| 1. |
- Hlal, Fatima, 1989, et al.
(författare)
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Life Cycle Cost and Life Cycle Assessment of Composite Bridge with Flat and Corrugated Webs
- 2023
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Ingår i: ce/papers. ; 6, s. 574-579
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Tidskriftsartikel (refereegranskat)abstract
- To satisfy the sustainability criteria, a bridge design must be economically viable during its entire service life with a minimal impact on the environment. While stainless steel is known for its excellent life cycle performance, its high cost prevents it from being used in bridges to a larger extent. This study evaluates a new design solution that takes advantage of using corrugated web in bridge girders to overcome this issue. Three design concepts are evaluated for a three-span case-study bridge. These include a bridge with carbon steel flat web, stainless steel flat web, and stainless-steel corrugated web girders. Each design is optimized using a genetic algorithm. The three optimal solutions are then evaluated in terms of investment costs, life cycle costs (LCC) and life cycle impact. The results show that the investment costs in a flat web girder bridge increase by 27% when stainless steel is used instead of C-Mn (carbon) steel. However, this increase is only 10% when corrugated web girders are used. On the other hand, the LCC savings increase from 6% to 18% for corrugated web girders. Finally, the use of corrugated web in stainless steel leads to a reduction in the climate impacts of up to 32% compared to carbon steel for the studied bridge.
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| 2. |
- Andersen, Julie Swartz, et al.
(författare)
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Economic comparison of mass timber and concrete construction in the nordic region
- 2023
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Ingår i: 13th World Conference on Timber Engineering, WCTE 2023. ; 7, s. 4360-4369
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Konferensbidrag (refereegranskat)abstract
- The timber sector has been growing strongly in various regions of the world. Yet, the construction industry is still far from being sustainable. One barrier is the economic concern in planning and construction works of timber constructions. This study aims to provide insights on the cost performance of Cross Laminated Timber (CLT) constructions for stakeholders to make an informed decision. It analysed the production cost of multi-story residential buildings with CLT in comparison to concrete in Norway and Sweden. The production cost data of various construction projects with either CLT or concrete was collected and analysed. Interviews with stakeholders were conducted to complement the interpretation of the cost data. The result showed that each project had its individual conditions in the economic background and requirements by client, and thus it was difficult to formulate a general tendency on the cost performance. The variability of the cost was larger and the average production cost was higher in CLT cases. Yet, there are high incentives of contractors and clients for a more sustainable alternative in general. The incentive is also reinforced by the general experience of contractors that the construction cost is better optimized as the contractor gains more experiences.
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| 3. |
- Feng, Haibo, et al.
(författare)
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Where to focus? Developing a LCA impact category selection tool for manufacturers of building materials
- 2023
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Ingår i: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526. ; 405
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Tidskriftsartikel (refereegranskat)abstract
- Life cycle assessment (LCA) has been widely applied to improve the environmental performance of the building sector. However, due to the complexity of LCA results including the multitude of impact categories, decision makers of the building materials manufacturing industry are grappling with allocating their limited resources to the most influential impact categories. The aim of this article, therefore, is to propose an impact category selection tool that enables performance improvement of building materials without sacrificing the validity of LCA results. The developed method selects common building materials, and defines foreground processes that can be influenced by manufacturers of building materials and background processes that can hardly be impacted using the US Input-Output database. Following the life cycle impact assessment (LCIA) analysis with the ReCiPe2016 Midpoint method, our results indicate that, among the 18 impact categories of the ReCiPe2016 Midpoint method, Global Warming Potential, Ozone Formation and Human Health, Fine Particulate Matter Formation, Ozone Formation and Terrestrial Ecosystems, Terrestrial Acidification, and Terrestrial Ecotoxicity should be considered the first priority group while Ionizing Radiation, Freshwater Eutrophication, Marine Eutrophication, Freshwater Ecotoxicity, Water Consumption should be placed in the last priority group. It further suggests that by shifting the limited available resources to the first priority group, decision makers can readily improve the environmental performance of building materials during the manufacturing process. The contribution of the proposed selection tool lies in that it can be adapted by decision makers to different geographical contexts, LCIA methods, and building materials to efficiently ameliorate the environmental performance of the building sector.
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| 4. |
- Forth, Kasimir, et al.
(författare)
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BIM4EarlyLCA: An interactive visualization approach for early design support based on uncertain LCA results using open BIM
- 2023
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Ingår i: Developments in the Built Environment. - 2666-1659. ; 16
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Tidskriftsartikel (refereegranskat)abstract
- To meet the European climate goals in the building sector, a holistic optimization of embodied greenhouse gas (GHG) emissions using the method of life cycle assessments (LCA) are necessary. The early design stages have high impact on the final performance of the buildings and are characterized by high uncertainty due to the lack of information and not yet taken decisions. Furthermore, most current LCA approaches based on Building Information Models (BIM) require high expertise and experience in both BIM and LCA and do not follow an intuitive visualization approach for other stakeholders and non-experts. This paper presents a novel design-decision-making approach for reducing embodied GHG emissions by interactive, model-based visualizations of uncertain LCA results. The proposed workflow is based on open BIM data formats, such as Industry Foundation Classes (IFC) and BIM Collaboration Format (BCF), and is developed for decision support for non-LCA experts in the early design stages. With the help of a user study, the prototypical implementation is tested by 103 participants with different levels of experience in BIM and LCA based on a case study. We evaluate the proposed approach regarding the support of open BIM data formats, different LCA visualization strategies, and the intuitiveness of different approaches to visualizing uncertain LCA results. The user study results show a broad acceptance and need for open BIM data formats and model-based LCA visualization but less for visualizing uncertainties, which needs further research. In conclusion, this interactive, model-based visualization approach using color coding supports non-LCA experts in the design decision-making process in early design stages.
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| 5. |
- Forth, Kasimir, et al.
(författare)
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Interactive visualization of uncertain embodied GHG emissions for design decision support in early stages using open BIM
- 2023
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Ingår i: Life-Cycle of Structures and Infrastructure Systems - Proceedings of the 8th International Symposium on Life-Cycle Civil Engineering, IALCCE 2023. ; , s. 3634-3641
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Konferensbidrag (refereegranskat)abstract
- To meet the European climate goals in the building sector, a holistic calculation and optimization of embodied greenhouse gas (GHG) emissions using the method of life cycle assessment (LCA) in early design stages are necessary. Hence, this paper presents a comprehensive and transparent design-decision-making approach for reducing embodied GHG emissions in early design stages by interactive, model-based visualizations of uncertain results. The proposed approach is based on a previously developed Natural Language Processing (NLP) based methodology of matching elements of a Building Information Model (BIM) to those of an LCA database. With the help of a prototypical implementation and a case study, the uncertainties of the derived LCA results are visualized using different levels of transparencies. This paper shows that open BIM models and the proposed 3D color coding support the hotspot analysis in combination with box plot diagrams for visualizing uncertain GWP results for decision-making in early design stages.
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| 6. |
- Galimshina, Alina, 1993, et al.
(författare)
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High-resolution and localized parametric embodied impact calculator of PV systems
- 2023
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Ingår i: IOP Conference Series: Earth and Environmental Science. - 1755-1307 .- 1755-1315. ; 1196:1
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Konferensbidrag (refereegranskat)abstract
- Buildings are responsible for a large amount of greenhouse gas emissions in the world. In order to decarbonize the electricity grid and reduce the environmental impact of the building stock, photovoltaic panels can be installed. However, in order to assess the environmental impact of PVs, the whole life cycle has to be considered including embodied emissions. Several options for photovoltaics exist on the market or are under development including silicon-based panels, thin films, and third generation panels. Currently, many configurations of the panels exist making it difficult to estimate the embodied impact. The goal of this paper is to close this gap by providing a parametric PV carbon calculator for designers and decision-makers. In this study, the embodied impact of different PV types and configurations is assessed. First, the life cycle inventories data and bill of quantities for different generations' panel types are gathered. Second, life cycle impact assessment is performed. The results of the analysis are presented in a form of a software application allowing users to select the panel's composition, e.g., frame and glass type, cell type, encapsulant, etc. The developed application will assist in understanding the impact of choices made in regards to PV systems and will support engineers and architects in the selection of the photovoltaic panels from embodied impact perspective.
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| 7. |
- Gonzalez Caceres, Alex Arnoldo, 1982, et al.
(författare)
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Application and validation of a method to assess the energy reduction and environmental impact of renovation alternatives
- 2023
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Ingår i: IOP Conference Series: Earth and Environmental Science. - 1755-1307 .- 1755-1315. ; 1196:1
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Konferensbidrag (refereegranskat)abstract
- The renovation of residential stock is one of the most promising areas, in terms of energy reduction, because these buildings are highly inefficient and represent the largest part of the building stock. However, the environmental impact assessment over the life cycle of building renovation is rare. It is more common to develop an assessment for new buildings. This study presents a method that combines the evaluation of the benefits of renovating residential buildings, considering cost, energy and environmental benefits using Life Cycle Assessment (LCA). The method is based on 3 stages of development. First, the database of energy certificates, costs and LCA was analysed. The second step is to develop a workflow in Rhino/Grasshopper/E-Plus to automatically model a residential building and feed the simulation model with the data obtained from the databases. Finally, a simulation campaign was carried out to obtain an optimal renovation package, minimising energy consumption and environmental impact. The research was carried out in a case study in Uddevalla, Sweden. The residential building has different measurements including energy consumption data before and after renovation. This was used to validate the proposed methodology. The validation shows that accurate results are achievable with potential for mass application.
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| 8. |
- Hollberg, Alexander, 1985
(författare)
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Does a flipped classroom approach help? – Experiences from a project-based engineering course
- 2023
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Ingår i: Proceedings Chalmers Conference on Teaching and Learning 2023. - 9789188041548 ; , s. 24-31
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Konferensbidrag (refereegranskat)abstract
- Many project-based courses start with theoretical background lectures. However, the application of this knowledge in the students’ projects is often limited. This paper explores the research question: Does a flipped classroom approach improve the connection between theoretical lectures and the practical project? The method consists of converting four conventional lectures into a flipped classroom approach and posing surveys to the students. Furthermore, the teachers reflect on the outcomes in comparison to previous years. The results show that the exercises after the pre-recorded flipped lectures are appreciated by the students. However, the quality of their final project reports and observations during supervision meetings do not show clear results. As the project was carried out in 2021 during the pandemic, the results might be overshadowed by the impact of the remote teaching situation. Finally, the continued work on the flipped classroom approach led to high quality reports and improved course evaluations in 2023.
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| 9. |
- Kedir, Firehiwot, et al.
(författare)
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Resource efficiency factors in industrialised construction-a study in developing economies
- 2023
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Ingår i: Proceedings of the Institution of Civil Engineers: Engineering Sustainability. - : Thomas Telford Ltd.. - 1478-4629 .- 1751-7680. ; 176:2, s. 94-105
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Tidskriftsartikel (refereegranskat)abstract
- Developing economies need to supply housing and ensure resource efficiency in the process. Industrialised construction, which increases productivity in construction, can be one means to deliver the needed housing. However, the resource efficiency of industrialised construction in developing economies is under-researched. This paper studies factors influencing resource efficiency in industrialised housing products from a perspective of value chain and environmental impact in Addis Ababa, Ethiopia; Nairobi, Kenya; and Cape Town, South Africa. Specifically, wall systems with varying degrees of industrialised construction implementation are studied. The study uncovers four main insights - first, the choice of materials influences the resource-efficiency of industrialised wall systems. However, the current value chain does not promote the adoption of new materials. Second, products used for industrialised wall systems are imported and incur added transportation-related impacts and beyond. Third, industrialised construction wall systems often use lightweight materials and have the potential for disassembly. However, end-users have reservations about such design strategies. Fourth, controlled production of wall systems reduces construction waste and increases the quality of products. Nevertheless, governments are currently promoting labour-intensive construction methods. Based on these insights, the paper concludes with recommendations, levers, and action points for stakeholders to promote resource efficiency in industrialised construction adoption.
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| 10. |
- McCarty, Justin, et al.
(författare)
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Do we need a saw? Carbon-based analysis of facade BIPV performance under partial shading from nearby trees
- 2023
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Ingår i: Journal of Physics: Conference Series. - 1742-6588 .- 1742-6596. ; 2600:4
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Konferensbidrag (refereegranskat)abstract
- Building integrated photovoltaics (BIPV) are becoming more common in urban spaces. The impact of shading from nearby trees on BIPV performance and the potential conflict between the carbon sequestration benefits of trees and the carbon mitigation benefits of BIPV is not well documented in research. Therefore, this paper investigates the cost-benefit relationship of the carbon storage potential of trees vs. their shading effects on a nearby BIPV facade from the perspective of a life cycle assessment (LCA) using a high-resolution BIPV model and temporally sensitive tree growth model. The study is based on a typical Swiss residential building with adjacent vegetation and includes various BIPV facade permutations with different cell types, module orientations, inverter types, facade azimuths, grid emissions profiles, and tree planting scenarios. The results indicate that the removal of trees does not necessarily influence the overall carbon balance when considering LCA to the same degree as other features of the model space such as the grid carbon intensity or the configuration of the BIPV array. Furthermore the parametric-based analysis enables reporting on which BIPV configurations operate with the highest system efficiency under partial shading.
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