Change search
Link to record
Permanent link

Direct link
BETA
Bernspång, Lars
Publications (10 of 22) Show all publications
Tran, A. T., Bernspång, L., Veljkovic, M., Rebelo, C. & Simões da Silva, L. (2018). Influence of cold-formed angle on high strength steel material properties. Advanced steel construction
Open this publication in new window or tab >>Influence of cold-formed angle on high strength steel material properties
Show others...
2018 (English)In: Advanced steel construction, ISSN 1816-112XArticle in journal (Refereed) Submitted
Keywords
High strength steel, Cold-formed angle, Tensile coupon test, Ductility, Experimental investigation, Finite element analysis
National Category
Building Technologies
Research subject
Steel Structures
Identifiers
urn:nbn:se:ltu:diva-62267 (URN)
Available from: 2017-03-02 Created: 2017-03-02 Last updated: 2019-09-13
Tran, A. T., Bernspång, L., Veljkovic, M., Rebelo, C. & Simões da Silva, L. (2018). Resistance of cold-formed high strength steel angles. Advanced steel construction
Open this publication in new window or tab >>Resistance of cold-formed high strength steel angles
Show others...
2018 (English)In: Advanced steel construction, ISSN 1816-112XArticle in journal (Refereed) Submitted
Keywords
High strength steel, Cold-formed angles, Geometrical imperfections, Proof stress, Experimental investigation, Finite element analysis
National Category
Civil Engineering Building Technologies
Research subject
Steel Structures
Identifiers
urn:nbn:se:ltu:diva-63086 (URN)
Available from: 2017-04-19 Created: 2017-04-19 Last updated: 2019-09-13
Puurula, A., Enochsson, O., Sas, G., Blanksvärd, T., Ohlsson, U., Bernspång, L., . . . Elfgren, L. (2016). 3D non-linear FE analysis of a full scale test to failure of a RC Railway Bridge strengthened with carbon fibre bars. In: Lennart Elfgren, Johan Jonsson, Mats Karlsson, Lahja Rydberg-Forssbeck and Britt Sigfrid (Ed.), IABSE CONGRESS, STOCKHOLM, 2016: Challenges in Design and Construction of an Innovativeand Sustainable Built Environment. Paper presented at 19th IABSE Congress, Strockholm, 21-23 September 2016 (pp. 2527-2535). CH - 8093 Zürich, Switzerland: International Association for Bridge and Structural Engineering
Open this publication in new window or tab >>3D non-linear FE analysis of a full scale test to failure of a RC Railway Bridge strengthened with carbon fibre bars
Show others...
2016 (English)In: 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, Published 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.

Place, publisher, year, edition, pages
CH - 8093 Zürich, Switzerland: International Association for Bridge and Structural Engineering, 2016
Series
IABSE Congress Reports
Keywords
Bridge, Strengthening, Full scale test, Failure Analysis, Bond, Shear, Near Surface Mounted reinforcement (NSMR), Carbon Fibre Reinforced Polymer CFRP), Ultimate load carrying capacity, 3D Non-linear finite element analysis.
National Category
Infrastructure Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-60997 (URN)2-s2.0-85018961713 (Scopus ID)978-3-85748-144-4 (ISBN)
Conference
19th IABSE Congress, Strockholm, 21-23 September 2016
Note

EU FP6, Sjätte ramprogrammet

Available from: 2016-12-10 Created: 2016-12-10 Last updated: 2018-03-27Bibliographically approved
Puurula, A., Enochsson, O., Sas, G., Blanksvärd, T., Ohlsson, U., Bernspång, L., . . . Elfgren, L. (2015). Assessment of the Strengthening of an RC Railway Bridge with CFRP utilizing a Full-Scale Failure Test and Finite-Element Analysis (ed.). Journal of Structural Engineering, 141(1 (Special Issue)), D4014008-1-D4014008-11, Article ID D4014008.
Open this publication in new window or tab >>Assessment of the Strengthening of an RC Railway Bridge with CFRP utilizing a Full-Scale Failure Test and Finite-Element Analysis
Show others...
2015 (English)In: 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) Published
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.

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 load-carrying 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 “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 (= 2630 kips).A computer model was developed using Brigade software (based on Abaqus), 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 6 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 U.S.

Keywords
Bridge, Train load, Failure analysis, Ultimate load-carrying capacity, Shear, Near-surfacemounted reinforcement (NSMR), Civil engineering and architecture - Building engineering, Samhällsbyggnadsteknik och arkitektur - Byggnadsteknik
National Category
Infrastructure Engineering
Research subject
Structural Engineering; Attractive built environment (AERI)
Identifiers
urn:nbn:se:ltu:diva-15842 (URN)10.1061/(ASCE)ST.1943-541X.0001116 (DOI)000346338100011 ()2-s2.0-84920771165 (Scopus ID)f66f5694-cfe1-40be-a43e-24618eb23eae (Local ID)f66f5694-cfe1-40be-a43e-24618eb23eae (Archive number)f66f5694-cfe1-40be-a43e-24618eb23eae (OAI)
Projects
Mainline-MAINtenance, renewaL and Improvement of rail transport iNfrastructure to reduce Economic and environmental impacts, Centrum för riskanalys och riskhantering, CRR, Sustainable Bridges
Note

Validerad; 2015; Nivå 2; Bibliografisk uppgift: This work is made available under the terms of the Creative Commons Attribution 4.0 International license, http://creativecommons.org/licenses/by/4.0/.; 20140524 (elfgren)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Bagge, N., Nilimaa, J., Blanksvärd, T., Bernspång, L., Täljsten, B., Elfgren, L., . . . Carolin, A. (2015). Performance of a prestressed concrete bridge loaded to failure (ed.). In: (Ed.), (Ed.), IABSE Conference Geneva 2015: Structural Engineering: Providing Solutions to Global Challenges. Paper presented at IABSE Conference : Structural Engineering: Providing Solutions to Global Challenges 23/09/2015 - 25/09/2015 (pp. 1088-1095). Geneva: International Association for Bridge and Structural Engineering
Open this publication in new window or tab >>Performance of a prestressed concrete bridge loaded to failure
Show others...
2015 (English)In: IABSE Conference Geneva 2015: Structural Engineering: Providing Solutions to Global Challenges, Geneva: International Association for Bridge and Structural Engineering, 2015, p. 1088-1095Conference paper, Published paper (Other academic)
Place, publisher, year, edition, pages
Geneva: International Association for Bridge and Structural Engineering, 2015
National Category
Infrastructure Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-31547 (URN)84971254517 (Scopus ID)5c48b48e-61ce-4a1b-bdd5-b95ff5f6bba6 (Local ID)9783857481406 (ISBN)5c48b48e-61ce-4a1b-bdd5-b95ff5f6bba6 (Archive number)5c48b48e-61ce-4a1b-bdd5-b95ff5f6bba6 (OAI)
Conference
IABSE Conference : Structural Engineering: Providing Solutions to Global Challenges 23/09/2015 - 25/09/2015
Note
Godkänd; 2015; 20150527 (nikbag)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2018-03-26Bibliographically approved
Bagge, N., Blanksvärd, T., Sas, G., Bernspång, L., Täljsten, B., Carolin, A. & Elfgren, L. (2014). Full-Scale Test to Failure of a Prestressed Concrete Bridge in Kiruna (ed.). Paper presented at Nordic Concrete Research Symposia : 13/08/2014 - 15/08/2014. Nordic Concrete Research, 50, 83-86
Open this publication in new window or tab >>Full-Scale Test to Failure of a Prestressed Concrete Bridge in Kiruna
Show others...
2014 (English)In: Nordic Concrete Research, ISSN 0800-6377, Vol. 50, p. 83-86Article in journal (Refereed) Published
Abstract [en]

To calibrate methods for condition assessment of prestressed concrete (PC) bridges, tests are planned for a 50 year old five-span bridge with a length of 121 m in Kiruna in northern Sweden. Both non-destructive and destructive full-scale tests will be performed. This paper summarises the test programme, which comprises evaluation of the structural behaviour of the bridge, the residual forces in the prestressed steel, methods for strengthening using carbon fibre reinforced polymers (CFRP) and the shear resistance of the bridge slab.

Abstract [en]

To calibrate methods for condition assessment of prestressed concrete (PC) bridges, tests are planned for a 50 year old five-span bridge with a length of 121 m in Kiruna in northern Sweden. Both non-destructive and destructive full-scale tests will be performed. This paper summarises the test programme, which comprises evaluation of the structural behaviour of the bridge, the residual forces in the prestressed steel, methods for strengthening using carbon fibre reinforced polymers (CFRP) and the punching capacity of the bridge slab.

Keywords
Civil engineering and architecture - Building engineering, Samhällsbyggnadsteknik och arkitektur - Byggnadsteknik
National Category
Infrastructure Engineering
Research subject
Structural Engineering; Attractive built environment (AERI)
Identifiers
urn:nbn:se:ltu:diva-40183 (URN)f3533c9c-4cdc-4ff4-aa92-a878cf88e5be (Local ID)f3533c9c-4cdc-4ff4-aa92-a878cf88e5be (Archive number)f3533c9c-4cdc-4ff4-aa92-a878cf88e5be (OAI)
Conference
Nordic Concrete Research Symposia : 13/08/2014 - 15/08/2014
Note

Godkänd; 2014; 20140829 (nikbag); Konferensartikel i tidskrift

Available from: 2016-10-03 Created: 2016-10-03 Last updated: 2018-03-20Bibliographically approved
Puurula, A., Enochsson, O., Sas, G., Blanksvärd, T., Ohlsson, U., Bernspång, L., . . . Elfgren, L. (2014). Loading to failure and 3D nonlinear FE modelling of a strengthened RC bridge. (ed.). Paper presented at . Structure and Infrastructure Engineering, 10(12), 1606-1619
Open this publication in new window or tab >>Loading to failure and 3D nonlinear FE modelling of a strengthened RC bridge.
Show others...
2014 (English)In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 10, no 12, p. 1606-1619Article in journal (Refereed) Published
Abstract [en]

A reinforced concrete railway trough bridge in Örnsköldsvik, Sweden, was strengthened in bending with rods of carbon-fibre-reinforced polymer and loaded to failure. The aim was to test and calibrate methods developed in the European Research Project ‘Sustainable Bridges’ regarding assessment and strengthening of existing bridges. A steel beam was placed in the middle of one of the two spans and was pulled downwards. Failure was reached at an applied load of 11.7 MN. It was initiated by a bond failure caused by a combined action of shear, torsion as well as bending after yielding in the longitudinal steel reinforcement and the stirrups. The bond failure led to a redistribution of the internal forces from the tensile reinforcement to the stirrups, causing the final failure. The computer models developed to simulate the loading process were improved step by step from linear shell models to more detailed models. The most developed model, a three-dimensional nonlinear finite element model with discrete reinforcement, gave accurate accounts of the response of the bridge.

Abstract [en]

A reinforced concrete railway trough bridge in Örnsköldsvik, Sweden, was strengthened in bending with rods of Carbon Fiber Reinforced Polymer (CFRP) and loaded to failure. The aim was to test and calibrate methods developed in the European Research Project "Sustainable Bridges" regarding assessment and strengthening of existing bridges. A steel beam was placed in the middle of one of the two spans and was pulled downwards. An interesting failure was reached, which included bond, shear and torsion as well as bending, for an applied load of 11,7 MN. Three dimensional nonlinear finite element calculations with discrete reinforcement were used to simulate the loading process. The developed models – after several trials and errors - gave accurate accounts of the response of the bridge during increasing loading.

Keywords
Civil engineering and architecture - Building engineering, Samhällsbyggnadsteknik och arkitektur - Byggnadsteknik
National Category
Infrastructure Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-14810 (URN)10.1080/15732479.2013.836546 (DOI)000348944400001 ()2-s2.0-84908043589 (Scopus ID)e3ae0583-b31d-4593-bf2d-f796601dcca4 (Local ID)e3ae0583-b31d-4593-bf2d-f796601dcca4 (Archive number)e3ae0583-b31d-4593-bf2d-f796601dcca4 (OAI)
Projects
Sustainable Bridges
Note
Validerad; 2014; 20130606 (elfgren)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Nilimaa, J., Häggström, J., Bagge, N., Blanksvärd, T., Sas, G., Ohlsson, U., . . . Paulsson, B. (2014). Maintenance and Renewal of Concrete Rail Bridges: Results from EC project MAINLINE (ed.). Paper presented at Nordic Concrete Research Symposia : 13/08/2014 - 15/08/2014. Nordic Concrete Research, 50, 25-28
Open this publication in new window or tab >>Maintenance and Renewal of Concrete Rail Bridges: Results from EC project MAINLINE
Show others...
2014 (English)In: Nordic Concrete Research, ISSN 0800-6377, Vol. 50, p. 25-28Article in journal (Refereed) Published
Abstract [en]

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

Keywords
Civil engineering and architecture - Building engineering, Samhällsbyggnadsteknik och arkitektur - Byggnadsteknik
National Category
Infrastructure Engineering
Research subject
Structural Engineering; Attractive built environment (AERI)
Identifiers
urn:nbn:se:ltu:diva-37680 (URN)bc5dcd40-5dc2-49de-a7aa-8ad276c767f9 (Local ID)bc5dcd40-5dc2-49de-a7aa-8ad276c767f9 (Archive number)bc5dcd40-5dc2-49de-a7aa-8ad276c767f9 (OAI)
Conference
Nordic Concrete Research Symposia : 13/08/2014 - 15/08/2014
Projects
Sveriges Bygguniversitet, Centrum för riskanalys och riskhantering, CRR, Mainline-MAINtenance, renewaL and Improvement of rail transport iNfrastructure to reduce Economic and environmental impacts
Note
Godkänd; 2014; 20140820 (jonnil); Konferensartikel i tidskriftAvailable from: 2016-10-03 Created: 2016-10-03 Last updated: 2018-03-27Bibliographically approved
Limam, M., Veljkovic, M., Bernspång, L., Rebelo, C. & silva, L. S. (2011). Modeling three dimensional friction connection for wind towers using finite element methods (ed.). In: (Ed.), (Ed.), Proceedings of the 6th European Conference on Steel and Composite Structures: Eurosteel 2011, August 31 - September 2, 2011, Budapest, Hungary. Paper presented at European Conference on Steel and Composite Structures : 31/08/2011 - 02/09/2011. Budapest: European Convention for Constructional Steelwork, ECCS
Open this publication in new window or tab >>Modeling three dimensional friction connection for wind towers using finite element methods
Show others...
2011 (English)In: Proceedings of the 6th European Conference on Steel and Composite Structures: Eurosteel 2011, August 31 - September 2, 2011, Budapest, Hungary, Budapest: European Convention for Constructional Steelwork, ECCS , 2011Conference paper, Published paper (Refereed)
Abstract [en]

The tubular steel towers supporting wind turbines account for about 15 to 20% of the total installation costs and their optimization may lead to substantial savings with regard to costs and use of material. An innovative solution for assembling joints of a tubular tower for wind turbines has been studied in an European research project called HISTWIN (High-Strength Steel Tower for Wind Turbine). This solution is simpler to produce and 80% less expensive than the traditional flange connection.The paper deals with connections used to assemble sections of tubular steel towers supporting wind turbines. The starting point is a rather simple lap joint connection .This connection is chosen for the sake of simplicity but still having possibility of general conclusions. After that more realistic connection between two tower segments is presented, each section has about 3m high and 2 m in diameter and they are connected by 222 M30 high-strength bolts.Modeling such FE models, which consists of several parts in contact, requires knowledge in contact mechanics with friction, meshing techniques as well as stability and convergence algorithms.A short parametric study is made to evaluate influence of number of bolts and the pretension force on the tubular tower failure mode.Results of FEA and resistance according to European codes, series EN1993-1-8 is considered. Keywords: Finite Element Model, Gap, High Strength Friction Grip Connection, Tubular Steel Tower, contact.

Place, publisher, year, edition, pages
Budapest: European Convention for Constructional Steelwork, ECCS, 2011
Keywords
Steel Structures, Civil engineering and architecture - Building engineering, Samhällsbyggnadsteknik och arkitektur - Byggnadsteknik
National Category
Building Technologies Infrastructure Engineering
Research subject
Steel Structures; Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-38617 (URN)d0f6878e-afbf-4522-a874-f97d5320b264 (Local ID)978-92-9147-103-4 (ISBN)d0f6878e-afbf-4522-a874-f97d5320b264 (Archive number)d0f6878e-afbf-4522-a874-f97d5320b264 (OAI)
Conference
European Conference on Steel and Composite Structures : 31/08/2011 - 02/09/2011
Note
Godkänd; 2011; 20110601 (marlim)Available from: 2016-10-03 Created: 2016-10-03 Last updated: 2018-06-08Bibliographically approved
Lundqvist, J., Bernspång, L., Täljsten, B. & Olofsson, T. (2007). A probability study of finite element analysis of near surface mounted carbon fiber reinforced polymer bonded to reinforced concrete (ed.). In: (Ed.), T.C. Triantafillou (Ed.), Fiber-Reinforced Polymer Reinforcement for Concrete Structures: Proceedings of the 8th International Symposium on Fiber Reinforced Polymer Reinforcement for Concrete Structures, FRPRCS-8. Paper presented at International Symposium on Fiber Reinforced Polymer Reinforcement for Concrete Structures : 16/07/2007 - 18/07/2007. Patras: FRPRCS-8 Symposium Secretariat
Open this publication in new window or tab >>A probability study of finite element analysis of near surface mounted carbon fiber reinforced polymer bonded to reinforced concrete
2007 (English)In: Fiber-Reinforced Polymer Reinforcement for Concrete Structures: Proceedings of the 8th International Symposium on Fiber Reinforced Polymer Reinforcement for Concrete Structures, FRPRCS-8 / [ed] T.C. Triantafillou, Patras: FRPRCS-8 Symposium Secretariat , 2007Conference paper, Published paper (Refereed)
Abstract [en]

A structure is typically designed for a long life and it is probable that the demands on it change over time, e.g. carry larger loads or fulfill new standards. The structure might also have been exposed to a harsh environment leading to a degradation of its structural capacity. These reasons, and more, may lead to a need for strengthening the structure. Strengthening of reinforced concrete structures with carbon fiber reinforced polymers (CFRP) has been shown to be a very effective and advantageous retrofitting technique. The weight-to-strength ratio and resistance to corrosion are some of the advantages. Several different strengthening systems are available with CFRP and a relatively new technique is the near surface mounted reinforcement (NSMR) method. As opposed to externally mounted strengthening systems, NSMR is composed of sawing a groove in a concrete member, applying an adhesive in the groove and inserting a CFRP bar. Although the idea of embedding reinforcing tendons in existing structures has been present for several decades [1], acceptance of the method has only been possible with the emergence of the FRP material. As NSMR comprise of the properties and advantages of an ordinary FRP strengthening system, e.g. plates, it also has the benefit of being embedded in the concrete. This means better protection against impact, fire, abrasion and a natural resistance to peeling stresses. Strengthening of concrete members with NSMR have been reported by e.g. [2], [3], [4], and [5]. For NSMR, or indeed for most FRP strengthening techniques, the bond between the concrete and the strengthening material is the most important issue. This is where the transfer of stresses takes place to realize full composite action. The behavior of strengthened reinforced concrete is quite complex and an approach to investigate this is to utilize the finite element (FE) method. Many numerical analyses of reinforced concrete strengthened with CFRP using the FE method have been carried out in recent years. These concern primarily studies of plate bonding though there are a few studies of bonding of NSMR. In [6], concrete beams are strengthened with plates and the analytical shear and peeling stresses are compared with a linear finite element (FE) analysis. Several authors, e.g. [7], have emphasized that sufficiently small elements must be used in a FE analysis to accurately describe stress distributions, particularly at the end of a bonded plate. Teng et al, [8], make further refinement of the FE mesh and examine the interfacial stresses in reinforced concrete beams bonded with a soffit plate. A concern for the element size where stress singularities occur was also raised. Nonlinear FE analyses of reinforced concrete strengthened with NSMR are performed in [3], [4], [5], and [9]. The common failure mode of a strengthening system with plates is in the outermost concrete layer close to the adhesive. This has been reported in many papers, e.g. [9]. The failure mode for NSMR is more complex. It spans from being a failure in the adhesive close to the FRP bar, i.e. pure pullout, to the concrete layer close to the adhesive, as for FRP plates but with the difference that more concrete is dislodged. In between, a mixed mode of failure is present with cracks in both the adhesive and the concrete. Where the failure occurs is determined by geometrical and material parameters. The thickness of the adhesive, the position of the bar in the adhesive, and the bonding length are possible geometrical parameters. Material parameters are the modulus of elasticity and Poisson's ratio of the concrete, adhesive and the FRP, and of course the tensile strength of the concrete and adhesive. Also, the configuration and the properties of the internal reinforcement may determine the failure mode. To study the bond behavior of reinforced concrete strengthened with NSMR, a test for CFRP bar pullout was devised. This is illustrated in Figure 1 and is reported in [10]. The concrete beam has a minimum amount of reinforcing steel not shown in the drawing. In this paper, the pullout of a rectangular NSMR CFRP bar bonded to reinforced concrete is studied by a finite element analysis in the linear elastic domain. Also, a Monte Carlo simulation, with the FE model incorporated, is carried out with the purpose of determining which geometrical and material parameters that are the most important for where the tensile strength is attained; in the adhesive or the concrete. The following simplifications have been made in this study; all materials are considered as isotropic and linear elastic, and the FE model utilizes symmetry.

Place, publisher, year, edition, pages
Patras: FRPRCS-8 Symposium Secretariat, 2007
National Category
Infrastructure Engineering Construction Management
Research subject
Structural Engineering; Construction Engineering and Management
Identifiers
urn:nbn:se:ltu:diva-31661 (URN)5e8d53b0-7733-11dc-80da-000ea68e967b (Local ID)978-960-8969-0-0 (ISBN)5e8d53b0-7733-11dc-80da-000ea68e967b (Archive number)5e8d53b0-7733-11dc-80da-000ea68e967b (OAI)
Conference
International Symposium on Fiber Reinforced Polymer Reinforcement for Concrete Structures : 16/07/2007 - 18/07/2007
Note
Godkänd; 2007; Bibliografisk uppgift: CD-ROM; 20071010 (lber)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2018-03-20Bibliographically approved
Organisations

Search in DiVA

Show all publications