare. Med hjälp av provningsresultaten har tryck- och draghållfasthetsklass samt karaktäristisk tryck- och draghållfasthet bestämts för aktuella broar. Studien visar att tryckhållfastheten i de studerade äldre konstruktionerna har ökat kraftigt jämfört med fordrad hållfasthet (aktuella objekt K40-45) men att de varierar från bro till bro. Resultaten visar att draghållfastheten varierar kraftigt mellan broarna (eg. deras sidobalkar) och att det inte på basis av enbart dessa försök går att säkerställa att draghållfastheten ökat i samma takt som tryckhållfastheten. Resultaten från de olika testmetoderna som använts på Lautajokki-bron antyder att det är olika hållfasthet i sidobalk respektive platta. Av denna orsak har en reduktion av hållfastheten föreslagits om provning skett i sidobalkarna och det är plattan som ska analyseras. I rapporten redovisas även metoder att ur provningsresultaten bestämma karaktäristisk hållfasthet.

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  • 45. Enochsson, Ola
    et al.
    Puurula, Arto
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Betongkonstruktioners bärförmåga vid tillståndsbedömning: interaktion mellan tvärkraft, vridmoment och böjmoment i Källösundsbron2004Report (Other academic)
    Abstract [sv]

    I rapporten studeras metoder för att bedöma bärförmågan vid olika grad av samverkan mellan tvärkraft, vridmoment och böjmoment i betongkonstruktioner, speciellt med tillämpningar på broar med lådtvärsnitt. De metoder som studeras är dels de som finns i nuvarande normer, BBK 94 och Bro 2002, dels de som finns i förslag till nya normer, EC 2-1 och BBK 04 och dels metoder baserade på plasticitetsteori och modifierad tryckfältsteori. Metoderna tillämpas på en av de första konsolutbyggda låbalksbroarna i Sverige, bron över Källösund vid Tjörn i Bohuslän (O497). Den färdigställdes 1959. Arbetet ingår i ett sammarbetsprojekt med namnet: Evaluering av bärförmåga med hjälp av förfinade analysmetoder, speciellt med avseende på freivorbaubroar. Det utförs på uppdrag av Vägverket tillsammans med Chalmers tekniska högskola och Lunds tekniska högskola. För lådtvärsnitt ger belastning med vridmoment och tvärkraft upphov till samverkande skjuvflöden i en av väggarna. Vridmoment och tvärkraft kan där ersättas med en ekvivalent tvärkraft. Följande slutsatser kan dras: För Källösundsbron gäller att mängden tvärkraftsarmering är mycket låg. BBK 94 ger högst bärförmåga beroende på att spännarmeringen i denna norm har en mycket gynnsam inverkan. I de övriga metoderna slår den låga bygelarmeringsmängden igenom och indikerar brott vid betydligt lägre kapacitet. Beräkningarna tyder på att Källösundsbron bör förstärkas i kritiska snitt med avseende på samverkande tvärkraft, vridmoment och böjmoment som orsakas av lastkombination A med boggielasten B ³ 210 kN. Ett alternativ kan vara att genom mätningar skaffa en bättre bild av brons funktion. Vi rekommenderar att mätningar utförs även innan och efter eventuell förstärkning. Mätningen innan förstärkningen har till uppgift att dokumentera aktuella påkänningar för ett antal kritiska typfordon med känd boggie-/axellast, för att ge möjlighet till jämförelser med framtagna påkänningar från den fördjupade utredning som genomförts här. Mätningen innan och efter förstärkningen har tillsammans till uppgift att försäkra och dokumentera uppnådd förstärkningseffekt ur ett säkerhetsperspektiv samt för att ge kunskap inför eventuella framtida uppklassningsbehov av andra broar. Fortsatta studier behöver göras av hur materialparametrar bestäms. Fortsatta studier behöver göras med den modifierade tryckfältsteorin och dess resultat bör jämföras med försök på lådbalkskonstruktioner såväl vad gäller bruksstadium (sprickbildning och sprickvidder) som brottstadium. Osäkerheten i studerade modeller för bärförmåga bör studeras närmare för att ge underlag för sannolikhetsteoretiska bedömningar.

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  • 46.
    Noghabai, Keivan
    et al.
    Luleå tekniska universitet.
    Olofsson, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Elfgren, Lennart
    Bond between concrete and reinforcement modelled by fracture mechanics1995In: Proceedings of Nordic Symposium on Modern Design of Concrete Structures / [ed] Kirsten Aakjaer, Aalborg: Department of Building Technology and Structural Enginering, Aalborg University , 1995, p. 85-96Conference paper (Refereed)
  • 47. Gylltoft, Kent
    et al.
    Cederwall, Krister
    Nilsson, Larsgunnar
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Bond failure in reinforced concrete under monotonic and cyclic loading: a fracture mechanics approach1982In: Fatigue of concrete structures, Detroit: American Concrete Institute, 1982, p. 269-287Chapter in book (Other academic)
  • 48.
    Elfgren, Lennart
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Söderlind, Gunnar
    Bonded anchors subjected to long time and cyclic loads1993In: Fracture and damage of concrete and rock : FDCR-2: proceedings of the second International Conference on Fracture and Damage of Concrete and Rock, Vienna, Austria, 9-13 November 1992 / [ed] H.P. Rossmanith, London: E & FN Spon, 1993, p. 513-526Conference paper (Refereed)
  • 49.
    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. WSP.
    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
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering. Trafikverket.
    Häggström, Jens
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering. Trafikverket.
    Bridges tested to failure in Sweden2018In: IABSE Conference 2018 – Engineering the Past, to Meet the Needs of the FutureJune 25-27 2018, Copenhagen, Denmark, 2018Conference 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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  • 50.
    Axelsson, Kenneth
    et al.
    Luleå tekniska universitet.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Bro1990In: Nationalencyclopedin, Höganäs: Bra Böcker , 1990, p. 320-324Chapter in book (Other academic)
1234567 1 - 50 of 331
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