| 1. |
- Mathern, Alexandre, 1986
(författare)
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Addressing the complexity of sustainability-driven structural design: Computational design, optimization, and decision making
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Being one of the sectors with the largest environmental burden and high socio-economic impacts sets high requirements on the construction industry. At the same time, this provides the sector with great opportunities to contribute to the globally pursued sustainability transition. To cope with the increasing need for infrastructure and, at the same time, limit their sustainability impacts, changes and innovation in the construction sector are required. The greatest possibility to limit the sustainability impact of construction works is at the early design phase of construction projects, as many of the choices influencing sustainability are made at that point. Traditionally, an early choice of a preferred design is often made based on limited knowledge and past experience, considering only a handful of options. This preferred design is then taken on to the successive stages in the stepwise design process, leading to suboptimization. Alternatively, many different design choices could be considered and evaluated in a more holistic approach in order to find the most sustainable design for a particular application. However, finding design solutions that offer the best sustainability performance and fulfil all structural, performance and buildability requirements, require methods that allow considering different design options, analysing them, and assessing their sustainability. The aim of this thesis is to explore and develop methods enabling structural engineers to take sustainability objectives into account in the design of structures. Throughout this thesis, a number of methods have been explored to take sustainability aspects into account in the structural design process. As a first step, highly parameterized computer codes for sustainability-driven design have been developed. These codes interoperate with FE analysis software to automatically model and analyse design concepts over the whole design space and verify compliance with structural design standards. The codes were complemented with a harmonized method for life cycle sustainability performance assessment, in line with the state-of-the-art standards. Here, sustainability criteria were defined covering environmental, social, economic, buildability and structural performance for multi-criteria assessment of design concepts. To identify the most sustainable designs within the set, multi-objective optimization algorithms were used. Algorithms that address the high expense of constraint function evaluations of structural design problems were developed and integrated in the parameterized computer codes for sustainability-driven design. To ensure the applicability and validity of these methods, case studies based on real-world projects and common structural engineering problems were used in this thesis. Case studies for bridges and wind turbine foundations as well as a benchmark case of a reinforced concrete beam were investigated. The case studies highlight the potential of the methods explored to support the design of more sustainable structures, as well as the applicability of the methods in structural engineering practice. It is concluded that it is possible and beneficial to combine computational design, life cycle sustainability assessment, and multi-objective design optimization as a basis for decision making in the design phase of civil engineering projects. A wide adoption of such a sustainability-driven design optimization approach in structural engineering practice can directly improve the sustainability of the construction sector.
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| 2. |
- Rempling, Rasmus, 1976, et al.
(författare)
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Performance requirements for Swedish transport infrastructure - A pre-study of challenges and possibilities
- 2022
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In recent years, significant worldwide research has been conducted regarding the performance assessment of bridges and the concept of performance indicator has been introduced However, there are still significant discrepancies in how these indicators are obtained and used. Simultaneously, it is desirable to achieve processes and methods that are direct, i.e. that measured values are directly compared with projected values over time. This project concerns methods for verification of technical performance requirements. The feasibility study brought together interdisciplinary researchers, consultants, and entrepreneurs to gather knowledge, anchor the research agenda, and implement performance requirements. The project concludes that there is a need for a “Holistic multi-parameter verification/validation system” that relies on the knowledge gained in structural health monitoring research.
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| 3. |
- Säwén, Toivo, 1993
(författare)
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Early Stage Architectural Design Practice Perspectives on Life Cycle Building Performance Assessment
- 2023
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Architectural practitioners can avoid negative social and environmental impacts of new construction by making decisions supported by impact quantification during design processes. However, most software tools developed for such quantification see little use in practice, especially in early design stages when decisions have the greatest influence. To identify ways for software developers to overcome this situation, a thorough literature meta-review of previously performed tool reviews was combined with interviews applying a practice lens. The first key finding is that a possible explanation for the low tool uptake in practice could be a missing practice perspective in previous tool development efforts. In a literature meta-review of publications on life cycle building performance tools identifying previously applied perspectives, most previous tool reviews were found to support tool development and selection, while disregarding how tools can be integrated in existing practices and design processes. As a proposed solution, a framework for defining software requirements using a practice perspective was developed. The second key finding is that a practice perspective could be applied during software development by implementing qualitative methodologies. Nine architectural practitioners in Sweden, Norway and France were interviewed using the interview to the double, a projective technique in which the interviewee is asked to describe their next workday in detail so that their tasks can be assumed by an imagined body double. The design activities described by the respondents were sequenced into user narratives which could serve as starting points for participatory software development processes within the architectural practice. The outcomes - a proposed framework for practice-centric software requirements, and a proposed methodology for collecting these requirements using a practice lens - indicate a research direction toward software development efforts which aligns with design process, architectural practice, and tool user needs. In the next stage of the research this direction will be pursued through application of the developed methodologies in participatory development case studies in early-stage architectural design practice.
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| 4. |
- Jockwer, Robert, 1984, et al.
(författare)
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Design for adaption - making timber buildings ready for circular use and extended service life
- 2021
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Ingår i: World Conference on Timber Engineering 2021, WCTE 2021.
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Konferensbidrag (refereegranskat)abstract
- The use of timber and the implementation of the concept of circularity in the process of the construction of buildings potentially has a high sustainability impact, both from the perspective of material and construction technique. The three most effective ways to ensure the benefit of the circularity in the building sector in general are (1) maintain the service life of structures and buildings materials as long as possible to avoid unnecessary emissions and costs for demolition and reconstruction (2) conserve the quality of materials as long as possible to avoid unnecessary emissions and costs for the replacement and processing of new materials and (3) recycle and repurpose only the parts and materials which cannot function any more for technical and/or socio-cultural reasons. In this paper an approach is discussed towards a more sustainable built environment by making buildings adaptable to the changes of demands and requirements to building functions and thus leading to an extended use of buildings in a maximum of life cycles. This design for adaption may enhance economic, social and environmental benefits to various stakeholders and key players related to the building process, i.e. developers, building owners, users, municipality and others.
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| 5. |
- Täljsten, Björn, 1961-, et al.
(författare)
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Assessment of prestressed concrete bridges - challenges
- 2020
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Ingår i: IABSE Symposium, Wroclaw 2020. - Zürich : International Association For Bridge And Structural Engineering (IABSE). ; , s. 487-494
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Konferensbidrag (refereegranskat)abstract
- Prestressed concrete bridges are important parts of our infrastructure. They are susceptible to different kinds of deterioration processes. Examples of damages and deficiencies are cracking, corrosion, voids, bond loss, reduction of cover layer, delamination, fatigue and loss of stiffness and strength. This necessitates methods to continuously assess their condition in order to avoid problems that might lead to shorter service life or reduction of structural integrity. Many of the existing prestressed bridges in Europe are now approaching their design life length. However, with proper and continuous inspection, monitoring and assessment, we may plan proactive maintenance and the structural safety can be assured or – if necessary - increased. This will save both money and decrease the environmental impact of the structure.
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| 6. |
- Armesto Barros, Jesús, et al.
(författare)
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Recent and future trends of onshore wind turbine foundations
- 2022
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Ingår i: Proceedings of the IABSE Symposium Prague 2022: Challenges for Existing and Oncoming Structures. - 9783857481819
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Konferensbidrag (refereegranskat)abstract
- The decarbonization of the economy and the growing need for electricity are two trends that call for greener energy sources. Wind is a growing renewable energy source, which is expected to become the first source of power in the European Union in the next decade. In particular, onshore wind energy is expected to double by then. Fundamental structural components of wind turbines are their foundations, which are large structures associated with important material consumption and many construction challenges. The dimensions of these foundations are continuously increasing as turbines with taller towers and larger rotor diameters are being built. Designing cost- and material-efficient foundations is crucial to reduce the economic and environmental impact of wind energy. An important factor to successfully address these evolving requirements in the planning and design process is to build on the experience from previous projects. The aim of this work is to investigate the evolution of onshore wind turbines and its consequences on the design and climate impact of gravity foundations by analysing data from Swedish wind farms set in operation between 2013 and 2022. The evolution of turbine size, and foundation dimensions, reinforcement layout, material types and quantities, and embodied carbon are analysed in this paper.
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| 7. |
- Bergenram, Felicia, et al.
(författare)
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Parametric Optimization of Slab Frame Bridges Considering Investment Cost, Environmental Impact and Buildability
- 2023
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Ingår i: Procedia Computer Science. - 1877-0509.
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Konferensbidrag (refereegranskat)abstract
- This paper presents research performed on set-based multi-criteria optimization for the preliminary design of slab frame bridges. As a result of immense CO2 emissions emerging from concrete production, there is a need for optimization methods decreasing the volume of concrete without affecting the function of the structure. Previous research suggests a general correlation between CO2 footprint- and cost reduction, due to minimized material use. However, the aspect of buildability may conflict with lessened material, as optimized designs might simultaneously be less buildable. This research aimed to develop an optimization method with respect to the investment cost and environmental impact while also considering buildability cost aspects. The optimization algorithm shows the possibilities of reducing the environmental impact by up to 13.7% for a slightly increased cost of 2.3%. Thus, by implementing optimization procedures in the early stages of the planning process the holistic cost effects related to green solutions can be presented, favoring the choice of sustainable designs amongst clients during tendering procedures.
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| 8. |
- Kiamili, Christina, et al.
(författare)
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Detailed Assessment of Embodied Carbon of HVAC Systems for a New Office Building Based on BIM
- 2020
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Ingår i: Sustainability. - : MDPI AG. - 2071-1050. ; 12:8
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Tidskriftsartikel (refereegranskat)abstract
- The global shift towards embodied carbon reduction in the building sector has indicated the need for a detailed analysis of environmental impacts across the whole lifecycle of buildings. The environmental impact of heating, ventilation, and air conditioning (HVAC) systems has rarely been studied in detail. Most of the published studies are based on assumptions and rule of thumb techniques. In this study, the requirements and methods to perform a detailed life cycle assessment (LCA) for HVAC systems based on building information modelling (BIM) are assessed and framed for the first time. The approach of linking external product data information to objects using visual programming language (VPL) is tested, and its benefits over the existing workflows are presented. The detailed BIM model of a newly built office building in Switzerland is used as a case study. In addition, detailed project documentation is used to ensure the plausibility of the calculated impact. The LCA results show that the embodied impact of the HVAC systems is three times higher than the targets provided by the Swiss Energy Efficiency Path (SIA 2040). Furthermore, it is shown that the embodied impact of HVAC systems lies in the range of 15–36% of the total embodied impact of office buildings. Nevertheless, further research and similar case studies are needed to provide a robust picture of the embodied environmental impact of HVAC systems. The results could contribute to setting stricter targets in line with the vision of decarbonization of the building sector.
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| 9. |
- Mathern, Alexandre, 1986, et al.
(författare)
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Practical metamodel‑assisted multi‑objective design optimization for improved sustainability and buildability of wind turbine foundations
- 2022
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Ingår i: Structural and Multidisciplinary Optimization. - : Springer Science and Business Media LLC. - 1615-1488 .- 1615-147X. ; 65:2
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Tidskriftsartikel (refereegranskat)abstract
- In this work, we study the potential of using kriging metamodelling to perform multi-objective structural design optimization using finite element analysis software and design standards while keeping the computational efforts low. A method is proposed, which includes sustainability and buildability objectives, and it is applied to a case study of reinforced concrete foundations for wind turbines based on data from a large Swedish wind farm project. Sensitivity analyses are conducted to investigate the influence of the penalty factor applied to unfeasible solutions and the size of the initial sample generated by Latin hypercube sampling. A multi-objective optimization is then performed to obtain the optimum designs for different weight combinations for the four objectives considered. Results show that the kriging-obtained designs from samples of 20 designs outperform the best designs in the samples of 1000 designs. The optimum designs obtained by the proposed method have a sustainability impact 8–15% lower than the designs developed by traditional methods.
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| 10. |
- de Wolf, Catherine, et al.
(författare)
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Database of Embodied Quantity Outputs: Lowering Material Impacts Through Engineering
- 2020
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Ingår i: Journal of Architectural Engineering. - 1076-0431. ; 26:3
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Tidskriftsartikel (refereegranskat)abstract
- Current studies and performance labels focus mainly on the operational energy demand of buildings due to heating, cooling, ventilation, lighting, and hot water, but they rarely account for embodied impacts. Performing a life cycle assessment (LCA) on an entire building structure, let alone a building, requires time and data, both of which are often lacking for practitioners in the construction industry. Limited knowledge on the embodied carbon equivalent of building structures led to the benchmarking effort of the database of embodied quantity outputs (DEQO), developed by the first author over the last 6 years in close collaboration with industry and academia. DEQO collects material quantities for existing buildings in a robust way directly from industry. This paper presents the lessons learned from this database to define the next steps for structural engineers to lower the environmental impacts related to the material quantities in their projects. To create confidence and comparability in the results, recommendations are given such as implementing uncertainty analysis into practice to avoid inaccurate comparisons with a false sense of precision.
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