| 1. |
- Silfwerbrand, Johan, et al.
(författare)
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Performance-based requirements in design-build contracting for highway construction and maintenance
- 2019
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Ingår i: FIB 2018 - Proceedings for the 2018 fib Congress. - : Federation Internationale du Beton (fib). ; , s. 470-478, s. 470-478
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Konferensbidrag (refereegranskat)abstract
- Design-build contracts with performance-based specifications are believed to raise productivity and the innovation rate. However, performance-based requirements used in specifications for highway and bridge contracts may suffer from being too detailed or too difficult to verify. A Swedish research project has been devoted to this issue. The aims were (i) to develop a definition of performance-based requirements and (ii) to evaluate performance-based requirements used in Swedish design-build contracts. The project consisted of three parts: (i) literature survey, (ii) investigation of current documents produced and used by the Swedish Transport Administration for design-build contracts, and (iii) case studies of six design-build contracts with performance-based requirements, including an analysis of specification documents and interviews with both client and contractor project managers. Current performance-based specifications show different degrees of detail. Measurable requirements are more frequently used on roads, and in particular on road surfaces, than on bridges. Further development is needed to promote technical innovations. Less detailed specifications and a shift to design-build-operate contracts with prolonged maintenance responsibility would also encourage the choice of more durable and long-lasting (=sustainable) solutions. The emphasis on Life Cycle Cost (LCC) in the reformulated contract award criteria in the EU public procurement directive might be insufficient to strengthen the competitive power of concrete pavements as compared to asphalt pavements, unless specifications are supported by Life Cycle Analysis (LCA) and the choice of contract type is reconsidered.
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| 2. |
- Kickert, Conrad Christiaan, et al.
(författare)
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Surveying density, urban characteristics, and development capacity of station areas in the Delta Metropolis
- 2014
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Ingår i: Environment and Planning B: Planning and Design. - : SAGE Publications. - 2399-8083 .- 2399-8091 .- 0265-8135 .- 1472-3417. ; 41, s. 69-92
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Tidskriftsartikel (refereegranskat)abstract
- The combination of growing mobility needs and dwindling transportation budgets in the Dutch Delta Metropolis has raised the need for smarter use of existing public transport infrastructure. A significant portion of this smarter use may come from strengthening the ties between infrastructure improvements and transit-oriented development. To further this goal, the Delta Metropolis Association has developed SprintCity (SprintStad in Dutch), a serious game and planning support tool that engages stakeholders in transit-oriented development to explore interaction between transport and land use, as described in Bertolini’s node–place model. However, its underlying database has proven insufficient to draw conclusions regarding urban character and development capacity around stations. This paper focuses on morphological research that aims to improve this database by exploring the density and urban morphology of station areas in the Delta Metropolis beyond readily available statistics, and discusses the methodological and theoretical underpinnings of this survey. The surveying of station areas in 2010 was conducted by a team of six researchers, based on the Spacemate© methodology developed by Berghauser Pont and Haupt. The methodology allows detailed quantitative measurement of the density and spatial characteristics of clearly demarcated urban districts, defining their so-called ‘spatial fingerprint’. The resulting database of 850 districts in 55 station areas has served descriptive goals, strengthening the realism in the SprintCity game, and serves as the database for further establishing the development potential of station areas.
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| 3. |
- Dervishaj, Arlind, et al.
(författare)
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A digital workflow for assessing lifespan, carbonation, and embodied carbon of reusing concrete in buildings
- 2024
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Ingår i: Journal of Building Engineering. - : Elsevier. - 2352-7102. ; 96, s. 1-23
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Tidskriftsartikel (refereegranskat)abstract
- Concrete is the most used construction material, accounting for 8% of global CO2 emissions. Various strategies aim to reduce concrete's embodied carbon, such as using supplementary cementitious materials, utilizing cleaner energy, and carbonation. However, a large potential lies in reusing concrete for new buildings in a Circular Economy, thereby closing material loops and avoiding CO2 emissions.This study focuses on the reuse of precast concrete elements. We present a digital workflow for assessing reuse by predicting the remaining service life, estimating CO2 uptake by natural carbonation, and calculating the embodied carbon savings of concrete reuse. Both carbonation rates from EN 16757 and our investigation were applied to a case study building.While EN 16757 rates suggest that most precast elements have reached the end of their service life, our assessment shows that these elements have a sufficient lifespan for reuse. Plaster and coverings significantly delay carbonation and extend service life. During the first service life following EN 16757, carbonation was 19,2 kg CO2/m3, whereas our prediction was 5,4 kg CO2/m3. Moreover, CO2 uptake during service life, including reuse, was less than 6% of the embodied carbon. The climate benefits of reuse greatly exceeded those of carbonation.Furthermore, carbonation did not have a decisive influence when applying Cut-Off, Distributed, and End-of-Life allocations for assessing embodied carbon of re-used elements in subsequent life cycles. The digital workflow is useful in quickly assessing lifespan, carbonation, and embodied carbon of concrete. It can be leveraged as a decision-making tool when designing for reuse.
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| 4. |
- Dervishaj, Arlind
(författare)
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From Sustainability to Regeneration : a digital framework with BIM and computational design methods
- 2023
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Ingår i: Architecture, Structures and Construction. - : Springer Nature. - 2730-9886 .- 2730-9894. ; 3:3, s. 315-336
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Tidskriftsartikel (refereegranskat)abstract
- Design methods, frameworks, and green building certifications have been developed to create a sustainable built environment. Despite sustainability advancements, urgent action remains necessary due to climate change and the high impact of the built environment. Regenerative Design represents a shift from current practices focused on reducing environmental impacts, as it aims to generate positive effects on both human and natural systems. Although digital design methods are commonly employed in sustainable design practice and research, there is presently no established framework to guide a digital regenerative design process. This study provides an analysis of existing literature on regenerative design and digital design methods and presents a framework based on building information modelling (BIM) methodology and computational design methods, that can be applied to both urban and building design. This framework identifies digital tools and organizes indicators based on the pillars of climate, people, and nature for regenerative design, drawing upon a comprehensive analysis of literature, including standards, sustainability frameworks and research studies. The framework is illustrated through a case study evaluation. The paper also highlights the potential and limitations of digital methods concerning regenerative design and suggests possibilities for future expansion by incorporating additional quantifiable indicators that reflect research developments, to achieve positive outcomes.
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| 5. |
- Dervishaj, Arlind
(författare)
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Sunlight Autonomy for Sustainable Buildings and Cities : Maximizing daylight potential outdoors and indoors
- 2024
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Konferensbidrag (refereegranskat)abstract
- Daylight, both outdoors and indoors, is essential for human well-being. However, daylight provision often faces challenges in various climates and locations, due to factors such as shortcomings in regulations, urban densification, deregulation or special exemptions, and the limitations of existing daylight and sunlight evaluation methods. To address these issues, we propose the Sunlight Autonomy, a new methodology and set of metrics, that aims to overcome the limitations of existing early-stage daylighting metrics and is valuable for urban planning and architectural design purposes.
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| 6. |
- Bin, Jiang, 1965-, et al.
(författare)
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Automatic generation of the axial lines of urban environments to capture what we perceive
- 2010
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Ingår i: International Journal of Geographical Information Science. - London : Taylor & Francis Group. - 1365-8816 .- 1365-8824 .- 1362-3087. ; 24:4, s. 545-558
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Tidskriftsartikel (refereegranskat)abstract
- Based on the concepts of isovists and medial axes, we developed a set of algorithms that can automatically generate axial lines for representing individual linearly stretched parts of open space of an urban environment. Open space is the space between buildings, where people can freely move around. The generation of the axial lines has been a key aspect of space syntax research, conventionally relying on hand-drawn axial lines of an urban environment, often called axial map, for urban morphological analysis. Although various attempts have been made towards an automatic solution, few of them can produce the axial map that consists of the least number of longest visibility lines, and none of them really works for different urban environments. Our algorithms provide a better solution than existing ones. Throughout this paper, we have also argued and demonstrated that the axial lines constitute a true skeleton, superior to medial axes, in capturing what we perceive about the urban environment.
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| 7. |
- Bin, Jiang, 1965-, et al.
(författare)
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Computing the fewest-turn map directions based on the connectivity of natural roads
- 2011
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Ingår i: International Journal of Geographical Information Science. - London : Taylor & Francis Group. - 1365-8816 .- 1365-8824 .- 1362-3087. ; 25:7, s. 1069-1082
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we introduced a novel approach to computing the fewest-turn map directions or routes based on the concept of natural roads. Natural roads are joined road segments that perceptually constitute good continuity. This approach relies on the connectivity of natural roads rather than that of road segments for computing routes or map directions. Because of this, the derived routes posses the fewest turns. However, what we intend to achieve are the routes that not only possess the fewest turns, but are also as short as possible. This kind of map direction is more effective and favorable by people, because they bear less cognitive burden. Furthermore, the computation of the routes is more efficient, since it is based on the graph encoding the connectivity of roads, which is significantly smaller than the graph of road segments. We made experiments applied to eight urban street networks from North America and Europe in order to illustrate the above stated advantages. The experimental results indicate that the fewest-turn routes posses fewer turns and shorter distances than the simplest paths and the routes provided by Google Maps. For example, the fewest-turn-and-shortest routes are on average 15% shorter than the routes suggested by Google Maps, while the number of turns is just half as much. This approach is a key technology behind FromToMap.org - a web mapping service using openstreetmap data.
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| 8. |
- Dervishaj, Arlind, et al.
(författare)
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Modelling Precast Concrete for a Circular Economy in the Built Environment : Level of Information Need guidelines for digital design and collaboration
- 2023
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Ingår i: eCAADe 2023. - Brussels, Graz : Graz University of Technology Faculty of Architecture. ; , s. 177-186
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Konferensbidrag (refereegranskat)abstract
- In recent years, there has been a growing interest in adopting circular approaches in the built environment, specifically reusing existing buildings or their components in new projects. To achieve this, drawings, laser scanning, photogrammetry and other techniques are used to capture data on buildings and their materials. Although previous studies have explored scan-to-BIM workflows, automation of 2D drawings to 3D models, and machine learning for identifying building components and materials, a significant gap remains in refining this data into the right level of information required for digital twins, to share information and for digital collaboration in designing for reuse. To address this gap, this paper proposes digital guidelines for reusing precast concrete based on the level of information need (LOIN) standard EN 17412-1:2020 and examines several CAD and BIM modelling strategies. These guidelines can be used to prepare digital templates that become digital twins of existing elements, develop information requirements for use cases, and facilitate data integration and sharing for a circular built environment.
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| 9. |
- Dervishaj, Arlind, et al.
(författare)
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Sunlight Autonomy for Buildings: A New Methodology for Evaluating Sunlight Performance in Urban and Architectural Design
- 2024
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Ingår i: LEUKOS The Journal of the Illuminating Engineering Society of North America. - : Informa UK Limited. - 1550-2724 .- 1550-2716. ; , s. 1-31
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Tidskriftsartikel (refereegranskat)abstract
- Due to urbanization and growing density in cities in the past century, metrics were introduced to assess daylight performance such as minimum sunlight hours and the daylight factor. The paper initially explores the shortcomings of early-stage daylight and sunlight evaluation methods. A novel methodology called Sunlight Autonomy (SA) is proposed for evaluating sunlight performance in buildings. The SA is based on the “Exposure to sunlight” criteria in EN 170307 “Daylight in Buildings,” where a computational method is used for the evaluation on a specified day. The SA concept expands the analysis temporally over the entire year, and spatially on building facades, leading to new metrics for a point of evaluation, and spatial metrics for buildings. The SA methodology is analyzed in a case study across four European cities. The SA metrics on facades between February 1st and March 21st, days in EN 17037, led to differences up to 63%. This revealed a significant shortcoming in EN 17037, relevant for Nordic regions. The differences of spatial metrics between March 21st and 50% of the year were within 5%, and up to 33% between February 1st and 75% of the year. The timestep affects the metrics and a window evaluation showed that the error of a 10-minute analysis was within 5% of daily insolation and 5 days for the annual SA. The potential of these metrics for urban planning and the architectural design process is examined. The interaction between SA and EN 17037, as well as other ongoing research developments, is discussed.
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| 10. |
- Du, Guangli, 1985-, et al.
(författare)
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Life cycle assessment as a decision support tool for bridge procurement : environmental impact comparison among five bridge designs
- 2014
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Ingår i: The International Journal of Life Cycle Assessment. - : Springer Science and Business Media LLC. - 0948-3349 .- 1614-7502. ; 19:12, s. 1948-1964
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Tidskriftsartikel (refereegranskat)abstract
- The conventional decision-making for bridges is mostly focusing on technical, economical, and safety perspectives. Nowadays, the society devotes an ever-increased effort to the construction sector regarding their environmental performance. However, considering the complexity of the environmental problems and the diverse character of bridges, the related research for bridge as a whole system is very rare. Most existing studies were only conducted for a single indicator, part of the structure components, or a specific life stage. Life Cycle Assessment (LCA) is an internationally standardized method for quantifying the environmental impact of a product, asset, or service throughout its whole life cycle. However, in the construction sector, LCA is usually applied in the procurement of buildings, but not bridges as yet. This paper presents a comprehensive LCA framework for road bridges, complied with LCA ReCiPe (H) methodology. The framework enables identification of the key structural components and life cycle stages of bridges, followed by aggregation of the environmental impacts into monetary values. The utility of the framework is illustrated by a practical case study comparing five designs for the Karlsnas Bridge in Sweden, which is currently under construction. This paper comprehensively analyzed 20 types of environmental indicators among five proposed bridge designs, which remedies the absence of full spectrum of environmental indicators in the current state of the art. The results show that the monetary weighting system and uncertainties in key variables such as the steel recycling rate and cement content may highly affect the LCA outcome. The materials, structural elements, and overall designs also have varying influences in different impact categories. The result can be largely affected by the system boundaries, surrounding environment, input uncertainties, considered impact indicators, and the weighting systems applied; thus, no general conclusions can be drawn without specifying such issues. Robustly evaluating and ranking the environmental impact of various bridge designs is far from straightforward. This paper is an important attempt to evaluate various designs from full dimensions. The results show that the indicators and weighting systems must be clearly specified to be applicable in a transparent procurement. This paper provides vital knowledge guiding the decision maker to select the most LCA-feasible proposal and mitigate the environmental burden in the early stage.
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