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| 2. |
- Casas, Joan Ramon, et al.
(författare)
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Guideline for Load and Resistance Assessment of Existing European Railway Bridges : Advices on the use of advanced methods
- 2007
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Rapport (refereegranskat)abstract
- The bridge assessment in many aspects is very similar to the bridge design. The same basic principles lie at the heart of the process. Nevertheless, an important difference lies in the fact that when a bridge is being designed, an element of conservatism is generally a good thing that can be achieved with very little additional costs. When a bridge is being assessed, it is important to avoid unnecessarily conservative measures because of the financial implications that may follow the decision of ratingthe bridge as deficient. Therefore, the design codes (e.g. EC codes) may not always be appropriate for assessment of existing bridges and some additional recommendations or guidelines are required that will lead to less conservative assessment of theirs load carrying capacity. Such guidelines have been already proposed for assessment of highway bridges in Europe. However, there is a lack of this type of documents that can be applied for the assessment of railway bridges.The present "Guideline for Load and Resistance Assessment of Existing European Railway Bridges - advices on the use of advanced methods" is providing guidance and recommendations for applying the most advanced and beneficial methods, models and tools for assessing the load carrying capacity of existing railway bridges. This includes systematized step-level assessment methodology, advanced safety formats (e.g. probabilistic or simplified probabilistic) refined structural analysis (e.g. non-linear or plastic, dynamic considering train-bridge interaction), better models of loads and resistance parameters (e.g. probabilistic and/or based on the results of measurements) and methods for incorporation of the results form monitoring and on-site testing (e.g. Bayesian updating).Basis for the "Guideline for Load and Resistance Assessment of Existing EuropeanRailway Bridges - advices on the use of advanced methods" is the research work carried out in the work package WP4 of the Sustainable Bridges project combined with the best practical experience and know-how of all the partners involved.The research activities within the work package WP4 have been carried out in the following five groups:− Loads and dynamic effects, with focus on train loads and dynamics (Deliverables D4.3, also referred as SB 4.3 Dynamic (2007), or just SB4.3 (2007));− Safety and probabilistic modelling (Deliverables D4.4, also referred as SB4.4Safety (2007), or just SB4.4 (2007));− Concrete bridges, with focus on non-linear analysis (Deliverables D4.5, also referred as SB4.5 Concrete (2007), or just SB4.5 (2007));− Metal bridges, with focus on riveted bridges (Deliverables D4.6, also referredas SB4.6 Metal (2007), or just SB4.6 (2007));− Masonry arch bridges including soil/structure interaction (Deliverables D4.7,also referred as SB4.7 Masonry (2007), or just SB4.7 (2007)).The results of these activities are reported in corresponding Background Documents (Deliverables) listed above within parenthesis.The main results from the research activities performed and the know-how of all the partners in the specific areas of bridge assessment are tried to be presented in this Sustainable Bridges SB-LRA 2007-11-30 6 (428) Guideline in such a way that the target reader of the Guideline, a structural engineer experienced in assessment of railway bridges, is able to apply them in the everyday practice, without necessity of searching for several specific scientific publications. Nevertheless, in some cases it has been necessary to refer to public available literature and Background Documents prepared in the Sustainable Bridges project.The present Guideline has been prepared aiming to follow somehow the structure of the EC codes and it is divided into 10 chapters and 12 Annexes concerning:− Assessment procedure (Chapter 2);− Requirements, safety formats and limit states (Chapter 3, Annexes 3.1-3.7);− Basic information for bridge assessment (Chapter 4);− Load and dynamic effects (Chapter 5, Annex 5.1);− Concrete bridges (Chapter 6);− Metal bridges (Chapter 7, Annex 7.1);− Masonry arch bridges (Chapter 8, Annexes 8.1 and 8.2);− Foundations and transition zones (Chapter 9);− Improvement of assessment using information from testing and monitoring (Chapter 10, Annex 10.1).In most of the topics related to railway bridges assessment the Guideline uses the current state-of-the-art knowledge and the presently best practice. Nevertheless, in many subjects it propose the use of original methods and models that have been developed, obtained or systematized due to research performed within one of the five groups of work package WP4.
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- Claeson-Jonsson, Christina, 1967, et al.
(författare)
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Slender concrete columns subjected to sustained and short-term eccentric loading
- 2000
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Ingår i: ACI Structural Journal. - 0889-3241. ; 97:1, s. 45-52
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Tidskriftsartikel (refereegranskat)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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| 4. |
- Elfgren, Lennart, et al.
(författare)
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Fatigue of anchor bolts in reinforced concrete foundations
- 1982
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Ingår i: Fatigue of Steel and Concrete Structures. - Zürich : International Association for Bridge and Structural Engineering. - 3857480300 ; , s. 463-470
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Konferensbidrag (refereegranskat)
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| 5. |
- Elfgren, Lennart, et al.
(författare)
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Krister Cederwall, 1932-2006 : Minnesord
- 2007
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Annan publikation (populärvet., debatt m.m.)abstract
- Krister Cederwall föddes I Borås den 1 oktober 1932. Efter civilingenjörsexamen I väg- och vattenbyggnad på KTH arbetade han som konstruktör. Han flyttade efter några år till Göteborg och knöts till Chalmers tekniska högskola som forskningsassistent vid Hjalmar Granholms institution för byggnadsteknik där han blev tekn lic 1961. Under åren 1960-65 var han brokonstruktör vid Granholms konstruktionsbyrå och var bland annat med om att utforma broarna i Essingeleden I Stockholm. År 1965 utnämndes han till universitetslektor I betongbyggnad vid Chalmers och disputerade 1971 på en avhandling om stabilitet och långstidsdeformationer I tryckta betongkonstruktioner. När den nya tekniska högskolan I Luleå byggdes upp blev Krister Cederwall dess förste innehavare av professuren I Konstruktionsteknik. Han byggde med stor energi upp nya forskningsinriktningar som byggteknik i kallt klimat och studier av isbärighet och ishållfasthet. Han initierade även studier av massiva betongkonstruktioner och deras sprickbenägenhet. Han arbetade nära samman med byggföretag och knöt adjungerade professorer till högskolan. Han var tidigt ute med att använda sannolikhetsteori för att studera bärighet och att använda brottmekanik för att förstå hur konstruktioner går sönder och hur man undviker spröda brott. När professuren i betongbyggnad blev ledig på Chalmers 1983 efter Anders Losberg flyttade han tillbaka till Göteborg. Hans hjärta fortsatte dock att klappa för Luleå, och han var många gånger på besök för att gästföreläsa och delta i disputationer och licentiatseminarier i ämnen som han en gång initierat. Han blev professor emeritus I januari 1995 och avled den 1 november 2006 vid 74 års ålder.
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| 6. |
- Elfgren, Lennart, et al.
(författare)
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Stefan Attefall - våra synpunkter håller!
- 2012
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Ingår i: Byggindustrin. - 1104-5981. ; 2012:36, s. 32-32
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- Den 6 november slog professor från fyra tekniska högskolor larm om att ras och olyckor beror på grova fel i byggnadernas konstruktioner. I Byggindustrin 35-2012 avfärdadade bostadsminister Stefan Attefall (KD) deras kritik med att detta var en följd av gamla regler. Här bemöter de ministerns svar.
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| 8. |
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| 9. |
- Elfgren, Lennart, et al.
(författare)
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Utmattningshållfasthet hos betongkonstruktioner
- 1997
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Rapport (populärvet., debatt m.m.)abstract
- En översikt om utmattning av betongkonstruktioner att användas i civilingenjörsutbildningen på Chalmers tekniska högskola och Luleå tekniska universitet
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| 10. |
- Fall, David, 1983, et al.
(författare)
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Non-linear Finite Element Analysis of Steel Fibre Reinforced Beams with Conventional Reinforcement
- 2012
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Ingår i: 8th RILEM International Symposium on Fiber Reinforced Concrete: challenges and opportunities (BEFIB 2012). - 9782351581322 ; , s. 1033-1045
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Konferensbidrag (refereegranskat)abstract
- The purpose of this study has been to investigate the behavior of elements reinforced with both conventional steel reinforcement and steel fibres in order to support future applications of such composites. Three beams of varying fibre content were tested in four-point bending. The results were then compared with results from nonlinear FE-analyses and the calculation method suggested in fib Model Code 2010. The beams were a part of a larger experimental programme where relevant properties were investigated in uniaxial tension tests and pull-out tests. The FE-modeling was performed using a two dimensional plane stress model. General agreement between experiments and the FE-analyses was obtained with regard to load-displacement behavior. The crack patterns from the FE-analysis and experiments agreed in general, although the crack patterns in the analysis were more distributed close to the reinforcement. Crack localization was enhanced by modifying the bond-slip behavior to include the bond loss at yielding. Calculations in accordance with fib Model Code 2010 yield conservative results in comparison with both experiments and FE-analysis.
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