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Nilimaa, J., Nilforoush, R. & Elfgren, L. (2022). Uniaxial tensile test method for cylindrical concrete cores from existing structures. In: Johan Silfwerbrand (Ed.), 24th NCR Symposium Proceedings: . Paper presented at XXIV Nordic Concrete Research Symposium 2022,Stockholm, Sweden, August 16-19, 2022. Nordic Concrete Federation
Open this publication in new window or tab >>Uniaxial tensile test method for cylindrical concrete cores from existing structures
2022 (English)In: 24th NCR Symposium Proceedings / [ed] Johan Silfwerbrand, Nordic Concrete Federation , 2022Conference paper, Oral presentation with published abstract (Refereed)
Abstract [en]

A method for direct tensile tests on cylindrical concrete cores from existing structures was developed at Luleå University of Technology and the method was tested on concrete from a 55 year old bridge from northern Sweden. The tests showed that the tensile strength of the concrete could be upgraded to a higher value.

Place, publisher, year, edition, pages
Nordic Concrete Federation, 2022
Keywords
Aging, Structural Design, Sustainability, Testing
National Category
Infrastructure Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-92631 (URN)
Conference
XXIV Nordic Concrete Research Symposium 2022,Stockholm, Sweden, August 16-19, 2022
Available from: 2022-08-22 Created: 2022-08-22 Last updated: 2023-09-05Bibliographically approved
Täljsten, B., Popescu, C. & Nilforoush, R. (2022). Wireless monitoring for assessment of concrete railway bridges – Experiences from field tests. In: Johan Silfwerbrand (Ed.), 24th NCR Symposium Proceedings: . Paper presented at XXIV Nordic Concrete Research Symposium 2022, Stockholm, Sweden, August 16-19, 2022. Nordic Concrete Federation
Open this publication in new window or tab >>Wireless monitoring for assessment of concrete railway bridges – Experiences from field tests
2022 (English)In: 24th NCR Symposium Proceedings / [ed] Johan Silfwerbrand, Nordic Concrete Federation , 2022Conference paper, Oral presentation with published abstract (Refereed)
Abstract [en]

This paper focus on assessment on a prestressed three span concrete box bridge by the use of a wireless monitoring system in combination with visual inspection. The bridge is located in the very north of Sweden, in Abisko. A visual inspection of the bridge carried out the 18th of August in 2016 several crack patterns were mapped on the inside of the box girder bridge located near supports in the spans on both sides of the bridge. The cause of the cracks are not completely clear. To reveal the reason for cracking a long term project has been initiated by Trafikverket. Here a new developed wireless system has been used. Investigating change in crack widths by the use of LVDTs and strain gauges. Also accelerations are monitored together with the temperatures. In addition also fibre optic systems and non-destructive tests were carried out (not reported here). The results/conclusions presented in the paper are preliminary and final results will be presented 2021.

Place, publisher, year, edition, pages
Nordic Concrete Federation, 2022
Keywords
Wireless Monitoring, Fibre Optic System, Concrete, Bridges, Structural Assessment
National Category
Infrastructure Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-94445 (URN)
Conference
XXIV Nordic Concrete Research Symposium 2022, Stockholm, Sweden, August 16-19, 2022
Projects
In2Track: Research into enhanced tracks, switches and structures
Funder
Swedish Transport Administration
Available from: 2022-12-01 Created: 2022-12-01 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
Nilforoush, R., Pia, G., Nilsson, M. & Elfgren, L. (2020). Anchorage capacity and performance in plain and steelfibre-reinforced-concrete. In: Jan Bien; Jan Biliszczuk; Pawel Hawryszkow; Maciej Hildebrand; Marta Knawa-Hawryszkow; Krzysztof Sadowski (Ed.), 1st IABSE Online Symposium 2020: Synergy of Culture and Civil Engineering - History and Challenges. Paper presented at 1st IABSE Online Symposium, Wroclaw, Poland (Online), October 7-9, 2020 (pp. 700-709). International Association for Bridge and Structural Engineering (IABSE)
Open this publication in new window or tab >>Anchorage capacity and performance in plain and steelfibre-reinforced-concrete
2020 (English)In: 1st IABSE Online Symposium 2020: Synergy of Culture and Civil Engineering - History and Challenges / [ed] Jan Bien; Jan Biliszczuk; Pawel Hawryszkow; Maciej Hildebrand; Marta Knawa-Hawryszkow; Krzysztof Sadowski, International Association for Bridge and Structural Engineering (IABSE) , 2020, p. 700-709Conference paper, Published paper (Refereed)
Abstract [en]

Nowadays, prefabricated concrete components made from Steel-Fiber-Reinforced Concrete (SFRC) are widely used in the construction industry. These components are often connected to existing or new structural elements through various fastening systems. Previous studies have shown that the addition of steel fibers to concrete mixture substantially improves the fracture properties of concrete. To date, however, rather limited research is available on the behavior of fastening systems in SFRC. To improve the current knowledge of fastening systems to SFRC structures, a pilot experimental study is carried out on cast-in-place anchor bolts embedded in Plain Concrete (PC) and SFRC members. In this study, the influence of the presence of steel fibers and concrete compressive strength on the anchorage capacity and performance is evaluated. Furthermore, the applicability of current design methods is evaluated for anchorage systems in SFRC.

Place, publisher, year, edition, pages
International Association for Bridge and Structural Engineering (IABSE), 2020
Keywords
Anchor bolt, Design recommendations, Fiber-reinforced concrete, Headed anchor, Plain concrete, Pull-out test
National Category
Other Civil Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-85852 (URN)2-s2.0-85103462408 (Scopus ID)
Conference
1st IABSE Online Symposium, Wroclaw, Poland (Online), October 7-9, 2020
Funder
Svenska Byggbranschens Utvecklingsfond (SBUF)
Note

ISBN för värdpublikation: 978-385748169-7

Available from: 2021-06-22 Created: 2021-06-22 Last updated: 2023-09-05Bibliographically approved
Täljsten, B., Paulsson, B., Popescu, C., Bagge, N., Nilforoush, R., Emborg, M., . . . Elfgren, L. (2020). Assessment of prestressed concrete bridges - challenges. In: Jan Bień, Jan Biliszczuk, Paweł Hawryszków, Maciej Hildebrand, Marta Knawa-Hawryszków, Krzysztof Sadowski (Ed.), IABSE Symposium, Wroclaw 2020: Synergy of Culture and Civil Engineering – History and Challenges. Paper presented at IABSE Symposium “Synergy of Culture and Civil Engineering – History and Challenges”, 7-9 October, 2020, Wrocław, Poland (pp. 487-494). Zürich: International Association For Bridge And Structural Engineering (IABSE)
Open this publication in new window or tab >>Assessment of prestressed concrete bridges - challenges
Show others...
2020 (English)In: IABSE Symposium, Wroclaw 2020: Synergy of Culture and Civil Engineering – History and Challenges / [ed] Jan Bień, Jan Biliszczuk, Paweł Hawryszków, Maciej Hildebrand, Marta Knawa-Hawryszków, Krzysztof Sadowski, Zürich: International Association For Bridge And Structural Engineering (IABSE) , 2020, p. 487-494Conference paper, Published paper (Refereed)
Abstract [en]

Prestressed concrete bridges are important parts of our infrastructure. They are susceptible to different kinds of deterioration processes. Examples of damages and deficiencies are cracking, corrosion, voids, bond loss, reduction of cover layer, delamination, fatigue and loss of stiffness and strength. This necessitates methods to continuously assess their condition in order to avoid problems that might lead to shorter service life or reduction of structural integrity. Many of the existing prestressed bridges in Europe are now approaching their design life length. However, with proper and continuous inspection, monitoring and assessment, we may plan proactive maintenance and the structural safety can be assured or – if necessary - increased. This will save both money and decrease the environmental impact of the structure.

Place, publisher, year, edition, pages
Zürich: International Association For Bridge And Structural Engineering (IABSE), 2020
Keywords
Prestressed Concrete Bridges, Challenges, Safety, Corrosion, Fatigue, Assessment, Monitoring, Repair, Strengthening
National Category
Other Civil Engineering Other Materials Engineering
Research subject
Structural Engineering; Building Materials
Identifiers
urn:nbn:se:ltu:diva-81135 (URN)2-s2.0-85103445841 (Scopus ID)
Conference
IABSE Symposium “Synergy of Culture and Civil Engineering – History and Challenges”, 7-9 October, 2020, Wrocław, Poland
Funder
Swedish Transport Administration, BBT 2017-011, TRV 2018/28332, ID 6686
Note

ISBN för värdpublikation: 978-3-85748-169-7

Available from: 2020-10-14 Created: 2020-10-14 Last updated: 2023-09-05Bibliographically approved
Nilforoush, R., Nilimaa, J., Bagge, N., Puurula, A., Ohlsson, U., Nilsson, M., . . . Elfgren, L. (2020). Fracture energy of concrete for bridge assessment. In: Jan Bien; Jan Biliszczuk; Pawel Hawryszkow; Maciej Hildebrand; Marta Knawa-Hawryszkow; Krzysztof Sadowski (Ed.), 1st IABSE Online Symposium 2020: Synergy of Culture and Civil Engineering - History and Challenges. Paper presented at 1st IABSE Online Symposium 2020, Wroclaw, Poland (Online), October 7-9, 2020 (pp. 692-699). International Association for Bridge and Structural Engineering (IABSE)
Open this publication in new window or tab >>Fracture energy of concrete for bridge assessment
Show others...
2020 (English)In: 1st IABSE Online Symposium 2020: Synergy of Culture and Civil Engineering - History and Challenges / [ed] Jan Bien; Jan Biliszczuk; Pawel Hawryszkow; Maciej Hildebrand; Marta Knawa-Hawryszkow; Krzysztof Sadowski, International Association for Bridge and Structural Engineering (IABSE) , 2020, p. 692-699Conference paper, Published paper (Refereed)
Abstract [en]

In numerical assessments of concrete bridges, the value of the concrete fracture energy GF plays an important role. However, mostly the fracture energy is only estimated based on the concrete compressive strength using empirical formulae. In order to study methods to determine the concrete fracture energy for existing bridges, tests were carried out on 55-year-old concrete from a bridge tested to failure in Kiruna in northern Sweden. Uniaxial tensile tests are performed on notched cylindrical concrete cores drilled out from this and other bridges. In the paper, different methods to determine the concrete fracture energy are discussed and recommendations are given for assessment procedures.

Place, publisher, year, edition, pages
International Association for Bridge and Structural Engineering (IABSE), 2020
Keywords
Assessment of structures, Brittleness, Concrete modelling, Fracture energy, Three-point-bending test, Uniaxial tensile test
National Category
Infrastructure Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-85850 (URN)2-s2.0-85103462867 (Scopus ID)
Conference
1st IABSE Online Symposium 2020, Wroclaw, Poland (Online), October 7-9, 2020
Funder
Swedish Transport AdministrationLuleå University of Technology
Note

ISBN för värdpublikation: 978-385748169-7

Available from: 2021-06-22 Created: 2021-06-22 Last updated: 2023-09-05Bibliographically approved
Nilimaa, J., Nilforoush, R., Bagge, N. & Elfgren, L. (2020). Testing to Failure of a 55-year-old Prestressed Concrete Bridge in Kiruna: Bending, Shear and Punching of Girders and Slab. Fracture Properties of Materials. Test Results, Modelling and Assessment. Final Report BBT 2017-030. Luleå: Luleå University of Technology
Open this publication in new window or tab >>Testing to Failure of a 55-year-old Prestressed Concrete Bridge in Kiruna: Bending, Shear and Punching of Girders and Slab. Fracture Properties of Materials. Test Results, Modelling and Assessment. Final Report BBT 2017-030
2020 (English)Report (Refereed)
Abstract [en]

Results are presented from the testing to failure of a 55-year-old prestressed concrete bridge with five continuous spans and a total length of 121.5 m. The bridge was situated in Kiruna in northern Sweden. Results are given from load, deflection and strain measurements during bending-shear tests of the girders and from a punching test of the slab. The testing was carried out in June 2014.

Extensive assessment and modelling of the bridge with finite element methods have taken place and is summarized. The strength of the bridge was much higher than what could be found with ordinary code methods. The advanced non-linear models were, after calibration, able to predict the behaviour in a good way.

In numerical assessments of concrete bridges, the value of the concrete tensile strength fct and the fracture energy GF plays an important role. However, mostly these properties are only estimated based on the concrete compressive strength using empirical formulae. In order to study methods to determine the concrete tensile strength and fracture energy for existing bridges, tests were carried out in 2019 on notched cylindrical concrete cores drilled out from the Kiruna Bridge. Different methods to determine the concrete fracture energy are discussed and recommendations are given for assessment procedures.

Place, publisher, year, edition, pages
Luleå: Luleå University of Technology, 2020. p. 77
Series
Research report / Luleå University of Technology, ISSN 1402-1528
Keywords
Bridges, Assessment, Full-Scale Test to Failure, Fracture Energy, Bending, Shear, Punching, Prestressed Concrete, Modelling, Measurements of Loads, Deflections and Strains
National Category
Other Civil Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-81122 (URN)978-91-7790-693-3 (ISBN)978-91-7790-694-0 (ISBN)
Projects
BBT 2017-030
Funder
Swedish Transport Administration, BBT 2017-030
Note

There are also Appendices A-F of 109 pp

Available from: 2020-10-13 Created: 2020-10-13 Last updated: 2023-09-05Bibliographically approved
Nilforoush, R. (2019). A Refined Model for Predicting Concrete-Related Failure Load of Tension Loaded Cast-in-Place Headed Anchors in Uncracked Concrete. Nordic Concrete Research, 60(1), 105-129
Open this publication in new window or tab >>A Refined Model for Predicting Concrete-Related Failure Load of Tension Loaded Cast-in-Place Headed Anchors in Uncracked Concrete
2019 (English)In: Nordic Concrete Research, ISSN 0800-6377, Vol. 60, no 1, p. 105-129Article in journal (Refereed) Published
Abstract [en]

Current theoretical models for predicting the concrete cone breakout capacity of tension loaded headed anchors do not consider the influence of member thickness, size of anchor head, and orthogonal surface reinforcement. In the present study, the influence of the aforementioned parameters was studied both numerically and experimentally. Both the numerical and experimental results showed that the tensile resistance of headed anchors increases by increasing the member thickness or if orthogonal surface reinforcement is present. In addition, the anchorage capacity further increases with increase of the anchor head size.

The current model for predicting the concrete cone failure load of tension loaded headed anchors were refined and extended by incorporating three modification factors to account for the influence of the member thickness, size of anchor head, and orthogonal surface reinforcement. The accuracy of the proposed model was verified based on the results of 124 tests on single headed anchors from literature.

Place, publisher, year, edition, pages
Sciendo, 2019
Keywords
Concrete Cone Breakout, Concrete Splitting, Anchor Bolt, Headed Anchor, Fastening System, Member Thickness, Anchor Head Size, Surface Reinforcement
National Category
Other Civil Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-75561 (URN)10.2478/ncr-2019-0091 (DOI)000475508100008 ()
Note

Validerad;2019;Nivå 2;2019-08-16 (johcin)

Available from: 2019-08-16 Created: 2019-08-16 Last updated: 2023-09-05Bibliographically approved
Nilforoush, R., Nilsson, M. & Elfgren, L. (2018). Experimental Evaluation of Influence of Member Thickness, Anchor-Head Size, and Orthogonal Surface Reinforcement on the Tensile Capacity of Headed Anchors in Uncracked Concrete. Journal of Structural Engineering, 144(4), Article ID 04018012.
Open this publication in new window or tab >>Experimental Evaluation of Influence of Member Thickness, Anchor-Head Size, and Orthogonal Surface Reinforcement on the Tensile Capacity of Headed Anchors in Uncracked Concrete
2018 (English)In: Journal of Structural Engineering, ISSN 0733-9445, E-ISSN 1943-541X, Vol. 144, no 4, article id 04018012Article in journal (Refereed) Published
Abstract [en]

Cast-in-place headed anchors with different head sizes embedded in plain and reinforced concrete members of various thicknesses were subjected to pullout tests. The influence of member thickness, size of the anchor head, and orthogonal surface reinforcement on the tensile capacity and performance of anchor bolts was evaluated. The member thickness varied from 1.5 to 3.0 times the anchor embedment depth and headed anchors with small, medium, and large heads were tested.

The experimental results of the present study showed that increasing member thickness and/or the use of orthogonal surface reinforcement lead to increased anchorage capacity and anchorage ductility, whereas the anchorage stiffness decreases slightly. In contrast to the anchorage ductility, the tensile breakout resistance and the anchorage stiffness increase significantly with increasing size of the anchor head.

The experimental results corresponded closely to numerical results from a previous study (Nilforoush et al. 2016 a & b), which suggested a modified model incorporating several modification factors for improving the predictive capability of the Concrete Capacity (CC) method. In the present study, these factors yielded improved prediction of the tensile breakout capacity of the tested headed anchors.

Place, publisher, year, edition, pages
American Society of Civil Engineers (ASCE), 2018
Keywords
headed anchor, anchor bolt, concrete cone breakout, concrete splitting, member thickness, anchor head, surface reinforcement
National Category
Civil Engineering Infrastructure Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-66332 (URN)10.1061/(ASCE)ST.1943-541X.0001976 (DOI)000425620500004 ()2-s2.0-85040823012 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-01-23 (andbra)

Available from: 2017-10-31 Created: 2017-10-31 Last updated: 2023-09-05Bibliographically approved
Nilforoush, R. (2017). Anchorage in Concrete Structures: Numerical and Experimental Evaluations of Load-Carrying Capacity of Cast-in-Place Headed Anchors and Post-Installed Adhesive Anchors. (Doctoral dissertation). Luleå: Luleå University of Technology
Open this publication in new window or tab >>Anchorage in Concrete Structures: Numerical and Experimental Evaluations of Load-Carrying Capacity of Cast-in-Place Headed Anchors and Post-Installed Adhesive Anchors
2017 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Various anchorage systems including both cast-in-place and post-installed anchors have been developed for fastening both non-structural and structural components to concrete structures. The need for increased flexibility in the design of new structures and strengthening of existing concrete structures has led to increased use of various metallic anchors in practice. Although millions of fasteners are used each year in the construction industry around the world, knowledge of the fastening technology remains poor. In a sustainable society, buildings and structures must, from time to time, be adjusted to meet new demands. Loads on structures must, in general, be increased to comply with new demands, and the structural components and the structural connections must also be upgraded. From the structural connection point of view, the adequacy of the current fastenings for the intended increased load must be determined, and inadequate fastenings must either be replaced or upgraded. The current design models are generally believed to be conservative, although the extent of this behavior is not very clear. To address these issues, the current models must be refined to allow the design of new fastenings and also the assessment of current anchorage systems in practice.

The research presented in this thesis consists of numerical and experimental studies of the load-carrying capacity of anchors in concrete structures. Two different types of anchors were studied: (I) cast-in-place headed anchors, and (II) post-installed adhesive anchors. This research focused particularly on the tensile load-carrying capacity of cast-in-place headed anchors and also on the sustained tension loading performance of post-installed adhesive anchors. The overall objective of this research was to provide knowledge for the development of improved methods of designing new fastening systems and assessing the current anchorage systems in practice.

For the cast-in-place headed anchors (I), the influence of various parameters including the size of anchor head, thickness of concrete member, amount of orthogonal surface reinforcement, presence of concrete cracks, concrete compressive strength, and addition of steel fibers to concrete were studied. Among these parameters, the influence of the anchor head size, member thickness, surface reinforcement, and cracked concrete was initially evaluated via numerical analysis of headed anchors at various embedment depths. Although these parameters have considerable influence on the anchorage capacity and performance, this influence is not explicitly considered by the current design models. The numerical results showed that the tensile breakout capacity of headed anchors increases with increasing member thickness and/or increasing size of the anchor head or the use of orthogonal surface reinforcement. However, their capacity decreased considerably in cracked concrete. Based on the numerical results, the current theoretical model for the tensile breakout capacity of headed anchors was extended by incorporating several modification factors that take the influence of the investigated parameters into account. In addition, a supplementary experimental study was performed to verify the numerically obtained findings and the proposed refined model. The experimental results corresponded closely to the numerical results, both in terms of failure load and failure pattern, thereby confirming the validity of the proposed model. The validity of the model was further confirmed through experimental results reported in the literature.

Additional experiments were performed to determine the influence of the concrete compressive strength and the addition of steel fiber to concrete on the anchorage capacity and performance. These experiments showed that the anchorage capacity and stiffness increase considerably with increasing concrete compressive strength, but the ductility of the anchor decreases. However, the anchorage capacity and ductility increased significantly with the addition of steel fibers to the concrete mixture. The test results also revealed that the tensile breakout capacity of headed anchors in steel fiber-reinforced concrete is significantly underestimated by the current design model.

The long-term performance and creep behavior of the post-installed headed anchors (II) was evaluated from the results of long-time tests on adhesive anchors under sustained loads. In this experimental study, adhesive anchors of various sizes were subjected to various sustained load levels for up to 28 years. The anchors were also exposed to several in-service conditions including indoor temperature, variations in the outdoor temperature and humidity, wetness (i.e., water on the surface of concrete), and the presence of salt (setting accelerant) additives in the concrete. Among the tested in-service conditions, variations in the outdoor temperature and humidity had the most adverse effect on the long-term sustained loading performance of the anchors. Based on the test results, recommendations were proposed for maximum sustained load levels under various conditions. The anchors tested under indoor conditions could carry sustained loads of up to 47% of their mean ultimate short-term capacities. However, compared with these anchors, the anchors tested under outdoor conditions exhibited larger creep deformation and failure occurred at sustained loads higher than 23% of their mean ultimate short-term capacities. Salt additives in concrete and wet conditions had negligible influence on the long-term performance of the anchors, although the wet condition resulted in progressive corrosion of the steel. Based on the experimental results, the suitability of the current testing and approval provisions for qualifying adhesive anchors subjected to long-term sustained tensile loads was evaluated. The evaluations revealed that the current approval provisions are not necessarily reliable for qualifying adhesive anchors for long-term sustained loading applications. Recommendations were given for modifying the current provisions to ensure safe long-term performance of adhesive anchors under sustained loads.

Place, publisher, year, edition, pages
Luleå: Luleå University of Technology, 2017. p. 352
Series
Doctoral thesis / Luleå University of Technology 1 jan 1997 → …, ISSN 1402-1544
Keywords
Headed anchor, Anchor bolt, Adhesive anchor, Concrete cone breakout, Concrete splitting, Pullout loading, Size effect, Member thickness, Anchor head size, Orthogonal surface reinforcement, Concrete Strength, High-strength concrete, Cracked concrete, Steel fiber-reinforced concrete, Sustained loading, Creep behavior
National Category
Civil Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-66333 (URN)978-91-7790-002-3 (ISBN)978-91-7790-003-0 (ISBN)
Public defence
2017-11-30, F1031, Luleå University of Technology, Luleå, 09:00 (English)
Opponent
Supervisors
Available from: 2017-11-06 Created: 2017-10-31 Last updated: 2023-09-05Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-9937-6072

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