| 1. |
- Cristescu, Carmen, et al.
(författare)
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Design for deconstruction and reuse of timber structures – state of the art review
- 2020
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Rapport (övrigt vetenskapligt/konstnärligt)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. |
- Bedon, Chiara, et al.
(författare)
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Special issue on "buildings and structures under extreme loads"
- 2020
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Ingår i: Applied Sciences. - : MDPI AG. - 2076-3417. ; 10:16
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Tidskriftsartikel (refereegranskat)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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| 3. |
- Blomqvist, Lars, 1962-, et al.
(författare)
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Development of novel structural connections - Inspiration from furniture industry
- 2021
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Ingår i: World Conference on Timber Engineering 2021, WCTE 2021. - Santiago, Chile : World Conference on Timber Engineering (WCTE).
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Konferensbidrag (refereegranskat)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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| 4. |
- Fjellgaard Mikalsen, Ragni, et al.
(författare)
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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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Ingår i: Journal of Emergency Management. - : NLM (Medline). - 1543-5865. ; 18:1, s. 51-72
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Tidskriftsartikel (refereegranskat)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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| 5. |
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| 6. |
- Honfi, Daniel, et al.
(författare)
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Experimental and Numerical Analysis of Thermo-Mechanical Behaviour of Glass Panes Exposed to Radiant Heating
- 2022
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Ingår i: Fire. - : MDPI. - 2571-6255. ; 5:4
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Tidskriftsartikel (refereegranskat)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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| 7. |
- Honfi, Daniel, et al.
(författare)
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Informed successive condition assessments in bridge maintenance
- 2020
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Ingår i: Journal of Civil Structural Health Monitoring. - : Springer. - 2190-5452 .- 2190-5479. ; 10:4, s. 729-737
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Tidskriftsartikel (refereegranskat)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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| 8. |
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| 9. |
- Larsson Ivanov, Oskar, et al.
(författare)
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The practical value of structural health information for time dependence in bridge maintenance
- 2021
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Ingår i: Structure and Infrastructure Engineering. - : Informa UK Limited. - 1573-2479 .- 1744-8980. ; , s. 1-16
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Tidskriftsartikel (refereegranskat)abstract
- For practical decisions on common recurring maintenance actions, the information from routine inspections form a decision basis for the bridge manager. It is often difficult to assess whether this information is sufficient for deciding on a repair action, or if more information is needed. For many bridges the information for supporting decisions may be limited, although those bridges cause large yearly maintenance costs for the society. The purpose of the study presented in this paper is to show how two different models for decision making based on Bayesian decision theory, a point-in-time decision model and a sequential updating decision model, can be used to improve the decision-making process for common maintenance decisions. The models use information from routine inspections and incorporates time dependent aspects such as material degradation and time value of money to improve the decision-making process. The focus is on presenting the methodology with a case study of a concrete bridge in Sweden where the edge beams may have to be replaced. Three assessment approaches are considered: (i) no assessment, (ii) desktop evaluation and (iii) measurements. The main finding is that sequential updating decision making will provide a higher benefit than a point-in-time decision, and thus give higher Value of Information. This value becomes even higher when the measurements are selected for the assessment. The results also show that the edge beams should be replaced. The general approach presented can be applicable to many decision scenarios related to maintenance of deteriorating structures.
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| 10. |
- Leander, John, et al.
(författare)
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Digitaliseringens möjligheter och utmaningar inom förvaltning och underhållsplanering av broar : Förstudie
- 2020
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Rapporten behandlar digitalisering – att införa ny digital teknik – i förvaltningsverksamheten av broar. Omfattningen är en förstudie med syftet att identifiera behovet av framtida forskning för en långsiktig utveckling av broförvaltningen. En grundläggande ansats var att en digitalisering ska minska behovet av kostsamma underhållsåtgärder men bibehålla en hög säkerhet för våra broar.Projektets mål var att samla information om digitala informationsmodeller som skapas under investeringsskedet, utvärdera överlämningen av digitala modeller till förvaltningsskedet, och värdera den eventuella nyttan med digital informationsinsamling för tillståndsbedömning och underhållsplanering. En viktig del av detta var beskrivningen av dagens förvaltningssystem och hur det skulle kunna utvecklas.Studierna har bedrivits genom en enkätundersökning med respondenter från konsultfirmor aktiva inom broprojektering, intervjuer med tekniska experter och litteratursökningar.Resultatet visar att projekteringen av broar idag huvudsakligen görs genom byggnads-informationsmodellering (BIM). Inriktningen är mot byggskedet där samordning och kommunikation bedöms vara de största nyttorna. Överlämningen till förvaltningen består dock av relationsritningar i formen av enkla ritningsfiler. Trots att Trafikverkets strategi för BIM beskriver att en informationsmodell bör leva kvar under hela brons livslängd, finns det tveksamheter huruvida en modell från projekteringen är lämplig som förvaltningsmodell. Istället lyfts andra metoder fram för att skapa en modell av det byggda utförandet. Till exempel optiska metoder för skanning och fotogrammetri.Förvaltningssystemen bör utvecklas med funktioner för att lagra och tillgängliggöra stora mängder digital information från sensorer maskinella inspektioner. Syftet är att minska osäkerheterna i det byggda utförandet och graden av nedbrytning, för att slutligen skapa ett bättre underlag för beslut om åtgärder. Ett framtida scenario är en digital tvilling som speglar den verkliga konstruktionen och uppdateras kontinuerligt genom sensordata.Gällande hårdvara för mätningar behöver sensorer och system utvecklas med avseende på energiförbrukning, energiskördning och underhållsåtgärder, t.ex. genom kombinationer av utbytbara komponenter med kort livslängd och andra delar med lång livslängd. Fiberoptiska sensorer visar på lovande egenskaper men utveckling behövs för att göra dem mer kostnadseffektiva i relation till konventionella sensorer.
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| 11. |
- Nasr, Amro, et al.
(författare)
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A review of the potential impacts of climate change on the safety and performance of bridges
- 2021
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Ingår i: Sustainable and Resilient Infrastructure. - : Informa UK Limited. - 2378-9689 .- 2378-9697. ; 6:3-4, s. 192-212
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Forskningsöversikt (refereegranskat)abstract
- An overabundance of evidence, both observational and from model projections, indicate that changes to the climate system are taking place at unprecedented rates. Although the magnitudes of these changes involve large uncertainties, the fact that our climate is changing is unequivocal. To ensure an unimpaired functionality of our societies,it is therefore of crucial importance to study the potential climate change impacts on infrastructure. Taking into account that bridges have a considerably long service life, it is of direct relevance to ascertain their reliable performance against climate change risks. This paper synthesizes the findings of over 190 research articles to identify the potential risks climate change may pose on bridges. Over 30 potential risks, supported by pertinent previous bridge damage (or failure) cases, are identified, categorized, and linked to the projected future climate changes. The identified risks can be used as a basis for future risk prioritization by bridge managers.
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| 12. |
- Nasr, Amro, et al.
(författare)
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Climate change risks and bridge design
- 2023
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Ingår i: Adapting the Built Environment for Climate Change : Design Principles for Climate Emergencies - Design Principles for Climate Emergencies. - 9780323953375 - 9780323953368 ; , s. 109-131
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Bokkapitel (refereegranskat)abstract
- Climate change can have substantial impacts on the safety and performance of infrastructure systems. Understanding these impacts is of paramount importance, especially for long-lived infrastructure elements, such as bridge structures. This chapter focuses on discussing the impacts of climate change to bridges and describes a conceptual framework as a guide for bridge designers on how to consider these impacts in bridge design. Several existing challenges are, however, highlighted that hinder the application of such a framework in practical contexts (e.g., climate change data availability and uncertainty). Overcoming these challenges is necessary to facilitate a rational consideration of climate change impacts in the design of bridge infrastructure. Although the current chapter mainly addresses bridges, the identified risks and proposed framework can be extended to other types of infrastructures and infrastructure elements.
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| 13. |
- Nasr, Amro, et al.
(författare)
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Probabilistic analysis of climate change impact on chloride-induced deterioration of reinforced concrete considering Nordic climate
- 2022
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Ingår i: Journal of Infrastructure Preservation and Resilience. - : Springer Science and Business Media LLC. - 2662-2521. ; 3
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Tidskriftsartikel (refereegranskat)abstract
- The impact of climate change on the deterioration of reinforced concrete elements have been frequently highlighted as worthy of investigation. This article addresses this important issue by presenting a time-variant reliability analysis to assess the effect of climate change on four limit states; the probabilities of corrosion initiation, crack initiation, severe cracking, and failure of a simply supported beam built in 2020 and exposed to chloride-induced corrosion. The historical and future climate conditions (as projected by three different emission scenarios) for different climate zones in Sweden are considered, including subarctic conditions where the impact of climate change may lead to large increases in temperature. The probabilities of all limit states are found to be: 1) higher for scenarios with higher GHG emissions and 2) higher for southern than for northern climate zones. However, the end-of-century impact of climate change on the probabilities of reaching the different limit states is found to be higher for northern than for southern climate zones. At 2100, the impact of climate change on the probability of failure can reach up to an increase of 123% for the northernmost zone. It is also noted that the end-of-century impact on the probability of failure is significantly higher (ranging from 3.5–4.9 times higher) than on the other limit states in all climate scenarios.
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| 14. |
- Nasr, Amro, et al.
(författare)
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Quantitative assessment of the impact of climate change on creep of concrete structures
- 2021
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Ingår i: Proceedings of the 31st European Safety and Reliability Conference (ESREL 2021). - Singapore : Research Publishing Services. - 9789811820168 ; , s. 1318-1325
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Konferensbidrag (refereegranskat)abstract
- Creep of concrete structures is in most cases regarded as a serviceability problem that may have impacts on maintenance and repair costs but cannot lead to structural collapse. However, several structural collapses during the past decades have been, at least partly, attributed to excessive creep deformations. Recent studies suggest that concrete creep may be further exacerbated by climate change. The current study demonstrates how this effect can be quantitatively assessed. For this purpose, six different creep models (i.e, Model Code 1999, Model Code 2010, MPF, B3, B4, and B4s models) are used under considerations of historical and future climatic conditions in southernmost Sweden as given by a regional climate model. Furthermore, two different simulations were performed as follows: 1) considering only climate uncertainty represented by the climate model, and 2) considering climate uncertainty, parameter uncertainty, and creep model uncertainty. The highest impact of climate change on end of century creep coefficient is observed using model B4 where the 75th percentile of the increase in creep coefficient is found to range from 8% to ∼14% depending on the climate scenario. The results of the assessment in this article show that the uncertainty related to climate change on creep of concrete structures (higher effect in RCP8.5 than in RCP2.6 and RCP4.5 which have very similar results) is much smaller than uncertainties resulting from creep modelling.
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| 15. |
- Nasr, Amro, et al.
(författare)
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Risk-based multi-criteria decision analysis method for considering the effects of climate change on bridges
- 2023
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Ingår i: Structure and Infrastructure Engineering. - : Informa UK Limited. - 1573-2479 .- 1744-8980. ; 19:10, s. 1445-1458
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Tidskriftsartikel (refereegranskat)abstract
- Recent studies have identified many potential climate change impacts on bridges. Considering the sheer number of these potential impacts, how can a bridge owner prioritise which impacts to consider, and for which bridges? This paper proposes a risk-based multi-criteria decision analysis method for systematically addressing these two questions simultaneously. The proposed method can be used to address both extreme and non-extreme impacts as opposed to focussing solely on extreme impacts as has been done in previous prioritisation studies related to climate change risks. The proposed method is based on four main components of risk: hazard, impact, vulnerability and consequences. Several indices characterising these components are used to address the previous two questions. To reflect the uncertainty in the analysis, the different indices are assessed optimistically and pessimistically. Additionally, to ensure a more transparent decision-making process the inclusion of a strength of evidence assessment is also proposed. The applicability of the method is then demonstrated on three illustrative case studies for three different potential climate change impacts. It is concluded that the proposed method is both feasible and appropriately fulfils its purpose. Nevertheless, the proposed method should be more elaborately tested on practical bridge case studies to further establish its applicability.
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| 16. |
- Nasr, Amro, et al.
(författare)
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Towards a conceptual framework for built infrastructure design in an uncertain climate : Challenges and research needs
- 2021
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Ingår i: Sustainability (Switzerland). - : MDPI AG. - 2071-1050. ; 13:21
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Tidskriftsartikel (refereegranskat)abstract
- The potential risks of climate change on the built environment involve large uncertain-ties. This poses an intricate problem to designers and challenges a long-standing tradition of built infrastructure design. More specifically, designers are faced with this challenging question: how to rationally account for climate change risks when designing a new asset? A framework that holistically addresses this difficult question is missing from the current literature. This study contributes to this gap by (1) proposing a conceptual framework for rationally considering the effects of climate change in the design of these assets and (2) identifying the challenges that need to be overcome to facilitate the transition, and further development, of the proposed framework into practice. First, a detailed overview of important infrastructure performance requirements that are relevant to the proposed framework is presented. The different stages of the proposed conceptual framework are then outlined. The proposed framework progresses in the following order: ranking the importance of the asset, identifying the potential climate change risks, analyzing these risks, selecting a design strategy, and finally evaluating the final design. Lastly, several challenges that impede the application of the proposed framework in practical settings are identified. The proposed conceptual framework and the identified challenges comprise a necessary steppingstone towards addressing this pressing issue and developing a more practically applicable framework for considering the risks of climate change in the design of built infrastructure assets.
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| 17. |
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