| 1. |
- Coric, Ibrahim, et al.
(författare)
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Eisenbahnbrücken auf der Erzbahnlinie in Nordschweden - Erhöhung der Achslasten von 14 auf 32.5 metrische Tonnen : [Railway bridges on the Iron Ore line in Northern Sweden - From axle loads of 14 to 32.5 metric tons]
- 2021
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Ingår i: Internationale Arbeitstagung Brücken- und Ingenieurbau 2021. - Berlin : Bundesministerium für Verkehr und digitale Infrastruktur. ; , s. 118-122
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Konferensbidrag (refereegranskat)abstract
- Die Erzbahnlinie wurde um 1900 gebaut und überquert in ihrem Verlauf über 100 Brücken. Sie ist mehr als 500 km lang und verläuft von den Minen in Nordschweden zu den Häfen am Atlantik und an der Ostsee. Die ursprüngliche Achslast betrug 14 Tonnen. Zur Senkung der Transportkosten wurde die Achslast kontinuierlich erhöht, 1955 auf 25 Tonnen, 1998 auf 30 Tonnen und schliesslich auf 32,5 Tonnen im Jahr 2017 bzw. 2019. Der Erhöhung der Achslast ging jeweils ein Monitoring und eine Begutachtung der Brücken voraus. Dabei zeigte sich, dass viele dieser Brücken eine höhere Last tragen können, als ursprünglich beim Entwurf vorgesehen. Es werden Erfahrungen aus Studien vorgestellt, die zeigen ,dass durch gut geplante Erhaltungs- und Instalthaltungsprogramme/Ersatzneubauten viel Geld gespart werden kann.
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| 2. |
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| 3. |
- Enochsson, Ola, 1960-, et al.
(författare)
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Tillståndsbedömning av järnvägsbro över Byske älv vid Myrheden, Bandelen Bastuträsk – Nyfors, km 1031+937
- 2010
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Rapport (refereegranskat)abstract
- Järnvägsbron över Byske Älv vid Myrheden är en bågbro av betong som färdigställdes 1941. Bågen har en spännvidd av 39,2 m och den totala längden är 59,6 m. Bågen blev fläckvis frysskadad i samband med gjutningen och har reparerats med ca 10 års mellanrum. År 2003 upptäcktes ånyo betongskador i underkant på bågen. Den dåliga betongen bilades bort och ersattes med torrbruk som sprutades på plats. Efter reparationen bedömdes bron kunna klara tåglast BV-2 (25 tons axellast och 7,2 ton/m utbreddlast). För att bedöma brons fortsatta livslängd och bärförmåga har Avd för Byggkonstruktion vid LTU tagit del avtidigare tillståndsbedömningar och besiktigat bron 2009-02-13 och 2009-08-25--26. Bron visade sig vara i förhållandevis gott skick. Vi bedömer att den kan klara tåglast BV-2 i ytterligare fem år under förutsättning att den hålls under uppsikt och att en närmare utredninggörs av gjutfogarna i bågen under skivstöden och av skivstödens ledformade anslutningar mot bågen. Bron borde hålla i 20 år eller mer om ballasten rensas från finare grusfraktioner så att dräneringen förbättras. Vattenavledningen från bron bör vidare ordnas så att vatten från brobanan förhindras rinna ner längs bågen och bidra till frost- och korrosionsangrepp. Dessutom bör dålig/skadad betong vattenbilas bort och ersätts med pågjutning av ny betong.
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| 4. |
- He, Guojing, 1964-, et al.
(författare)
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Assessment of a railway concrete arch bridge by numerical modelling and measurements
- 2008
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Ingår i: <em>Bridge Maintenance, Safety, Management, Health Monitoring and Informatics</em>. - Leiden : CRC Press. ; , s. 3733-3742
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Konferensbidrag (refereegranskat)abstract
- Two main railway concrete arch bridges have been investigated in northern Sweden: the Vindel Bridge over the Vindel River with a span of 110 m and the Långforsen Bridge over the Kalix River with a span of 90 m. The bridges were constructed in the 1950s with similar designs. In order to investigate the possibility to increase the axle load from 225 kN to 250kN, two 3-D Finite Element models with shell elements were developed and two field tests were carried out with passing trains and ambient vibrations. The measurement frequencies and mode shapes were studied with the stochastic subspace identification method in the time domain. Based on a comparison of the predictions of the FE analyses and the results of the field tests, the FE models were updated. It was found that it was possible to make good predictions of the actual dynamic response with reasonable assumptions of material properties and joint stiffness in the structure.
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| 5. |
- Puurula, Arto, 1956-, et al.
(författare)
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3D non-linear FE analysis of a full scale test to failure of a RC Railway Bridge strengthened with carbon fibre bars
- 2016
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Ingår i: IABSE CONGRESS, STOCKHOLM, 2016. - CH - 8093 Zürich, Switzerland : International Association for Bridge and Structural Engineering. - 9783857481444 ; , s. 2527-2535
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Konferensbidrag (refereegranskat)abstract
- At a full scale loading test to failure a 50 year old concrete railway trough bridge in Örnsköldsvik, in northern Sweden was tested to failure. The test was a part of the European Research Project “Sustainable Bridges” regarding assessment and strengthening of existing bridges. In the projectnew calculation methods were developed to capture the behaviour of the bridge during increasing load. The bridge was strengthened in bending with rods of Carbon Fiber Reinforced Polymer (CFRP) before the loading test. Failure was reached for an applied load of 11.7 MN by pulling a steel beam placed in the middle of one of the two spans downwards. The achieved failure was a combination of bond, shear, torsion and bending. The developed model, a 3D -non-linear finiteelement (FE) model with discrete reinforcement, gave accurate accounts of the response of thebridge. The FE calculations show the effect of the strengthening with CFRP and even the effect of the epoxy when using the Near Surface Mounted Reinforcement (NSMR) strengthening method.
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| 6. |
- Puurula, Arto M., et al.
(författare)
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Failure of a RC Bridge initiated by debonding : 3-D Non-Linear Finite Element Analysis of Near Surface Mounted Fibre Reinforced Polymer Bars (NSM FRPB)
- 2021
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Rapport (refereegranskat)abstract
- The bond failure is studied of a reinforced concrete trough bridge strengthened with near surface mounted reinforcement of carbon fibre reinforced polymer (CFRP) bars. The bars were embedded in epoxy resin in pre-sawed groves in the soffit of the bridge edge beams. The failure was modelled with 3D nonlinear finite elements, and it was possible to study the process from initiation to final collapse. A local bond failure in the interface between the concrete and the epoxy resin initiated a redistribution of forces in the bridge leading to yielding in the longitudinal and vertical steel reinforcement, rupture of stirrups and finally a full failure of the bridge. The bridge was a 50-year-old typical concrete railway trough bridge in Örnsköldsvik, in northern Sweden. It was going to be dismantled due to a relocation of the railway line. The aim of the loading test was to get detailed information of the bridge behaviour all the way up to the final failure. The test was a part of the European Research Project “Sustainable Bridges” regarding assessment and strengthening of existing bridges. The bridge was strengthened in bending before the loading test to avoid an uninteresting flexural failure. Failure was reached for an applied load of 11,7 MN by pulling downwards a steel beam placed in the middle of one of the two spans. The FE calculations presented here show the effect of the strengthening with CFRP, the effect of the epoxy when using the Near Surface Mounted Reinforcement (NSMR) strengthening method and the high load-carrying capacity of this bridge type
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| 7. |
- Sabourova, Natalia, 1975-, et al.
(författare)
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Railway Concrete Arch Bridge over Kalix River at Långforsen : Dynamic Properties and Load-Carrying Capacity
- 2019
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Rapport (refereegranskat)abstract
- 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.
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| 8. |
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Stål- och samverkansbroar : seminarieuppgifter i doktorandkurs 2004
- 2005
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Samlingsverk (redaktörskap) (populärvet., debatt m.m.)abstract
- Luleå tekniska universitet, LTU och Kungliga tekniska högskolan, KTH anordnade under 2004 en doktorandkurs i stål- och samverkansbroar. Kursen gavs inom det Vinnova stödda FOU-konsortiet Väg/Bro/Tunnel. Kursens syfte var att deltagarna skulle få en inblick i stål- och samverkansbroar genom föreläsningar och studiebesök, samt även få chansen att träna upp sina egna konstruktionsfärdigheter genom att själv välja och göra en konstruktionsuppgift. Kursen genomfördes med tre 2-dagars kurstillfällen antingen på KTH eller på LTU, samt med ett avslutande seminarium och studiebesök i Paris.
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| 9. |
- Wang, Chao, 1991-, et al.
(författare)
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Development of proof loading method for railway bridges with masonry abutments
- 2024
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Ingår i: Bridge Maintenance, Safety, Management, Digitalization and Sustainability. - : CRC Press. ; , s. 399-408
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Konferensbidrag (refereegranskat)abstract
- Railway bridges with masonry abutments represent a significant portion of aging infrastructure in north Sweden. The assessment of their structural integrity is crucial to ensure safe and efficient railway operations. This paper presents the development of a proof loading method tailored specifically for railway bridges with masonry abuments.Before conducting the tests, the bridge condition was assessed through visual inspections using ground-based photogrammetry and Ground Penetration Radar (GPR). Realistic loads were simulated using a carefully chosen train fleet during the tests to evaluate load-carrying capacity and structural integrity. Comprehensive data, including strains, displacements, temperature, and acceleration measurements, were collected to gain insights into the bridges' behavior under real-life loading conditions. This data played a crucial role in making predictions and guiding maintenance decisions for targeted rehabilitation efforts. To enhance capacity assessments, finite element models were calibrated using test results, enabling predictions of how the bridges would respond to varioius loads.
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