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Publications (10 of 32) Show all publications
Vestman, V., Collin, P., Lilja, H., Tirkkonen, T., Peltomaa, M., Jordan, J., . . . Hällmark, R. (2022). Horizontal bracing in steel I-girder bridges with composite concrete decks. In: František Wald, Pavel Ryjáček (Ed.), IABSE Symposium Prague 2022: Challenges for Existing and Oncoming Structures - Report, International Association for Bridge and Structural Engineering: . Paper presented at IABSE Symposium Prague 2022: Challenges for Existing and Oncoming Structures, Prague, Czech Republic, May 25-27, 2022 (pp. 1684-1690). International Association for Bridge and Structural Engineering
Open this publication in new window or tab >>Horizontal bracing in steel I-girder bridges with composite concrete decks
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2022 (English)In: IABSE Symposium Prague 2022: Challenges for Existing and Oncoming Structures - Report, International Association for Bridge and Structural Engineering / [ed] František Wald, Pavel Ryjáček, International Association for Bridge and Structural Engineering, 2022, p. 1684-1690Conference paper, Published paper (Refereed)
Abstract [en]

This paper treats the use of horizontal trusses between the bottom flanges of new I-girder bridges, to create a box-like behaviour. In contrast to the general vertical cross frames of an I-girder bridge, the horizontal trusses bring along substantial torsional stiffness of the cross section of a bridge. The concept gives large advantages when it comes to fatigue caused by eccentric loading, since the I-girders will share the load more equally. The concept is exemplified by bridges in Finland, Guatemala and France, and some design aspects as well as practical aspects are discussed. 

Place, publisher, year, edition, pages
International Association for Bridge and Structural Engineering, 2022
Keywords
box action, bracings, bridge fatigue, I-girders bridges, trusses
National Category
Reliability and Maintenance
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-92201 (URN)10.2749/prague.2022.1684 (DOI)2-s2.0-85133509021 (Scopus ID)
Conference
IABSE Symposium Prague 2022: Challenges for Existing and Oncoming Structures, Prague, Czech Republic, May 25-27, 2022
Note

ISBN for host publication: 978-3-85748-181-9

Available from: 2022-07-19 Created: 2022-07-19 Last updated: 2023-09-13Bibliographically approved
Vestman, V., Collin, P. & Hällmark, R. (2022). Strengthening of a Composite I-girder Bridge by Trusses Introducing Box-Action. In: : . Paper presented at 10th International symposium on steel bridges – for A Green Planet, September 20 - 22, 2022 Istanbul, Turkey.
Open this publication in new window or tab >>Strengthening of a Composite I-girder Bridge by Trusses Introducing Box-Action
2022 (English)Conference paper, Oral presentation only (Other academic)
Abstract [en]

The increased amount of traffic and the increasingly heavier loads on the road network push the existing infrastructure to its design limit. Bridges, which are an important part of the road network, need to be adopted to the new traffic demands regarding both the load capacity and the fatigue limit state, FLS. Steel-concrete composite bridges, with twin steel I-girders, is a common bridge type in the Nordic countries. These bridges are often designed using beam models, assuming that the concrete deck is a statically determinate structure supported on the two steel girders in the transversal direction. This assumption implies that the most loaded girder can sometimes be subjected to even more than 100% of an eccentric load, e.g., the traffic loads in the design codes. If the girders are strengthened to be able to share the eccentric loads more equally, it would have a significant impact on the load capacity, especially for the fatigue limit state. By introducing horizontal trusses between the bottom flanges of the girders, making the cross-section act more like a box-girder, the torsional stiffness will increase so that the girders will share the eccentric loads more equally. The bracing system of the trusses can be designed in different shapes, each of them with pros and cons for the existing bridge structure. In this paper, the effects from different shapes of the bracing are evaluated of a single span I-girder composite bridge. The increased torsional stiffness and the change of the internal shear flow will increase the load capacity of the steel girders.

Keywords
bridge, steel-concrete composite, I-girder, case study, horizontal trusses, torsional stiffness, strengthening, composite bridges
National Category
Infrastructure Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-96211 (URN)
Conference
10th International symposium on steel bridges – for A Green Planet, September 20 - 22, 2022 Istanbul, Turkey
Available from: 2023-03-22 Created: 2023-03-22 Last updated: 2023-09-05
Vestman, V., Collin, P., Hällmark, R. & Arason, M. (2021). Monitoring of a Norwegian steel-concrete bridge strengthening forcomposite action. In: Snijder H.H.; De Pauw, B.; van Alphen, S.; Mengeot, P. (Ed.), IABSE Congress Ghent 2021: Structural Engineering for Future Societal Needs. Paper presented at IABSE Congress 2021: Structural Engineering for Future Societal Needs, Ghent, Belgium [Online], September 22-24, 2021 (pp. 1709-1717). International Association for Bridge and Structural Engineering (IABSE)
Open this publication in new window or tab >>Monitoring of a Norwegian steel-concrete bridge strengthening forcomposite action
2021 (English)In: IABSE Congress Ghent 2021: Structural Engineering for Future Societal Needs / [ed] Snijder H.H.; De Pauw, B.; van Alphen, S.; Mengeot, P., International Association for Bridge and Structural Engineering (IABSE) , 2021, p. 1709-1717Conference paper, Published paper (Refereed)
Abstract [en]

Traffic density and vehicle weight have been increasing over time, which implies that many existing road bridges were not designed for the high service loads and the increased number of load cycles that they are exposed to today. One way to increase the traffic load capacity of non-composite steel-concrete bridges is to use post-install shear connectors and one type of shear connector is the coiled spring pin. This type of connector has advantages for strengthening of existing bridges, since it enables an installation from below while the bridge is still in service and does not bring along removal of concrete and pavement, nor welding to the top flange.

This paper describes one ~50 years old Norwegian single span steel-concrete bridge that was strengthened with post-installed coiled spring pins. The strengthening method and the design procedure are presented, along with the results from a field monitoring on Sagstu bridge, performed to evaluate the behaviour of the strengthened structure. The results show that the coiled spring pins counteract the slip and bring along a very good degree of composite action.

Place, publisher, year, edition, pages
International Association for Bridge and Structural Engineering (IABSE), 2021
Series
IABSE Congress Reports ; 21
Keywords
composite bridges, coiled spring pins, monitoring, post-installed shear connectors
National Category
Infrastructure Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-87390 (URN)10.2749/ghent.2021.1709 (DOI)2-s2.0-85119058194 (Scopus ID)
Conference
IABSE Congress 2021: Structural Engineering for Future Societal Needs, Ghent, Belgium [Online], September 22-24, 2021
Note

ISBN för värdpublikation: 978-3-85748-176-5

Available from: 2021-10-06 Created: 2021-10-06 Last updated: 2023-09-05Bibliographically approved
Hällmark, R., Nilforoush, R., Vestman, V. & Collin, P. (2021). Testing of composite girders with coiled spring pin shear connectors. In: H. H. (Bert) Snijder; Bart De Pauw; Sander van Alphen; Pierre Mengeot (Ed.), IABSE Congress Ghent 2021: Structural Engineering for Future Societal Needs. Paper presented at IABSE Congress 2021: Structural Engineering for Future Societal Needs, Ghent, Belgium, 22-24 September, 2021 (pp. 1700-1708). International Association for Bridge and Structural Engineering (IABSE)
Open this publication in new window or tab >>Testing of composite girders with coiled spring pin shear connectors
2021 (English)In: IABSE Congress Ghent 2021: Structural Engineering for Future Societal Needs / [ed] H. H. (Bert) Snijder; Bart De Pauw; Sander van Alphen; Pierre Mengeot, International Association for Bridge and Structural Engineering (IABSE) , 2021, p. 1700-1708Conference paper, Published paper (Refereed)
Abstract [en]

Today, steel girder bridges with concrete deck slabs are generally constructed as steel-concrete composite structures, to utilize the material and the structural parts in an efficient way. However, many existing bridges constructed before the early 1980´s were designed without shear connectors at the steel-concrete interface. With increasing traffics loads and higher amount of load cycles, there is sometimes a need to strengthen these bridges. One way to increase the bending moment capacity is to create composite action by post-installation of shear connectors. The authors have studied the concept of strengthening by post-installed shear connectors, with a focus on a connector called coiled spring pin. This paper presents the results from the first beam tests performed with this kind of shear connector. In line with the previous push-out tests, the test results indicate a very ductile shear connection, with a potential to be a material- and cost-efficient strengthening alternative.

Place, publisher, year, edition, pages
International Association for Bridge and Structural Engineering (IABSE), 2021
Keywords
bridge, strengthening, rehabilitation, shear connector, test, composite girder, coiled spring pin
National Category
Infrastructure Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-87385 (URN)10.2749/ghent.2021.1700 (DOI)2-s2.0-85119084525 (Scopus ID)
Conference
IABSE Congress 2021: Structural Engineering for Future Societal Needs, Ghent, Belgium, 22-24 September, 2021
Funder
Swedish Transport AdministrationSvenska Byggbranschens Utvecklingsfond (SBUF)
Available from: 2021-10-05 Created: 2021-10-05 Last updated: 2023-09-05Bibliographically approved
Pipinato, A., Geier, R., Ivanov, S., Rebelo, C., Collin, P. & Hällmark, R. (2021). UHPFRC strengthening strategies on existing steel and steel-concrete bridges. In: Hiroshi Yokota; Dan M. Frangopol (Ed.), Bridge Maintenance, Safety, Management, Life-Cycle Sustainability and Innovations: Proceedings of the Tenth International Conference on Bridge Maintenance, Safety and Management (IABMAS 2020), June 28-July 2, 2020, Sapporo, Japan. Paper presented at 10th International Conference on Bridge Maintenance, Safety, and Management (IABMAS2020), Sapporo, Japan [ONLINE], April 11-18, 2021 (pp. 598-605). CRC Press
Open this publication in new window or tab >>UHPFRC strengthening strategies on existing steel and steel-concrete bridges
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2021 (English)In: Bridge Maintenance, Safety, Management, Life-Cycle Sustainability and Innovations: Proceedings of the Tenth International Conference on Bridge Maintenance, Safety and Management (IABMAS 2020), June 28-July 2, 2020, Sapporo, Japan / [ed] Hiroshi Yokota; Dan M. Frangopol, CRC Press, 2021, p. 598-605Conference paper, Published paper (Refereed)
Abstract [en]

The overall traffic density and the allowed vehicle weights have been increasing over the last decades. As a response, new roads and railway lines are continuously planned and built. On the other hand, the existing bridges must also be capable of dealing with the increasing traffic volume and the increasing vehicle weights. Many existing bridges were not originally designed for the high traffic loads and todays traffic volume. To cope with the increased loads and load frequencies, the aged structures need repair and strengthening. To avoid the replacement of existing structures, the overall objective is to improve the structural performance of existing steel and steel-concrete bridges by providing innovative and well documented repair and strengthening solutions to bridge designers and road/railway-administrations in Europe. In this paper the use of UHPFRC as a solution for bridge and viaduct repair and strengthening has been presented.

Place, publisher, year, edition, pages
CRC Press, 2021
National Category
Infrastructure Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-93907 (URN)10.1201/9780429279119-78 (DOI)000844440300078 ()2-s2.0-85117582597 (Scopus ID)
Conference
10th International Conference on Bridge Maintenance, Safety, and Management (IABMAS2020), Sapporo, Japan [ONLINE], April 11-18, 2021
Note

ISBN för värdpublikation: 978-0-367-23278-8 (tryckt), 978-0-429-27911-9 (digital)

Available from: 2022-11-08 Created: 2022-11-08 Last updated: 2023-11-10Bibliographically approved
Hällmark, R., Collin, P. & Hicks, S. J. (2019). Post-installed shear connectors: Fatigue push-out tests of coiled spring pins. Journal of constructional steel research, 153, 298-309
Open this publication in new window or tab >>Post-installed shear connectors: Fatigue push-out tests of coiled spring pins
2019 (English)In: Journal of constructional steel research, ISSN 0143-974X, E-ISSN 1873-5983, Vol. 153, p. 298-309Article in journal (Refereed) Published
Abstract [en]

The number of heavy vehicles and their weight have been increasing over time, implying that many bridges are experiencing traffic loads with higher magnitude and frequency than they were originally designed for. In some cases, it will be necessary to either replace or strengthen the structures to keep the bridges in service. For existing non-composite steel girder bridges, post-installation of shear connectors can often be used to increase the traffic load capacity significantly. One type of shear connector that is suitable for post-installation, even though not commonly used, is the Coiled Spring Pin. These interference fit connectors can be installed from below the bridge deck during traffic, in order to minimize the impact on road users. This paper describes an experimental study on the fatigue strength of Coiled Spring Pins and a compilation of previously performed fatigue tests on this type of connector. The new test series, with nine specimens, are evaluated statistically and a fatigue strength design equation is proposed. The results show that there are large variations between different test series, while tests within the same series show good agreement. The reasons for this are discussed in the paper along with recommendations for future testing.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
push-out test, fatigue, coiled spring pin, shear studs, strengthening, shear connector, post installation, composite, steel, concrete
National Category
Infrastructure Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-70889 (URN)10.1016/j.jcsr.2018.10.017 (DOI)000457510200022 ()2-s2.0-85055559362 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-10-30 (johcin)

Available from: 2018-09-18 Created: 2018-09-18 Last updated: 2023-09-05Bibliographically approved
Hällmark, R. & Collin, P. (2019). Post-Installed Shear Connectors: Monitoring a Bridge Strengthened with Coiled Spring Pins. Structural Engineering International, 29(2), 225-233
Open this publication in new window or tab >>Post-Installed Shear Connectors: Monitoring a Bridge Strengthened with Coiled Spring Pins
2019 (English)In: Structural Engineering International, ISSN 1016-8664, E-ISSN 1683-0350, Vol. 29, no 2, p. 225-233Article in journal (Refereed) Published
Abstract [en]

Traffic density and vehicle weight have been increasing over time, which implies that many existing road bridges were not designed for the high service loads and increased number of load cycles that they are subjected to today. One way to increase the traffic load capacity of non-composite steel–concrete bridges is to post-install shear connectors. This paper presents a study of a steel–concrete bridge that has been strengthened with post-installed coiled spring pins, a type of connector which can be installed from below while the bridge is still in service. The strengthening method and design procedure are presented, along with the results from field monitoring performed to evaluate the behaviour of the strengthened structure. The results from the strengthened and non-strengthened sections show that the coiled spring pins counteract the slip and increases the degree of composite action. Finite-element models of the field tests were created in order to compare the results using different design assumptions and establish a suitable level of detail for modelling the shear connectors.

Place, publisher, year, edition, pages
Taylor & Francis, 2019
Keywords
shear connector, composite action, monitoring, strengthening, coiled spring pin
National Category
Other Civil Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-70192 (URN)10.1080/10168664.2018.1456893 (DOI)000472557400004 ()2-s2.0-85055508944 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-07-10 (johcin)

Available from: 2018-08-01 Created: 2018-08-01 Last updated: 2023-09-05Bibliographically approved
Hällmark, R., Collin, P. & Hicks, S. J. (2019). Post-installed Shear Connectors: Push-out Tests of Coiled Spring Pins vs. Headed Studs. Journal of constructional steel research, 161, 1-16
Open this publication in new window or tab >>Post-installed Shear Connectors: Push-out Tests of Coiled Spring Pins vs. Headed Studs
2019 (English)In: Journal of constructional steel research, ISSN 0143-974X, E-ISSN 1873-5983, Vol. 161, p. 1-16Article in journal (Refereed) Published
Abstract [en]

Steadily increasing traffic volumes and traffic loads lead to a continuously growing demand for bridge rehabilitation, strengthening and replacement projects. For existing steel girder bridges with non-composite concrete decks, the traffic load capacity can often be increased significantly if composite action can be created afterwards. Different kinds of shear connectors are more or less suitable for post-installation. Coiled spring pins are one type of interference fit connector that can be installed from below the bridge deck during traffic, in order to minimize the impact on road users. This paper describes an experimental study on the static capacity and stiffness of coiled spring pins used as shear connectors at steel-concrete interfaces. Six push-out test series are presented, with a total of 28 tests, together with an alternative type of test set-up. The results show that the failure of the coiled spring pins is very ductile and that the load capacity is predictable and sufficient for a cost-effective application. The tests also indicate a significantly lower stiffness of the connectors in comparison to welded headed studs of similar dimensions, which might be of great importance if an existing shear connection is strengthened.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
push-out test, coiled spring pin, headed shear studs, strengthening, shear connector, post installation, composite, steel, concrete
National Category
Infrastructure Engineering Other Civil Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-70888 (URN)10.1016/j.jcsr.2019.06.009 (DOI)000488660300001 ()2-s2.0-85068071491 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-07-08 (johcin)

Available from: 2018-09-18 Created: 2018-09-18 Last updated: 2023-09-05Bibliographically approved
Pipinato, A., Collin, P. & Hällmark, R. (2019). Prolonging the Lifetime of Old Steel and Steel–Concrete Bridges: Assessment Procedures and Retrofitting Interventions. Structural Engineering International, 29(4)
Open this publication in new window or tab >>Prolonging the Lifetime of Old Steel and Steel–Concrete Bridges: Assessment Procedures and Retrofitting Interventions
2019 (English)In: Structural Engineering International, ISSN 1016-8664, E-ISSN 1683-0350, Vol. 29, no 4Article in journal (Refereed) Published
Abstract [en]

The structural analysis of existing bridges is not widely covered by the various codes and standards, resulting in the insecure and, in some cases, critical condition of this type of structure. Regarding national regulation, few states include compulsory codes that define the methods and procedures of inspection, assessment, maintenance and retrofitting of bridges. Although an accurate retrofitting procedure can prolong the life of an existing bridge, the more accurate management of national infrastructure assets can result in financial savings in the long term. This article deals with: (a) the assessment step-level procedure, (b) suggestions for bridge load tests and bridge categories, (c) bridge material analysis, (d) structural testing analysis, and (e) the main retrofitting interventions to prolong the life of existing steel and steel composite bridges. Furthermore, a representative case study is analysed and discussed, including examples of the retrofitting solutions implemented to prolong the service life of the bridge.

Place, publisher, year, edition, pages
Taylor & Francis, 2019
Keywords
steel bridges, composite bridges, multi-criteria decision analysis, existing bridges, inspection, assessment, retrofitting
National Category
Infrastructure Engineering Other Civil Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-76127 (URN)10.1080/10168664.2019.1660602 (DOI)000491251700001 ()2-s2.0-85073994676 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-11-19 (johcin)

Available from: 2019-09-26 Created: 2019-09-26 Last updated: 2023-09-05Bibliographically approved
Hällmark, R., Jackson, P., Collin, P. & White, H. (2019). Strengthening Bridges with Postinstalled Coiled Spring Pin Shear Connectors: State-of-the-Art Review. Practice Periodical on Structural Design and Construction, 24(1), Article ID 03118001.
Open this publication in new window or tab >>Strengthening Bridges with Postinstalled Coiled Spring Pin Shear Connectors: State-of-the-Art Review
2019 (English)In: Practice Periodical on Structural Design and Construction, ISSN 1084-0680, E-ISSN 1943-5576, Vol. 24, no 1, article id 03118001Article in journal (Refereed) Published
Abstract [en]

Many existing bridge structures experience much more significant loads and load cycles than were anticipated when the bridges were originally designed. An effective way to increase the load capacity and fatigue resistance of steel girder with non-composite concrete deck bridge structures is to retrofit the structure with shear connectors to create a composite girder-deck structure. This paper presents a state-of the art study of post-installed shear connectors in general and coiled spring connectors in particular. The strengthening method is described together with experiences from real bridge strengthening projects, along with a study of load capacity and structural behavior.

Place, publisher, year, edition, pages
American Society of Civil Engineers (ASCE), 2019
Keywords
Shear connector, composite action, coiled spring pin, bridge strengthening, rehabilitation, bridge
National Category
Infrastructure Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-70887 (URN)10.1061/(ASCE)SC.1943-5576.0000394 (DOI)000453221500002 ()2-s2.0-85056078406 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-12-05 (johcin)

Available from: 2018-09-18 Created: 2018-09-18 Last updated: 2023-09-05Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0003-1435-0071

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