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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)
Note

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

Available from: 2018-09-18 Created: 2018-09-18 Last updated: 2018-11-07Bibliographically 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)
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 1Article in journal (Refereed) Epub ahead of print
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)
Available from: 2018-09-18 Created: 2018-09-18 Last updated: 2018-11-05
Hällmark, R. & Collin, P. (2018). Post-Installed Shear Connectors: Monitoring a Bridge Strengthened with Coiled Spring Pins. Structural Engineering International
Open this publication in new window or tab >>Post-Installed Shear Connectors: Monitoring a Bridge Strengthened with Coiled Spring Pins
2018 (English)In: Structural Engineering International, ISSN 1016-8664, E-ISSN 1683-0350Article in journal (Refereed) Epub ahead of print
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, 2018
Keywords
shear connector, composite action, monitoring, strengthening, coiled spring pin
National Category
Infrastructure Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-70192 (URN)10.1080/10168664.2018.1456893 (DOI)
Available from: 2018-08-01 Created: 2018-08-01 Last updated: 2018-09-18
Varedian, M., Collin, P. & Eriksson, K. (2017). A new improved type of friction connection: An experimental study. In: IABSE Conference, Vancouver 2017: Engineering the Future. Paper presented at 39th IABSE Symposium, Engineering the Future, Vancouver, Canada, Sept 21-23, 2017 (pp. 214-221). Zürich, Switzerland: IABSE -International Association for Bridges and Structural Engineering
Open this publication in new window or tab >>A new improved type of friction connection: An experimental study
2017 (English)In: IABSE Conference, Vancouver 2017: Engineering the Future, Zürich, Switzerland: IABSE -International Association for Bridges and Structural Engineering , 2017, p. 214-221Conference paper, Published paper (Refereed)
Abstract [en]

Indenters in the slip planes of a bolted lap joint increase its load bearing capacity. In an experimental study, conducted at the Luleå University of Technology, Sweden, a part of the European R&D project PROLIFE, RFCS 2015-00025, indenters between two plates a) were loaded in compression and b) shear loaded in a lap joint. The load to press a 2.5 mm diameter stainless steel indenter 2.3 mm into the plates was 11 kN and the effective friction of the joint was improved. In a reference test with two shear planes and plain as rolled plates, no indenters and an M30 bolt pre-loaded to 320 kN, the joint slip resistance force was 54.5 kN and the effective friction coefficient μeff=0.09. For an identical arrangement but with 29 indenters per shear plane, the slip resistance was close to 250 kN and μeff was increased to 0.40, at the current Eurocode acceptable joint slip of 0.15 mm.

Place, publisher, year, edition, pages
Zürich, Switzerland: IABSE -International Association for Bridges and Structural Engineering, 2017
National Category
Infrastructure Engineering Applied Mechanics
Research subject
Structural Engineering; Solid Mechanics
Identifiers
urn:nbn:se:ltu:diva-70269 (URN)2-s2.0-85050035776 (Scopus ID)978-3-85748-153-6 (ISBN)
Conference
39th IABSE Symposium, Engineering the Future, Vancouver, Canada, Sept 21-23, 2017
Available from: 2018-08-08 Created: 2018-08-08 Last updated: 2018-08-08Bibliographically approved
Häggström, J., Blanksvärd, T., Collin, P. & Tu, Y. (2017). Full-scale testing to failure of a steel truss railway bridge. Proceedings of the Institution of Civil Engineers: Engineering Sustainability, 170(2), 93-101
Open this publication in new window or tab >>Full-scale testing to failure of a steel truss railway bridge
2017 (English)In: Proceedings of the Institution of Civil Engineers: Engineering Sustainability, ISSN 1478-4637, E-ISSN 1751-7664, Vol. 170, no 2, p. 93-101Article in journal (Refereed) Published
Abstract [en]

Significant resources have been invested in maintaining existing infrastructure. Many structures are becoming old, do not meet current requirements, or are reaching the end of their life cycle. It is not feasible or sustainable to replace all of those that may be deemed obsolete; however, often their specified capacities are very conservative. So there is an urgent need to obtain more robust knowledge of their true status. This paper describes a unique project, in which a 33 m long steel truss railway bridge (over the Åby River) was tested to failure. The findings can be used to identify optimal solutions for other bridges of the same design that are still in use, notably the bridge over Rautasjokk (a river in Sweden). These two bridges were tested in three stages. This paper focuses on the second stage, wherein Åby Bridge was subjected to static full-scale testing to failure, by pulling it downwards. The global failure mode consisted of buckling of the top chord with yielding of the steel starting at a total load of 8 MN and the peak load being reached at around 11 MN, corresponding to a load approximately four to five times higher than the characteristic design load.

Place, publisher, year, edition, pages
Institution of Civil Engineers, 2017
Keywords
bridges field testing & monitoring steel structures
National Category
Infrastructure Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-62708 (URN)10.1680/jbren.15.00025 (DOI)000405988000002 ()
Note

Validerad;2017;Nivå 2;2017-06-07 (rokbeg)

Available from: 2017-03-27 Created: 2017-03-27 Last updated: 2018-07-10Bibliographically approved
Hällmark, R., Collin, P., Petersson, M. & Andersson, E. (2017). Monitoring of a bridge strengthened with post-installed coiled spring pins. In: IABSE Symposium, Vancouver, 2017: Engineering the Future. Paper presented at 39th IABSE Symposium, Engineering the Future, Vancouver, Canada, Sept 21-23, 2017 (pp. 1201-1208). Zürich, Switzerland: IABSE - International Association for Bridges and Structural Engineering
Open this publication in new window or tab >>Monitoring of a bridge strengthened with post-installed coiled spring pins
2017 (English)In: IABSE Symposium, Vancouver, 2017: Engineering the Future, Zürich, Switzerland: IABSE - International Association for Bridges and Structural Engineering , 2017, p. 1201-1208Conference paper, Published paper (Refereed)
Abstract [en]

Many existing bridges were not originally designed for the traffic loads and the number of load cycles which they now experience. In order to increase the load capacity of non-composite steel-concrete bridges, post installed shear connectors can be used. This paper describes a field monitoring of a steel-concrete bridge which have been strengthened with post-installed coiled spring pins as shear connectors. During the monitoring, the bridge was loaded with a 31 tonnes truck placed in specific positions while strains were measured in the steel main girders, together with the horizontal slip at the steel-concrete interface. The results indicate that the coiled spring pins prevent the slip and that they can be used for strengthening purpose. It is also observed that the friction in the steel-concrete interface can contribute quite a lot to the composite action, even though that effect cannot be accounted for in the design.

Place, publisher, year, edition, pages
Zürich, Switzerland: IABSE - International Association for Bridges and Structural Engineering, 2017
Keywords
Shear connector; bridge monitoring; composite bridge; composite action; coiled spring pin; shear studs; bridge strengthening; rehabilitation;
National Category
Infrastructure Engineering Building Technologies
Research subject
Structural Engineering; Steel Structures
Identifiers
urn:nbn:se:ltu:diva-66148 (URN)2-s2.0-85050016139 (Scopus ID)978-3-85748-153-6 (ISBN)
Conference
39th IABSE Symposium, Engineering the Future, Vancouver, Canada, Sept 21-23, 2017
Available from: 2017-10-16 Created: 2017-10-16 Last updated: 2018-08-08Bibliographically approved
Hällmark, R., Collin, P. & Möller, M. (2017). Testing of coiled spring pins as shear connectors. In: IABSE Symposium, Vancouver, 2017: Engineering the Future. Paper presented at 39th IABSE Symposium, Engineering the Future, Vancouver, Canada, Sept 21-23, 2017 (pp. 1209-1216). Zürich, Switzerland: IABSE - International Association for Bridges and Structural Engineering
Open this publication in new window or tab >>Testing of coiled spring pins as shear connectors
2017 (English)In: IABSE Symposium, Vancouver, 2017: Engineering the Future, Zürich, Switzerland: IABSE - International Association for Bridges and Structural Engineering , 2017, p. 1209-1216Conference paper, Published paper (Refereed)
Abstract [en]

A few decades ago, steel-concrete composite bridges were quite rare structures, whereas steel girder bridges with non-composite concrete decks were rather common. For the latter type of structure, composite action can be obtained long after the bridges were constructed by post installation of shear connectors. Most installation procedures involve reconstruction of pavement and concrete deck, which will result in traffic disturbance. There are however some types of shear connectors that can be installed from underneath, connecting the top flanges to the concrete deck, without affecting the upper surface. This means that the bridge can be strengthened during traffic. One type of such a shear connector is the coiled spring pin, which is an interference fit connector. This paper presents the results from push-out tests conducted in order to find the static capacity and the load-slip behaviour of coiled spring pins used as shear connectors.

Place, publisher, year, edition, pages
Zürich, Switzerland: IABSE - International Association for Bridges and Structural Engineering, 2017
National Category
Infrastructure Engineering Building Technologies
Research subject
Structural Engineering; Steel Structures
Identifiers
urn:nbn:se:ltu:diva-66146 (URN)2-s2.0-85050026942 (Scopus ID)978-3-85748-153-6 (ISBN)
Conference
39th IABSE Symposium, Engineering the Future, Vancouver, Canada, Sept 21-23, 2017
Available from: 2017-10-16 Created: 2017-10-16 Last updated: 2018-08-08Bibliographically approved
Häggström, J., Blanksvärd, T. & Collin, P. (2016). Fatigue assessment of stringer beams using structural healthmonitoring. In: ennart Elfgren, Johan Jonsson, Mats Karlsson, Lahja Rydberg-Forssbeck and Britt Sigfrid (Ed.), 19th IABSE Congress Strockholm 21-23 September 2016: Challenges in Design and Construction of an Innovative ans Sustainable Built Environment. Paper presented at 19th IABSE Congress, Strockholm, 21-23 September 2016 (pp. 1455-1462). CH - 8093 Zürich, Switzerland
Open this publication in new window or tab >>Fatigue assessment of stringer beams using structural healthmonitoring
2016 (English)In: 19th IABSE Congress Strockholm 21-23 September 2016: Challenges in Design and Construction of an Innovative ans Sustainable Built Environment / [ed] ennart Elfgren, Johan Jonsson, Mats Karlsson, Lahja Rydberg-Forssbeck and Britt Sigfrid, CH - 8093 Zürich, Switzerland, 2016, p. 1455-1462Conference paper, Published paper (Refereed)
Abstract [en]

Fatigue assessment of existing bridges is often carried out through simple calculations where the nominalstress range is compared with the fatigue strength based on a number of detail categories specified incodes. Presented in this paper, is the stepwise fatigue assessment through measurements of the 60 yearold bridge over Rautasjokk located in northern Sweden. According to the code‐based assessment of thestringers, it has already exceeded its lifetime about four times; however no cracks have been identified. Bymeasuring strains the real state of stress was identified, where both nominal stresses and local approacheshave been evaluated and compared. Even though the local approach should provide a better accuracy incomparison with the nominal stresses, this approach was only favorable for one out of the three studiedlocations.

Place, publisher, year, edition, pages
CH - 8093 Zürich, Switzerland: , 2016
Series
IABSE Congress Reports
National Category
Infrastructure Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-59786 (URN)2-s2.0-85018994618 (Scopus ID)978-3-85748-144-4 (ISBN)
Conference
19th IABSE Congress, Strockholm, 21-23 September 2016
Available from: 2016-10-17 Created: 2016-10-17 Last updated: 2018-06-20Bibliographically approved
Vestman, V., Collin, P. & Häggström, J. (2016). Improvement of fatigue resistance through box-action for I-girder composite bridges. In: ennart 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 9th IABSE Congress, Stockholm 2016, September 21-23 (pp. 1988-1994). CH - 8093 Zürich, Switzerland
Open this publication in new window or tab >>Improvement of fatigue resistance through box-action for I-girder composite bridges
2016 (English)In: IABSE CONGRESS, STOCKHOLM, 2016: Challenges in Design and Construction of an Innovativeand Sustainable Built Environment / [ed] ennart Elfgren, Johan Jonsson, Mats Karlsson, Lahja Rydberg-Forssbeck and Britt Sigfrid, CH - 8093 Zürich, Switzerland, 2016, p. 1988-1994Conference paper, Published paper (Refereed)
Abstract [en]

When strengthening existing I-girder composite bridges one idea is to make the cross section act like a box section, by adding a horizontal truss between the bottom flanges. This means that eccentric loads produce a torque that is transferred by shear forces around the section. The magnitude of the effects coming from introducing such a framework between girders is addressed in this article. The fatigue resistance will be improved by the reduced stress ranges and increased amount of tolerated load cycles and extend the lifetime of the details, and by so the lifetime for the bridge.

Place, publisher, year, edition, pages
CH - 8093 Zürich, Switzerland: , 2016
Series
IABSE Congress Reports
National Category
Infrastructure Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-63561 (URN)2-s2.0-85018962854 (Scopus ID)978-3-85748-144-4 (ISBN)
Conference
9th IABSE Congress, Stockholm 2016, September 21-23
Available from: 2017-05-29 Created: 2017-05-29 Last updated: 2018-06-20Bibliographically approved
Hällmark, R., Jackson, P. & Collin, P. (2016). Post-installed shear connectors: coiled spring pins. 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 Innovative and Sustainable Built Environment. Paper presented at 19th IABSE Congress Stockholm, 21-23 September 2016 (pp. 1227-1234). CH - 8093 Zürich, Switzerland
Open this publication in new window or tab >>Post-installed shear connectors: coiled spring pins
2016 (English)In: IABSE CONGRESS, STOCKHOLM, 2016: Challenges in Design and Construction of an Innovative and Sustainable Built Environment / [ed] Lennart Elfgren, Johan Jonsson, Mats Karlsson, Lahja Rydberg-Forssbeck and Britt Sigfrid, CH - 8093 Zürich, Switzerland, 2016, p. 1227-1234Conference paper, Published paper (Refereed)
Abstract [en]

Many existing bridges were not originally designed for the traffic loads and the number of load cycles which they now experience. In order to increase the load capacity of steel-concrete bridges, post installed shear connectors can be used. This paper presents a state-of the art study of postinstalled shear connectors in general and coiled spring connectors in particular

Place, publisher, year, edition, pages
CH - 8093 Zürich, Switzerland: , 2016
Series
IABSE Congress Report
Keywords
Shear connector; composite bridge; composite action; coiled spring pin; bridge strengthening; rehabilitation
National Category
Infrastructure Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-63030 (URN)2-s2.0-85018959894 (Scopus ID)978-3-85748-144-4 (ISBN)
Conference
19th IABSE Congress Stockholm, 21-23 September 2016
Projects
PROLIFE - Prolonging life time of old steel- and steel-concrete bridges
Available from: 2017-04-13 Created: 2017-04-13 Last updated: 2018-06-20Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-8353-9225

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