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  • 151.
    Täljsten, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Full scale tests on concrete structures strengthened with plate bonding in Sweden2001In: Concrete under severe conditions: environment and loading : proceedings of the Third International Conference on Concrete under Severe Conditions, CONSEC'01, Vancouver, BC, Canada, 18-20 June 2001 / [ed] Nemkumar Banthia, Vancouver: University of British Columbia, Dept. of Civil Engineering , 2001, p. 2133-2142Conference paper (Refereed)
    Abstract [en]

    A concrete structure without any form of reinforcement will crack and fail when subjected to a relatively small load. The failure occurs suddenly and brittle in most situations. The commonest way to reinforce a concrete structure is to use cast in steel reinforcing bars. Since a concrete structure usually has a very long life, is it not unusual for the demands on the structure to change with time. The structure may have to carry larger loads at a later date or fulfil new standards. In extreme cases a structure will have to be repaired or strengthened due to an accident. Another reason can be that errors have been made during the design or construction phase. There exists several methods to repair or upgrade existing concrete structures. In recent years the development of strong epoxy adhesives has led to the plate bonding repair technique. This technique may be defined as one in which a composite sheet or plate of relatively small thickness is bonded with an epoxy adhesive to, in most cases, a concrete structure to improve its structural behaviour and strength. At Lulea University of Technology, research is taking place in the field of Plate Bonding. The research work started in 1988, then with steel plates and is today continued with FRP (Fibre Reinforced Polymer) materials. Both comprehensive experimental and theoretical work has been undertaken. The laboratory tests include strengthening for bending as well as for shear and torsion. In addition several full-scale tests have been performed over the years. This paper will present two full-scale tests, the first one a road bridge strengthen with steel plates and the second, a rail way bridge strengthen with CFRP (Carbon Fibre Reinforced Polymer) sheets. The tests show that Plate Bonding with steel or CFRP sheets are effective methods to strengthen concrete structures.

  • 152.
    Täljsten, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Fullscale testing of concrete bridge strengthened by plate bonding1990In: British Swedish seminar on concrete repairs / [ed] Satish Chandra, Chalmers tekniska högskola , 1990, p. 16:1-16:10Conference paper (Refereed)
  • 153.
    Täljsten, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Förstärkning av befintliga betongkonstruktioner med kolfiberväv eller kolfiberlaminat: dimensionering, material och utförande1999Report (Other academic)
  • 154.
    Täljsten, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Förstärkning av befintliga betongkonstruktioner med kolfiberväv eller kolfiberlaminat: dimensionering, material och utförande2000Report (Other academic)
    Abstract [sv]

    Sverige, liksom övriga västvärlden, börjar få ett relativt ålderstiget byggnadsbestånd, både vad gäller bostäder och infrastruktur. Betänker vi också att det byggda beståndet idag kommer att utgöra ca 85-90 % av beståndet år 2020, förstår vi att behovet av underhåll kommer att öka. Väger vi här in miljö, resursförbrukning och energiaspekter blir det ohållbart att byta ut befintliga konstruktioner utan en förlängning av livslängden är oftast att föredra. Studerar vi t ex broar som ständigt måste klassas upp pga. höjda tillåtna axeltryck leder detta till att man försöker nyttja konstruktioner till högre bärighetsnivåer än vad de från början var ämnade för. Här kan man då tänka sig en noggrannare kartläggning av konstruktionen och en mer detaljerad studie av aktuella hållfastheter hos ingående material. Andra metoder kan vara att använda bättre beräkningsmodeller än vad som användes vid nybyggnadsskedet så att större laster klaras. Om ingen av dessa metoder är lämpliga kan en förstärkningsåtgärd vara på sin plats och skulle även detta möta hinder, då finns det inget annat alternativ än att byta ut konstruktionen. Det finns ett flertal metoder att förstärka och/eller förbättra en befintlig konstruktion, t ex sprutbetong och olika typer av pågjutningar med eller utan fibrer. En ytterligare metod kan vara utanpåliggande armering. Den utanpåliggande armeringen kan vara i form av stålplåt, kompositlaminat eller väv av glas-, kol- eller aramidfibrer, en kombination av fibrer är också möjlig, så kallade hybridkompositer. I rapporten beskriver kapitel 1 översiktligt kompositmaterial och dess tillämpning inom byggnadsindustrin, bl a diskuteras kompositmaterialens möjligheter inom byggnadssidan. Dessutom ges en kortfattad beskrivning hur projektet har genomförts. I kapitel 2 redovisas ett normkapitel med bindande krav. Kompositteori beskrivs kortfattat i kapitel 3 och i kapitel 4 börjar själva metodiken gällande förstärkning av betongkonstruktioner, här presenteras speciellt förstärkning för böjning. Här diskuteras olika brottmoder, förankringslängder och avskalningskrafter vid laminatets ändar. Kapitel 5 tar upp dimensioneringsfilosofin gällande tvärkraft och relativt komplicerade beräkningssamband förenklas till en ingenjörsmässig tillämpning. I kapitel 6 redovisas grunder för vriddimensionering och hur en förstärkning med avseende på vridning kan utföras. I kapitel 7 diskuteras möjligheter gällande utmattning och kapitel 8 vilka utförandekrav som ska ställas på en betongkonstruktion för förstärkning. I kapitel 9 ges förslag på partialkoeffecienter, som baserar sig på befintliga regler och förutsättningar, men med speciell hänsyn till användandet av kompositer. Rapporten avslutas därefter med fyra beräkningsexempel, ett vardera gällande böjning, tvärkraft, vridning och utmattning som förhoppningsvis ska vara en vägledning inför framtida dimensionering förstärkningar med kolfiberväv eller laminat.

  • 155.
    Täljsten, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Förstärkning av betongkonstruktioner genom pålimning av stålplåtar1990Licentiate thesis, monograph (Other academic)
  • 156.
    Täljsten, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Förstärkning av betongkonstruktioner genom pålimning av yttre armering1988Report (Other academic)
  • 157.
    Täljsten, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Förstärkning av betongkonstruktioner med pålimmad armering1994In: Bygga framtid, Vol. 5, p. 68-70Article in journal (Other (popular science, discussion, etc.))
  • 158.
    Täljsten, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Förstärkning av betongkonstruktioner med stålplåt och avancerade kompositmaterial utsatta för vridning1998Report (Other academic)
  • 159.
    Täljsten, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Kompositmaterial passar bra till reparationer2007In: Husbyggaren : bygg, el, VVS, anläggning, ISSN 0018-7968, no 5, p. 44-48Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Behövs det nya material i byggbranschen? Har till exempel kompositmaterial egenskaper som kan öka hållbarheten eller sänka kostnaderna. Eller lämpar det sig kanske bäst för reparationer.

  • 160.
    Täljsten, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Limmad förstärkning gör gammal bro som ny1996In: Byggindustrin, ISSN 1104-5981, no 7, p. 35-Article in journal (Other (popular science, discussion, etc.))
  • 161.
    Täljsten, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Mineral Based Bonding Agents for CFRP Strengthening of Concrete Structures2005In: ConMat05, Performance, innovation and Structural Implications, 2005Conference paper (Refereed)
  • 162.
    Täljsten, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Plate bonding: strengthening of existing concrete structures with epoxy bonded plates of steel or fibre reinforced plastics1994Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis deals with several aspects of the plate bonding problem, i.e. when steel or fibre reinforced plastics (FRP) plates are bonded to a concrete structure with the use of an epoxy adhesive. Both theoretical work and laboratory tests are presented as well as a full scale test on a strengthened concrete bridge. Earlier work in the area of plate bonding as well as the use of epoxy adhesives in civil engineering are discussed. This report presents several original and new features, both in theory and practice. A linear elastic model is introduced for calculation of shear and peeling stresses at the end of an epoxy bonded plate situated underneath a concrete beam subjected to bending. For the non linear behaviour, when the concrete starts to fracture, a non linear fracture mechanics (NLFM) model is introduced. The report is divided into two main parts, the main text and the appendices. The appendices are mainly used to give detailed derivations and test results. One exception is an illustrative example of how to strengthen a T-beam. is given in Appendix H. The main text begins with an introduction and is followed by a presentation of earlier work in the area of plate bonding. The theory for plate bonding is presented, beginning with the simple truss model which is useful for design of plated structures for both bending and shear. The theory of elasticity applied to bars loaded in pure shear is investigated. Moreover, linear elastic formulas are derived for calculation of the shear and peeling stresses in the adhesive layer. The original differential formulas are quite easy to put together but very complicated to solve; therefore, a simplification is needed It has thus been ass~ that the steel plate has negligible stiffness in comparison to the concrete beam being strengthened. This is a fully acceptable simplification and leads to solutions that give good results compared with FE-analysis. When the concrete starts to fracture, linear elastic theory can not be used. Here a new concept for NLFM is introduced. This concept is based on criteria from Hillerborg, 1977, and also ideas from Gustavsson, 1987. For stiff adhesives is it easy to calculate the failure load by means of the fracture energy, Gf. However for softer bond zones numerical calculations are needed. The laboratory tests performed show that the derived truss model is acceptable for design purposes and that good agreement with test results are attained for both bending and shear. Also the theory of Volkersen, 1938, corresponds very well with the test results. When using FRP plates, however, strain levels must be taken into considerations in the design stage. The tests shows that CFRP (Carbon Fibre Reinforced Plastics) material is preferable to (GFRP) Glass Fibre Reinforced Plastics) material. Finally a full scale test on a strengthened bridge is presented. The results from this test show that the strengthening method, being both useful and practical, is acceptable for strengthening of existing concrete structures.

  • 163.
    Täljsten, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Pålimmad armering förstärker befintliga betongkonstruktioner1995In: Bygga framtid, p. 34-36Article in journal (Other (popular science, discussion, etc.))
  • 164.
    Täljsten, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Repair of concrete structures by plate bonding1996In: Proceedings: Nordic Concrete Research Meeting, Espoo, Finland 1996, Oslo: Norsk Betongforening , 1996, p. 249-251Conference paper (Refereed)
  • 165.
    Täljsten, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Replacement of stud connectors with epoxy adhesive in composite structures of steel and concrete1997In: Concrete way to development: symposium papers, FIP symposium, in association with International Association for Bridge and Structural Engineering, Concrete Society of Southern Africa , 1997, p. 547-554Conference paper (Refereed)
  • 166.
    Täljsten, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Strenghten of concrete structures: from steel plates to carbon fibre reinforced plastic1997In: Concrete way to development: symposium papers, FIP symposium, in association with International Association for Bridge and Structural Engineering, Concrete Society of Southern Africa , 1997, p. 873-884Conference paper (Refereed)
  • 167.
    Täljsten, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Strenghtening of concrete structures with CFRP materials1997In: Advanced design of concrete structures: [papers presented at the Symposium on Advanced Design of Concrete Structures, held in Chalmers University of Technology in Göteborg, Sweden on June 12 - 14, 1997] / [ed] Kent Gylltoft, Barcelona: International Center for Numerical Methods in Engineering (CIMNE), 1997Conference paper (Refereed)
  • 168.
    Täljsten, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Strengthening building structures by means of epoxy bonded plates: state of the art report1994Report (Other academic)
  • 169.
    Täljsten, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Strengthening concrete beams for shear with CFRP sheets2003In: Construction and Building Materials, ISSN 0950-0618, E-ISSN 1879-0526, Vol. 17, no 1, p. 15-26Article in journal (Refereed)
    Abstract [en]

    The method of strengthening concrete structures with FRP composites has existed for over a decade; the most common way to strengthen structures is in bending, but also wrapping of columns is quite common. There are also needs for strengthening concrete structures in shear, for example concrete beams, slabs, columns, etc. A typical structure can be a parking garage. However, strengthening concrete structures for shear is not as common as for bending and confinement. This paper presents examples to strengthen concrete beams for shear. First traditional strengthening methods are presented briefly, then the use of CFRP (Carbon Fibre reinforced Polymers) composites for shear strengthening is presented. Tests on beams strengthened in shear with CFRP sheets are presented and a short presentation on how to design for shear strengthening with CFRP is given. Furthermore, a field application of a parking slab strengthened for shear with CFRP unidirectional fabric is presented. The laboratory tests show the importance of considering the principal directions of the shear crack in relation to the unidirectional fibre. The field application shows that it is easy to strengthen existing structures for shear with CFRP fabrics.

  • 170.
    Täljsten, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Strengthening of beams by plate bonding1997In: Journal of materials in civil engineering, ISSN 0899-1561, E-ISSN 1943-5533, Vol. 9, no 4, p. 206-211Article in journal (Refereed)
    Abstract [en]

    At Luleå University of Technology, Sweden, research has been carried out in the area of plate bonding, i.e., the problems that can arise when concrete members need to be strengthened using epoxy-bonded plates. Both comprehensive experimental and theoretical work have been done. In this paper a derivation of the shear and peeling stresses in the adhesive layer of a beam with a strengthening plate bonded to its soffit and loaded with an arbitrary point load are presented. The results from both theory and finite-element analysis show that the stresses are very large at the end of the plate, but they quickly diminish as we move nearer the center of the beam. The magnitude of the stresses is influenced not only by the geometrical and material parameters of the beam, but also by the adhesive and the strengthening material.

  • 171.
    Täljsten, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Strengthening of building structures with FRP-fabrics1998In: Saving Buildings in Central and Eastern Europe: IABSE Colloquium Berlin 1998 / organised by Institute for Rehabilitation and Modernisation of Buildings (IEMB) at the Technical University Berlin, Zürich: International Association for Bridge and Structural Engineering, 1998Conference paper (Refereed)
  • 172.
    Täljsten, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Strengthening of concrete prisms using the plate-bonding technique1996In: International Journal of Fracture, ISSN 0376-9429, E-ISSN 1573-2673, Vol. 82, no 3, p. 253-266Article in journal (Refereed)
    Abstract [en]

    This paper presents the use of fracture mechanics for the plate bonding technique. Plates of steel or carbon-fibre reinforced plastic are bonded with an epoxy adhesive to rectangular concrete prisms and loaded in shear up to failure, what is normally known in fracture mechanics as mode II failure. In this special application a linear and a nonlinear approach are presented. The nonlinear equation derived for a realistic shear-deformation curve can only be used for numerical calculations. However, for simplified shear-deformation curves, the derived formula can be solved analytically. Results from tests, which are compared with the theory, are also presented.

  • 173.
    Täljsten, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Strengthening of concrete structure for shear with bonded carbon fibre fabrics1998In: Progress through innovation and cost effectivness: proceedings of the 19th International SAMPE Europe Conference of the Society for the Advancement of Material and Process Engineering, Paris, La Défense, France, April 22 - 24, 1998 / [ed] Markus A. Erath, Niederglatt: SAMPE , 1998Conference paper (Refereed)
  • 174.
    Täljsten, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Strengthening of concrete structures for shear with CFRP-fabrics: test and theory1998In: Concrete under severe conditions 2: Environment and loading : proceedings of the Second International Conference on Concrete Under Severe Conditions CONSEC '98, Tromsø, Norway, June 21-24, 1998 / [ed] Odd E. Gjørv, London: Taylor and Francis Group , 1998, Vol. 2, p. 1298-1310Conference paper (Refereed)
  • 175.
    Täljsten, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Strengthening of concrete structures with CFRP-sheets: applications and full scale tests in Sweden2000In: Advanced composite materials in bridges and structures: 3rd international conference ; Ottawa, Ontario, Canada, August 15 - 18, 2000 / [ed] J. L. Humar, Montréal: Canadian Society for Civil Engineering , 2000, p. 513-520Conference paper (Refereed)
  • 176.
    Täljsten, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Strengthening of existing concrete structures by epoxy bonded steel plates of steel or fibre reinforced plastics1996In: Concrete in the service of mankind: proceedings of the international conferences held during the Congress "Concrete in the Service of Mankind", 24 - 28 June 1996 / [ed] Ravindra K. Dhir; M. Roderick Jones, Taylor and Francis Group , 1996, p. 623-632Conference paper (Refereed)
  • 177.
    Täljsten, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Strengthening of structures using epoxy bonded steel- or fibre reinforced plastic plates1995In: IABSE Symposium, San Francisco 1995: Extending the lifespan of structures, Zürich: International Association for Bridge and Structural Engineering, 1995, p. 1173-1178Conference paper (Refereed)
  • 178.
    Täljsten, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Stålplåt eller kolfiberlaminat förstärker konstruktion1996In: Byggforskning : Byggforskningsrådets tidning för en bättre byggd miljö, ISSN 1102-3686, no 3, p. 40-Article in journal (Other (popular science, discussion, etc.))
  • 179.
    Täljsten, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    The importance of bonding: an historic overview and future possibilities2005In: Proceedings of the International Symposium on Bond Behaviour of FRP in Structures: BBFS 2005 / [ed] J.F. Chen; J.G. Teng, International Institute for FRP in Construction , 2005, p. 1-10Conference paper (Refereed)
    Abstract [en]

    An adhesive is a substance that has the capability to hold materials together. The manner by which adhesives are able to serve this function is due to a surface attachment that is resistant to separation. A bond occurs when the adhesive molecules adsorb onto a solid surface and chemically react with it. Adhesives have a very large importance for most industries, both for structural and for non-structural use. In this paper, an overview of the use of adhesives in different industries is presented - with focus on the building industry and on structural use. Not surprisingly, the use of structural bonding has increased considerably during the last decade. The main reasons for this are probably a combination of lower cost, more need of lightweight structures, development of more durable adhesives and improved structural adhesive performance. Additionally, adhesives often provide better load transfer than welded structures.In this paper, an overview of the use of adhesive in the service of man is presented. The overview is brief, but nonetheless gives an idea of the possibilities of adhering materials by bonding. The paper briefly discusses the use of adhesives in the aerospace, automotive and marine industries, but focuses on the construction industry. Finally some ideas about "sticking things together" tomorrow are presented.

  • 180.
    Täljsten, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Tvärkraftsförstärkning med pålimmade stålplåtar: en pilotstudie1993Report (Other academic)
  • 181.
    Täljsten, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Upgrading of infrastructure with fibre reinforced plastic materials, especially shear strengthening1997In: Innovation in composite materials and structures: [a selection of papers presented at the Mouchel Centenary Conference on Innovation in Civil and Structural Engineering, held in Cambridge, England, 19th - 21st August 1997] / [ed] M. B. Leeming; B. H. V. Topping, Edinburgh: Civil-Comp Press , 1997, p. 25-34Conference paper (Refereed)
  • 182.
    Täljsten, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Upgrading the infrastructure with composites1997In: Proceedings from the 8th SICOMP Conference on Manufacturing and Design of Composites: Piteå, June 2-3, 1997, Piteå, 1997Conference paper (Refereed)
  • 183.
    Täljsten, Björn
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Aboudrar, Abderahim
    Burghauser, Andreas
    Carolin, Anders
    Fullskaleförsök på silor förstärkta med kolfiberväv2000Report (Other academic)
    Abstract [sv]

    Under sommaren 1999 utförde Stabilator AB i Samverkan med Odal Ek. förening och Luleå tekniska universitet, Testlab, förstärkning av fyra spannmålssilor med hjälp av utanpåliggande kolfiberväv. Denna teknik har vidareutvecklats vid Luleå tekniska universitet, avdelningen för Konstruktionsteknik. Kortfattat innebär förstärkningstekniken att armering i form av kolfiberväv limmas mot utsidan av en konstruktion. På så sätt bygger man upp en befintlig komposit på en existerande konstruktion. Metoden är flexibel och oftast mycket kostnadseffektiv. Två av de förstärkta anläggningarna var belägna i Västerås och två i Kvänum. I Kvänum förstärktes en silo på utsidan med remsor och en på insidan med heltäckande komposit. I Västerås förstärktes båda silorna på utsidan med remsor. Anledningen till förstärkning var att anläggningarna var underdimensionerade med avseende på tömningstrycket. Detta har medfört omfattande sprickbildning, korrosion samt i vissa snitt överskridande av armeringens flytgräns. I samband med förstärkningen applicerades töjningsgivare på såväl stålarmering och på den härdade kolfiberkompositen. Efter förstärking provades de förstärkta silorna genom att spannmål fylldes och tömdes i silorna. Registrering utfördes då av töjningar och belastning. Resultaten efter förstärkning var positivt och de befintliga armeringsjärnen avlastades väsentligt.

  • 184.
    Täljsten, Björn
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Bergström, Markus
    Enochsson, Ola
    Elfgren, Lennart
    CFRP strengthening of the Örnsköldsvik bridge: field tests2007In: Sustainable bridges: assessment for future traffic demands and longer lives / [ed] Jan Bien; Lennart Elfgren; Jan Olofsson, Wrocław: Dolnoslaskie Wydawnictwo Edukacyjne , 2007, p. 355-364Conference paper (Refereed)
  • 185. Täljsten, Björn
    et al.
    Bergström, Markus
    Nordin, Håkan
    Enochsson, Ola
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Test of a concrete bridge in Sweden: II. CRP strengthening and structural health monitoring2008In: 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 M Frangopol, Boca Raton, Fla: CRC Press, Taylor & Francis Group , 2008, p. 3593-3600Conference paper (Refereed)
  • 186.
    Täljsten, Björn
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Blanksvärd, Thomas
    Mineral based bonding of carbon FRP to strengthen concrete structures2007In: Journal of composites for construction, ISSN 1090-0268, E-ISSN 1943-5614, Vol. 11, no 2, p. 120-128Article in journal (Refereed)
    Abstract [en]

    The advantages of fiber-reinforced polymer (FRP)-strengthening have been shown time and again during the last decade. Several thousand structures retrofitted with FRPs exist worldwide. There are various reasons why the retrofit is needed, but it is not uncommon for the demands on the structure to change with time, as buildings and civil structures usually have a very long life. The structures may have to eventually carry larger loads or fulfill new standards. In extreme cases, a structure may need repair due to an accident or to errors made during the design or construction phases, and must therefore be strengthened before it can be used. Different methods to retrofit with FRPs also exist, such as bonding of plates or sheets, with their use of epoxy as the bonding agent being the commonality. Epoxy provides very good bond to concrete and is durable and resistant to most environments in the building industry. However, epoxy may also create problems in the working environment, needs a minimum application temperature, and creates diffusion-closed surfaces. These drawbacks can be overcome if the epoxy can be replaced with a cementitious bonding agent. In this paper tests are presented where the epoxy has been replaced with a cement based bonding agent for retrofitting. Pilot tests show that very good composite action can be achieved and that only minor changes in the design procedure need to be taken.

  • 187.
    Täljsten, Björn
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Blanksvärd, Thomas
    Carolin, Anders
    Mineral based bonding of CFRP to strengthen concrete structures2007In: Sustainable bridges: assessment for future traffic demands and longer lives / [ed] Jan Bien; Lennart Elfgren; Jan Olofsson, Wrocław: Dolnoslaskie Wydawnictwo Edukacyjne , 2007, p. 331-339Conference paper (Refereed)
    Abstract [en]

    Strengthening of concrete structures with epoxy bonded carbon fiber reinforced polymers (CFRP) has been proved to be a good strengthening technique. However, this strengthening technique with epoxy adhesives do contain some disadvantages such as diffusion closeness, thermal incompatibility to the base concrete, working environment and minimum application temperature. Some of these drawbacks can be overcome by substituting the epoxy to a polymer reinforced mortar as the bonding agent. This work presents a study with CFRP strengthened concrete beams. In this case the epoxy has been replaced with a mineral based composite (MBC). The results from the study indicates that the MBC strengthening system do achieve very good composite action and strengthening effects. These results warrant for further research and improvement of the MBC strengthening system The project was a part of the European funded research project Sustainable Bridges.

  • 188.
    Täljsten, Björn
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Blanksvärd, Thomas
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Handbok för dimensionering och utförande i samband med förstärkning av betongkonstruktioner med pålimmade fiberkompositer2012Book (Other academic)
  • 189.
    Täljsten, Björn
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Blanksvärd, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    Sas, Gabriel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Kompositförstärkning av betong2016Book (Other academic)
  • 190.
    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

  • 191.
    Täljsten, Björn
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Carolin, Anders
    CFRP - strengthening: concrete beams strengthened with near surface mounted CFRP laminates2001In: FRPRCS-5 :: fibre-reinforced plastics for reinforced concrete structures : proceedings of the Fifth International Conference on Fibre-Reinforced Plastics for Reinforced Concrete Structures, Cambridge, UK, 16-18 July 2001 / [ed] Chris Burgoyne, London: Thomas Telford Ltd , 2001, p. 107-116Conference paper (Refereed)
  • 192.
    Täljsten, Björn
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Carolin, Anders
    CFRP strengthening of concrete beams: testing in sub-zero temperature2007In: International journal of materials & product technology, ISSN 0268-1900, E-ISSN 1741-5209, Vol. 28, no 1/2, p. 29-45Article in journal (Refereed)
    Abstract [en]

    Strengthening structures with epoxy bonded Carbon Fibre- Reinforced Polymer (CFRP) plates and sheets are today a well-known and over the world common used method to improve a structure performance. The composite materials used for strengthening are very light and easy to handle, have good durability and do not normally need to be maintained over time. However, disadvantages might be mechanical damage and long term properties. There is also a question regarding the behaviour of CFRP strengthen structures in cold climates, for example will the structure become more brittle during the winter compared to the summer period? In this paper the last issue will be addressed. CFRP strengthen concrete beams have been tested in sub-zero temperature and loaded up to failure. The cold climate tests are then compared with similar beams tested in room climate. From the tests no significant difference between the beams tested in sub-zero and room temperatures could be found.

  • 193.
    Täljsten, Björn
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Carolin, Anders
    Förstärkning av betongkonstruktioner med fiberarmerade kompositer: en överblick2006In: Bygg & Teknik, ISSN 0281-658X, no 7Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Betongkonstruktioner har normalt en lång livslängd och har bra prestanda, speciellt om underhållet sköts korrekt. Brister det i underhåll kan man behöva reparera konstruktionen till ursprunglig prestanda. I de fall prestanda behöver ökas kan uppgradering vara nödvändigt. Prestanda kan delas in i fyra olika delar, estetik, funktion, beständighet och bärförmåga. Faktorer som inverkar på estetiken kan gälla så enkla delar som klotter eller icke konstruktiva åtgärder som målning. Brister i funktion kan till exempel vara om en bro är i fullgott skick med avseende på beständighet, utseende och bärförmåga, men en breddning av befintlig väg medför att bron är för smal och av den orsaken behöver ersättas. Vilket i ytterlighetsfallet kan innebära att bron byts ut.

  • 194.
    Täljsten, Björn
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Carolin, Anders
    Near surface mounted reinforcement (NSMR) to strengthen concrete structures2007In: Sustainable bridges: assessment for future traffic demands and longer lives / [ed] Jan Bien; Lennart Elfgren; Jan Olofsson, Wrocław: Dolnoslaskie Wydawnictwo Edukacyjne , 2007, p. 341-354Conference paper (Refereed)
  • 195.
    Täljsten, Björn
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Carolin, Anders
    Strengthening of a concrete railway bridge in Luleå with carbon fibre reinforced polymers - CFRP: load bearing capacity before and after strengthening1999Report (Other academic)
    Abstract [en]

    The railroad between Gällivare and Luleå in the northern part of Sweden is called Malmbanan. Heavy loads of iron ore are transported on this railroad daily. During long time the weight of the load has been approximately 5 000 tons per train which correspond to 25 tons per axle. A wish from LKAB to increase the load up to 30 tons per axle or 6 000 tons per train exists. Calculations of the load bearing capacity of the bridges show that many of them will not be able to carry these higher loads without strengthening. There exist several methods for strengthening of a concrete structure. A strengthening method that have been more and more used during the last years is bonding of carbon fibre composite fabrics or laminates to the surface of the structure. The Swedish Rail Road authorities wanted to investigate the method more closely and of that reason a bridge were strengthened in Luleå during the summer of 1998. The bridge is built of concrete and has three spans. It is located at Kallkällan NW of the city centre. The objective of the test was not only to investigate the strengthening effect but also to study the work methods and the work environment during handling of the thermosetting plastic. Before the strengthening system was applied, the concrete surface was smoothened by sandblasting and grinding. Putty was used for bigger irregularities. The strengthening system consists of a hand lay up system with epoxy and unidirectional carbon fibre sheets. Later the concrete surface was coated by a polyurethane paint, with function to protect against UV-radiation and mechanical damage and also to give an increased aesthetic value. During the work the environmental and health aspects were taken into account and the epoxy, as well as the epoxy components were handled in a strict and careful manner, for example all the waste were placed in closed containers and sent to destruction. In the report, general equations, modes of action and design principles for strengthening by externally bonded fibre-reinforced polymers are described shortly. Some of the calculations that have been done for the bridge are also shown. For investigation of the strengthening system a comprehensive test program was undertaken on the bridge before and after the strengthening system was mounted. Both strains and deformations were measured when ore trains at different speeds passed on the bridge. The weight of each train was measured to be able to compare measurements of different trains with each other. Measured values from testing were relatively close to theoretical calculated levels, before and after the strengthening, both regarding strains and deformation. The measurement showed that the strengthening had increased the stiffness of the bridge by about 16%. Also measurements of the concrete quality were undertaken as well as an investigation of the bridge condition. The difficulties to decide the clamping of the slab in the load bearing beams and the chosen models for calculations have a big influence of the theoretical results. However, the measurements show that the method of strengthening concrete bridges by bonding carbon fibres to the surface works in an effective manner even when trains are frequenting the bridge during the strengthening work. In chapter 1 a short introduction and background to the project is given. In chapter 2 theoretical work are described and in chapter 3 the execution of the strengthening work is described. In chapter 4 the results and the performance from the measurements are recorded. In chapter 5 a comparison between theory and tests are made. In chapter 6 conclusions are presented and finally in chapter 7 proposal to further work is given.

  • 196.
    Täljsten, Björn
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Carolin, Anders
    Strengthening of concrete beams in shear: theory and test2001In: FRP Composites in Civil Engineering: Proceedings of the International Conference on FRP composites in Civil Engineering, Amsterdam: Elsevier, 2001, Vol. 1, p. 657-667Conference paper (Refereed)
    Abstract [en]

    The paper provides a summary of a theoretical derivation of equations for strengthening concrete beams in shear with CFRP (carbon fiber reinforced polymer) sheets and presents a limited number of laboratory tests. A fairly good agreement is obtained with a comparison between theory and testing. Still, additional tests will be necessary to verify and control the derived theory. The future tests should focus not only on the different angles of the fiber but also the number of layers and different stiffnesses of the fibers used. The aim of these tests is to find a factor for safety where the design equations can be used on the safe side without putting strong limitations on the strengthening system used.

  • 197.
    Täljsten, Björn
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Carolin, Anders
    Helmerich, Rosmarie
    Bundesanstalt für Materialforschung.
    Rehabilitation of railway bridges2007In: Sustainable bridges: assessment for future traffic demands and longer lives / [ed] Jan Bien; Lennart Elfgren; Jan Olofsson, Wrocław: Dolnoslaskie Wydawnictwo Edukacyjne , 2007, p. 303-312Conference paper (Refereed)
    Abstract [en]

    The presented work in work package 6 is a part of the European funded research project Sustainable Bridges. The objectives of this project are to: Increase the transport capacity of existing bridges by allowing axle loads up to 33 tons for freight traffic with moderate speeds or for speeds up to 350 km/hour for passenger traffic with low axle loads. Increase the mean residual service lives of existing bridges with up to 25 %. The project contains 9 work packages, where WP6 deals with new and innovative repair and strengthening methods for railway bridges. All work-packages are correlated. However in this paper the work carried out in work package 6 and how development of environmental friendly and non disturbing repair and strengthening methods may enhance management, strengthening and repair systems is presented.

  • 198.
    Täljsten, Björn
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Carolin, Anders
    Nordin, Håkan
    Concrete structures strengthened with near surface mounted reinforcement of CFRP2003In: Advances in Structural Engineering, ISSN 1369-4332, E-ISSN 2048-4011, Vol. 6, no 3, p. 201-213Article in journal (Refereed)
    Abstract [en]

    The need of maintenance, repair and upgrading of concrete structures has increased considerably over the last decade and will most likely continue to do so. There can be several reasons for this, but it can often be attributed to normal change of use, increased demands on the structure, errors in the design and/or construction phase or in the worst case, accidents. Different methods have been developed over the years for solving different rehabilitation problems. Recently, advanced composites used for external bonding in the form of fabrics or laminates have become an accepted method. Several thousands of objects around the world have been upgraded with advanced composites bonded to its surface. In most cases, this method is very competitive regarding both structural behaviour and economy, but there are also some drawbacks. The surface bonded composite material is relatively sensitive to fire, accidents or vandalism. In addition, the pre-treatment is relatively intensive and time consuming. However, if the composite material is placed in slots in the concrete cover some of these drawbacks can be overcome. This paper presents work carried out on near surface mounted reinforcement (NSMR) at Luleå University of Technology in Sweden.

  • 199.
    Täljsten, Björn
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Carolin, Anders
    Pedersen, Henning
    COWI A/S.
    Repair and strengthening of railway bridges: guideline2007In: Sustainable bridges: assessment for future traffic demands and longer lives / [ed] Jan Bien; Lennart Elfgren; Jan Olofsson, Wrocław: Dolnoslaskie Wydawnictwo Edukacyjne , 2007, p. 313-320Conference paper (Refereed)
    Abstract [en]

    This paper presents how a range of suitable strengthening method can be selected from the vast number of existing methods via a guideline. The guideline considers the structural system, type of problem and relevant circumstances. In the guideline, only methods that can be considered as new and investigated in the project Sustainable Bridges are at this moment introduced. However, the guideline can easily be updated with additional methods and systems following the same suggested approach. Furthermore, the guideline's precision in suggesting strengthening methods can be improved by use of future experience from real applications and development of different strengthening methods.

  • 200. Täljsten, Björn
    et al.
    Elfgren, Lennart
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Construction Engineering.
    Förstärkning av betongbroar med pålimmad armering1993In: Bygg & Teknik, ISSN 0281-658X, no 7, p. 19-22Article in journal (Other (popular science, discussion, etc.))
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