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Wang, C., Zhang, J., Tu, Y., Sabourova, N., Grip, N., Blanksvärd, T. & Elfgren, L. (2020). Fatigue Assessment of Reinforced Concrete Railway Bridge based on a Coupled Dynamic System. Structure and Infrastructure Engineering
Open this publication in new window or tab >>Fatigue Assessment of Reinforced Concrete Railway Bridge based on a Coupled Dynamic System
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2020 (English)In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980Article in journal (Refereed) In press
Abstract [en]

This paper proposes a fatigue damage assessment methodology of a reinforced concrete bridge based on a train bridge coupled dynamic analysis system. This coupling system is composed of a vehicle a ballasted track and a bridge structure to realize a coupled vibration analysis during train passages. This methodology adopts the Palmgren Miner rule to linearly accumulate fatigue damage, and accomplishes fatigue assessment based on recommended SN relationships for reinforced concrete from various criteria. In this paper, the dynamic performances of a bridge structure are analyzed with two different vehicle models, a moving load model (and a moving spring mass damper model). Calculated dynamic stresses areused to evaluate the fatigue damage of critical positions in a reinforced concrete bridge. A case study is carried out of a railway arch bridge with a span of 89 m, Långforsen Bridge. It runs over Kalix River on the railway between Kalix and Morjärv in northern Sweden The fatigue assessment is made by combining the presented methodology with measurements. Furthermore, the effects of train speed and axle load on fatigue damage are investigated. The results indicate that good estimations of the fatigue damage assessment are made for four measured cases based on a train-bridge coupled dynamic analysis. For low speeds and light loads no difference could be seen in the cumulative fatigue damage for the two vehicle models. But high speeds and/or heavy load ssignificantly affect the fatigue damage.

Place, publisher, year, edition, pages
Taylor & Francis Group, 2020
Keywords
Train Bridge Coupling System; Fatigue Damage; Moving Load ( Model; Moving Spring Mass Damper ( Model; Reinforced Concrete Railway Bridge
National Category
Infrastructure Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-76136 (URN)10.1080/15732479.2019.1671467 (DOI)
Available from: 2019-09-26 Created: 2019-09-26 Last updated: 2019-09-30
Popescu, C., Täljsten, B., Blanksvärd, T. & Elfgren, L. (2019). 3D reconstruction of existing concrete bridges using optical methods. Structure and Infrastructure Engineering, 15(7), 912-924
Open this publication in new window or tab >>3D reconstruction of existing concrete bridges using optical methods
2019 (English)In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 15, no 7, p. 912-924Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
Taylor & Francis, 2019
Keywords
3D geometric modeling, terrestrial laser scanning, photogrammetry, infrared scanning, bridge inspection, remote sensing
National Category
Infrastructure Engineering Other Civil Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-73644 (URN)10.1080/15732479.2019.1594315 (DOI)000466668000001 ()2-s2.0-85064494122 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-07-12 (johcin)

Available from: 2019-04-15 Created: 2019-04-15 Last updated: 2019-07-12Bibliographically approved
Elfgren, L., Täljsten, B. & Blanksvärd, T. (2019). Load Testing as Part of Bridge Management in Sweden.: Chapter 11 (1ed.). In: Eva O.L. Landsoght (Vol 13), Dan M. Frangopol (Series Editor) (Ed.), Load Testing of Bridges: Proof load Testing and the Future of Load Testing, Volume Editor Eva O. L. Landsoght: Series: Structures and Infrastructures, Vol. 13, Series Editor Dan M. Frangopol, (pp. 333-346). London/Leiden: Taylor and Francis Group
Open this publication in new window or tab >>Load Testing as Part of Bridge Management in Sweden.: Chapter 11
2019 (English)In: Load Testing of Bridges: Proof load Testing and the Future of Load Testing, Volume Editor Eva O. L. Landsoght: Series: Structures and Infrastructures, Vol. 13, Series Editor Dan M. Frangopol, / [ed] Eva O.L. Landsoght (Vol 13), Dan M. Frangopol (Series Editor), London/Leiden: Taylor and Francis Group , 2019, 1, p. 333-346Chapter in book (Refereed)
Abstract [en]

Load testing of new and existing bridges was performed regularly in Sweden up to the 1960ies. It was then abandoned due to high costs versus little extra information obtained. Most bridges behaved well in the serviceability limit range and no knowledge of the ultimate limit stage could be obtained without destroying the bridge. At the same time the methods for calculating the capacity developed and new numerical methods were introduced. Detailed rules were given on how these methods should be used. Some decommissioned bridges were tested to their maximum capacity to be able to study their failure mechanisms and to calibrate the numerical methods. In this paper some examples are given on how allowable loads have increased over the years and of tests being performed. Nowadays, load testing may be on its way back, especially to test existing rural prestressed concrete bridges, where no design calculations have been retained

Place, publisher, year, edition, pages
London/Leiden: Taylor and Francis Group, 2019 Edition: 1
Series
Structures and Infrastructures ; 13
Keywords
Load Testing, Bridges, Management, Sweden
National Category
Infrastructure Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-76135 (URN)9780429265969 (DOI)9781138091986 (ISBN)
Available from: 2019-09-26 Created: 2019-09-26 Last updated: 2019-09-26
Sabau, C., Popescu, C., Bagge, N., Sas, G., Blanksvärd, T. & Täljsten, B. (2019). Local and global behavior of walls with cut-out openings in multi-story reinforced concrete buildings. Engineering structures, 187, 57-72
Open this publication in new window or tab >>Local and global behavior of walls with cut-out openings in multi-story reinforced concrete buildings
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2019 (English)In: Engineering structures, ISSN 0141-0296, E-ISSN 1873-7323, Vol. 187, p. 57-72Article in journal (Refereed) Published
Abstract [en]

This paper presents the finite element analysis (FEA) results of a multi-story reinforced concrete (RC) building having precast and cast-in-place load bearing walls. Door-type cut-out openings (height: 2.1 m, width: 0.9–4.4 m) were created at the first and second story of the building. Results from experimental tests on axially loaded RC panels were used to verify the modeling approach. The influence of cut-out openings on the response of individual RC panels, failure modes, and load redistribution to adjacent members was analyzed. Moreover, the wall bearing capacities obtained from FEA were compared with the values calculated from design equations. The results revealed that the robustness of multi-story buildings having RC load bearing wall systems decrease considerably with the creation of cut-out openings. However, owing to the initial robustness of the buildings, large cut-outopenings could be created under normal service conditions without strengthening of the building structure. Furthermore, design equations provided very conservative predictions of the ultimate capacity characterizing the solid walls and walls with small openings, whereas similar FEA and analytically predicted capacities were obtained for walls with large openings.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
FEM, reinforced concrete, building assessment, wall, openings
National Category
Building Technologies Other Civil Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-70883 (URN)10.1016/j.engstruct.2019.02.046 (DOI)000462689900006 ()2-s2.0-85062088838 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-03-07 (inah)

Available from: 2018-09-18 Created: 2018-09-18 Last updated: 2019-04-23Bibliographically approved
Sabourova, N., Grip, N., Tu, Y., Wang, C., Enochsson, O., Blanksvärd, T., . . . Elfgren, L. (2019). Railway Concrete Arch Bridge over Kalix River at Långforsen: Dynamic Properties and Load-Carrying Capacity. Luleå: Luleå University of Technology
Open this publication in new window or tab >>Railway Concrete Arch Bridge over Kalix River at Långforsen: Dynamic Properties and Load-Carrying Capacity
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2019 (English)Report (Refereed)
Abstract [en]

The concrete arch bridge over Kalix River at Långforsen was built in 1960 and has a mid-span of 89,5 m and a height of 13,7 m. The bridge owner, Trafikverket, wanted to increase its allowable axle load from 225 to 300 kN. Field tests were carried out under service condition and with ambient vibrations. The test results were used to update and validate Finite Element Models. At last, the refined models were used to check the possibility to increase the axle load.

 

According to earlier assessments, most parts of the bridge is capable of carrying an axle load of 330 kN. The only critical sections are located in the beams carrying the rail on top of the arch in the section where the beams are united with the arch. Here the stresses in the longitudinal bottom reinforcement are slightly too high.

 

These sections have been studied in a FEM model for different loads and results show maximum strains of about 50·10-6 corresponding to stresses of only about 10 MPa in the reinforcement in the critical sections. Live load vertical deflections of the crown of the arch is of the order of only ± 6 mm. Dynamic studies have also been made showing that fatigue is no issue. Altogether the studies show that the bridge is able to carry an increased axle load of 300 kN without problems.

Place, publisher, year, edition, pages
Luleå: Luleå University of Technology, 2019. p. 43
Series
Research report / Luleå University of Technology, ISSN 1402-1528
Keywords
Concrete Arch Bridge, Railway, Dynamic Properties, Load-Carrying Capacity
National Category
Infrastructure Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-76116 (URN)978-91-7790-473-1 (ISBN)
Funder
Swedish Transport Administration
Available from: 2019-09-25 Created: 2019-09-25 Last updated: 2019-10-15
Huang, Z., Tu, Y., Meng, S., Bagge, N., Nilimaa, J. & Blanksvärd, T. (2019). Validation of a numerical method for predicting shear deformation of reinforced concrete beams. Engineering structures, 197, Article ID 109367.
Open this publication in new window or tab >>Validation of a numerical method for predicting shear deformation of reinforced concrete beams
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2019 (English)In: Engineering structures, ISSN 0141-0296, E-ISSN 1873-7323, Vol. 197, article id 109367Article in journal (Refereed) Published
Abstract [en]

The objective of this paper is to validate a 2D nonlinear finite element (FE) model for estimating the post-cracking shear deformation of reinforced concrete (RC) beams. The proposed FE model treated the cracked concrete as an orthotropic material in the framework of the fixed-crack approach. The experimental data for both the overall response (including the total and shear-induced deflection) and the detailed response (including the mean shear strain, mean vertical strain and principal compressive strain angle) of five I-section RC beams, monitored by the main authors of this paper with the Digital Image Correlation technique, were used to verify the proposed model. In addition, 27 further test beams evaluated in independent research programs were collected to assemble a database. The proposed FE model was further verified against the database. Two additional FE models (the rotating-crack model developed in this work and Response-2000 developed by Bentz (2000)) were also evaluated by simulating the detailed responses of the beams in the database. The results obtained validate the proposed FE model for predicting the post-cracking shear deformation of RC beams and indicate that the proposed FE model is more suitable for simulating the shear behaviour of RC beams than the rotating-crack model or Response-2000.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Reinforced concrete beams, Shear deformation, Nonlinear finite element model, Model verification, Digital image correlation
National Category
Engineering and Technology Other Civil Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-75389 (URN)10.1016/j.engstruct.2019.109367 (DOI)
Note

Validerad;2019;Nivå 2;2019-08-14 (johcin)

Available from: 2019-08-05 Created: 2019-08-05 Last updated: 2019-08-14Bibliographically approved
Nilimaa, J., Sabau, C., Bagge, N., Puurula, A., Sas, G., Blanksvärd, T., . . . Elfgren, L. (2018). Assessment and Loading to Failure of Three Swedish RC Bridges. In: Eva Lantsoght and Pinar Okumus (Ed.), Evaluation of Concrete Bridge Behavior through Load Testing: International Perspectives (pp. 8.1-8.18). Faarmington Hills, MI: American Concrete Institute, 323, Article ID SP-323-8.
Open this publication in new window or tab >>Assessment and Loading to Failure of Three Swedish RC Bridges
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2018 (English)In: 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.

Place, publisher, year, edition, pages
Faarmington Hills, MI: American Concrete Institute, 2018
National Category
Infrastructure Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-69992 (URN)978-1-64195-007-7 (ISBN)
Available from: 2018-06-29 Created: 2018-06-29 Last updated: 2018-08-10Bibliographically approved
Sabau, C., Popescu, C., Sas, G., Blanksvärd, T. & Täljsten, B. (2018). Axially Loaded RC Walls with Cutout Openings Strengthened with FRCM Composites. Journal of composites for construction, 22(6), 04018046-1-04018046-16, Article ID 04018046.
Open this publication in new window or tab >>Axially Loaded RC Walls with Cutout Openings Strengthened with FRCM Composites
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2018 (English)In: Journal of composites for construction, ISSN 1090-0268, E-ISSN 1943-5614, Vol. 22, no 6, p. 04018046-1-04018046-16, article id 04018046Article in journal (Refereed) Published
Abstract [en]

Upgrading existing buildings to new functional requirements may require new openings that can weaken the structure, promptingthe need for strengthening. In such cases traditional strengthening solutions, such as creating a reinforced concrete (RC) or steel frame aroundthe opening, imply long-term restrictions in the use of the structure compared to solutions that use externally bonded composites. Two fabricreinforcedcementitious matrix (FRCM) composites were used in this study to restore the capacity of panels with newly created doortype openings to that of a solid panel. Five half-scale RC panels acting as two-way action compression members were tested to failure.Two full-field optical deformation measurement systems were used to monitor and analyze the global structural response of each testedpanel (i.e., crack pattern, failure mechanism, and displacement/strain fields). The performance of existing design methods for RC panelshas been assessed in comparison with the experimental results. The capacity of strengthened panels with small openings (450 × 1,050 mm) was entirely restored to that of the solid panel. However, for panels with large openings (900 × 1,050 mm), only 75% of the solid panel’scapacity was restored. The capacity of the strengthened panels was about 175 and 150% higher compared to that of reference panels withsmall and large openings, respectively.

Place, publisher, year, edition, pages
American Society of Civil Engineers (ASCE), 2018
Keywords
FRCM, Reinforced concrete, Walls with openings, Digital image correlation
National Category
Infrastructure Engineering Building Technologies
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-70579 (URN)10.1061/(ASCE)CC.1943-5614.0000867 (DOI)000447252600001 ()2-s2.0-85051927413 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-08-24 (andbra)

Available from: 2018-08-24 Created: 2018-08-24 Last updated: 2018-10-29Bibliographically approved
Täljsten, B., Blanksvärd, T., Sas, G., Bagge, N., Nilimaa, J., Popescu, C., . . . Häggström, J. (2018). Bridges tested to failure in Sweden. In: IABSE Conference 2018 – Engineering the Past, to Meet the Needs of the FutureJune 25-27 2018, Copenhagen, Denmark: . Paper presented at IABSE Conference 2018 – Engineering the Past, to Meet the Needs of the Future June 25-27 2018, Copenhagen, Denmark.
Open this publication in new window or tab >>Bridges tested to failure in Sweden
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2018 (English)In: IABSE Conference 2018 – Engineering the Past, to Meet the Needs of the FutureJune 25-27 2018, Copenhagen, Denmark, 2018Conference paper, Published 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

Keywords
Test to failure, bridges of concrete and steel, Assessment, Strengthening, Monitoring, Bending, Shar, Torsion, Bond, Fatigue, Carbon Fibre Reinforced Polymers (CFRP)
National Category
Infrastructure Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-72378 (URN)
Conference
IABSE Conference 2018 – Engineering the Past, to Meet the Needs of the Future June 25-27 2018, Copenhagen, Denmark
Available from: 2018-12-28 Created: 2018-12-28 Last updated: 2019-09-06
Huang, Z., Lu, Z., Song, S., Tu, Y., Blanksvärd, T., Sas, G. & Elfgren, L. (2018). Finite element analysis of shear deformation in reinforced concrete shear-critical beams. Structure and Infrastructure Engineering, 14(6), 791-806
Open this publication in new window or tab >>Finite element analysis of shear deformation in reinforced concrete shear-critical beams
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2018 (English)In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 14, no 6, p. 791-806Article in journal (Refereed) Published
Abstract [en]

The objective of this paper was to study the contribution of shear deformation in reinforced concrete (RC) shear-critical beams. A 2D concrete material model based on smeared fixed crack was presented and incorporated into a commercial finite element (FE) software. A method of calculating shear and flexure deformation separately out of total deformation in the shear span was presented and implemented into the FE analysis. Several experiments of RC shear-critical beams were simulated and good agreement between the experimental and numerical results was obtained in terms of total deformation, flexure deformation, shear deformation and crack patterns. The results show that after shear cracking, the contribution of shear deformation to total deformation increases rapidly. The shear span-to-depth ratio, the longitudinal reinforcement, the shear reinforcement and the load level could be the critical factor to influence the contribution of shear deformation. It appears that for RC shear-critical beams without shear reinforcement, the deformational behaviour is governed by flexure deformation. However, for RC beams with shear reinforcement, the contribution of shear deformation is not negligible after shear cracks develop. Moreover, the measuring method could also affect the measured shear deformation. Finally, future work on experimental investigation into this topic is recommended.

Place, publisher, year, edition, pages
Taylor & Francis, 2018
National Category
Infrastructure Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-65169 (URN)10.1080/15732479.2017.1360915 (DOI)000429038000009 ()
Note

Validerad;2018;Nivå 2;2018-04-10 (andbra)

Available from: 2017-08-17 Created: 2017-08-17 Last updated: 2018-04-19Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-5154-7044

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