| 1. |
- Cristescu, Carmen, et al.
(author)
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Design for deconstruction and reuse of timber structures – state of the art review
- 2020
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Reports (other academic/artistic)abstract
- This report is a state-of-the-art on timber construction in selected european countries and and discusses technical premises for a potential circular use of timber in building construction, focusing on Design for Deconstruction and Reuse (DfDR) in low-rise timber buildings, up to 3 storeys. It describes the historic and contemporary building techniques of timber buildings in all project countries (Sweden, Finland, Ireland, UK, Spain, Germany, Slovenia) and finds, that all of these countries have a long history of building with timber, but in most regions other materials dominated the housing output from the beginning of the 20th century. Only in the second half of the 20th century timber started gaining importance as a building material in Europe again, with light timber frame construction becoming an important construction system. From the beginning of the 21st century, innovations in the sector started transforming the construction industry. Mass timber products like CLT opened the market for high-rise timber buildings and in some countries office blocks, schools and hotels are built using timber, although the majority of timber construction remains residential. An even more important development might be the uptake of offsite construction, that makes timber construction more accurate, material efficient, fast and it reduces waste. These modern methods of construction are gaining importance in the construction sector of all partner countries and are likely to dominate the European housing output in the future. There will be some regional differences in the level of prefabrication, material choices and designs, so that any design guidelines for DfDR need to be adapted to the regional context. However, modern timber construction is not currently aligned with circular economy principles and is seldomly taking buildings endof-life-into account.Therefore, the report continues to summarise novel design concepts for deconstruction and reuse, that could be used in modern timber buildings. It outlines that the feasibility as well as the reuse potential depends on the scale of reclaimed components, where larger components and assemblies are often considered beneficial in terms of time, greenhouse gas emissions and waste production. If volumetric or planar units could be salvaged in the future, they also need to be adaptable for altered regulations or standards or alternative functions. It is further necessary that assemblies can be altered within buildings, since different building components have different life expectancies. Various examples for DfDR in buildings with the accompanying design strategies are presented. The buildings in the examples are often designed to be in one place for a limited timeframe and can be deconstructed and re-erected elsewhere without replacement of components. Key-features often include modularity of components, reversible connections, adaptability of the floor-plan and circular procurement. Even though it is evidently possible, the structural reuse of timber is not a wide-spread approach to date. Barriers to the use of reclaimed structural components are mainly a lack in demand for salvaged materials, but also prohibitive building regulations and the lack of design standards. Demolition practices play a crucial role as well and need to be considered in the design of buildings, to avoid damage to the components.Finally, the report summarises principles and guidelines for DfDR by different authors. As a generic approach an indicator system for deconstructability and reusability could be introduced. Time, Separability, Risk and Safety, Simplicity and Interchangeability are identified5as the main indicators for DfDR, that remain somewhat abstract. As opposed to using a generic indicator system, a more practical approach of assessing DfDR on an individual basis could be taken. This way specific shortcomings of the design can be addressed. But if DfDR found a wider application in the future, this approach may be too time consuming and there is a need for a more directed decision-making tool that can be used during the design phase of buildings to enhance DfDR. As the InFutUReWood project proceeds, it will examine a more granular approach to DfDR, relating it to the actual construction stages used in practice, developing a general template to be appropriated and adjusted to account for regional variations in construction. A strategic matrix is in development which will provide designers with a methodology based on relating principles, strategies and specific tactics to the typical design stages, to aid design decisions that promote DfDR.
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| 2. |
- Flansbjer, Mathias, et al.
(author)
-
Structural Concept of Novel RPC Sandwich Façade Elements with GFRP Connectors
- 2016
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In: IABSE Congress Stockholm 2016. - : IABSE c/o ETH Hönggerberg. - 9783857481444 ; , s. 2164-2171
-
Conference paper (peer-reviewed)abstract
- The SESBE research project aims to develop novel smart sandwich façade elements with high insulating capabilities while providing a reduced thickness in conjunction with superior mechanical and durability properties. The present paper mainly focuses on the verification of the mechanical performance of the glass fibre reinforced polymer (GFRP) connectors in the façade element composed of reactive powder concrete (RPC) panels with foam concrete insulation between them. Because of the reduced thickness of the large façade elements, the performance of the connectors is critical for the entire structural concept. A description of structural performance and results based on experimental methods and finite element (FE) analysis are presented.
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| 3. |
- Flansbjer, Mathias, et al.
(author)
-
Strutural performance of GFRP connectors in Composite sandwich facade elements
- 2016
-
In: Journal of Facade Design and Engineering. - 2213-302X .- 2213-3038. ; 4:1-2, s. 35-52
-
Journal article (peer-reviewed)abstract
- A systematic testing and modelling program has been developed for the verification of the structural performance of facade sandwich elements to take structural aspects into consideration in the SESBE research project, focusing on the development of “smart” facade elements.The present paper mainly focuses on the verification of the mechanical performance of the glass fibre reinforced polymer (GFRP) connectors of the novel type of facade element composed of reactive powder concrete (RPC) panels with foam concrete insulation between them. Because of the reduced thickness of the large facade elements, the performance of the connectors is critical for the entire structural concept. The first series of the testing and modelling programme concerning connector performance are presented here. The results suggest that sufficient strength and ductility of the connectors can be ensured using GFRP in the proposed thin light-weight facade elements.
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| 4. |
- Vennetti, Daniel, et al.
(author)
-
Safety of temporary stands
- 2016
-
In: IABSE Congress Stockholm 2016. - 9783857481444 ; , s. 2788-2795
-
Conference paper (peer-reviewed)abstract
- The paper gives an overview of some relevant technical aspects related to temporary stands. Since these kinds of structures are often used by a large number of people, consequences of structural failure could be significant. However, the effort put into their design and maintenance is often less than in case of permanent structures. Furthermore, it is not always clear who bears the responsibility if accidents happen. The current study concludes that the structural behaviour of these systems is much more complex than one might think; therefore clear regulations, guidelines and approaches are needed. A major concern is the requirements for validation of structural performance by numerical modelling and testing. Improvements in standardisation also require further research in several areas, such as e.g. structural dynamics, nature of loads, requirements, human-structure interaction.
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| 5. |
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| 6. |
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| 7. |
- Bedon, Chiara, et al.
(author)
-
Numerical Modelling of Structural Glass Elements under Thermal Exposure
- 2018
-
Conference paper (peer-reviewed)abstract
- Glass is largely used in engineering applications as a structural material, especially for laminated glass (LG) sections. However, the well-known temperature-dependent behaviour of visco-elastic interlayers for LG sections should be properly accounted for safety purposes, even in ambient conditions. The materials thermo-mechanical degradation with increase of temperature could further severely affect the load-bearing performance of such assemblies. Thermo-mechanical Finite Element (FE) numerical modelling, in this regard, can represent a robust tool and support for designers. Key input parameters and possible limits in FE models, however, should be properly taken into account and calibrated, especially for geometrically simplified models, to enable realistic and reliable estimations of real structural behavior. In this paper, FE simulations are proposed for monolithic (MG) and LG specimens under radiant heating, based on one-dimensional (1D) models. With the use of experimental results from the literature, parametric studies are discussed, indicating limits and issues at several modelling assuptions. Careful consideration is paid for various thermal material properties (conductivity, specific heat), boundary conditions (conductivity, emissivity) as well as geometrical features (thickness tolerances, etc.) and composition of LG sections (interlayer type, thickness). Comparative parametric results are hence discussed in the paper.
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| 8. |
- Bedon, Chiara, et al.
(author)
-
Performance of structural glass facades under extreme loads – Design methods, existing research, current issues and trends
- 2018
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In: Construction and Building Materials. - : Elsevier BV. - 0950-0618 .- 1879-0526. ; 163, s. 921-937
-
Journal article (peer-reviewed)abstract
- Glass has been overwhelmingly used for windows and facades in modern constructions, for many practical reasons, including thermal, energy, light and aesthetics. Nevertheless, due to the relatively low tensile strength and mostly brittle behaviour of glass, compared to other traditional materials, as well as to a multitude of interacting structural and non-structural components, windows/facades are one of the most fragile and vulnerable components of buildings, being representative of the physical line of separation between interior and exterior spaces. As such, multidisciplinary approaches, as well as specific fail-safe design criteria and analysis methods are required, especially under extreme loading conditions, so that casualties and injuries in the event of failure could be avoided and appropriate safety levels could be guaranteed. In this context, this paper presents a review of the state of art on analysis and design methods in use for glass facades, with careful consideration for extreme loading configurations, including natural events, such as seismic events, extreme wind or other climatic exposures, and man-made threats, i.e. blast loads and fire. Major results of available experimental outcomes, current issues and trends are also reported, summarising still open challenges.
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| 9. |
- Bedon, Chiara, et al.
(author)
-
Special issue on "buildings and structures under extreme loads"
- 2020
-
In: Applied Sciences. - : MDPI AG. - 2076-3417. ; 10:16
-
Journal article (peer-reviewed)abstract
- Exceptional loads on buildings and structures may have different causes, including high-strain dynamic effects due to natural hazards, man-made attacks, and accidents, as well as extreme operational conditions (severe temperature variations, humidity, etc.). All these aspects can be critical for specific structural typologies and/or materials that are particularly sensitive to unfavorable external conditions. In this regard, dedicated and refined methods are required for their design, analysis, and maintenance under the expected lifetime. However, major challenges are usually related to the structural typology and materials object of study, with respect to the key features of the imposed design loads. Further issues can be derived from the need for the mitigation of adverse effects or retrofit of existing structures, as well as from the optimal and safe design of innovative materials/systems. Finally, in some cases, no appropriate design recommendations are currently available in support of practitioners, and thus experimental investigations (both on-site or on laboratory prototypes) can have a key role within the overall structural design and assessment process. This Special Issue presents 19 original research studies and two review papers dealing with the structural performance of buildings and structures under exceptional loads, and can represent a useful answer to the above-mentioned problems.
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| 10. |
- Bedon, Chiara, et al.
(author)
-
Structural characterisation of adaptive facades in Europe – Part I : Insight on classification rules, performance metrics and design methods
- 2019
-
In: Journal of Building Engineering. - : Elsevier BV. - 2352-7102. ; 25
-
Journal article (peer-reviewed)abstract
- Adaptive facades are increasingly used in modern buildings, where they can take the form of complex systems and manifest their adaptivity in several ways. Adaptive envelopes must meet the requirements defined by structural considerations, which include structural safety, serviceability, durability, robustness and fire safety. For these novel skins, based on innovative design solutions, experimentation at the component and / or assembly level is required to prove that these requirements are fulfilled. The definition of appropriate metrics is hence also recommended. A more complex combination of material-related, kinematic, geometrical and mechanical aspects should in fact be properly taken into account, compared to traditional, static facades. Accordingly, specific experimental methods and regulations are required for these novel skins. As an outcome of the European COST Action TU1403 ‘Adaptive facades network’ - ‘Structural’ Task Group, this paper collects some recent examples and design concepts of adaptive systems, specifically including a new classification proposal and the definition of some possible metrics for their structural performance assessment. The aim is to provide a robust background and detailed state-of-the-art information for these novel structural systems, towards the development of standardised and reliable procedures for their mechanical and thermo-physical characterisation.
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| 11. |
- Bedon, Chiara, et al.
(author)
-
Structural characterisation of adaptive facades in Europe - Part II : Validity of conventional experimental testing methods and key issues
- 2019
-
In: Journal of Building Engineering. - : Elsevier Ltd. - 2352-7102. ; 25
-
Journal article (peer-reviewed)abstract
- Given their intrinsic features, adaptive facades are required to satisfy rigid structural performances, in addition to typical insulation, thermal and energy requirements. These include a minimum of safety and serviceability levels under ordinary design loads, durability, robustness, fire resistance, capacity to sustain severe seismic events or other natural hazards, etc. The overall design process of adaptive facades may include further challenges and uncertainties especially in the case of complex assemblies, where multiple combinations of material-related phenomena, kinematic effects, geometrical and mechanical characteristics could take place. In this context, experimental testing at the component and/or at the full-scale assembly level has a fundamental role, to prove that all the expected performance parameters are properly fulfilled. Several standards and guideline documents are available in the literature, and provide recommendations and procedures in support of conventional testing approaches for the certification and performance assessment of facades. These documents, however, are specifically focused on ordinary, static envelopes, and no provisions are given for the experimental testing of dynamic, adaptive skins. In this regard, it is hence expected that a minimum of conventional experimental procedures may be directly extended from static to dynamic facades. However, the validity of standardized procedures for adaptive skins is still an open issue. Novel and specific experimental approaches are then necessarily required, to assess the structural characteristics of adaptive facades, depending on their properties and on the design detailing. In this paper, existing fundamental standards for testing traditional facades are first recalled and commented. Special care is spent for the validity and reliability of conventional testing methods for innovative, adaptive envelopes, including a discussion on selected experimental methods for facade components and systems. Non-conventional testing procedures which may be useful for adaptive skins are then also discussed in the paper, as resulting from the research efforts of the European COST Action TU1403 ‘Adaptive facades network’ - ‘Structural’ Task Group.
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| 12. |
- Bedon, Chiara, et al.
(author)
-
Thermal assessment of glass façade panels under radiant heating : Experimental and preliminary numerical studies
- 2018
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In: Journal of Facade Design and Engineering. - 2213-302X. ; 6:3, s. 049-064
-
Journal article (peer-reviewed)abstract
- Nowadays, glass is increasingly being used as a load-bearing material for structural components in buildings and façades. Different structural member solutions (such as panels, beams, columns) and loading conditions were the subjects of several research studies in recent years. Most of them, however, were typically limited to experimental testing and numerical simulations on glass elements and assemblies at room temperature. Thermo-mechanical investigations, inclusive of the temperature-dependent behaviour of visco-elastic interlayers used in laminated glass solutions, as well as the typical thermo-mechanical degradation of glass properties in line with temperature increase, in this regard, are still limited. Such an aspect can be particularly important for adaptive façades, in which the continuous variation of thermal and mechanical boundary conditions should be properly taken into account at all the design stages, as well as during the lifetime of a constructed facility. Given the key role that thermo-mechanical studies of glazing systems can pe use of glass in façades, this paper focuses on Finite Element (FE) numerical modelling of monolithic and laminated glass panels exposed to radiant heating, by taking advantage of past experimental investigations. In the study discussed herein, being representative of some major outcomes of a more extended research project, one-dimensional (1D) FE models are used to reproduce the thermal behaviour of selected glass specimens under radiant heating, as observed in the past experiments. Given the high computational efficiency but very basic assumptions of 1D assemblies, a critical discussion of experimental-to-numerical comparisons is then proposed for a selection of specimens.
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| 13. |
- Björnsson, Ivar, et al.
(author)
-
Decision support framework for bridge condition assessments
- 2019
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In: Structural Safety. - : Elsevier BV. - 0167-4730 .- 1879-3355. ; 81
-
Journal article (peer-reviewed)abstract
- An essential aspect in the maintenance of existing bridges is the ability to adequately and accurately assess and evaluate the condition of the structure. Condition assessments, which can be carried out in any number of ways, provide valuable information concerning the actual state of a bridge, including the severity of potential damages, and form the basis for further maintenance decisions. Any decision support concerning the management of existing structures thus requires attention towards the uncertainties associated with the assessment methods when applied in practice as well as the maintenance actions these support. These uncertainties cannot be solely described as model uncertainties but are also a result of the variation in engineering performance observed in practice. In the current paper a rational and systematic framework is presented which provides practical decision support concerning whether condition assessments are necessary, what assessment methods are recommended, if invasive actions are needed, or if some other non-invasive option may be more appropriate. The framework takes into account three main attributes of an enhanced condition assessment, namely, modelling sophistication, considerations of uncertainties and risks, and knowledge/information content. Increasing the level of one or more of these attributes may be advantageous only if the expected benefits or added value of information is considered appropriate in relation to the cost of implementation in practice. A decision making model, based on Bayesian decision theory, is adopted to evaluate this problem. Two case studies, in which the framework is applied, are provided for illustrative purposes; the first is a generic numerical example and the second a decision scenario related to the fatigue assessment of an existing railway bridge.
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| 14. |
- Björnsson, Ivar, et al.
(author)
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Suitable degree of crudeness in engineering practice
- 2019
-
In: IABSE Symposium, Guimaraes 2019. - : International Association for Bridge and Structural Engineering (IABSE). - 9783857481635 ; , s. 1592-1599
-
Conference paper (peer-reviewed)abstract
- Practicing structural engineers may be familiar with the main principles of structural reliability but may not necessarily be experts in using such methods. This may lead to a lack in understanding the effect of uncertainties on the ensuing structural safety and to sub-optimization of more traditional structural engineering aspects. The aim of the current paper is to highlight the importance of considering risks and uncertainties in design and to improve the awareness of practicing engineers to such considerations. The importance of a consistent treatment of uncertainties in structural engineering is brought to attention with focus on the modelling approaches which often underlie decisions. Different aspects discussed are: decision making in light of uncertainty, principles of consistent crudeness and the influence of engineering performance in practice on the safety of structures. A simplified model, considering strategies for improving engineering models, is considered and examples, based on simplified decision models, are also provided.
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| 15. |
- Blomfors, Mattias, 1990, et al.
(author)
-
Engineering Assessment Method for Anchorage in Corroded Reinforced Concrete
- 2016
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In: IABSE Congress Stockholm 2016. - : IABSE c/o ETH Hönggerberg. - 9783857481444 ; , s. 2109-2116
-
Conference paper (peer-reviewed)abstract
- There is an increasing need for reliable methods to assess load-carrying capacity and remaining service life of existing infrastructure. Several previous research projects have resulted in a verified, simple 1D model for assessment of anchorage in corroded reinforced concrete structures. Previous verification has involved both experiments and detailed 3D NLFE analyses. To further develop the 1D model it needs to be extended to comprise more practical situations. In order to facilitate an efficient extension procedure in the future, the size of 3D NLFE model that is required to capture the bond behaviour between corroded reinforcement and concrete is investigated. Beam-end models and models of sub-sections were studied, and the results in terms of bond stress and crack pattern were compared. Preliminary results indicate good agreement for some situations; however for some cases a section model seems to overestimate the capacity.
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| 16. |
- Blomfors, Mattias, 1990, et al.
(author)
-
Partial safety factors for the anchorage capacity of corroded reinforcement bars in concrete
- 2019
-
In: Engineering structures. - : Elsevier BV. - 0141-0296 .- 1873-7323. ; 181, s. 579-588
-
Journal article (peer-reviewed)abstract
- Many reinforced concrete bridges in Europe and around the world are damaged by reinforcement corrosion and the annual maintenance costs are enormous. It is therefore important to develop reliable methods to assess the structural capacity of corroded reinforced concrete structures and avoid unnecessary maintenance costs. Although there are advanced models for determining the load carrying capacity of structures, it is not obvious how they should be used to verify the performance of existing structures. To confidently assess the bond of corroded reinforcement in concrete, for example, the calculation model must give a sufficient safety margin. When designing new structures, semi-probabilistic approaches (such as the partial safety factor method) are adopted to achieve the target reliabilities specified in structural design codes. This paper uses probabilistic methods to develop partial factors for application in an existing bond model, to assess the safety of corroded reinforced concrete structures. The response of the bond model was studied using Monte Carlo (MC) simulations for several design cases, with probability distributions fitted to the results. Partial factors were then derived, based on these distributions. Furthermore, an MC-based simulation technique called “importance sampling” was used to study the reliability of several deterministic bond assessments conducted using these partial factors. The results show that deterministic assessments which use the proposed partial factors lead to a safety level at least equal to the target value. The results presented in this paper will support the assessment of reinforced concrete structures with anchorage problems and give a reasonable approximation of the anchorage capacity with sufficient safety margin. When generalised to cover other failure modes and structural configurations, this will enable better utilisation of damaged structures and lead to major environmental and economical savings for society.
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| 17. |
- Blomfors, Mattias, 1990, et al.
(author)
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Practical bond model for corroded RC bridges
- 2017
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In: High Tech Concrete. - Cham : Springer International Publishing. - 2617-4820. - 9783319594705 ; , s. 1793-1803
-
Conference paper (peer-reviewed)abstract
- Corrosion of steel reinforcement is a common cause of deterioration in reinforced concrete bridges and many existing bridges are damaged to varying degrees. The rate of deterioration of the bridge stock has been shown to increase due to climate change. Unsympathetically, the demand for load-carrying capacity is however often increased with time. Therefore there is an increasing need for reliable methods to assess the load-carrying capacity and remaining service-life of existing infrastructure. A simple model for the assessment of Anchorage in corroded Reinforced Concrete structures (ARC) has previously been developed. It was originally based on fib Model Code 1990 and has been verified with experiments and three-dimensional nonlinear finite element (3D NLFE) analyses for both accelerated and natural corrosion as well as for different degrees of corrosion. The model was applied when assessing two road bridges in Sweden. The investigation demonstrated great cost savings but also areas for improvement, in particular regarding (a) applicability to practical cases and (b) incorporation of uncertainties in the assessment. The primary focal point of this paper is to present an overview of the development of the ARC model together with recent verifications against a large bond test database as well as foreseen future developments. It was found that the ARC model represents the physical behaviour reasonably well, and gives conservative values of bond strength compared to the bond tests database. In future works, among others, uncertainties of the input variables will be incorporated by means of probabilistic modelling, making way for implementation of the ARC model into semi-probabilistic safety concepts by extraction of modification factors. Overall, with more accurate and reliable assessment methods for corroded RC structures, environmental and economic savings are imminent as more of the potential of existing structures can be realized.
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| 18. |
- Blomfors, Martin, et al.
(author)
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Reliability analysis of corroded reinforced concrete beam with regards to anchorage failure
- 2019
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In: Life-Cycle Analysis and Assessment in Civil Engineering. - : CRC Press/Balkema. - 9781138626331 - 9781351857574 ; , s. 337-344, s. 337-344
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Conference paper (peer-reviewed)abstract
- Reinforcement corrosion is a common problem in reinforced concrete infrastructure today, and it is expected to increase in the future. To simply replace the corroded structures with new ones requires large resources, both in financial and environmental terms. Therefore it is important that existing structures are used to their full potential, also after the onset of corrosion. This paper presents a reliability study of the anchorage capacity of a reinforced concrete beam including reinforcement corrosion. The sensitivity of the different input parameters is also studied. As expected, the results show that the reliability is reduced with corrosion; the magnitude depends to a large extent on the modelling uncertainty used for the bond model for corroded reinforcement. The sensitivity analysis shows an influence of corrosion also on the sensitivities of the input parameters, which is expected based on the properties of the underlying bond model. This paper demonstrates that probabilistic evaluations give valuable insight of the reliability, which can be used to prolong the service-life of existing infrastructure and save both money and the environment.
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| 19. |
- Blomfors, Mattias, 1990, et al.
(author)
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Reliable engineering assessments of corroded concrete structures
- 2017
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In: Nordic Concrete Research : Proceedings of the XXIII Nordic Concrete Research Symposium, Aalborg, Denmark, 21-23 August, 2017 - Proceedings of the XXIII Nordic Concrete Research Symposium, Aalborg, Denmark, 21-23 August, 2017. ; , s. 245-248
-
Conference paper (peer-reviewed)abstract
- Corrosion of steel reinforcement is a large and increasing problem for reinforced concrete structures. Simple and reliable assessment methods are required to use the full capacity of existing infrastructure. In this paper, a reliable engineering assessment method is outlined. A model for anchorage has been developed and verified against a large database of bond tests. Also the influence of corrosion on the bending and shear capacity is to be included, and a probabilistic model will be established. The outcome of this work will enable practising engineers to perform reliable assessments of concrete structures with corroded reinforcement.
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| 20. |
- Blomqvist, Lars, 1962-, et al.
(author)
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Development of novel structural connections - Inspiration from furniture industry
- 2021
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In: World Conference on Timber Engineering 2021, WCTE 2021. - Santiago, Chile : World Conference on Timber Engineering (WCTE).
-
Conference paper (peer-reviewed)abstract
- The presented project aims to develop prototypes for building connections inspired by the furniture and interior industry and explore them with representatives from the timber construction industry. The long-term vision is that actors from furniture and building industry together develop a smart system for assembly of building elements, which provide higher precision, faster and more efficient assembly than what is available today. The prototype connection developed in this project shows that the idea is ripe for full-scale investigation. Laboratory tests showed promising results due to the high failure loads obtained with very high stiffness.
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| 21. |
- Blomqvist, Lars, 1962-, et al.
(author)
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Spin-off från möbelindustrin till byggbranschen
- 2019
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Reports (other academic/artistic)abstract
- There is a deficit of housing in Sweden and it is built too little to compensate for this according to the National Board of Housing, Building and Planning, which, among other things, indicate resource shortages as a reason.The furniture and construction industry have much in common. However, the furniture industry has a larger share of industrial production, which means production at a lower cost. By retrieving production ideas in other industries, there is an opportunity to radically renew and transform the (wood) construction industry and thus streamline the construction process. Historically, cross-sectoral spin-off effects have been shown to generate success factors.The goal of this project is to develop prototypes for building connections inspired by the furniture and interior industry and explore them together with industry actors. This, in turn, serves as an inspiration for a larger project, together with industry actors aiming at developing systems for assembly of building elements, which provide higher precision and are faster to perform than today's system. The pilot developed in this project shows that the idea is ripe for a more full-scale investigation.
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| 22. |
- Cabrero, Jose Manuel, et al.
(author)
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A probabilistic study of brittle failure in dowel-type timber connections with steel plates loaded parallel to the grain
- 2019
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In: Wood Material Science and Engineering. - : Informa UK Limited. - 1748-0272 .- 1748-0280. ; 14:5, s. 298-311
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Journal article (peer-reviewed)abstract
- Dowel-type connections in timber structures should be typically designed in a way that, if the load bearing capacity is exceeded, desirable ductile failure should likely occur, i.e. yielding of the metal dowel or embedment of the timber. However, the probability of brittle failures cannot be completely avoided in many cases. If the connection is loaded parallel to the grain direction, splitting, row-shear, plug/block shear and tensile failure are examples of such brittle failure modes. To ensure a beneficial structural performance locally and sufficient structural robustness globally, the probability of such brittle failures should be kept at a sufficiently low level. However, in the current version of EN1995, the probability of such failure is not considered explicitly. The final aim of the presented research study is to develop a rational approach for the consideration of brittle failure in timber connections with dowel-type fasteners and steel plates loaded parallel to the grain, consistently with the partial factor method. As a first step, a probabilistic model has been used to study the susceptibility to brittle failure and provide a rational basis for the calibration of a “brittle overstrength factor”. The results of this study are reported in the current contribution.
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| 23. |
- Debuyser, Michael, et al.
(author)
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Behaviour of monolithic and laminated glass exposed to radiant heating
- 2017
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In: Construction and Building Materials. - : Elsevier BV. - 0950-0618 .- 1879-0526. ; 130, s. 212-229
-
Journal article (peer-reviewed)abstract
- Glass is seeing a growing interest as a structural material as a result of its relatively good strength to weight ratio and the obvious aesthetic benefits of its use in buildings. However due to the sensitivity of glass to thermal shock and the considerably temperature-dependent behaviour of interlayer materials as a result of their visco-elastic nature, the mechanical behaviour of laminated glass will be severely influenced by exposure to fire. Relatively little research has been conducted in the past to study the response of load bearing structural glass, and laminated glass in particular to radiant heating. This paper represents an effort to try to understand the effects of through depth radiation absorption and temperature conduction through laminated glass with a view to ultimately developing a model for studying load bearing glass exposed to elevated temperatures, such as those that would be expected in a fire. The paper reports on an experimental research programme in which several monolithic and laminated glass configurations were exposed to a radiant heat flux to study the different phenomena that occur upon exposure to fire conditions, including the ratios of absorbed, transmitted and reflected heat flux to the incident heat flux. The paper then presents a numerical heat transfer model which is developed based on these experimental results and that is able to determine the evolution of the temperature profile as a result of a given incident heat flux. The effectiveness of the heat transfer model is demonstrated through comparison with the temperatures measured during the experimental work.
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| 24. |
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| 25. |
- Fjellgaard Mikalsen, Ragni, et al.
(author)
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Efficient emergency responses to vehicle collision, earthquake, snowfall, and flooding on highways and bridges : A review
- 2020
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In: Journal of Emergency Management. - : NLM (Medline). - 1543-5865. ; 18:1, s. 51-72
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Journal article (peer-reviewed)abstract
- This review article analyzes factors affecting emergency response to hazardous events on highways and their bridges, with focus on man-made and natural scenarios: heavy vehicle collision with a bridge, earthquake, heavy snowfall, and flooding. For each disaster scenario, selected historical events were compiled to determine influential factors and success criteria for efficient emergency response, both related to organizational and technical measures. This study constituted a part of a resilience management process, recently developed and demonstrated within the European Union (EU)-funded H2020 project IMPROVER and can be a useful approach in aiding operators of transportation infrastructure to improve their resilience to emergency incidents.
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| 26. |
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| 27. |
- Honfi, Daniel, et al.
(author)
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A practical approach for supporting decisions in bridge condition assessment and monitoring
- 2019
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In: 20th Congress of IABSE, New York City 2019. - : International Association for Bridge and Structural Engineering (IABSE). - 9783857481659 ; , s. 2137-2142, s. 2137-2142
-
Conference paper (peer-reviewed)abstract
- In this contribution a practical and rational decision-making approach is presented to be applied for common bridges typically managed by public authorities. The authors have developed a model with the intention to be applicable for practical cases for common bridges in the daily work of bride operators responsible for a large number of assets, yet still maintain the principles of more generic frameworks based on probabilistic decision-theory. Three main attributes of the verification of sufficiency of structural performance are considered, namely: 1) the level of sophistication of modelling performance, 2) the degree of verification and acceptance criteria in terms of dealing with uncertainties and consequences, 3) the extent of information is obtained and incorporated in the verification. The simplicity of the approach is demonstrated through an illustrative case study inspired by practical condition assessment decision problems. It is argued that in practical cases it may be desirable to utilize less advanced methods owing to constraints in resources or lack of reliable data (e.g. based on structural health monitoring or other on-site measurement techniques).
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| 28. |
- Honfi, Daniel, et al.
(author)
-
Behavior of load-bearing glass at elevated temperature
- 2018
-
In: ce/papers. - : Wiley. - 2509-7075. ; 2:5-6, s. 533-540
-
Journal article (peer-reviewed)abstract
- ABSTRACT The use of glass as a structural material has increased in the built environment over the last decades. Despite the large number of research projects and studies, it still poses difficulties in structural design. This particularly applies to the behaviour of glass in fire and under elevated temperatures since the available data on temperature dependent mechanical and thermal properties of glass is still limited. This contribution provides a brief overview of material properties of glass at elevated temperature and elaborates on current requirements for the fire safety included in standards.
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| 29. |
- Honfi, Daniel, et al.
(author)
-
Decision support for bridge condition assessment
- 2017
-
In: SMAR 2017 Proceedings.
-
Conference paper (peer-reviewed)abstract
- The paper presents the first steps of the development of a theoretical framework for a rational yet practical decision making process concerning the condition assessment of existing bridges in Sweden. The main focus is on how to choose the appropriate level of enhanced conditions assessment considering aspects of model sophistication, uncertainty consideration and knowledge content utilisation. A conceptual case study is presented exemplifying how the framework can be used to structure the assessment actions of a steel bridge subjected to fatigue deterioration.
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| 30. |
- Honfi, Daniel, et al.
(author)
-
Decision support for maintenance and upgrading of existing bridges
- 2017
-
In: IABSE Conference, Vancouver 2017. - : International Association for Bridge and Structural Engineering (IABSE). - 9783857481536 ; , s. 336-345, s. 336-345
-
Conference paper (peer-reviewed)abstract
- Maintenance of transportation infrastructure assets can be relatively expensive, since it does not only include the direct cost of interventions, but also the indirect consequences of traffic disruptions. To make optimal decisions about maintenance actions, including rehabilitation and upgrading, reliable information about the performance of existing structures is needed. However, obtaining such information might require significant efforts and can be done in various ways. The purpose of an ongoing Swedish research project BIG BRO is to develop a framework for a decision support methodology that can be used for implementing maintenance strategies for bridges on a rational basis. The present paper provides a brief overview about the project as well as describes some of the ongoing work.
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| 31. |
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| 32. |
- Honfi, Daniel
(author)
-
Design for Serviceability - A probabilistic approach
- 2013
-
Doctoral thesis (other academic/artistic)abstract
- In many design situations the acceptable performance of structures is defined by serviceability requirements. To estimate the probability of serviceability failure three main design aspects should be considered: (1) the relevant exposures, (2) the structural response and (3) the performance criteria. This thesis presents background information and new findings on structural serviceability related to all three aforementioned aspects. To study current practice concerning serviceability design two surveys with experts are presented: (1) serviceability issues in present Swedish design practice and (2) research interviews with international experts working with glass structures. The main conclusion of the two surveys is the general need for better understanding and guidance about serviceability, both in education and design codes. Since load history and long-term deformations may have a large influence on serviceability, an advanced finite element model has been developed to estimate the deflections of structural sized timber beams in natural environment. The model is capable to take into account the combined effect of the variations of relative humidity in the surrounding environment and the time-variant mechanical loading. Based on the results of the model, possibilities of simplified modelling are investigated to predict long-term deflections of timber structures. The reliability of serviceability limit states in current design codes is investigated mainly focusing on static deflections. Simple models are used to compare various construction materials – steel, concrete and timer – in terms of serviceability reliability, based on design according to Eurocode prescriptions using second order reliability methods. It is shown that the reliability of Eurocodes is not consistent. The inconsistency exists among different materials, variable to total load ratios and loaded areas. The proposed method may provide a basis for code calibration with regard to serviceability. As a final step the time-dependent reliability for serviceability design for beams is estimated using Monte Carlo simulation. The study presented in the time-variant analysis is restricted to timber floor beams in offices and residential buildings. However, the presented method provides a framework to calibrate proper deflection limits, load factors and creep coefficients based on a probabilistic investigation involving uncertainties in all important aspects of structural serviceability.
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| 33. |
- Honfi, Daniel, et al.
(author)
-
Experimental and Numerical Analysis of Thermo-Mechanical Behaviour of Glass Panes Exposed to Radiant Heating
- 2022
-
In: Fire. - : MDPI. - 2571-6255. ; 5:4
-
Journal article (peer-reviewed)abstract
- Despite much research and applications, glass material and its use in buildings is still challenging for engineers due to its inherent brittleness and characteristic features such as sensitivity to stress concentrations, reduction in strength over time and from temperature, and breakage due to the stresses that may build up because of thermal gradients. This paper presents the results of an original test series carried out on monolithic glass panes with the dimensions of 500 × 500 mm2 and different thicknesses, under the exposure to radiant heating. The research study also includes a one-dimensional (1D) heat transfer model and a numerical, three-dimensional (3D) thermo-mechanical model that are used to investigate in greater detail the phenomena observed during the experiments. As shown, the behaviour of glass under radiant heating is rather complex and confirms the high vulnerability of this material for building applications. The usability and potential of thermo-mechanical numerical models is discussed towards experimental feedback. © 2022 by the authors.
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| 34. |
- Honfi, Daniel, et al.
(author)
-
Glass structures – learning from experts
- 2013
-
In: COST Action TU0905, Mid-term Conference on Structural Glass. - : CRC Press. - 9781138000445 ; , s. 527-535
-
Conference paper (peer-reviewed)abstract
- Despite the increasing research activity on structural use of glass in the past years, there is still a lack of comprehensive design codes and standards linked to real-life applications on a structural level. However, more and more ambitious buildings and structures are built every year. Thus the knowledge is out there. The aim of the presented project is to collect data on the existing design philosophy and glass failure cases. The investigation includes a survey about how practicing structural engineers deal with different design aspects of glass with a special focus on robustness and serviceability. The current document gives a brief overview about the findings of the interviews
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| 35. |
- Honfi, Daniel, et al.
(author)
-
Informed successive condition assessments in bridge maintenance
- 2020
-
In: Journal of Civil Structural Health Monitoring. - : Springer. - 2190-5452 .- 2190-5479. ; 10:4, s. 729-737
-
Journal article (peer-reviewed)abstract
- The condition assessment of bridges considers a combination of information from different sources rendering multiple levels of assessment possible. This paper illustrates how successive condition assessment strategies increase the expected utility compared to single choice decisions through Bayesian inference. Multiple levels of assessment allow for additional possibilities for obtaining structural health information and updating one's beliefs about structural condition. Thus, more informed decision-making is possible with respect to the gain in accuracy versus the costs of the assessment options. The paper aims to introduce how the successive approach can be implemented and in which scenarios it provides an increase in expected utility in comparison to one instant decision. To highlight this, a few pedagogical numerical examples are provided.
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| 36. |
- Honfi, Daniel, et al.
(author)
-
Inspection and monitoring of bridges in Sweden
- 2018
-
Reports (other academic/artistic)abstract
- This report provides an overview about recent research activities and current practice concerning inspection and monitoring of the structural performance of bridges and the related decision-making process. A brief review of common methods of collecting information on structural performance of bridges is presented, followed by a description of the use of the information collected in structural analysis and maintenance planning. An overview about the state of the art is given including recent scientific developments. Finally, the current Swedish practice for bridge management is presented.
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| 37. |
- Honfi, Daniel, et al.
(author)
-
Modelling of bending creep of low- and high-temperature-dried spruce timber
- 2013
-
In: Wood Science and Technology. - : Springer Science and Business Media LLC. - 1432-5225 .- 0043-7719.
-
Journal article (peer-reviewed)abstract
- In the current project, a finite element model is developed to analyse the long-term behaviour of timber beams. The time-dependent response of wood subjected to bending and moisture changes is investigated in terms of strains and stresses. A rheological model is implemented to capture the effects of creep, mechano-sorption and hygroexpansion. The model is validated against test results from Bengtsson and Kliger (Holzforschung 57:95–100, 2003). The results of the analysis showed that the mechano-sorptive creep of low- (LT) and high-temperature-dried (HT) timber beams can be sufficiently modelled with a spring and a single Kelvin body. The different mechano-sorptive behaviour of LT- and HT-dried specimens is considered with different mechano-sorptive and shrinkage–swelling parameters. The presented model could be used to derive general mechano-sorptive parameters: (1) for better prediction of creep over the service life and (2) to provide a basis of time-dependent probabilistic calculations for structural-sized timber in serviceability limit state.
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| 38. |
- Honfi, Daniel, et al.
(author)
-
On the contribution of technological concepts to the resilience of bridges as critical infrastructure assets
- 2016
-
In: IABSE Congress Stockholm 2016. - 9783857481444 ; , s. 975-982
-
Conference paper (peer-reviewed)abstract
- The current paper reports about the progress in the ongoing European project IMPROVER (Improved risk evaluation and implementation of resilience concepts to critical infrastructure), in which a fundamental part is devoted to technological resilience concepts. Within the project a general methodology for resilience evaluation is developed, in which existing concepts in the field of structural engineering are aligned with non-technological domains (e.g. organizational and societal) contributing to resilience. A shift from protection to enhancing resilience leads to a shift in focus from traditional risk management towards crisis management. Some of these issues are exemplified here with the application on bridges as critical infrastructures.
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| 39. |
- Honfi, Daniel
(author)
-
Practical considerations in utilizing structural health information in bridge maintenance
- 2019
-
In: Structural Health Monitoring 2019. - : DEStech Publications Inc.. - 9781605956015 ; , s. 1533-1540
-
Conference paper (peer-reviewed)abstract
- The paper presents two illustrative examples about the utilization of structural health information for rational decision making in everyday bridge management. It is suggested that Bayesian decision analysis could be useful even in sample cases to help efficiently use specific and generic information about structural condition. However, there are some challenges concerning practical application.
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| 40. |
- Honfi, Daniel, et al.
(author)
-
Rational maintenance of timber bridges
- 2017
-
In: Conference proceedings, ICTB 2017. 3rd International Conference on Timber Bridges.
-
Conference paper (peer-reviewed)abstract
- The present paper provides some ideas about how decisions concerning maintenance of timber bridges should be made in a rational way. First, a brief discussion is provided concerning the evolution of maintenance strategies in general and it is suggested that maintenance of timber bridges should follow a risk-based approach. Then the discussion moves on to the condition assessment of timber bridges with a main focus on inspection and monitoring. The use of non-destructive testing methods and structural health monitoring is highlighted with regard to collecting useful information for maintenance decisions. It is argued that the information collected, should be used in a Bayesian decision analysis framework, which is especially useful in quantifying to value of information and thus the worth of various inspection and monitoring alternatives.
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| 41. |
- Honfi, Daniel, et al.
(author)
-
Reliability of beams according to Eurocodes in serviceability limit state
- 2012
-
In: Engineering Structures. - : Elsevier BV. - 1873-7323 .- 0141-0296. ; 35, s. 48-54
-
Journal article (peer-reviewed)abstract
- To achieve a relatively consistent probability of failure for structural elements, most design codes apply reliability based code calibration process. Such approaches commonly focus on the strength of the structural members, which is related to the ultimate limit state (ULS). However in the design of beams the performance of the structural elements is often limited by the serviceability requirements, which are related to the serviceability limit state (SLS) using different load combinations than applied in the ultimate limit state. The current study aims to investigate the reliability for serviceability design for flexural members made of different materials (steel, concrete and timber) according to the specifications of the Eurocodes. Second-order reliability method (SORM) is applied to determine the reliability index for different design situations for beams subjected to bending. The probabilistic models of basic variables for time invariant analysis have been taken from the JCSS Probabilistic Model Code. The characteristic, the frequent and the quasi-permanent combination of actions are investigated and compared. The differences in service reliability for different materials are discussed. The results show that there are differences between the achieved reliability indices in the serviceability state between different materials and that for the given load combinations in the Eurocode the reliability index is often below the one given in the code. (C) 2011 Elsevier Ltd. All rights reserved.
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| 42. |
- Honfi, Daniel, et al.
(author)
-
Reliability of steel flexural members according to EC in serviceability limit state
- 2009
-
In: Proceedings of 11th Nordic Steel Construction Conference. - 9171270582 ; , s. 446-453
-
Conference paper (peer-reviewed)abstract
- To achieve a relatively consistent probability of failure for structural elements, most design codes apply reliability based code calibration process. Such approaches commonly focus on the ultimate strength of the structural members, which is related to the ultimate limit state (ULS). In the design of steel beams the performance of the structural elements is often limited by the serviceability requirements, which are related to the serviceability limit state (SLS) using different load combinations than those applied in the ultimate limit state. The current study aims to investigate the reliability for serviceability design for flexural steel members according to the specifications of the Eurocode. Second-order reliability method (SORM) is applied to determine the reliability index for different load ratios.
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| 43. |
- Honfi, Daniel
(author)
-
Serviceability floor loads
- 2014
-
In: Structural Safety. - : Elsevier BV. - 0167-4730. ; 50, s. 27-38
-
Journal article (peer-reviewed)abstract
- Serviceability of structures has to be verified for a lower load level than the design load used for safety considerations. Representative values of actions used in serviceability load combinations are often defined in a way that the fraction of time spent above a given load level should be limited to a certain value. To determine these load levels more information on the stochastic nature of the loading process is needed than to estimate the design load. A convenient way in structural design codes is to express representative values (rare, frequent and quasi-permanent) as a fraction of the characteristic value by using load reduction factors. However, the characteristic value is usually defined in a different way i.e. with a certain probability of not being exceeded (in a chosen period of time). The current paper estimates representative values of floor live loads by numerical simulation using stochastic live load models with a special focus on serviceability. The results are compared to values given in existing standards (Eurocode on first place). Improvements are suggested concerning the load reduction factors, the definitions of the representative values and the stochastic load parameters. (C) 2014 Elsevier Ltd. All rights reserved.
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| 44. |
- Honfi, Daniel, et al.
(author)
-
Structural reliability according to Eurocodes in serviceability limit state
- 2011
-
In: IABSE-IASS 2011 London Symposium Report. - 9780707971223
-
Conference paper (peer-reviewed)abstract
- The current study aims to investigate the reliability for serviceability design for flexural members made of different materials (steel, concrete and timber) according to the specifications of the current versions of Eurocodes. Second-order reliability method is applied to determine the reliability index for different design situations for simply supported beams subjected to bending. The characteristic, the frequent and the quasi-permanent combination of actions has been investigated and compared. The differences in service reliability for different materials have been discussed.
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| 45. |
- Honfi, Daniel
(author)
-
Time-variant reliability of timber beams according to Eurocodes considering long-term deflections
- 2019
-
In: Wood Material Science & Engineering. - : Informa UK Limited. - 1748-0272 .- 1748-0280. ; 26:3, s. 167-178
-
Journal article (peer-reviewed)abstract
- In order to achieve a consistent level of failure probability, structural design codes are optimized using probabilistic methods. This optimization process traditionally focuses on the ultimate limit states (ULS). However, in the design of timber structures the performance of the structural members is often governed by the serviceability limit state (SLS) associated with different load levels than applied in the ULS. The probability of serviceability failure is strongly dependent on the loading sequence and the time-dependent response of timber; therefore, a time-variant probabilistic model is recommended to estimate them properly. This study aims to investigate the time-dependent reliability for long-term deflections of timber office and residential floor beams according to the specifications of the Eurocodes. A simple creep model is used to calculate the deflections and Monte Carlo simulation is carried out to determine the reliability index. It was found that the creep factor and the suggested deflection limits given in Eurocode 5 might not be appropriate to achieve the expected target reliabilities. To obtain a more consistent reliability, more suitable values for the mentioned parameters were suggested. However, the primary aim was to present a framework to determine appropriate deflection limits for structural codes.
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| 46. |
- Honfi, Daniel
(author)
-
Ultimate and serviceability limit state optimization of cold-formed steel hat-shaped beams
- 2009
-
In: Proceedings of 11th Nordic Steel Construction Conference. - 9171270582 ; , s. 510-515
-
Conference paper (peer-reviewed)abstract
- Cold-formed steel hat-shaped beams are commonly used in light-weight steel construction systems, such as residential housing structures. The ultimate strength of these sections is affected by their complex stability behavior (e.g. local, distortional and global buckling), therefore an advanced design methodology is needed to calculate the load bearing resistance in the ultimate limit state. On the other hand the limiting requirements in the design of such structural elements are often the serviceability provisions of the applied design code, which are investigated under the serviceability limit state load conditions. The aim of the present study is to find the optimal cross-sectional dimensions for cold-formed steel hat-profiles with various supporting conditions according to the Eurocode.
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| 47. |
-
IMPROVER D2.2 Report of criteria for evaluating resilience
- 2016
-
Reports (other academic/artistic)abstract
- In the recent years, the focus has moved from critical infrastructure protection to that of resilience. But how do we know whether a critical infrastructure is resilient or not, how can it be evaluated, measured and enhanced? Drawing on, combining and developing the ideas of the existing literature and practices, the current report develops a holistic, easy-to-use and computable methodology to evaluate critical infrastructure resilience, called Critical Infrastructure Resilience Index (CIRI). The methodology is applicable to all types of critical infrastructure, including a possibility to tailor it to the specific needs of different sectors, facilities and hazard scenarios. The proposed methodology is especially suitable for organizational and technological resilience evaluation, but permits including also elements of societal resilience indicators to the evaluations. The methodology is based on four levels of hierarchically organized indicators. Level 1 consists of the phases well known from the so-called crisis management cycle. Under these phases, we find sets of Level 2 rather generic indicators. Thus under level 1 ‘Prevention’, for instance, we may find a Level 2 indicator such as ‘Resilient design’, further divided into Level 3 more detailed indicators such as ‘Physical robustness’, ‘Cyber robustness’, ‘Redundancy’, ‘Modularity’, and ‘Independency’. The task is to study these indicators on Level 4 in the context of concrete critical infrastructure facilities and hazard scenarios, that is, applying Level 3 indicators into concrete circumstances. The methodology then permits to transfer quantitative, semi-quantitative and qualitative evaluations of individual sector-specific resilience indicators into uniform metrics, based on process maturity levels. This in turn makes it possible to give a specific critical infrastructure, or its part, a resilience value on the scale 0-5. While the real resilience value becomes clear only when one engages in the analysis of several indicators, the methodology can be used also as a step-by-step measurement and development tool for resilience, without necessary immediately engaging in time-consuming total resilience analysis. The user of this methodology is supposed to be the operator of critical infrastructure, or part of it, in the spirit of self-auditing. In case it would be implemented in a wider scale, in cooperation between the operators and authorities, it would give the authorities a holistic picture about the respective society’s critical infrastructure resilience. In this report, we draw a concise picture of the methodology and illustrate how this methodology could be applied to a specific infrastructure and hazard scenario.
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| 48. |
- Ioannou, Ioanna, et al.
(author)
-
IMPROVER D2.1 Methodology for identifying hazard scenarios to assess the resilience of critical infrastructure
- 2015
-
Reports (other academic/artistic)abstract
- Critical infrastructure is exposed to a wide range of hazards, capable to disrupt its operations in various degrees. This raises the question of which hazard scenario an operator shall use to assess the resilience of their critical infrastructure asset. Various techniques aiming to prioritize the various risks are commonly used in the literature. This study proposed an 8-step methodology, which aims to rank the risks of pre-defined hazard scenarios by eliciting the opinions of the stakeholders through a structured expert elicitation technique termed paired comparison. The novelty of the proposed technique is its ability to quantify the degree of disagreement regarding the ranking order of the scenarios and thus to capture the uncertainty associated with these risks. The proposed methodology has been applied to four living labs, namely: the Oresund region, the port of Oslo, the A31 Highway in France and the potable water network in Barreiro. The applications aims to rank scenarios of natural and operational hazards according to their disaster- and emergency-risk. Despite the small number of participants, the results provide an excellent basis for further discussion regarding the most likely disaster or emergency risk scenarios. For most living labs, the ranking of the hazards using paired comparison was successful in identifying the scenarios associated with the highest risk. Overall, ranking the natural hazards according to their disaster- or emergency-risk has been associated with a higher degree of consensus than the ranking of the operational hazards reflecting on the higher complexity and perhaps the limited understanding of the later. In more detail, snow storm is the hazard with the highest disaster risk for the A31 Highway. Similarly, earthquake is the hazard with the highest disaster risk for the water network in Barreiro. Three meteorological hazards ranked the highest for both the likelihood to occur and to cause disaster to the Øresund region. By contrast, the ranking of the hazards for the port of Oslo identified several scenarios with similar likelihood to cause disaster, which ranked very different in their likelihood to occur in the next 5 years. This raises question as to whether the most of least likely to occur scenarios is most suitable which can be answered in collaboration with the stakeholders. With regard to the operational hazards, the contamination of the water in the water source or the distribution network due to an accident at the high-risk industrial SEVECO operations has been identified as the single scenario with the highest risk of disaster for the water network in Barreiro. Three events including a multiple day strike and two accidents in the wet bulk terminal have been identified as having the highest disaster risk for the port of Oslo. By contrast, no operational hazards can be identified as having the highest risk of occurrence for the A31 highway and the Øresund region
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| 49. |
- Kozlowski, Marcin, et al.
(author)
-
Numerical Analysis and 1D/2D Sensitivity Study for Monolithic and Laminated Structural Glass Elements under Thermal Exposure
- 2018
-
In: Materials. - : MDPI AG. - 1996-1944. ; 11:8
-
Journal article (peer-reviewed)abstract
- Glass is largely used in architectural and engineering applications (i.e., buildings and vehicles) as a structural material, especially in the form of laminated glass (LG) sections. To achieve adequate and controlled safety levels in these applications, the well-known temperature-dependent behavior of viscoelastic interlayers for LG sections should be properly accounted for during the design process. Furthermore, the materials' thermomechanical degradation with increases of temperature could severely affect the load-bearing performance of glass assemblies. In this context, uncoupled thermomechanical finite element (FE) numerical models could represent a robust tool and support for design engineers. Key input parameters and possible limits of the FE method, however, should be properly calibrated and assessed, so as to enable reliable estimations for the real behavior of glazing systems. In this paper, FE simulations are proposed for monolithic (MG) and LG specimens under radiant heating, based on one-dimensional (1D) and two-dimensional (2D) models. A special attention is focused on thermal effects, being representative of the first step for conventional uncoupled, thermomechanical analyses. Based on experimental results available in the literature, FE parametric studies are discussed, giving evidence of limits and issues due to several modeling assumptions. In particular, careful consideration is paid for various thermal material properties (conductivity, specific heat) and thermal boundaries (conductivity, emissivity), but also for other influencing parameters like the geometrical features of samples (thickness tolerances, cross-sectional properties, etc.), the composition of LG sections (interlayer type, thickness), the loading pattern (heat transfer distribution) and the presence of additional mechanical restraints (i.e., supports of different materials). Comparative FE results are hence critically discussed, highlighting the major effects of such influencing parameters.
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| 50. |
- Kozłowski, Marcin, et al.
(author)
-
Structural considerations on timber-glass composites at fire scenarios
- 2018
-
In: Challenging Glass 6. - : TU Delft Open. - 9789463660440 ; , s. 229-240
-
Conference paper (peer-reviewed)abstract
- This paper focuses on a recently developed concept, in which glass is combined with timber to provide post-breakage strength and ductility. This combination allows for good post-breakage performance and overall robustness of timber-glass composite beams and wall elements, which has been reported in several publications. The application of timber-glass elements in practice, however, raises important issues related to structural fire performance. The paper elaborates on this issue and provides general information about the behavior of glass, timber and adhesives at elevated temperatures and under fire conditions. Furthermore, it presents ideas and strategies developed for potential application of timber-glass composites in practical situations. The paper presents also initial results from an on-going research project on fire performance of timber-glass composites Copyright © with the authors. All rights reserved.
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