Endre søk
Link to record
Permanent link

Direct link
Häggström, Jens
Publikasjoner (10 av 20) Visa alla publikasjoner
Täljsten, B., Blanksvärd, T., Sas, G., Bagge, N., Nilimaa, J., Popescu, C., . . . Häggström, J. (2018). Bridges tested to failure in Sweden. In: IABSE Conference Copenhagen 2018: Engineering the Past, to Meet the Needs of the Future. Paper presented at IABSE Conference 2018 'Engineering the Past, to Meet the Needs of the Future', 25-27 June, 2018, Copenhagen, Denmark (pp. 64-70). International Association for Bridge and Structural Engineering (IABSE)
Åpne denne publikasjonen i ny fane eller vindu >>Bridges tested to failure in Sweden
Vise andre…
2018 (engelsk)Inngår i: IABSE Conference Copenhagen 2018: Engineering the Past, to Meet the Needs of the Future, International Association for Bridge and Structural Engineering (IABSE) , 2018, s. 64-70Konferansepaper, Publicerat paper (Fagfellevurdert)
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

sted, utgiver, år, opplag, sider
International Association for Bridge and Structural Engineering (IABSE), 2018
Serie
IABSE Symposium Report ; 111
Emneord
Test to failure, bridges of concrete and steel, Assessment, Strengthening, Monitoring, Bending, Shar, Torsion, Bond, Fatigue, Carbon Fibre Reinforced Polymers (CFRP)
HSV kategori
Forskningsprogram
Konstruktionsteknik
Identifikatorer
urn:nbn:se:ltu:diva-72378 (URN)2-s2.0-85067126405 (Scopus ID)
Konferanse
IABSE Conference 2018 'Engineering the Past, to Meet the Needs of the Future', 25-27 June, 2018, Copenhagen, Denmark
Merknad

ISBN för värdpublikation: 978-1-5108-9208-8

Tilgjengelig fra: 2018-12-28 Laget: 2018-12-28 Sist oppdatert: 2023-10-06bibliografisk kontrollert
Häggström, J., Blanksvärd, T. & Täljsten, B. (2017). Bridge over Åby River: Evaluation of full scale testing.
Åpne denne publikasjonen i ny fane eller vindu >>Bridge over Åby River: Evaluation of full scale testing
2017 (engelsk)Rapport (Annet vitenskapelig)
Alternativ tittel[sv]
Bro över Åby älv : Utvärding av fullskaleförsök
Publisher
s. 131
Serie
Teknisk rapport / Luleå tekniska universitet, ISSN 1402-1536
Emneord
Full-scale monitoring steel truss bridge
HSV kategori
Forskningsprogram
Konstruktionsteknik
Identifikatorer
urn:nbn:se:ltu:diva-61614 (URN)978-91-7583-823-6 (ISBN)
Tilgjengelig fra: 2017-01-24 Laget: 2017-01-24 Sist oppdatert: 2018-03-20bibliografisk kontrollert
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
Åpne denne publikasjonen i ny fane eller vindu >>Full-scale testing to failure of a steel truss railway bridge
2017 (engelsk)Inngår i: Proceedings of the Institution of Civil Engineers: Engineering Sustainability, ISSN 1478-4637, E-ISSN 1751-7664, Vol. 170, nr 2, s. 93-101Artikkel i tidsskrift (Fagfellevurdert) 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.

sted, utgiver, år, opplag, sider
Institution of Civil Engineers (ICE), 2017
Emneord
bridges, field testing & monitoring, steel structures
HSV kategori
Forskningsprogram
Konstruktionsteknik
Identifikatorer
urn:nbn:se:ltu:diva-62708 (URN)10.1680/jbren.15.00025 (DOI)000405988000002 ()2-s2.0-85030479014 (Scopus ID)
Merknad

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

Tilgjengelig fra: 2017-03-27 Laget: 2017-03-27 Sist oppdatert: 2023-09-05bibliografisk kontrollert
Häggström, J., Bagge, N., Nilimaa, J., Sas, G., Blanksvärd, T., Täljsten, B., . . . Carolin, A. (2017). Testing Bridges to Failure: Experiences. In: IABSE Symposium, Vancouver, 2017: Engineering the Future. Paper presented at 39th IABSE Symposium, Engineering the Future, Vancouver, Canada, Sept 21-23, 2017 (pp. 2832-2839). Zürich, Switzerland: IABSE - International Association for Bridges and Structural Engineering
Åpne denne publikasjonen i ny fane eller vindu >>Testing Bridges to Failure: Experiences
Vise andre…
2017 (engelsk)Inngår i: IABSE Symposium, Vancouver, 2017: Engineering the Future, Zürich, Switzerland: IABSE - International Association for Bridges and Structural Engineering , 2017, s. 2832-2839Konferansepaper, Publicerat paper (Fagfellevurdert)
Abstract [en]

Four bridges of different types have been tested to failure and the results have been compared to the load-carrying capacity calculated using standard code models and advanced numerical methods. The results may help to make accurate assessments of similar existing bridges. Here 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 four bridges were: (1) a one span steel truss railway bridge; (2) a two span strengthened concrete trough railway bridge; (3) a one span concrete trough bridge tested in fatigue; and (4) a five span prestressed concrete road bridge.

The unique results in the paper are the experiences of the real failure types, the robustness/weakness of the bridges, and the accuracy of different codes and models.

sted, utgiver, år, opplag, sider
Zürich, Switzerland: IABSE - International Association for Bridges and Structural Engineering, 2017
Emneord
bridges, testing, assessment, load-carrying capacity, reinforced concrete, prestressed concrete, steel, analysis, codes
HSV kategori
Forskningsprogram
Konstruktionsteknik
Identifikatorer
urn:nbn:se:ltu:diva-66134 (URN)2-s2.0-85050030469 (Scopus ID)978-3-85748-153-6 (ISBN)
Konferanse
39th IABSE Symposium, Engineering the Future, Vancouver, Canada, Sept 21-23, 2017
Forskningsfinansiär
EU, FP7, Seventh Framework ProgrammeSwedish Transport Administration
Tilgjengelig fra: 2017-10-15 Laget: 2017-10-15 Sist oppdatert: 2018-08-08bibliografisk kontrollert
Häggström, J. (2016). Evaluation of the Load Carrying Capacity of a Steel Truss Railway Bridge: Testing, Theory and Evaluation. (Licentiate dissertation). Luleå: Luleå University of Technology
Åpne denne publikasjonen i ny fane eller vindu >>Evaluation of the Load Carrying Capacity of a Steel Truss Railway Bridge: Testing, Theory and Evaluation
2016 (engelsk)Licentiatavhandling, med artikler (Annet vitenskapelig)
Abstract [en]

A good deal of resources has been invested in building and maintaining existing infrastructure.Many structures are now becoming old and do not meet the requirements of an increasingtraffic load, or are reaching the end of their lifecycle. It is not possible or sustainable to replaceall those structures that have been judged to be obsolete or nearly obsolete. However, in manycases, their specified load carrying capacities are understated, so there is an urgent need toobtain more robust knowledge of their true status. In the design of new structures, a numberof assumptions relating to loading and structural behaviour have to be made, a number that canbe reduced by finding out more about the actual behaviour of the structure.

This licentiate thesis describes the structural behaviour of existing unballasted open steel trussrailway bridges in general and methods for assessment in particular, with the aim of keepingthese structures in service for longer.

An extensive program, divided into three phases of experimental studies, was carried out toincrease the understanding of existing unballasted steel truss railway bridges.

Phase I consisted of instrumentation and monitoring of a 60 year-old railway bridge (ÅbyBridge) while it was still in service. A description of the object and the monitoring in thisphase of measurements is presented in Chapter 3 with some results and analysis in Chapter 4.Some of the findings from Phase I are described in Paper A, from which it was concluded thatthe stringer beams were subjected to large stresses originating from torsion and out-of-planebending. These effects are not normally considered yet may have significant consequences inrelation to fatigue.

In Phase II, the former bridge over the Åby River was replaced and put beside the railwaytracks, where the instrumentation from Phase I was extended. The bridge was statically testedin 18 pre-defined load series before reaching failure. Phase II is described in Chapter 3 andsummarized in Paper B. It was found that the bridge could withstand loading corresponding tofour times the highest permitted axle-loading, or twice the design load for new bridges, beforeexhibiting an obvious non-linear behaviour with regard to vertical displacement in the midspan.The peak load was achieved at loading approximately 50% higher than the initial nonlinearbehaviour, where lateral buckling of the top chord limited the structure from carryingmore load. The failure can be concluded as being redundant without brittle failure of any ofthe connections.

In Phase III, a different bridge was fitted with instrumentation and monitored while subjectedto live loading: the bridge over the river Rautasjokk. The Rautasjokk Bridge was constructedfive years later than the Åby Bridge, using the same drawings thus making it theoreticallyidentical in terms of geometry and material. It is situated along the “Ore line”, meaning that itis subjected to higher loads compared to the Åby Bridge which was located along the “Mainline”. The program for measurements originated from a code-based assessment which ruled thebridge unsafe to use with regard to fatigue of the stringers due to the gusset plates welded tothe top flange of the stringers. Paper C describes the measurement of local fatigue strains (hotspot)and comparison with nominal strains. In that paper, it was concluded that the hot-spotapproach was only favourable for one out of three studied positions, with regard to fatiguelifespan.

This thesis ends with conclusions and suggestions for further research.

sted, utgiver, år, opplag, sider
Luleå: Luleå University of Technology, 2016. s. 139
Serie
Licentiate thesis / Luleå University of Technology, ISSN 1402-1757
HSV kategori
Forskningsprogram
Konstruktionsteknik
Identifikatorer
urn:nbn:se:ltu:diva-60029 (URN)978-91-7583-739-0 (ISBN)978-91-7583-740-6 (ISBN)
Presentation
2016-12-15, F1031, Luleå tekniska universitet, Luleå, 10:00
Opponent
Tilgjengelig fra: 2016-10-31 Laget: 2016-10-28 Sist oppdatert: 2017-11-24bibliografisk kontrollert
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
Åpne denne publikasjonen i ny fane eller vindu >>Fatigue assessment of stringer beams using structural healthmonitoring
2016 (engelsk)Inngår i: 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, s. 1455-1462Konferansepaper, Publicerat paper (Fagfellevurdert)
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.

sted, utgiver, år, opplag, sider
CH - 8093 Zürich, Switzerland: , 2016
Serie
IABSE Congress Reports
HSV kategori
Forskningsprogram
Konstruktionsteknik
Identifikatorer
urn:nbn:se:ltu:diva-59786 (URN)2-s2.0-85018994618 (Scopus ID)978-3-85748-144-4 (ISBN)
Konferanse
19th IABSE Congress, Strockholm, 21-23 September 2016
Tilgjengelig fra: 2016-10-17 Laget: 2016-10-17 Sist oppdatert: 2023-09-05bibliografisk kontrollert
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
Åpne denne publikasjonen i ny fane eller vindu >>Improvement of fatigue resistance through box-action for I-girder composite bridges
2016 (engelsk)Inngår i: 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, s. 1988-1994Konferansepaper, Publicerat paper (Fagfellevurdert)
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.

sted, utgiver, år, opplag, sider
CH - 8093 Zürich, Switzerland: , 2016
Serie
IABSE Congress Reports
HSV kategori
Forskningsprogram
Konstruktionsteknik
Identifikatorer
urn:nbn:se:ltu:diva-63561 (URN)2-s2.0-85018962854 (Scopus ID)978-3-85748-144-4 (ISBN)
Konferanse
9th IABSE Congress, Stockholm 2016, September 21-23
Tilgjengelig fra: 2017-05-29 Laget: 2017-05-29 Sist oppdatert: 2023-09-05bibliografisk kontrollert
Nilimaa, J., Bagge, N., Häggström, J., Blanksvärd, T., Sas, G., Täljsten, B. & Elfgren, L. (2016). More Realistic Codes for Existing Bridges. In: Elfgren, Lennart; Jonsson, Johan; Karlsson, Mats; Rydberg-Forssbeck, Laja; Sigfrid, Britt (Ed.), IABSE CONGRESS, STOCKHOLM, 2016: Challenges in Design and Construction of an Innovativeand Sustainable Built Environment. Paper presented at 19th IABSE Congress Stockholm, 21-23 september 2016 (pp. 399-407). CH - 8093 Zürich, Switzerland
Åpne denne publikasjonen i ny fane eller vindu >>More Realistic Codes for Existing Bridges
Vise andre…
2016 (engelsk)Inngår i: IABSE CONGRESS, STOCKHOLM, 2016: Challenges in Design and Construction of an Innovativeand Sustainable Built Environment / [ed] Elfgren, Lennart; Jonsson, Johan; Karlsson, Mats; Rydberg-Forssbeck, Laja; Sigfrid, Britt, CH - 8093 Zürich, Switzerland, 2016, s. 399-407Konferansepaper, Publicerat paper (Fagfellevurdert)
Abstract [en]

Examples are given from comparisons of analyses based on (1) code models, (2) finite element models and (3) full scale tests to failure of three bridges. The analyses based on the code models gave very conservative results, while the finite element models could better predict the real behaviour.

sted, utgiver, år, opplag, sider
CH - 8093 Zürich, Switzerland: , 2016
Serie
IABSE Congress Reports
Emneord
Bridges, Assessment, Codes, Full Scale Tests
HSV kategori
Forskningsprogram
Konstruktionsteknik
Identifikatorer
urn:nbn:se:ltu:diva-61979 (URN)2-s2.0-85018989154 (Scopus ID)978-3-85748-144-4 (ISBN)
Konferanse
19th IABSE Congress Stockholm, 21-23 september 2016
Prosjekter
MAINLINE
Forskningsfinansiär
EU, FP7, Seventh Framework ProgrammeSwedish Transport Administration
Tilgjengelig fra: 2017-02-13 Laget: 2017-02-13 Sist oppdatert: 2018-03-26bibliografisk kontrollert
Häggström, J., Blanksvärd, T., Collin, P. & Täljsten, B. (2015). Assessment and full scale failure test of a steel truss bridge (ed.). In: (Ed.), IABSE symposium Madrid 2014: Engineering for progress, nature and people. Paper presented at IABSE Symposium : Engineering for Pprogress, Nature and People 02/09/2014 - 05/09/2014 (pp. 2757-2764). Zürich: International Association for Bridge and Structural Engineering
Åpne denne publikasjonen i ny fane eller vindu >>Assessment and full scale failure test of a steel truss bridge
2015 (engelsk)Inngår i: IABSE symposium Madrid 2014: Engineering for progress, nature and people, Zürich: International Association for Bridge and Structural Engineering, 2015, s. 2757-2764Konferansepaper, Publicerat paper (Fagfellevurdert)
Abstract [en]

Large amount of resources has been invested in maintaining existing infrastructure. Several of these structures are now becoming old and do not meet the requirements of today or are reaching the end of their lifecycle. It is not possible to replace all of these structures that are deemed or are about to be deemed obsolete, due to high cost and environmental impacts.One way to keep these structures in use for a longer time is innovative and intelligent assessment of the actual state of stress and behaviour. In such cases, using structural health monitoring to assess the structure might be an efficient way to extend the life of the structure.This paper will describe a unique monitoring program over two similar 33 m long steel truss bridges situated in Sweden. One of these bridges, Aby River, has a regulated axle load of 25 tons and is deemed to have reached is end of life due to fatigue. The other bridge, Rautasjokk, has a regulated axle load of 30 tons but will be in use for the coming years.The monitoring program has the following outline; monitoring of the bridge over Aby river when it is in service, after replacement this bridge will be moved and tested under static loads to assess boundary conditions and state of stress, then parts of this bridge will be disassembled and these parts will be tested in laboratory environment for fatigue life assessment, all of these results will then be controlled by monitoring of the bridge over Rautasjokk in service limit state.The outline of this project will give input for the fatigue life models that are used today and probably upgrade the fatigue life of the bridge over Rautasjokk.

sted, utgiver, år, opplag, sider
Zürich: International Association for Bridge and Structural Engineering, 2015
Serie
I A B S E Symposium Report, ISSN 2221-3783 ; 102
Emneord
Structural health monitoring, Steel truss bridge, Fatigue, Model updating, Assessment
HSV kategori
Forskningsprogram
Konstruktionsteknik
Identifikatorer
urn:nbn:se:ltu:diva-31315 (URN)10.2749/222137814814070299 (DOI)2-s2.0-84929430214 (Scopus ID)575bb645-cb68-41a7-99fd-81b421961d5f (Lokal ID)575bb645-cb68-41a7-99fd-81b421961d5f (Arkivnummer)575bb645-cb68-41a7-99fd-81b421961d5f (OAI)
Konferanse
IABSE Symposium : Engineering for Pprogress, Nature and People 02/09/2014 - 05/09/2014
Merknad

Godkänd; 2014; 20140918 (hagjen)

Tilgjengelig fra: 2016-09-30 Laget: 2016-09-30 Sist oppdatert: 2023-09-05bibliografisk kontrollert
Häggström, J. & Blanksvärd, T. (2015). Assessment and full scale failure test of a steel truss bridge (ed.). In: (Ed.), IABSE Workshop Helsinki 2015: Safety, Robustness and Condition Assessments of Structures. Paper presented at IABSE Workshop Helsinki 2015 : Safety, Robustness and Condition Assessment of Structures 11/02/2015 - 12/02/2015 (pp. 288-295). Zürich: International Association for Bridge and Structural Engineering
Åpne denne publikasjonen i ny fane eller vindu >>Assessment and full scale failure test of a steel truss bridge
2015 (engelsk)Inngår i: IABSE Workshop Helsinki 2015: Safety, Robustness and Condition Assessments of Structures, Zürich: International Association for Bridge and Structural Engineering, 2015, s. 288-295Konferansepaper, Publicerat paper (Fagfellevurdert)
Abstract [en]

Large amount of resources has been invested in maintaining existing infrastructure. Several of thesestructures are now becoming old and do not meet the requirements of today or are reaching the endof their lifecycle. It is not possible to replace all of these structures that are deemed or are about tobe deemed obsolete, due to high cost and environmental impacts.One way to keep these structures in use for a longer time is innovative and intelligent assessment ofthe actual state of stress and behaviour. In such cases, using structural health monitoring to assessthe structure might be an efficient way to extend the life of the structure.This paper will describe a unique monitoring program over two similar 33 m long steel trussbridges situated in Sweden. One of these bridges, Aby River, had a regulated axle load of 25 tonsand was tested to failure in 2013. The other bridge, Rautasjokk, has a regulated axle load of 30 tonswhich will be upgraded to 32.5 tons and will be in use for the coming years.The monitoring program was performed as; monitoring of the bridge over Aby river when it wasstill in service. After replacement the old bridge was moved and tested under static loads to assessboundary conditions and state of stress. Parts of this bridge were then disassembled to be tested formaterial properties and fatigue capacity. A theoretical assessment of the Rautasjokk bridge was thenperformed based on the conclusions from the measurements on the Aby bridge. Finally the plan isto verify findings by performing measurements on live loading for the Rautasjokk bridge in servicelimit state.The aim for this project is to verify the continuous safety for the Rautasjokk bridge by using inputfrom tests performed at both bridges.

sted, utgiver, år, opplag, sider
Zürich: International Association for Bridge and Structural Engineering, 2015
Emneord
structural health monitoring, steel truss bridge, fatigue, model updating, Assessment
HSV kategori
Forskningsprogram
Konstruktionsteknik
Identifikatorer
urn:nbn:se:ltu:diva-32214 (URN)10.2749/222137815815622951 (DOI)2-s2.0-84929298768 (Scopus ID)6a302837-7023-4ca9-ad12-bfc4326ddc44 (Lokal ID)978-3-85748-137-6 (ISBN)6a302837-7023-4ca9-ad12-bfc4326ddc44 (Arkivnummer)6a302837-7023-4ca9-ad12-bfc4326ddc44 (OAI)
Konferanse
IABSE Workshop Helsinki 2015 : Safety, Robustness and Condition Assessment of Structures 11/02/2015 - 12/02/2015
Merknad

Godkänd; 2015; 20150218 (andbra)

Tilgjengelig fra: 2016-09-30 Laget: 2016-09-30 Sist oppdatert: 2024-01-17bibliografisk kontrollert
Organisasjoner