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Sabourova, Natalia
Publikasjoner (10 av 21) Visa alla publikasjoner
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
Åpne denne publikasjonen i ny fane eller vindu >>Fatigue Assessment of Reinforced Concrete Railway Bridge based on a Coupled Dynamic System
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2020 (engelsk)Inngår i: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980Artikkel i tidsskrift (Fagfellevurdert) Epub ahead of print
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.

sted, utgiver, år, opplag, sider
Taylor & Francis Group, 2020
Emneord
Train Bridge Coupling System, Fatigue Damage, Moving Load Model, Moving Spring Mass Damper Model, Reinforced Concrete Railway Bridge
HSV kategori
Forskningsprogram
Byggkonstruktion
Identifikatorer
urn:nbn:se:ltu:diva-76136 (URN)10.1080/15732479.2019.1671467 (DOI)000488187400001 ()
Tilgjengelig fra: 2019-09-26 Laget: 2019-09-26 Sist oppdatert: 2019-10-18
Duvnjak, I., Damjanović, D., Sabourova, N., Grip, N., Ohlsson, U., Elfgren, L. & Tu, Y. (2019). Damage Detection in Structures – Examples. In: IABSE Symposium 2019: Towards a Resilent Built Environment - Risk and Asset Management. Paper presented at IABSE Symposium 2019, Towards a Resilient Built Environment - Risk and Asset Management, March 27-29, 2019, Guimarães, Portugal.
Åpne denne publikasjonen i ny fane eller vindu >>Damage Detection in Structures – Examples
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2019 (engelsk)Inngår i: IABSE Symposium 2019: Towards a Resilent Built Environment - Risk and Asset Management, 2019Konferansepaper, Publicerat paper (Fagfellevurdert)
Abstract [en]

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

Emneord
mode shape damage detection, finite element model updating, 𝑙1-norm regularization
HSV kategori
Forskningsprogram
Matematik; Byggkonstruktion
Identifikatorer
urn:nbn:se:ltu:diva-73334 (URN)
Konferanse
IABSE Symposium 2019, Towards a Resilient Built Environment - Risk and Asset Management, March 27-29, 2019, Guimarães, Portugal
Tilgjengelig fra: 2019-03-28 Laget: 2019-03-28 Sist oppdatert: 2019-04-15bibliografisk kontrollert
Sabourova, N., Grip, N., Ohlsson, U., Elfgren, L., Tu, Y., Duvnjak, I. & Damjanović, D. (2019). Detection of Sparse Damages in Structures. In: IABSE Symposium 2019: Towards a Resilent Built Environment - Risk and Asset Management. Paper presented at IABSE Symposium 2019, Towards a Resilient Built Environment - Risk and Asset Management, March 27-29, 2019, Guimarães, Portugal.
Åpne denne publikasjonen i ny fane eller vindu >>Detection of Sparse Damages in Structures
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2019 (engelsk)Inngår i: IABSE Symposium 2019: Towards a Resilent Built Environment - Risk and Asset Management, 2019Konferansepaper, Publicerat paper (Fagfellevurdert)
Abstract [en]

Structural damage is often a spatially sparse phenomenon, i.e. it occurs only in a small part of the structure. This property of damage has not been utilized in the field of structural damage identification until quite recently, when the sparsity-based regularization developed in the compressed sensing found its application in this field.

In this paper we consider classical sensitivity-based finite element model updating combined with a regularization technique appropriate for the expected type of sparse damage. Traditionally (1) 𝑙2-norm regularization was used to solve the ill-posed inverse problems, such as damage identification. However, using (2) already well established 𝑙1-norm regularization or (3) our proposed 𝑙1-norm total variation regularization and (4) general dictionary-based regularization allows us to find damages with special spatial properties quite precisely using much fewer measurement locations than the number of possibly damaged elements of the structure. The validity of the proposed methods is demonstrated using simulations on a Kirchhoff plate model. The pros and cons of these methods are discussed.

Emneord
sparse damage, 𝑙2-norm, 𝑙1-norm, total variation, dictionary-based regularization, sensitivity
HSV kategori
Forskningsprogram
Matematik; Byggkonstruktion
Identifikatorer
urn:nbn:se:ltu:diva-73335 (URN)
Konferanse
IABSE Symposium 2019, Towards a Resilient Built Environment - Risk and Asset Management, March 27-29, 2019, Guimarães, Portugal
Tilgjengelig fra: 2019-03-28 Laget: 2019-03-28 Sist oppdatert: 2019-04-15
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
Åpne denne publikasjonen i ny fane eller vindu >>Railway Concrete Arch Bridge over Kalix River at Långforsen: Dynamic Properties and Load-Carrying Capacity
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2019 (engelsk)Rapport (Fagfellevurdert)
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.

sted, utgiver, år, opplag, sider
Luleå: Luleå University of Technology, 2019. s. 44
Serie
Forskningsrapport / Luleå tekniska universitet, ISSN 1402-1528
Emneord
Concrete Arch Bridge, Railway, Dynamic Properties, Load-Carrying Capacity
HSV kategori
Forskningsprogram
Byggkonstruktion
Identifikatorer
urn:nbn:se:ltu:diva-76116 (URN)978-91-7790-473-1 (ISBN)
Forskningsfinansiär
Swedish Transport Administration
Tilgjengelig fra: 2019-09-25 Laget: 2019-09-25 Sist oppdatert: 2019-10-18bibliografisk kontrollert
Grip, N., Sabourova, N. & Tu, Y. (2017). Sensitivity-based model updating for structural damage identification using total variation regularization (ed.). Mechanical systems and signal processing, 84(A), 365-383
Åpne denne publikasjonen i ny fane eller vindu >>Sensitivity-based model updating for structural damage identification using total variation regularization
2017 (engelsk)Inngår i: Mechanical systems and signal processing, ISSN 0888-3270, E-ISSN 1096-1216, Vol. 84, nr A, s. 365-383Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Sensitivity-based Finite Element Model Updating (FEMU) is one of the widely accepted techniques used for damage identification in structures. FEMU can be formulated as a numerical optimization problem and solved iteratively making automatic updating of the unknown model parameters by minimizing the difference between measured and analytical structural properties. However, in the presence of noise in the measurements, the updating results are usually prone to errors. This is mathematically described as instability of the damage identification as an inverse problem. One way to resolve this problem is by using regularization. In this paper, we compare a well established interpolation-based regularization method against methods based on the minimization of the total variation of the unknown model parameters. These are new regularization methods for structural damage identification. We investigate how using Huber and pseudo Huber functions in the definition of total variation affects important properties of the methods. For instance, for well-localized damages the results show a clear advantage of the total variation based regularization in terms of the identified location and severity of damage compared with the interpolation-based solution.For a practical test of the proposed method we use a reinforced concrete plate. Measurements and analysis were performed first on an undamaged plate, and then repeated after applying four different degrees of damage.

sted, utgiver, år, opplag, sider
Elsevier, 2017
HSV kategori
Forskningsprogram
Matematik; Konstruktionsteknik
Identifikatorer
urn:nbn:se:ltu:diva-7622 (URN)10.1016/j.ymssp.2016.07.012 (DOI)000388785700020 ()2-s2.0-84991782200 (Scopus ID)605f69d8-d15c-4b74-947a-926770375ecc (Lokal ID)605f69d8-d15c-4b74-947a-926770375ecc (Arkivnummer)605f69d8-d15c-4b74-947a-926770375ecc (OAI)
Merknad

Validerad; 2016; Nivå 2; 20160816 (andbra)

Tilgjengelig fra: 2016-09-29 Laget: 2016-09-29 Sist oppdatert: 2018-09-13bibliografisk kontrollert
Grip, N., Sabourova, N., Tu, Y. & Elfgren, L. (2017). Vibrationsanalys för tillståndsbedömning av byggkonstruktioner: Tillämpningsexempel : (Main results and summary in Swedish. Detailed results in English Appendices.). Stockholm
Åpne denne publikasjonen i ny fane eller vindu >>Vibrationsanalys för tillståndsbedömning av byggkonstruktioner: Tillämpningsexempel : (Main results and summary in Swedish. Detailed results in English Appendices.)
2017 (svensk)Rapport (Annet vitenskapelig)
Abstract [sv]

I projektet beskrivs och tillämpasnågra metoder för tillståndsbedömningav olika typer av konstruktioner med och utan skador.Tillståndsbedömningen skermed hjälp av vibrationsanalys.Detektering av skador av olika typ och storlekdiskuteras. Randvillkorens betydelse undersöks för att få överensstämmelse mellan förutspådda och uppmätta egenmoder och egenfrekvenser.Med den programvara som utvecklats är det möjligt att detektera sprickor i enkla betongplattor med hjälp av vibrationsmätningar. För mer avancerade konstruktioner finns en potential att vidareutveckla programvaran.Mätningar och analyser presenterasför femkonstruktioner: (1) En betongplatta –Sprickor har kunnat identifieras utifrån vibrationsmätningar och en successivt uppdaterad finit element modell (FEM).(2) En bågbro av betong över Långforsen i Kalix älv–Okända randvillkor har kunnat bestämmasför t ex undergrundens styvhetmedhjälp avuppmätta vibrationer. Detekteringav specifika skadorhar ännu inte kunnat genomföras.(3) En fackverksbro av stålöver Åby älv–Enviss skadedetektering har kunnat genomföras med vibrationsmätningar. Brons sårbarhet för korrosion och lokala mekaniska skador har studerats.(4) En förspänd betongbrotill gruvan i Kiruna–Modeller av bron har arbetats framför obelastatoch brottbelastat tillståndoch jämförts med uppmätta vibrationer med gott resultat.(5) Ett betonghus med nio våningar i Luleå –En FEM-modell av huseti bruksstadiethar tagits fram och resultat från den har jämförts med uppmätta vibrationer med gott resultat.Metoder och resultatpresenteras översiktligti rapportens huvudtext. Detaljerade beskrivningar gesi appendix.I appendix presenterasäven en programvaramed färdiga moduler för de undersökta konstruktionerna. Programmet kan laddas ner och användasfritt

Abstract [en]

In the project,methods are presented and appliedfor assessment ofdifferent types ofbuilding structures with and without damages.The assessmentis done withhelp ofvibration analysis.Detection of defects of different types and sizes are discussed. The influence of boundary conditions isstudied in order to get agreement between predicted and measured Eigen modes and Eigen frequencies.With the program that has been developed,is it now possible to detect cracks in simple concrete structures with help of measurements of vibrations. For more advanced structures there is a potentialto further develop the program. Measurements and analyses have been made for fivestructures:(1) A concrete slab–Cracks have been detected based on vibrationmeasurementsand a successivelyupdated Finite Element Model (FEM).(2) Aconcrete archbridge at Långforsen in Kalix River-Unknown boundary conditions havebeen possible todetermine with help of vibration measurementsregarding for example foundation properties. Detection of specific damages hasnot yet been possible.(3) A steel truss bridge over Åby River–Some detection of damages hasbeen possible to carry outwith Finite Element Model updatingregarding corrosion and mechanical damages.. (4) A prestressed concrete bridge to the mine in Kiruna-Several models of theundamaged and damagedbridgehave been established and they have been calibrated to measured vibration propertieswith good results.(5) A nine storey concrete building in Luleå–A FEM model has been developedfor the serviceability limit stateand results from it has been compared to measured vibrationswith good results.A general presentation is given ofthe developedmethods and resultsin the main text. Detailed descriptions are provided in Appendices.A program is presented with ready-to-use models for the studied structures. The program may be downloaded and is presented in detail in an Appendix.

sted, utgiver, år, opplag, sider
Stockholm: , 2017. s. 305
HSV kategori
Forskningsprogram
Matematik; Konstruktionsteknik
Identifikatorer
urn:nbn:se:ltu:diva-66140 (URN)
Prosjekter
SBUF (Svenska Byggbranschens Utvecklingsfond)
Merknad

Dessutom har Zheng Huang, Chao Wang, Niklas Bagge, Jens Häggström, Jonny Nilimaa, Thomas Forsberg,Ola Enokson,Thomas Blanksvärd och Ulf Ohlsson bidragit med material och synpunkteroch som medförfattare i artiklar och konferensbidrag.

Tilgjengelig fra: 2017-10-15 Laget: 2017-10-15 Sist oppdatert: 2017-11-24bibliografisk kontrollert
Qin, X.-C., Meng, S.-P., Cao, D.-F., Tu, Y.-M., Sabourova, N., Grip, N., . . . Elfgren, L. (2016). Evaluation of freeze-thaw damage on concrete material and prestressed concrete specimens. Construction and Building Materials, 125, 892-904
Åpne denne publikasjonen i ny fane eller vindu >>Evaluation of freeze-thaw damage on concrete material and prestressed concrete specimens
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2016 (engelsk)Inngår i: Construction and Building Materials, ISSN 0950-0618, E-ISSN 1879-0526, Vol. 125, s. 892-904Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

The pore structure of the hardened concrete and the microscopic changes of a few selected pores throughout the freeze-thaw test were investigated by a method combining RapidAir and digital metalloscope. Traditional tests were also performed to evaluate the macroscopic change caused by freeze-thaw cycles (FTCs). The investigation shows that the concrete material, of which the spacing factor is 0.405 mm and the air content is 2.38%, can still withstand more than 300 FTCs. Severe microscopic damages occurred after approximately 200 FTCs and the freeze-thaw damage were gradually aggravated afterwards. Prestress forces have a remarkable impact on the failure pattern under FTCs. It was further found that the compressive strength as an indicator is more reliable than the relative dynamic modulus of elasticity in evaluating the freeze-thaw damage on concrete material. In addition, the test and analysis show that the measured prestress losses of bonded specimen are larger than that of unbounded specimen under the attack of FTCs due to the duct grouting effect. The ultimate freeze-thaw prestress loss is about 5% of σconσcon for both the bonded and unbonded specimens because the grouting cement paste will eventually be completely destroyed.

sted, utgiver, år, opplag, sider
Elsevier, 2016
HSV kategori
Forskningsprogram
Konstruktionsteknik
Identifikatorer
urn:nbn:se:ltu:diva-59653 (URN)10.1016/j.conbuildmat.2016.08.098 (DOI)000385600100088 ()2-s2.0-84984828018 (Scopus ID)
Merknad

Validerad; 2016; Nivå 2; 2016-10-10 (andbra)

Tilgjengelig fra: 2016-10-11 Laget: 2016-10-11 Sist oppdatert: 2019-02-22bibliografisk kontrollert
Huang, Z., Grip, N., Sabourova, N., Bagge, N., Tu, Y.-M. & Elfgren, L. (2016). Modelling of Damage and its Use in Assessment of a Prestressed Bridge. Luleå: Luleå tekniska universitet
Åpne denne publikasjonen i ny fane eller vindu >>Modelling of Damage and its Use in Assessment of a Prestressed Bridge
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2016 (engelsk)Rapport (Annet vitenskapelig)
Abstract [en]

A 55 years old and 121.5 m long ve-span prestressed bridge has been subjected toshear failure test in Kiruna, Sweden. This in-situ test is a desirable test to validate andcalibrate the existing nonlinear nite element program for predicting the shear behaviorof reinforced and prestressed concrete structures.Two 3D nite element (FE) models of the Kiruna Bridge are built in commercial soft-ware Abaqus, one using shell-elements and one using a combination of shell and beam ele-ments. Predictions obtained from these two models are well consistent with mode shapesand eigenfrequencies computed from acceleration measurements on the bridge before andafter loading it to failure. Shear-failure test of this bridge performed by Lulea Universityof Technology (LTU) is also simulated using the built-in concrete damage plasticity (CDP)model in Abaqus. The predicted load-displacement curve is in good agreement with themeasurement. Verication of the CDP model is conducted at element and member levelwith two dierent damage parameter evolutions. According to the verication, it indi-cates the damage parameter will aect the predicted shear behavior of reinforced concretestructures and it is not reliable to adopt the CDP model to simulate the shear behaviorof reinforced concrete structures based on the present research.A long term goal is to use use the measured mode shapes, eigenfrequencies and FEmodels for evaluating methods for damage identication. Such methods are important formaintenance of dierent structures, for extending their life span and for better knowledgeof their load carrying capacity. We describe how so-called sparse regularization niteelement method updating (FEMU) methods can be used. We then demonstrate someimportant properties of such methods with simulations on a Kirchho plate. For instance,the simulations suggest that both eigenfrequencies and mode shapes should be used forprecise localization of the damage.

sted, utgiver, år, opplag, sider
Luleå: Luleå tekniska universitet, 2016. s. 21
Serie
Forskningsrapport / Luleå tekniska universitet, ISSN 1402-1528
HSV kategori
Forskningsprogram
Konstruktionsteknik
Identifikatorer
urn:nbn:se:ltu:diva-61185 (URN)978-91-7583-820-5 (ISBN)
Tilgjengelig fra: 2016-12-21 Laget: 2016-12-21 Sist oppdatert: 2018-05-22bibliografisk kontrollert
Huang, Z., Tu, Y.-M., Grip, N., Sabourova, N., Bagge, N., Blanksvärd, T., . . . Elfgren, L. (2016). Modelling of Damage and its use in Assessment of a PrestressedConcrete Bridge. 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, Stockholm 2016, September 21-23 (pp. 2093-2108). CH - 8093 Zürich, Switzerland
Åpne denne publikasjonen i ny fane eller vindu >>Modelling of Damage and its use in Assessment of a PrestressedConcrete Bridge
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2016 (engelsk)Inngår i: 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, 2016, s. 2093-2108Konferansepaper, Publicerat paper (Fagfellevurdert)
Abstract [en]

A five-span prestressed concrete bridge has been subjected to a loading test up to failure in Kiruna, Sweden. The bridge was 55 years old and had a length of 121.5 m. The test has been used to validate and calibrate existing nonlinear finite element programs for predicting the shear behavior of reinforced and prestressed concrete structures. Two 3D finite element (FE) models of the Kiruna Bridge are built in commercial software Abaqus, one using shell-elements and one using a combination of shell and beam elements. Predictions obtained from these two models are well consistent with mode shapes and eigenfrequencies computed from acceleration measurements on the bridge before and after loading it to failure.The shear failure of the bridge is also simulated using the built-in concrete damage plasticity (CDP)model in Abaqus. The predicted load-displacement curve is in good agreement with the measurements. Verification of the CDP model is conducted at element and member level with two different damage parameter evolutions. The verification indicates that the damage parameter will affect the predicted shear behavior. It does not seem to be reliable to adopt the CDP model to simulate the shear behavior in the present research. A long term goal is to use use the measured mode shapes, eigenfrequencies and FE models for evaluating methods for damage identification. Such methods are important for maintenance of different structures, for extending their life span and for better knowledge of their load carrying capacity. The use is described of so-called sparse regularized finite element method updating (FEMU) methods. Some important properties of such methods are demonstrated using simulations on a Kirchhoff plate. For instance, the simulations suggest that both eigenfrequencies and mode shapes should be used for precise localization of the damage.

sted, utgiver, år, opplag, sider
CH - 8093 Zürich, Switzerland: , 2016
Serie
IABSE Congress Reports
Emneord
Concrete damage plasticity model, refined shell element model, shear failure test, shear behavior, five-span prestressed concrete bridge, FEM updating, sparse regularization, Kirchhoff plate.
HSV kategori
Forskningsprogram
Konstruktionsteknik
Identifikatorer
urn:nbn:se:ltu:diva-60996 (URN)2-s2.0-85018991487 (Scopus ID)978-3-85748-144-4 (ISBN)
Konferanse
19th IABSE Congress, Stockholm 2016, September 21-23
Tilgjengelig fra: 2016-12-10 Laget: 2016-12-10 Sist oppdatert: 2018-03-27bibliografisk kontrollert
Bagge, N., Nilimaa, J., Enochsson, O., Sabourova, N., Grip, N., Emborg, M., . . . Tu, Y. (2015). Protecting a five span prestressed bridge against ground deformations (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. 255-262). Geneva: International Association for Bridge and Structural Engineering
Åpne denne publikasjonen i ny fane eller vindu >>Protecting a five span prestressed bridge against ground deformations
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2015 (engelsk)Inngår i: IABSE Conference Geneva 2015: Structural Engineering: Providing Solutions to Global Challenges, Geneva: International Association for Bridge and Structural Engineering, 2015, s. 255-262Konferansepaper, Publicerat paper (Annet vitenskapelig)
Abstract [en]

A 55 year-old, 121.5 m long, five span prestressed bridge was situated in the deformation zone close to a mine in Kiruna in northern Sweden. There was a risk for uneven ground deformations so the bridge was analyzed and monitored. Results and measures taken to ascertain the robustness of the bridge are presented.The analysis resulted in an estimate that the bridge could sustain 24 mm in uneven horizontal and 83 mm in uneven vertical displacement of the two supports of a span. To be able to sustain larger deformations, the columns of the bridge were provided with joints, where shims could be inserted to counteract the settlements. To accomplish this, each one of the 18 columns of the bridge was unloaded by help of provisional steel supports. The column was then cut and a new foot was mounted to it. This made it possible to lift each individual column with two jacks, when needed, and to adjust its height by inserting or taking away shim plates.The deformations of the bridge and the surrounding ground were monitored. The eigenmodes of the bridge were studied with accelerometers and by analysis with finite elements (FE) models. Comparison indicated good agreement between the model and the actual bridge, with calculated eigenfrequencies of 2.17, 4.15 and 4.67 Hz, for the first transversal, vertical and torsional modes, respectively. Measurements during winter resulted in higher values due to increased stiffness caused by frozen materials.

sted, utgiver, år, opplag, sider
Geneva: International Association for Bridge and Structural Engineering, 2015
HSV kategori
Forskningsprogram
Konstruktionsteknik; Matematik; Attraktivt samhällsbyggande (FOI)
Identifikatorer
urn:nbn:se:ltu:diva-34954 (URN)94595912-e47e-4600-8e52-15aff592265e (Lokal ID)9783857481406 (ISBN)94595912-e47e-4600-8e52-15aff592265e (Arkivnummer)94595912-e47e-4600-8e52-15aff592265e (OAI)
Konferanse
IABSE Conference : Structural Engineering: Providing Solutions to Global Challenges 23/09/2015 - 25/09/2015
Merknad
Godkänd; 2015; 20150527 (nikbag)Tilgjengelig fra: 2016-09-30 Laget: 2016-09-30 Sist oppdatert: 2018-03-26bibliografisk kontrollert
Organisasjoner