| 1. |
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| 2. |
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| 3. |
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| 4. |
- Bergström, Markus, et al.
(author)
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Structural health monitoring of degrading concrete beams in a laboratory environment
- 2006
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In: Composites in Civil Engineering. - : International Institute for FRP in Construction (IIFC). ; , s. 335-338
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Conference paper (other academic/artistic)abstract
- Much effort has been invested separately on degradation, repair and upgrading of concrete structures. However, few holistic studies including laboratory testing have been performed on the entire cycle during a structures life. Reinforced concrete is the most widely used building material in the world. Normally the life of concrete structures is very long. However, concrete structures possess one drawback; at least in severe environments, the steel reinforcement may corrode. The effects can clearly be seen when the steel reinforcement is attacked by chlorides. The reduced steel cross-section area and loss of bond strength between steel and concrete will lead to increased deformations, cracking and premature ultimate load, thus affecting both the serviceability limit state (SLS) and the ultimate limit state (ULS). Procedures to repair and upgrade the damaged structure are used to increase the structural performance. They follow the structural member of time, a SHM (Structural Health Monitoring) approach is adapted to this project. By applying SHM to a degrading structure it assures that it will keep up to current standards by continuous monitoring, analysing, evaluation and eventually also retrofitting.
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| 5. |
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| 6. |
- Plos, Mario, 1963, et al.
(author)
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Structural assessment of concrete bridges
- 2008
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In: Nordic Concrete Research. - 0800-6377. ; 38:2008/2, s. 89-101
-
Journal article (peer-reviewed)abstract
- The paper summarises the work on concrete bridges performed in the EU project Sustainable Bridges. The work provides enhanced assessment methods that are able to prove higher load-carrying capacities and longer fatigue lives for existing concrete railway bridges, and is implemented in a Guideline [1]. Methods for determination of in-situ material properties and advanced methods for structural analysis were developed. One main focus was non-linear analysis, since these provides the greatest potential for discovering of additional sources for load-carrying capacity. Furthermore, methods to assess the remaining structural resistance of deteriorated concrete bridges with respect to corrosion and fatigue were developed.
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| 7. |
- Al-Emrani, Mohammad, 1967, et al.
(author)
-
You have full text access to this content Experimentelle Untersuchung des Ermüdungsverhaltens genieteter Träger
- 2002
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In: Stahlbau. - 1437-1049 .- 0038-9145. ; :2, s. 145-150
-
Journal article (peer-reviewed)abstract
- The results from ten fatigue tests performed on six full-scale riveted stringers are presented and discussed. The stringers were taken from a 100 year old bridge, and the tests were performed at two different stress ranges: 60 and ~100 MPa. The tested stringers showed an excellent fatigue performance and their fatigue lives were in correspondence with or above the fatigue design curve given by the codes. Furthermore, the efficiency of using stop-holes to retard fatigue crack propagation in riveted girders was examined. The method was found to be an effective measure when aimed at temporarily arrest the crack propagation in riveted girders.
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| 8. |
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| 9. |
- Fransson, Lennart, et al.
(author)
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Ice loads for wind-power foundations in the Gulf of Bothnia
- 2009
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In: Proceedings of the 20th International Conference on Port and Ocean Engineering under Arctic Conditions. ; June 9-12, 2009, s. 12-19
-
Conference paper (peer-reviewed)abstract
- Ice loads measured on lighthouses in the Gulf of Bothnia can serve as guidance for design of foundations for wind-power generators. At some locations in the sea these structures must withstand high pressure from solid land fast ice as well as from ridges or other compacted ice masses that are drifting. Recommendations for design of offshore foundations around the Swedish coastline have recently been written by the authors. For the purpose of design, effective pressure as well as compressive strength is assumed to be independent of ice thickness. All structures should be designed for dynamic ice loads that are dependent on the natural frequency of the structure and the ice drift velocity. Increased effective pressure has earlier been indicated for high speed ice crushing both in field studies and compression tests. The presented results from ice load measurements on lighthouse Norströmsgrund support the suspicion that also design ice loads should increase with drift speed. This rate effect and other uncertainties about the worst case scenario for ice-induced vibrations suggest a more conservative design of wind-power foundations inside the dynamic ice zone.
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| 10. |
- Jonsson, Thomas, et al.
(author)
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Crash Prediction Models for Intersections on Rural Multilane Highways: Differences by Collision Type
- 2007
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In: Proceedings of the 86th Annual meeting of TRB, CD-ROM. - : SAGE Publications. ; 2019, s. 91-98
-
Conference paper (peer-reviewed)abstract
- Accident prediction models are often used to predict the number of accidents on segments and at intersections in the road network. Most often the models are developed for a total number of crashes for the facility, or crashes by severity. However, the frequency and severity of crashes of different types can be expected to vary with regards to the underlying phenomena that cause them to occur. To better account for this variation, this paper describes modeling of accidents at intersections on rural four-lane highways in California separately for four different collision types: Opposite direction crashes, Same direction crashes, Intersecting direction crashes and Single vehicle crashes. The findings from this modeling are reported with a special focus on the differences among crash types with regards to: 1) severity distribution, 2) the dependence on traffic flow, and 3) which variables are best at explaining between site variations in the occurrence of different crash types. There are evident differences in severity as well as the relationship of flow among several of the crash types. Intersecting and Opposite direction crashes are more severe than Same direction crashes. Same and Opposite direction crashes exhibit similar relationships with traffic flow, but there are differences compared to Intersecting direction crashes as well as to Single vehicle crashes. Also the variables that turn out as good predictor variables differ somewhat for each crash type.
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| 11. |
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| 12. |
- Lundgren, Karin, 1968, et al.
(author)
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Three-dimensional modelling of anchorage zones in reinforced concrete
- 2001
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In: Journal of Engineering Mechanics - ASCE. - 1943-7889 .- 0733-9399. ; 127:7, s. 693-699
-
Journal article (peer-reviewed)abstract
- A new 3D micromechanics-based framework is proposed for the nonlinear analysis of pultruded fiber-reinforced polymeric composites. The proposed 3D modeling framework is a nested multiscale approach that explicitly recognizes the response of the composite systems (layers) within the cross section of the pultruded member. These layers can have reinforcements in the form of roving, continuous filament mat (CFM), and/or woven fabrics. Different 3D micromechanical models for the layers can be used to recognize the basic response of the fiber and matrix materials. The framework is implemented with both shell and 3D finite elements. The 3D lamination theory is used to generate a homogenized nonlinear effective response for a through-thickness representative stacking sequence. The proposed modeling framework for pultruded composites is used to predict the stiffness and nonlinear stress-strain response of E-glass/vinylester pultruded materials reinforced with roving and CFM. The roving layer is idealized using a 3D nonlinear micromechanics model for a unidirectional fiber-reinforced material. A simple nonlinear micromechanics model for the CFM layer is also applied. The proposed model shows very good predictive capabilities of the overall effective properties and the nonlinear response of pultruded composites, based on the in situ material properties, and the volume fractions of the constituents. Experimental data from off-axis tests of pultruded plates under uniaxial compression are used to verify the proposed model. The proposed framework can be easily incorporated within displacement-based finite-element models of composite structures.
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| 13. |
- Offrell, Petra, et al.
(author)
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Repeatability in crack data collection on flexible pavements : Comparision between surveys using video cameras, laser cameras, and a simplified manual survey
- 2005
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In: Journal of transportation engineering. - 0733-947X .- 1943-5436. ; 131:7, s. 552-562
-
Journal article (peer-reviewed)abstract
- Crack data can be collected using manual or automatic surveys. Traditionally, manual methods are used, and they are still the most common. Changing into automatic systems will enhance the efficiency of data collection as well as the objectivity. In this study the repeatability of an automatic crack data collection system using video images was evaluated. Ten repetitive measurements were made on a 10-km-long road section. Cracking was measured using six laser cameras attached to the same vehicle.The results from the two methods were compared. Simultaneously, a simplified manual windshield survey was conducted by three different persons, and the repeatability obtained was used for comparison with the repeatability established using the image and laser method, respectively. The correlation between repeated measurements using the two automatic systems was high, while the repeatability for the manual, subjective method was low. Suitable measures for crack characterization are discussed.
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| 14. |
- Plos, Mario, 1963, et al.
(author)
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Finite Element Analysis of the New Svinesund Bridge: Design model conversion and analysis of the arch launching
- 2004
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Reports (other academic/artistic)abstract
- During the construction of the New Svinesund Bridge, a monitoring project is conducted on behalf of the Swedish road administration (Vägverket). The Royal Institute of Technology (KTH) is leading this project and is responsible for instrumentation, analysis and documentation in the project. As a part of the monitoring project, a finite element model was accomplished at Chalmers University of Technology, department of structural Engineering and Mechanics. Parallel to the monitoring project, a project concerning bridge assessment and maintenance based on FE analysis and field measurements was initiated at Chalmers University of Technology (Chalmers) on behalf of the Swedish road administration (Vägverket) and the Swedish railway administration (Banverket). The FE model was further developed within this project. The model is intended to be used both by the Royal Institute and Chalmers in their further work with the bridge.A finite element (FE) model of the New Svinesund Bridge was developed, and a simplified analysis of the construction of the bridge was made. The FE model was based on the structural model made by the bridge contractor, Bilfinger Berger (2004). The FE model was verified through comparisons with results obtained from the contractor, using the design model of the bridge. Eigenfrequencies and eigenmodes for different stages during the arch launching were calculated. These were found to correspond reasonably well to what was calculated by Bilfinger Berger, even though the FE analysis gave a little lower eigenfrequencies. The completed bridge was analysed for distributed external loads on the carriageways. The sectional moments and forces in the arch, obtained in the FE analysis showed a good agreement with the results from Bilfinger Berger. The deformations of the arch showed a reasonably good agreement between the models.
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| 15. |
- Plos, Mario, 1963, et al.
(author)
-
Structural assessment of concrete bridges
- 2007
-
In: Nordic Concrete Research. - 0800-6377. ; 30:2, s. 89-102
-
Journal article (peer-reviewed)abstract
- The paper summarises the work on concrete bridges performed in the EU project Sustainable Bridges. The work provides enhanced assessment methods that are able to prove higher load-carrying capacities and longer fatigue lives for existing concrete railway bridges, and is implemented in a Guideline [1]. Methods for determination of in-situ material properties and advanced methods for structural analysis were developed. One main focus was non-linear analysis, since these provides the greatest potential for discovering of additional sources for load-carrying capacity. Furthermore, methods to assess the remaining structural resistance of deteriorated concrete bridges with respect to corrosion and fatigue were developed.
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| 16. |
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| 17. |
- Bennitz, Anders, et al.
(author)
-
Dynamic behaviour of the Vindel River railway bridge
- 2006
-
In: Condition Monitoring and Diagnostic Engineering Management. - Luleå : Luleå tekniska universitet. - 9789163188060 ; , s. 721-729
-
Conference paper (peer-reviewed)abstract
- The Swedish Railway administration has launched several projects aimed at increasing the accessibility of the railway lines in northern Sweden to meet future demands. One of these lines connects the southern and northern parts of Sweden and constitutes one of the major arteries for the transportation of heavy goods. Major investment are planned to upgrade the load bearing capacity of this railway line. The work is mainly focused on the larger structures and their dynamical properties. These properties can be used to assess existing infrastructure and to evaluate the performance. Advantages are obvious since the existing structural integrity form the base for investments in structural repair and upgrade of bridges. The Vindel River Railway Bridge situated 55 kilometers northwest of Umeå came into focus when large motion was discovered during train passages. The behaviour of the bridge crossing the river of Vindeln has been measured two times. Measurements of displacements and acceleration of the bridge during train passages has been conducted, the first measurements was done to give more experience on the motion of the bridge and to try out new sensors. The second measurement gave more information about the bridge's motion, results that could be used to calibrate a 3D FE-Model of the bridge used in the study. Based on the measurements, eigenfrequencies in the range of 0 to 8 Hz could be detected, modal shapes up to the ninth order could be extracted, deflections and transverse displacements for different sets of train and different train speeds were also found. However, new measurements are planned for this summer and will hopefully reinforce the already attained result and give answers to some of the unresolved questions.
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| 18. |
- Bernander, Stig
(author)
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Progressive landslides in long natural slopes : potential extension and configuration of finished slides in strain-softening soils
- 2000
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Licentiate thesis (other academic/artistic)abstract
- A finite difference method is presented for progressive slides in long natural slopes. The method is based on a strain softening material model. A detailed worked out example is given as well as examples using a spread sheet PC program and a PC program for Windows. Several Scandinavian slides are analysed and discussed as case studies e g Tuve (1977), Surte (1951), Bekkelaget (1953), Rollsbo (1967), Rävekärr (1971), Tre-styckevattnet (1990) and Svärtaån (1938). The nature of down-slope progressive failures in natural slopes is described and the applicability of ideal-plastic failure analysis is questioned. Principles and procedures for investigation potential landslides are presented. A short historical background to the landslide problem is given in an introductory chapter.
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| 19. |
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| 20. |
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| 21. |
- Claeson-Jonsson, Christina, 1967, et al.
(author)
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Slender concrete columns subjected to sustained and short-term eccentric loading
- 2000
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In: ACI Structural Journal. - 0889-3241. ; 97:1, s. 45-52
-
Journal article (peer-reviewed)abstract
- A test series examining the structural behavior of six slender reinforced concrete columns subjected to short-term and sustained loading is presented. The columns had cross sections 200 x 200 mm and were 4 m long. Concrete strengths used were 35 and 92 MPa with a load eccentricity of 20 mm. Key parameters such as concrete strength, concrete and steel strains, cracking, midheight deflection, and loading rate were studied. The high-strength (HSC) columns subjected to short-term loading displayed less ductility and more sudden failures than the normal strength concrete (NSC) columns. Furthermore, the tests conducted indicated that the structural behaviour of the HSC is favorable under sustained loading, i.e., the HSC column exhibited less tendency to creep and could sustain the axial load without much increase in deformation for a longer period of time. An analysis based on a simplified stability analysis, using a stress-strain relation for concrete that includes creep, aging, and the confining effect of the stirrups was carried out. The model was shown to simulate the load-deflection curves satisfactorily for all of the concrete columns.
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| 22. |
- Collin, Peter, et al.
(author)
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Bridges in high strength steel
- 2006
-
In: Responding to Tomorrow's Challenges in Structural Engineering. - Zürich : International Association for Bridge and Structural Engineering. - 9783857481147 ; , s. 434-435
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Conference paper (peer-reviewed)
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| 23. |
- Collin, Peter, et al.
(author)
-
Bättre samverkansbroar på väg
- 2001
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In: V-byggaren : väg- och vattenbyggaren. - 0283-5363. ; :1, s. 35-40
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Journal article (other academic/artistic)
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| 24. |
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| 25. |
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| 26. |
- Collin, Peter, et al.
(author)
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Innovative prefabricated composite bridges
- 2002
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In: IABSE symposium Melbourne 2002. - Zürich : International Association for Bridge and Structural Engineering.
-
Conference paper (peer-reviewed)abstract
- The competitiveness of composite bridges depends on several circumstances such as site conditions, local costs of material and staff and the contractor's experience. One major advantage compared to concrete bridges is that the steel girders can carry the weight of the formwork and the wet concrete. Another advantage is the savings in construction time, which saves some money for the contractor but even more so for the road users, a fact that usually is neglected when evaluating alternative bridge designs. A further step to improve the competitiveness of composite bridges is to prefabricate not only the steel girders, but also the concrete deck. In this paper a new concept with dry joints between the elements is described.
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| 27. |
- Collin, Peter, et al.
(author)
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Undermatching butt welds in high strength steel
- 2009
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In: Sustainable infrastructure. - Zürich : International Association for Bridge and Structural Engineering. - 9783857481215 ; , s. 280-281
-
Conference paper (peer-reviewed)
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| 28. |
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| 29. |
- Ditrani, Marco, et al.
(author)
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Improving transportation investment decision through life-cycle cost analysis : case study on some bridges in the north of Sweden
- 2009
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In: Sustainability of Constructions - Integrated Approach to Life-time Structural Engineering. - 9789736384288 ; , s. 266-275
-
Conference paper (peer-reviewed)abstract
- The scope of this project is to perform Life Cycle Cost Analysis (LCCA) on different types of bridges, in order to learn which is most cost-efficient in a particular situation. A second scope is to study the impact of different cost items on the whole Life Cycle Cost. The work is performed to enable optimal strategic decisions regarding future investments.Beam and Slab Bridges, Slab Bridges and Slab Frame Bridges are analyzed. The bridges are located in the north of Sweden, in the regions of Norrbotten and Västerbotten. All bridges have a total length of around 20 m, which is the most common length in Sweden and in Europe. Furthermore, the analysis includes Timber and Soil-Steel bridges in order to understand the prospects for this types of bridges in Sweden. The analysis does not focus on a particular bridge but, based on information from some Swedish producers, it studies different scenarios.The data collection covers initial investments, maintenance, repair and rehabilitation (MR&R) costs, user and demolition costs.
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| 30. |
- Elfgren, Lennart, et al.
(author)
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Guidelines for strengthening of railway bridges
- 2009
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In: Proceedings of Workshop: COST Action C25 : Sustainability of Constructions - Integrated Approach to Life-time Structural Engineering. - 9789736384288 ; , s. 141-145
-
Conference paper (peer-reviewed)abstract
- In the international project "Sustainable Bridges", one of the deliverables is a design guide for strengthening of bridges. This paper gives the reader a first look into this guidelinewhich can be found at the projects website: www.sustainablebridges.net
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| 31. |
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| 32. |
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| 33. |
- Emborg, Mats, et al.
(author)
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Produktmodeller för platsgjuten betong
- 2004
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Reports (other academic/artistic)abstract
- Applikation av IT-baserade produktmodeller på byggande med platsgjuten betong för att medge optimerad och industrialiserad byggprocess. Två delområden har studerats: a) utvecklande av ett erfarenhetsbibliotek och b) konstruktions- och planeringsstöd för entreprenör och materialleverantör. Rapporten är en sammanfattning av utförlig rapport av Jongeling R: Product Models för Cast in Place Concrete, Avdelningen för Konstruktionsteknik, Teknisk Rapport 2003:01, 104 sid
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| 34. |
- Enochsson, Ola, et al.
(author)
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Assessment and condition monitoring of a concrete railway bridge in Kiruna, Sweden
- 2006
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In: Bridge maintenance, safety, management, life-cycle performance and cost. - London : Taylor and Francis Group. - 0415403154
-
Conference paper (peer-reviewed)abstract
- A two-span railway concrete trough bridge over Luossajokk in Kiruna in northern Sweden has been studied. The owner wanted to increase the axle loads from 250 to 300 kN in order to reduce freight costs for iron ore. Examples are given of methods used and results obtained from the assessment where bending, shear and fatigue were studied. Material properties, loads and load carrying capacity were evaluated using deterministic and probabilistic methods. It was shown that the bridge could carry the higher loads with a safety index β > 4.7 for reasonable assumptions of the load distributions. A measurement system was installed to check the actual level of critical strains and the worst positions of the train. Results are also given from a condition monitoring program 2001-2006, launched to periodically check the development of strains with time.
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| 35. |
- Enochsson, Ola, et al.
(author)
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Bro över Luossajokk : övervakning för trafikering med 30 tons axellast
- 2006
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Reports (other academic/artistic)abstract
- I samband med projektet "30 ton på Malmbanan", Paulson-Töyrä (1996), konstaterades att bron över Luossajokk i Kiruna inte klarade de nya förhöjda lasterna. Bron har två spann och en utkragande konsol 10,25 + 6,3 + 3,4 m. Överbyggnaden utgörs av ett slak-armerat betongtråg med ett nytt mellanstöd som uppfördes 1965 då en äldre överbyggnad byttes ut. En klassningsberäkning och en utredning av förstärkningsbehov utfördes. Efter en förnyad översyn av brons bärförmåga utfördes töjningsmätningar vintern och sommaren 2001. Töjningsmätningarna indikerade förvånansvärt små påkänningar i bron. En närmare utredning av brons säkerhet att bära uppträdande laster utfördes 2002 genom en nyanserad säkerhetsberäkning med säkerhetsindexmetod. Bron bedömdes utifrån utredningen och mätresultat ha erforderlig bärförmåga om hastigheten begränsades så att eventuella dynamiska tillskott blir låga och/eller inverkan av ojämn temperatur försummas. Ett program med mätningar varje halvår igångsattes för att kontrollera brons fortsatta uppförande. Kontrollen bestod i en övervakning av aktuella töjningsnivåer i armeringen.I denna rapport redovisas resultat från mätningar mellan år 2001-2006. Resultaten visar ingen ökning av töjningsnivåerna fram till brons avlägsnande hösten 2006.
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| 36. |
- Enochsson, Ola, et al.
(author)
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Bro över Luossajokk : beräkning med säkerhetsindexmetod, böjdragkapacitet i överkant i mittsnittet i korta spannet
- 2002
-
Reports (other academic/artistic)abstract
- I samband med projektet "30 ton på Malmbanan", Paulson-Töyrä (1996), konstaterades att bron över Luossajokk i Kiruna inte klarade de nya förhöjda lasterna. Bron har två spann och en utkragande konsol 10,25 + 6,3 + 3,4 m. Överbyggnaden utgörs av ett slakarmerat betongtråg med ett nytt mellanstöd som uppfördes 1965 då en äldre överbyggnad byttes ut. En klassningsberäkning och en utredning av förstärkningsbehov utfördes. Efter en förnyad översyn av brons bärförmåga utfördes töjningsmätningar vintern och sommaren 2001. Töjningsmätningarna indikerade förvånansvärt små påkänningar i bron. En närmare utredning av brons säkerhet att bära uppträdande laster genomförs därför i denna rapport. Detta sker med hjälp av en nyanserad säkerhetsberäkning med säkerhetsindexmetod. Den nya genomgången visar att medelvärdet för bärförmågan för moment är 2,89 MNm med standardavvikelsen 0,19 MNm i det mest utsatta snittet med dragpåkänningar i överkant i korta spannet. Detta kan jämföras med det formella dimensioneringsvärdet 1,99 MNm som erhölls i klassningsberäkningen med beaktande av aktuella partialkoefficienter. I det nya medelvärdet har en lägre uppmätt effektiv höjd beaktats, att ett av tolv armeringsjärn borrats av samt att betong- och armeringshållfastheterna är högre än de nominella dimensioneringsvärdena. På lastsidan gav klassningsberäkningen i motsvarande snitt att det formella dimensioneringsvärdet för momentet är 2,79 MNm. En analys av verkliga uppträdande laster ger att medelvärdet maximalt uppgår till 2,05 MNm. Detta lastfall utgörs av ett lok placerat med tre axlar i längsta spannet och tre axlar placerade på konsolen, om såväl bromslast som ojämn temperaturlast och dynamiskt tillskott uppträder samtidigt. Enligt BV Bärighet (1996) behöver ojämn temperatur inte beaktas, vilket är rimligt med tanke på att detta är ett statiskt obestämt lastfall som försvinner vid uppsprickning i brottstadiet. Det har heller inte medräknats i tidigare klassningsberäkningar. I så fall fås att lasten har medelvärdet 1,66 MNm och att säkerhetsindex β varierar mellan 3,8 och 6,0 beroende på vilka antaganden som görs om lasternas statistiska fördelning. För en rimlig fördelning innehålls kravet i säkerhetsklass 3 att säkerhetsindex β 4,75. Bron visar sig därför, enligt vår bedömning och med beaktande av erhållna mätresultat, ha erforderlig bärförmåga om hastigheten begränsas på bron så att eventuella dynamiska tillskott blir låga och/eller inverkan av ojämn temperatur försummas. Brons fortsatta uppförande bör kontrolleras genom ett mätprogram. Detta bör förutom armeringstöjningar med befintliga givare även inkludera mätningar av nedböjningar för att säkerställa att använda beräkningsmodeller och randvillkor på ett korrekt sätt återger brons beteende. Storleken på den dynamiska förstoringsfaktorn D bör även mätas liksom inverkan av bromskrafter och ojämn temperaturfördelning. På så sätt kan ett säkrare underlag erhållas för bedömning av frekvensfunktionerna för dessa vanliga lasteffekter. Dessa värden borde även vara av intresse vid säkerhetsbedömning av likartade järnvägsbroar.
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| 37. |
- Enochsson, Ola, et al.
(author)
-
CFRP Strengthened openings in two-way concrete slabs
- 2005
-
In: FRP composites in civil engineering - CICE 2004. - Leiden : Balkema Publishers, A.A. / Taylor & Francis The Netherlands. - 9058096386
-
Conference paper (peer-reviewed)
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| 38. |
- Enochsson, Ola, et al.
(author)
-
CFRP strengthened openings in two-way concrete slabs : an experimental and numerical study
- 2007
-
In: Construction and Building Materials. - : Elsevier BV. - 0950-0618 .- 1879-0526. ; 21:4, s. 810-826
-
Journal article (peer-reviewed)abstract
- Rehabilitation and strengthening of concrete structures with externally bonded fibre reinforced polymers (FRPs) has been a viable technique for at least a decade. An interesting and useful application is strengthening of slabs or walls where openings are introduced. In these situations, FRP sheets are very suitable; not only because of their strength, but also due to that they are easy to apply in comparison to traditional steel girders or other lintel systems. Even though many benefits have been shown by strengthening openings with FRPs not much research have been presented in the literature. In this paper, laboratory tests on 11 slabs with openings, loaded with a distributed load are presented together with analytical and numerical evaluations. Six slabs with openings have been strengthened with carbon fibre reinforced polymers (CFRPs) sheets. These slabs are compared with traditionally steel reinforced slabs, both with (four slabs) and without openings (one slab). The slabs are quadratic with a side length of 2.6 m and a thickness of 100 mm. Two different sizes of openings are used, 0.85 × 0.85 m and 1.2 × 1.2 m. The results from the tests show that slabs with openings can be strengthened with externally bonded CFRP sheets. The performance is even better than for traditionally steel reinforced slabs. The numerical and analytical evaluations show good agreement with the experimental results.
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| 39. |
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| 40. |
- Enochsson, Ola, et al.
(author)
-
Condition assessment of concrete bridges in Sweden
- 2005
-
In: Concrete repair, rehabilitation and retrofitting. - London : Taylor and Francis Group. - 0415396565 ; , s. 257-259
-
Conference paper (peer-reviewed)abstract
- Examples are given of methods used and results obtained from two bridges assessed in Sweden. The following sectional forces were critical: (a) Bending, shear and fatigue in a two-span railway trough bridge and (b) Shear and torsion in a three-span prestressed cantilever box girder road bridge. In the assessments we evaluated material properties, loads and load carrying capacity using deterministic and probabilistic methods
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| 41. |
- Enochsson, Ola, et al.
(author)
-
Structural health monitoring of a concrete bridge in Sweden
- 2006
-
In: Proceedings of SPIE, the International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. ; 6176:18
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Journal article (peer-reviewed)abstract
- Over the past decade the interests in upgrading, assessment and maintenance of our ageing infrastructure has grown avalanche-like. The main reason is economical aspects but also reasons due to accessibility environmental consideration play a vital role. Recently the Swedish and Norwegian Railway Association decided to upgrade the Iron Ore Line "Malmbanan", a railway line for transportation of iron from northern Sweden to the coasts of Norway and Sweden. Here the owner wanted to increase the axle loads from 25 to 30 tons to reduce the transportation costs. In one of the cases, the Luossajokk Bridge, a recalculation according to design codes showed that the increased axle loads would exceed the yield limit in the reinforcement. Before any decision was taken regarding strengthening or replacing the bridge an assessment with probabilistic methods was used. It appeared that the bridge could carry the higher load with a safety index β ≥ 4.7 for reasonable assumptions of the load distributions. A measurement system was installed to check the real worst placement of the new iron ore locomotive (IORE), and the actually level of strains in the reinforcement for the worst load case1. It was shown that the strain level was far from critical and that the evaluated worst placement of the locomotive was almost correct2. To assure a reliable transportation a long term monitoring program was arranged to check the development of strains with time. Examples from the probabilistic evaluation and the monitoring of the bridge are given and discussed.
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- Govindarajan, Venkatesh, 1972-, et al.
(author)
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Combined MFA-LCA for analysis of wastewater pipeline networks : Case study of Oslo (Norway).
- 2009
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In: Journal of Industrial Ecology. - Malden, MA, USA : Wiley-Blackwell. - 1088-1980 .- 1530-9290. ; 13:4, s. 532-550
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Journal article (peer-reviewed)abstract
- Oslo's wastewater pipeline network has an aging stock of concrete, steel, and polyvinyl chloride (PVC) pipelines, which calls for a good portion of expenditures to be directed toward maintenance and investments in rehabilitation. The stock, as it is in 2008, is a direct consequence of the influx of pipelines of different sizes, lengths, and materials of construction into the system over the years. A material flow analysis (MFA) facilitates an analysis of the environmental impacts associated with the manufacture, installation, operation, maintenance, rehabilitation, and retirement of the pipelines. The forecast of the future flows of materials-which, again, is highly interlinked with the historic flows-provides insight into the likely future environmental impacts. This will enable decision makers keen on alleviating such impacts to think along the lines of eco-friendlier processes and technologies or simply different ways of doing business. Needless to say, the operation and maintenance phase accounts for the major bulk of emissions and calls for energy-efficient approaches to this phase of the life cycle, even as manufacturers strive to make their processes energy-efficient and attempt to include captive renewable energy in their total energy consumption. This article focuses on the life cycle greenhouse gas emissions associated with the wastewater pipeline network in the city of Oslo.
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High performance concrete structures : design examples & properties
- 2000
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Editorial collection (other academic/artistic)abstract
- The report presents examples of design calculations for high performance concrete structures. It also summarizes some of the test results and material properties in a Swedish Research Program on High Performance Concrete. The aim is to give a background to and propose characteristic material properties to be used in design of high strength concrete.
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| 49. |
- Hällmark, Robert, et al.
(author)
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Simulation of low-cycle fatigue in integral abutment piles
- 2007
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In: Improving Infrastructure Worldwide. - Zürich : International Association for Bridge and Structural Engineering. - 9783857481161
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Conference paper (peer-reviewed)abstract
- Integral abutment bridges are bridges without any expansion joints, and their largest benefits are the lower construction- and maintenance costs. In order to build longer integral bridges it might be necessary to allow plastic hinges to be developed in the piles. Lateral thermal movements are the major reason to plastic deformations, and since temperature variations are cyclic it has to be proved that low-cycle fatigue will not occur. A simulation of the pile strain spectra should be able to take into account the strains caused by temperature variations and traffic loads. Such a model has been created from real temperature data and traffic loads measured by Bridge-Weigh-In-Motion technology. Monte Carlo simulations have been performed in order to simulate daily and annual temperature changes as well as the varying traffic loads. Piles strains have been calculated, and their fatigue effect has been evaluated.
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| 50. |
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International workshop on the bridges with integral abutments : topics of relevance for the INTAB project
- 2006
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Reports (other academic/artistic)abstract
- Since mid 2005 a European R&D project, INTAB (Economic and Durable Design of Composite Bridges with Integral Abutments), is running with support from RFCS, RFSR-CT-2005-00041, and national sponsors. The project concerns bridges with integral abutments, a concept saving investment as well as maintenance costs. The project includes international comparisons, theoretical studies, in situ and laboratory testing of bridges and the preparing of guidelines for design of such bridges. A bridge for monitoring was constructed in mid Sweden in the summer of 2006. In May 2006 an international workshop with participants from eight countries was held at Ramböll’s Swedish head office in Stockholm. The report consists of contributions from the leading structural engineers from these countries and addresses problems relevant for the INTAB project.
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