| 1. |
- Mathern, Alexandre, 1986, et al.
(författare)
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Concrete Support Structures for Offshore Wind Turbines: Current Status, Challenges, and Future Trends
- 2021
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Ingår i: Energies. - : MDPI AG. - 1996-1073 .- 1996-1073. ; 14:7
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Forskningsöversikt (refereegranskat)abstract
- Today’s offshore wind turbine support structures market is largely dominated by steel structures, since steel monopiles account for the vast majority of installations in the last decade and new types of multi-leg steel structures have been developed in recent years. However, as wind turbines become bigger, and potential sites for offshore wind farms are located in ever deeper waters and ever further from the shore, the conditions for the design, transport, and installation of support structures are changing. In light of these facts, this paper identifies and categorizes the challenges and future trends related to the use of concrete for support structures of future offshore wind projects. To do so, recent advances and technologies still under development for both bottom-fixed and floating concrete support structures have been reviewed. It was found that these new developments meet the challenges associated with the use of concrete support structures, as they will allow the production costs to be lowered and transport and installation to be facilitated. New technologies for concrete support structures used at medium and great water depths are also being developed and are expected to become more common in future offshore wind installations. Therefore, the new developments identified in this paper show the likelihood of an increase in the use of concrete support structures in future offshore wind farms. These developments also indicate that the complexity of future support structures will increase due to the development of hybrid structures combining steel and concrete. These evolutions call for new knowledge and technical know-how in order to allow reliable structures to be built and risk-free offshore installation to be executed.
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| 2. |
- 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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| 3. |
- Sundell, Jonas, 1984, et al.
(författare)
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Comprehensive risk assessment of groundwater drawdown induced subsidence
- 2019
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Ingår i: Stochastic Environmental Research and Risk Assessment. - : Springer Science and Business Media LLC. - 1436-3240 .- 1436-3259. ; 33:2, s. 427-449
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Tidskriftsartikel (refereegranskat)abstract
- © 2019, The Author(s). We present a method for risk assessment of groundwater drawdown induced land subsidence when planning for sub-surface infrastructure. Since groundwater drawdown and related subsidence can occur at large distances from the points of inflow, the large spatial extent often implies heterogeneous geological conditions that cannot be described in complete detail. This calls for estimation of uncertainties in all components of the cause-effect chain with probabilistic methods. In this study, we couple four probabilistic methods into a comprehensive model for economic risk quantification: a geostatistical soil-stratification model, an inverse calibrated groundwater model, an elasto-plastic subsidence model, and a model describing the resulting damages and costs on individual buildings and constructions. Groundwater head measurements, hydraulic tests, statistical analyses of stratification and soil properties and an inventory of buildings are inputs to the models. In the coupled method, different design alternatives for risk reduction measures are evaluated. Integration of probabilities and damage costs result in an economic risk estimate for each alternative. Compared with the risk for a reference alternative, the best prior alternative is identified as the alternative with the highest expected net benefit. The results include spatial probabilistic risk estimates for each alternative where areas with significant risk are distinguished from low-risk areas. The efficiency and usefulness of this modelling approach as a tool for communication to stakeholders, decision support for prioritization of risk reducing measures, and identification of the need for further investigations and monitoring are demonstrated with a case study of a planned railway tunnel in Varberg, Sweden.
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| 4. |
- Mathern, Alexandre, 1986, et al.
(författare)
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Experimental study of time-dependent properties of a low-pH concrete for deposition tunnels
- 2018
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Ingår i: fib Symposium. - 2617-4820. ; , s. 1726-1735
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Konferensbidrag (refereegranskat)abstract
- The Swedish Nuclear Fuel and Waste Management Company developed a method for the final disposal of canisters for spent nuclear fuel in tunnels at depths of about 500 meters. The concept for closure of the deposition tunnels is based on a bentonite seal supported by a spherical concrete dome structure. In order to fulfil the requirements specific to the repository concept, a special mix of low-pH self-compacting concrete was developed. A series of large-scale castings and laboratory tests were conducted to gain experience on this low-pH concrete mix, in conjunction with the full-scale demonstration test of an unreinforced concrete dome plug in the underground hard rock laboratory in Äspö, Sweden. The laboratory tests aimed at studying the creep properties under high sustained compressive stresses of the low-pH concrete mix, its shrinkage properties and the properties of the rock-concrete interface. This paper provides an overview of these tests and analyses the latest results of the recently completed creep tests, which include 6 years of measurements. These results allow to improve understanding of the structural behaviour of the concrete plug and to assess the effects of the very high pressure acting on the plug on its deformations, cracking and water tightness.
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| 5. |
- van Eldert, Jeroen, 1987-, et al.
(författare)
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Application of Measurement While Drilling Technology to Predict Rock Mass Quality and Rock Support for Tunnelling
- 2020
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Ingår i: Rock Mechanics and Rock Engineering. - : Springer. - 0723-2632 .- 1434-453X. ; 53:3, s. 1349-1358
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Tidskriftsartikel (refereegranskat)abstract
- A tunnelling project is normally initiated with a site investigation to determine the in situ rock mass conditions and to generate the basis for the tunnel design and rock support. However, since site investigations often are based on limited information (surface mapping, geophysical profiles, few bore holes, etc.), the estimation of the rock mass conditions may contain inaccuracies, resulting in underestimating the required rock support. The study hypothesised that these inaccuracies could be reduced using Measurement While Drilling (MWD) technology to assist in the decision-making process. A case study of two tunnels in the Stockholm bypass found the rock mass quality was severely overestimated by the site investigation; more than 45% of the investigated sections had a lower rock mass quality than expected. MWD data were recorded in 25 m grout holes and 6 m blast holes. The MWD data were normalised so that the long grout holes with larger hole diameters and the shorter blast holes with smaller hole diameters gave similar results. With normalised MWD data, it was possible to mimic the tunnel contour mapping; results showed good correlation with mapped Q-value and installed rock support. MWD technology can improve the accuracy of forecasting the rock mass ahead of the face. It can bridge the information gap between the early, somewhat uncertain geotechnical site investigation and the geological mapping done after excavation to optimise rock support.
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| 6. |
- Sundell, Jonas, 1984, et al.
(författare)
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Economic valuation of hydrogeological information when managing groundwater drawdown
- 2019
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Ingår i: Hydrogeology Journal. - : Springer Science and Business Media LLC. - 1431-2174 .- 1435-0157. ; 27:4, s. 1111-1130
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Tidskriftsartikel (refereegranskat)abstract
- © 2019, The Author(s). A procedure is presented for valuation of information analysis (VOIA) to determine the need for additional information when assessing the effect of several design alternatives to manage future disturbances in hydrogeological systems. When planning for groundwater extraction and drawdown in areas where risks—such as land subsidence, wells running dry and drainage of streams and wetlands—are present, the need for risk-reducing safety measures must be carefully evaluated and managed. The heterogeneity of the subsurface calls for an assessment of trade-offs between the benefits of additional information to reduce the risk of erroneous decisions and the cost of collecting this information. A method is suggested that combines existing procedures for inverse probabilistic groundwater modelling with a novel method for VOIA. The method results in (1) a prior analysis where uncertainties regarding the efficiency of safety measures are estimated, and (2) a pre-posterior analysis, where the benefits of expected uncertainty reduction deriving from additional information are compared with the costs for obtaining this information. In comparison with existing approaches for VOIA, the method can assess multiple design alternatives, use hydrogeological parameters as proxies for failure, and produce spatially distributed VOIA maps. The method is demonstrated for a case study of a planned tunnel in Stockholm, Sweden, where additional investigations produce a low number of benefits as a result of low failure rates for the studied alternatives and a cause-effect chain where the resulting failure probability is more dependent on interactions within the whole system rather than on specific features.
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| 7. |
- Ait Ali, Abderrahman, et al.
(författare)
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Evaluating the mix of maintenance activities on railway crossings with respect to life-cycle costs
- 2024
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Ingår i: European Journal of Transport and Infrastructure Research. - : TU Delft OPEN Publishing. - 1567-7141 .- 1567-7133. ; 24:1, s. 1-29
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Tidskriftsartikel (refereegranskat)abstract
- Switches & crossings (S&Cs) are vital assets as they allow for increased railway capacity by introducing flexibility and connectivity in railway networks. At the same time, this makes them critical since they can cause costly delays and disruptions if they are not well maintained. This motivates studies to improve maintenance strategies of S&Cs, considering both the life-cycle costs (LCCs) of the assets and socio-economic transportation costs for passengers and freight customers. In this paper, the interdependence between deterioration mechanisms, maintenance activities, and expected LCC (including transportation costs) for the crossing panel – an S&C subsystem – is investigated using a combination of mechanical and econometric modelling. The interrelation between the degradation of contact geometry and track settlement is analysed using simulations of dynamic vehicle– turnout interaction. Long-term mechanical degradation of the crossing panel is simulated for different maintenance strategies that correspond to different timing of the associated maintenance measures (crossing repair welding and tamping). This provides the basis for analysing the interdependence between preventive and corrective activities using econometric modelling. Based on a case study of a common type of S&Cs in the Swedish infrastructure, the impact of different maintenance strategies on LCC and transportation costs is analysed. Opportunities and challenges in the development of more economically effective maintenance strategies of S&Cs are discussed.
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| 8. |
- Rempling, Rasmus, 1976, et al.
(författare)
-
Utmattning
- 2021
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Ingår i: Betonghandbok material - Hårdnad betong, fysikaliska egenskaper och beständighet. - 9789179170882 ; , s. 485-510
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 9. |
- Petersson, Jesper, 1974
(författare)
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Blurring the shoreline: De- and re-infrastructuring and the changing colors of European flood policy
- 2021
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Ingår i: Environment and Planning E: Nature and Space. - : SAGE Publications. - 2514-8494 .- 2514-8494 .- 2514-8486. ; 4:2, s. 623-644
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Tidskriftsartikel (refereegranskat)abstract
- This paper provides a genealogy of the emergence of a common EU flood policy, including the scope and direction of this policy. Noticing how EU policy proposes green infrastructure (associated with using nature as a buffer zone in managing floods) as an alternative to grey infrastructure (implying fixed installations of concrete and cement), this paper adopts the theoretical lens of the so-called infrastructural turn, which advocates a relational investigation of infrastructure. By engaging this approach, the paper shows how flood infrastructure can contain very different compositions of (unruly) water and (settled) land. A narrative of a historically strong focus on guarding society from the powerful forces of nature through a fixed line of defense is increasingly giving way to more muddy states—quite literally—where society is expected to learn to live with flooding and show ecological consideration. To capture the EU’s, and especially the European Commission’s efforts to establish a pan-European flood infrastructure that accommodates this turn, the concepts of de- and re-infrastructuring are developed. These concepts act as heuristic devices to capture how policy performs some combinations between water and land as constituting an attractive and functional flood infrastructure, but constitutes other infrastructural relations of the aquatic and the terrestrial as undesirable and, hence, as malfunctioning. This performative act of distinguishing between what constitutes “good and proper” versus “bad and undesirable” infrastructure is referred to as a politics of infrastructure.
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| 10. |
- Dymitrow, Mirek, et al.
(författare)
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Crossing dichotomies and breaking mental patterns: Green business development when all else fails?
- 2017
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Ingår i: 8th International Scientific Conference “Rural Development 2017: Bioeconomy Challenges”, 23–24 November, 2017 Kaunas, Lithuania.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Obtaining sustainable and inclusive societal organization is not merely a simple matter of ‘doing it’ by subscribing to some winning formula. Given that conceptual frameworks always guide our thoughts, judgments and actions (Latour, 2013; Harvey, 1996; Dennett, 1993), the ways in which we relate to concepts chosen to serve as guiding forces for future development will eventually determine its outcome. As scholarly evidence continuously suggests the concepts ‘rural’ and ‘urban’ are increasingly recognized as artificial barriers for conducting sound and integrated development endeavors in a globalized reality of interconnectedness. In line with the Sustainable Development Goals, which aim to eradicate poverty, shield the planet and safeguard prosperity for all, commitment to universal access to healthy food year round has become an important agenda point. This, however, has been exacerbated by binary thinking and separate ways of doing policy. This paper aims to share experiences from a unique project launched in the northern parts of Gothenburg, Sweden’s second largest city. While the area offers ample resources and immense opportunities for areal economies, it at the same time remains one of Gothenburg’s most segregated, with high levels of unemployment, ill health and crime. The uniqueness of the project lies not only in its way of abridging the rural-urban divide, but also by consciously deferring from the debilitating rhetoric of previous ‘immigrant policies’, and instead focusing on agricultural productivity, small-scale food producers and sustainable food strategies. Such exhortations to bridge between philosophical and material polarities, however, have not come without conceptual and practical challenges, something this paper aims to subsume and open up to debate.
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| 11. |
- Ek, Kristine, 1975, et al.
(författare)
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Multi-criteria decision analysis methods to support sustainable infrastructure construction
- 2019
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Ingår i: IABSE Symposium, Guimaraes 2019: Towards a Resilient Built Environment Risk and Asset Management - Report. ; , s. 1084-1091
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Konferensbidrag (refereegranskat)abstract
- The construction of infrastructure projects represents a large sustainability impact, both positive and negative. Increased positive and reduced negative impacts can be achieved through better design and planning of the construction. To make more sustainable choices, well‐defined predictive sustainability assessment methods are required. Multi‐criteria decision analysis (MCDA) is a well-suited method for predictive sustainability assessment. This paper evaluates two MCDA methods for sustainability assessment of infrastructure construction and exemplifies their application with two case studies. The aim of this paper is to discuss if the methods are suitable for identifying the most sustainable alternative during the procurement process of an infrastructure project. It is recommended that MCDA methods are further developed to comply with the recently published EN standard on sustainability assessment of civil engineering works.
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| 12. |
- Skagestad, Ragnhild, 1978, et al.
(författare)
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GCCSI Webinar: Cutting Cost of CO2 Capture in Process Industry (CO2stCap) Project overview & first results for partial CO2 capture at integrated steelworks
- 2017
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- GCCSI Webinar: Cutting Cost of CO2 Capture in Process Industry (CO2stCap) Project overview & first results for partial CO2 capture at integrated steelworks This publication has the format of a webinar: The CO2StCap project is a four year initiative carried out by industry and academic partners with the aim of reducing capture costs from CO2 intensive industries (more information here). The project, led by Tel-Tek, is based on the idea that cost reduction is possible by capturing only a share of the CO2 emissions from a given facility, instead of striving for maximized capture rates. This can be done in multiple ways, for instance by capturing only from the largest CO2 sources at individual multi-stack sites utilising cheap waste heat or adapting the capture volumes to seasonal changes in operations. The main focus of this research is to perform techno-economic analyses for multiple partial CO2 capture concepts in order to identify economic optimums between cost and volumes captured. In total for four different case studies are developed for cement, iron & steel, pulp & paper and ferroalloys industries. The first part of the webinar gave an overview of the project with insights into the cost estimation method used. The second part presented the iron & steel industry case study based on the Lulea site in Sweden, for which waste-heat mapping methodology has been used to assess the potential for partial capture via MEA-absorption. Capture costs for different CO2 sources were discussed, demonstrating the viability of partial capture in an integrated steelworks.
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| 13. |
- 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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| 14. |
- Heshmati, Mohsen, 1987, et al.
(författare)
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Dependency of cohesive laws of a structural adhesive in Mode-I and Mode-II loading on moisture, freeze-thaw cycling, and their synergy
- 2017
-
Ingår i: Materials and Design. - : Elsevier BV. - 1873-4197 .- 0264-1275. ; 122, s. 433-447
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Tidskriftsartikel (refereegranskat)abstract
- In recent years, adhesive bonding has found its way to construction applications such as bridges. Given the harsh conditions that such structures are usually exposed to, it is necessary to account for environmental factors, particularly moisture and temperature, in the design phase. Cohesive zone modelling has attracted much attention in the last decade as a promising method to design adhesive joints. Despite this interest, the effects of moisture and thermal cycles on cohesive laws have not been investigated to the knowledge of the authors. In this paper, we present a method to directly measure the environmental-dependent cohesive laws of a structural adhesive loaded in pure Mode-I and Mode-II. Special consideration is given to overcome issues such as the time-consuming nature of moisture ingression and specimen dimensions, which could be problematic due to the size-limitations of conditioning equipment. The accuracy of this method was verified through simulation of the experiments using the finite element analysis. The effects of exposure to 95% relative humidity, immersion in saltwater and distilled water, and freeze-thaw cycles in the presence or absence of moisture were investigated. The results indicate the damaging effects of combined saltwater and freeze-thaw cycles which were clearly reflected on the shape of the cohesive laws.
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| 15. |
- 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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| 16. |
- Rempling, Rasmus, 1976, et al.
(författare)
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Aspects of Integrated Design of Structures: Parametric Models, Creative Space and Linked Knowledge
- 2015
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Ingår i: Civil Engineering and Architecture. - 2332-1121. ; 3, s. 143-152
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Tidskriftsartikel (refereegranskat)abstract
- In the construction industry, collaborative working methods with overlapping domains have been developing side by side with information and communication technology. Recently, efforts have been made to combine these methods in order to facilitate the integration of disciplines. Research on collaborative work has resulted in the promising "integrated project delivery" methodology, whereas research on information and communication technology has resulted in building information modelling. In this paper, we propose three principles for integrated design: "parametric models", "creative space" and "linked knowledge". These principles have been derived during the course of the TailorCrete Project. The project involves contributions from architects, structural engineers, contractors and building material manufacturers, as well as scientists of the built environment. All principles are elaborated upon with regard to their connection to integrated design and how they are carried out in practice; the elaboration is based on results collected from the TailorCrete project and from research results found in the literature. This paper concludes that parametric models, creative space and linked knowledge are the three main aspects that should be pursued in order to achieve and implement a practical integrated design process
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| 17. |
- Hoeft, Madeleine, et al.
(författare)
-
Construction Automation and Robotics in Infrastructure
- 2022
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In Sweden, as in many other countries, the construction andinfrastructure sector are of large and growing importance for the economyand society. For instance, the construction industry’s turnover equals 11% ofthe Swedish gross domestic product (GDP) (Byggföretagen 2021), and theSwedish Transport Administration plans to invest SEK 799 billion during theperiod 2022-2033 (Regeringen 2021). At the same time, the cost ofinfrastructure projects has increased more than the consumer price index(CPI) (Trafikverket (2021)), partly due to a poorer development of theproductivity compared to other industries. An improved productivity andefficiency in the transport infrastructure and construction industry istherefore necessary. One way to increase productivity, improve theoccupational health and safety, and sustainability is through automation anddigitalization of the construction industry.The aim of the present report has been to identify ongoing initiatives andexisting research trends in construction automation with a focus on civilengineering, both nationally and internationally; and to identify potentialsand challenges that exist for the development of construction automation.Furthermore, the prerequisites for the implementation of automation in theconstruction industry have been studied. The research questions were studiedthrough a literature study and two thematic days on the subject.The results from the literature study shows that a clear increasing trendexists, both nationally and internationally, in automation, digitization androbotisation in the construction industry. The same trend can also be seen incivil engineering for roads, bridges, tunnels, as well as in the mining industry.With the mining industry as a role model, construction companies,universities, suppliers and clients together with small and medium-sizedenterprises (SMEs) should come together to develop a common vision and astrategic roadmap to enforce automation and digitization of the constructionindustry. A development of both technical, organizational and financialstructures is required, where an attractive business ecosystem can bedeveloped, enabling the upscaling of construction automation.Interdisciplinary collaborations, test-beds at an early stage, competencedevelopment, new financing infrastructure and a common vision are crucialto create conditions for construction automation.
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| 18. |
- Desivyana, Nindya, 1997, et al.
(författare)
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Challenges in the adoption of sustainable criteria in the Swedish property development industry
- 2023
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Ingår i: Procedia Computer Science. - : Elsevier BV. - 1877-0509. ; 219, s. 1752-1759
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Konferensbidrag (refereegranskat)abstract
- The construction industry is facing an increased focus on sustainability and climate neutrality, causing property developers to implement new requirements into the procurement documents, which are also driven by the national agenda. This study explores the current state of sustainability practice among Swedish property developers and identifies the main obstacles to expand further the implementation of the sustainability criteria. How the property developers define and implement sustainability requirements has been assessed through qualitative semi-structured interviews, focusing on sustainability certification systems, Life Cycle Assessment (LCA), and social sustainability. The results show usage of sustainability certification systems for marketing purposes and high awareness and practice of LCA, even though the accuracy of LCA was questioned. This study also identified guideline gaps for circular economy and social sustainability measurements, which could relate to low initiatives from the certification systems.
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| 19. |
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| 20. |
- Armesto Barros, Jesús, et al.
(författare)
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Recent and future trends of onshore wind turbine foundations
- 2022
-
Ingår i: Proceedings of the IABSE Symposium Prague 2022: Challenges for Existing and Oncoming Structures. - 9783857481819
-
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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| 21. |
- Kharazmi, Parastou, 1977-
(författare)
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Experimental evaluation of a rubber-epoxy polymeric system used in the rehabilitation of sewer infrastructure- Dataset
- 2019
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Annan publikationabstract
- This dataset includes data related to water sorption analyses to support research findings stated in the article:"Experimental evaluation of a rubber-epoxy polymeric system used in the rehabilitation of sewer infrastructure: a case study in Sweden" with the following abstract: One rehabilitation method used mainly for wastewater sewers in residential buildings involves applying a rubber-epoxy composite to the inner surface of the aged pipeline. In order to understand the material’s performance and stability in operation, during which it is constantly exposed to deteriorative factors, the properties of the material were studied in the laboratory under artificial water and air aging conditions. Changes in the material were monitored by means of tests such as thermal analyses, mechanical testing and water absorption assessment.
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| 22. |
- Ståhle, Alexander, et al.
(författare)
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Designguide för Smarta gator
- 2022
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- Designguiden för smarta gator konkretiserar hur de fyra megatrenderna urbanisering, digitalisering, samhällsförändringar och miljöförändringar leder till nya krav och utformningsprinciper för framtidens gator. Guiden är tänkt att fungera som en inspiration och ett underlag för att förnya svensk gatupolicy på nationell, regional och kommunal nivå.Guiden innehåller utöver en inledning följande kapitel: en historisk tillbakablick (gatans utveckling), gatans användning, gatans delar, gatans design, designprocessen, guidens genomförande.
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| 23. |
- Blomfors, Mattias, 1990, et al.
(författare)
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Partial safety factors for the anchorage capacity of corroded reinforcement bars in concrete
- 2019
-
Ingår i: Engineering structures. - : Elsevier BV. - 0141-0296 .- 1873-7323. ; 181, s. 579-588
-
Tidskriftsartikel (refereegranskat)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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| 24. |
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| 25. |
- Nasrollahi, Kourosh, 1991
(författare)
-
Differential railway track settlement in a transition zone – Field measurements and numerical simulations
- 2023
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In a transition zone between two different railway track forms, there is a discontinuity in track structure leading to a gradient in track stiffness. Examples include transitions between different superstructures, e.g., slab track to ballasted track, and/or between different substructures, e.g., embankment to a bridge or tunnel structure. Differences in loading and support conditions at the interfaces between track superstructure and substructure on either side of the transition may lead to differential track settlement and an irregularity in longitudinal rail level soon after construction because of densification of ballast and consolidation in the subsoil. This results in an amplification of the dynamic traffic loading along the transition. To ensure the safety of railway operation and reduce maintenance costs, it is necessary to monitor the condition of the transition zone and detect any operational change at an early stage. A methodology for the simulation of long-term differential track settlement, the development of voided sleepers leading to a redistribution of rail seat loads, and the evolving irregularity in vertical track geometry at a transition between two track forms, is presented. For a prescribed traffic load, the accumulated settlement is predicted using an iterative approach. It is based on a time-domain model of vertical dynamic vehicle–track interaction to calculate the contact forces between sleepers and ballast in the short term. These are used in an empirical model to determine the long-term settlement of the ballast and subgrade below each sleeper. Gravity loads and state-dependent track conditions are accounted for. The methodology is applied to a transition zone between a ballasted track and a slab track that is subjected to heavy haul traffic. The influence of higher axle loads and the implementation of under sleeper pads on sleeper settlement is assessed. Based on fibre Bragg grating sensors, a setup for in-situ long-term condition monitoring of track bed degradation in a transition zone has been developed and implemented to provide data for verification and calibration of the simulation model. The system is designed for measurements in an operational railway track in harsh conditions in the north of Sweden. The instrumentation along the transition comprises four clusters, each with an optical strain gauge array on the rail web in one sleeper bay, and an accelerometer and a displacement transducer on the sleeper end. Two additional accelerometers are installed far from the transition zone to measure a reference state. Combined, the data should not only provide details on long-term settlements, but also the change in dynamic response it underpins.
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| 26. |
- Petersson, Jesper, 1974, et al.
(författare)
-
Defend, Retreat and Attack: Urban Waters and Valuation Practices
- 2022
-
Ingår i: Water Alternatives. - : Water Alternatives Association. - 1965-0175. ; 15:1, s. 175-192
-
Tidskriftsartikel (refereegranskat)abstract
- This paper explores the river landscapes and concomitant values resulting from tensions between flood management and visions of a River City. The aim is to contribute to an understanding of the management of urban waters as valuation practices. We regard valuation practices as co-constitutive of current and future river landscapes. Sweden’s second-largest city, Gothenburg, is located next to the sea, and the Göta River, Sweden’s largest water system, runs through it. Our empirical focus is on how this city approaches increasing risks of flooding. We explore three approaches that have been formulated in relation to flood management: defend, retreat and attack. We ask how these approaches are applied in the management of Göta River flooding and in the city’s vision of a future Gothenburg that embraces the river as a genuinely positive aspect of urban life. We present the case as a journey that takes us upstream from the river’s sea inlet port and through Gothenburg. During our kilometre by kilometre journey, the river’s appearance shifts. The varied river landscape mirrors the diversity in how its waters are valuated, both historically and in present times. The perception of urban waters is shaped by practices of valuation. These valuations are generative. They connect the value of water to other entities, actors, plans, activities and buildings, and they are thus key to the river landscapes that will eventually be realised. By way of conclusion, we identify a number of governance challenges that are particularly relevant to urban rivers.
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| 27. |
- Honfi, Daniel, et al.
(författare)
-
Decision support for maintenance and upgrading of existing bridges
- 2017
-
Ingår i: IABSE Conference, Vancouver 2017. - : International Association for Bridge and Structural Engineering (IABSE). - 9783857481536 ; 109, s. 336-345, s. 336-345
-
Konferensbidrag (refereegranskat)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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| 28. |
- Aldenlöv, Jens, et al.
(författare)
-
Public procurement of railway infrastructuremaintenance : a literature review
- 2017
-
Ingår i: Proceedings of the 9th Nordic Conference on Construction Economics and Organization. - Lyngby : Polyteknisk Boghandel og Forlag. - 9788750211259 ; , s. 10-21
-
Konferensbidrag (refereegranskat)abstract
- The maintenance of railway infrastructure has in several instances been changed from government-based to being based on public procurement, with varying degrees of flexibility for the contractor to design their maintenance work. The purpose of-giving contractors a larger freedom of choice of how to perform maintenance is to stimulate them to innovate and develop their maintenance processes. Since the contracts differ in between and there are changes in government policies over time that affects both existing and new contracts, a comparison between different contracts becomes challenging. A literature review has been conducted to understand the change in procurement strategy and how to encourage contractors to innovate. The research questions include: What procurement strategies are there? How is maintenance evaluated? How does procurement affect the innovation opportunities for entrepreneurs?The literature review focuses on railway maintenance and contract design between client and contractor. In total, 17 articles matched the search criteria and were selected for the review. To have successful maintenance service, five articles suggested partnering as a strategy with common goals in combination with good communication during the entirety of the contract. When selecting incentive plan, four articles mentions that a focus on performance-based incentives in combination with riskmanagement is better rather than actual payment schemes. The reason being that payment is often themain cause of conflicts between client and contractor. The scientific literature suggests that improvement in incentives improves quality of maintenance, decreases delays and technical failures. The conclusion from the literature review is that partnering in railway maintenance is considered successful. With accurate knowledge about railway assets the incentive plan becomes accurate which reduces costs.The literature review is a part of a research project with an overall goal to develop a model to guide the selection of appropriate type of procurement strategy, contract and control of maintenance for a moresustainable railway system.
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| 29. |
- Frischknecht, Rolf, et al.
(författare)
-
Comparative Life Cycle Assessment of Geosyhnthetics versus Conventional filter layer
- 2013
-
Ingår i: Proceedings of the 18th International Conference on Soil Mechanics and Geotechnical Engineering. - 9782859784744 ; 4, s. 3203-3206
-
Konferensbidrag (refereegranskat)abstract
- Geosynthetics made from plastics can replace filter layers made of gravel. In this article goal and scope, basic data and the results of a comparative life cycle assessment of gravel and geosynthetics based filter layers are described. The filter layers of a road made of 30 cm gravel and a filter geosynthetic, respectively, form the basis for the comparison. The filter layers have the same technical performance and the same life time of 30 years. The product system includes the supply of the raw materials, the manufacture of the geotextiles and the extraction of mineral resources, the construction of the road filter, its use and its end of life phase. The life cycle assessment reveals that the geosynthetics based filter layer causes lower environmental impacts per square metre. The cumulative greenhouse gas emissions amount to 7.8 kg CO2-eq (mineral filter) and to 0.81 kg CO2-eq (geosynthetic filter). The variation of the thickness of the gravel based filter layer confirms the lower environmental impacts of a geosynthetics based filter layer. Environmental impacts of the geosynthetic production are dominated by the raw material provision (plastic granulate) and electricity consumption during manufacturing.
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| 30. |
- Nilsson, Martin, et al.
(författare)
-
Adapting Cdio To Civil Engineering: Investigate – Plan – Design – Construct – Operate And Maintain
- 2016
-
Ingår i: The 12th International CDIO Conference. - Turku. - 9789522166104 - 9789522166104 ; , s. 164-172
-
Konferensbidrag (refereegranskat)abstract
- The aim of this paper is to propose an alternative expression for engineering practice in the context of the civil engineering and built environment sector. Our first objective is to demonstrate that the CDIO approach can, with these modifications, be applied in developing civil engineering and built environment programs. Our second objective is to showcase the adaptability of the CDIO approach, thereby encouraging other thoughtful modifications and transformations. We outline the ideas underpinning the original expression, and identify the role it plays in the CDIO methodology for curriculum development. Taking these factors into account, a modified expression is proposed to describe the engineering process in civil engineering and built environment. We divide the process into ‘investigation – planning – design – construction – operation and management’. Further, to ‘products, processes and systems’, we propose the addition of ‘environments’.
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| 31. |
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| 32. |
- Mathern, Alexandre, 1986, et al.
(författare)
-
Practical metamodel‑assisted multi‑objective design optimization for improved sustainability and buildability of wind turbine foundations
- 2022
-
Ingår i: Structural and Multidisciplinary Optimization. - : Springer Science and Business Media LLC. - 1615-1488 .- 1615-147X. ; 65:2
-
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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| 33. |
- Böhm, Annette, et al.
(författare)
-
Evaluating CALM M5-based vehicle-to-vehicle communication in various road settings through field trials
- 2010
-
Ingår i: Proceedings - Conference on Local Computer Networks, LCN, (2010 12 01): 613-620. - Piscataway, N.J. : IEEE Press. - 9781424483877 ; , s. 613-620
-
Konferensbidrag (refereegranskat)abstract
- Future cooperative Intelligent Transport Systems (ITS) applications aimed to improve safety, efficiency and comfort on our roads put high demands on the underlying wireless communication system. To gain better understanding of the limitations of the 5.9 GHz frequency band and the set of communication protocols for medium range vehicle to vehicle (V2V) communication, a set of field trials with CALM M5 enabled prototypes has been conducted. This paper describes five different real vehicle traffic scenarios covering both urban and rural settings at varying vehicle speeds and under varying line-of-sight (LOS) conditions and discusses the connectivity (measured as Packet Reception Ratio) that could be achieved between the two test vehicles. Our measurements indicate a quite problematic LOS sensitivity that strongly influences the performance of V2V-based applications. We further discuss how the awareness of these context-based connectivity problems can be used to improve the design of possible future cooperative ITS safety applications.
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| 34. |
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| 35. |
- Lanau, Maud, 1989, et al.
(författare)
-
The Industrial Ecology of the Göteborg City Region — a first appraisal
- 2015
-
Ingår i: International Society for Industrial Ecology 2015.
-
Konferensbidrag (refereegranskat)abstract
- An infrastructure system – here, the industrial ecology of Gothenburg — is more important for society than we usually credit it for (cf. Technology is society made durable, Latour 1990) and is taken for granted by most inhabitants. Gothenburg is an unusually well-developed and interconnected infrastructure system. The first district heating facility was put in operation in 1952. Soon enough, waste was re-used and recycled into energy, into both electricity and heat. With time, more varied materials and sources became integrated into the system to also produce biogas and compost. The project makes a historiographic description of how the industrial ecology of the Gothenburg city region developed since the Gothenburg technical environmental flow system is unique in size, age, diversity of flows and functions. The study describes environmental flows and their actors in a networked organization. The focus on interconnectivity of the different actors, flows and sectors of Gothenburg requires the combination of several theoretical fields. Such theoretical fields include Networked Learning, which takes a relational stance in which learning takes place both in relation to others, and in relation to learning resources (Dirckinck-Homfeld et al., 2009); STS (Science Technology and Society), which study how technical innovation are affected by social, political and cultural values, and how these innovation affect, in turn, political, social and cultural values; (Joerges & Novotny, 2003); and Urban Metabolism, which uses models to facilitate the description and analysis of the flows of the energy and materials within cities, such as Material Flow Analysis of a city, and provides a metaphorical framework to study the interactions of natural and human systems in specific regions. Preliminary findings will be presented.
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| 36. |
- Soleimani-Chamkhorami, Khosro, et al.
(författare)
-
Identifying climate-related failures in railway infrastructure using machine learning
- 2024
-
Ingår i: Transportation Research Part D. - : Elsevier. - 1361-9209 .- 1879-2340. ; 135
-
Tidskriftsartikel (refereegranskat)abstract
- Climate change impacts pose challenges to a dependable operation of railway infrastructure assets, thus necessitating understanding and mitigating its effects. This study proposes a machine learning framework to distinguish between climatic and non-climatic failures in railway infrastructure. The maintenance data of turnout assets from Sweden’s railway were collected and integrated with asset design, geographical and meteorological parameters. Various machine learning algorithms were employed to classify failures across multiple time horizons. The Random Forest model demonstrated a high accuracy of 0.827 and stable F1-scores across all time horizons. The study identified minimum-temperature and quantity of snow and rain prior to the event as the most influential factors. The 24-hour time horizon prior to failure emerged as the most effective time window for the classification. The practical implications and applications include enhancement of maintenance and renewal process, supporting more effective resource allocation, and implementing climate adaptation measures towards resilience railway infrastructure management.
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| 37. |
- Ek, Kristine, 1975, et al.
(författare)
-
A harmonized method for automatable life cycle sustainability performance assessment and comparison of civil engineering works design concepts
- 2020
-
Ingår i: IOP Conference Series: Earth and Environmental Science. - : IOP Publishing. - 1755-1307 .- 1755-1315. ; 588:5
-
Konferensbidrag (refereegranskat)abstract
- The life cycle sustainability performance of civil engineering works is increasingly important. The possibility to influence the sustainability of a project design is larger in the conceptual stage than in later stages. Better-informed decisions regarding design choices’ impact on sustainability can be made by comparing conceptual project designs based on an assessment of their life cycle sustainability performance. It is essential that concepts are assessed in a harmonized way and compared impartially. Current standards provide the general framework for the assessment of sustainability performance, but do not give detailed guidance on calculation of sustainability indicators and their aggregation. Since design in automated systems is becoming increasingly common, there is a growing need for machine-readable data and automatable assessment methods. Assessment methods which can be applied using open-access data is important to achieve fair competition. This paper aims to provide a method for life cycle sustainability performance assessment and comparison of civil engineering works design concepts, possible to apply using open-access Environmental Product Declarations (EPDs) and life cycle assessment (LCA) data. The purpose is to enable fair and automatable sustainability assessments of design concepts, to facilitate impartial comparisons of such assessments as a basis for choosing sustainable designs. A literature review of relevant standards and scientific papers on sustainability assessment of construction and civil engineering works was performed. A harmonized, fair and automatable method for life cycle sustainability assessment and comparison of civil engineering works design concepts, well-suited for optimization purposes, is presented. However, the aim currently limits categories and indicators possible to include. The proposed method includes guidance on the calculation of environmental, social and economic indicators, based on LCA, life cycle costing (LCC) and external costs, and aggregation using normalisation and weighting factors of the Product Environmental Footprint (PEF). The proposed method allows for an impartial comparison of the sustainability of design concepts, resulting in better-informed decisions.
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| 38. |
- Andersson-Sköld, Yvonne, 1957-, et al.
(författare)
-
Mikroplast från däck- och vägslitage : en kunskapssammanställning
- 2020
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Denna kunskapssammanställning handlar om mikroplast från vägtrafikens däck- och vägslitage. Eftersom kunskapen om mikroplaster från vägtrafiken är begränsad samtidigt som däckslitage bedöms vara den största källan till utsläpp av mikroplast i Sverige, gav regeringen inom ramen för sitt arbete med plast och mikroplast Statens väg- och transportforskningsinstitut (VTI) i uppdrag att under 2018– 2020 ta fram och sprida kunskap om mikroplast från vägtrafiken. Varje kapitel i denna rapport sammanfattar befintlig kunskap om mikroplast från vägtrafiken avseende en eller flera aspekter. Dessa aspekter är: källor, spridning och förekomst; miljö- och hälsoeffekter samt risker; egenskaper och kemisk sammansättning; däck- och vägslitage; provtagningsmetoder; analys- och provberedningsmetoder samt åtgärder. Dessutom finns ett kapitel med sammanfattande slutsatser och allra sist ett kapitel om forsknings-, utvecklings- och utredningsbehov.Syftet med rapporten är att den ska utgöra ett underlag för att minska emissioner och spridning av mikroplast från vägtrafiken. Ett mål med rapporten är att sammanställa och sprida kunskap om mikroplast från däck- och vägslitage och att redogöra för nuvarande kunskapsläge. Ytterligare ett mål är att identifiera kunskaps- och forskningsbehov avseende mikroplast från vägtrafiken.Underlaget till denna kunskapssammanställning utgörs av vetenskapliga artiklar och rapporter samt facklitteratur och information från branschen och från experter.
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| 39. |
- Carneiro, Erica, et al.
(författare)
-
Potential improvements in the life-cycle performance of support structures for onshore wind turbines – an interview study in Sweden
- 2022
-
Ingår i: Proceedings of XXIV Nordic Concrete Research Symposium.
-
Konferensbidrag (refereegranskat)abstract
- Wind energy is one of the fastest growing renewable energy sources thanks to its cost-effectivity and sustainability. This paper investigates how construction and maintenance of support structures for onshore wind turbines can be improved. Interviews were performed to identify potential areas for improvement in design, construction, operation, maintenance, and end-of-life. Defects due to poor detailing in design and construction have been recurring and may have important consequences. More structured data collection during the construction stages and more robust inspection protocols can help to ensure adequate life-cycle performance of the support structures. Possibilities to reuse and recycle foundations by the end of the turbine’s operational lifetime, which remain unexploited and unresearched, are also discussed.
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| 40. |
|
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| 41. |
- Garmabaki, Amir H. Soleimani, et al.
(författare)
-
A Survey on Underground Pipelines and Railway Infrastructure at Cross-Sections
- 2019
-
Ingår i: Proceedings of the 29th European Safety and Reliability Conference (ESREL 2019). - Singapore : Research Publishing Services. ; , s. 1094-1101
-
Konferensbidrag (refereegranskat)abstract
- Underground pipelines are an essential part of the transportation infrastructure. The structural deterioration of pipelines crossing railways and their subsequent failures are critical for society and industry resulting in direct and indirect costs for all the related stakeholders. Pipeline failures are complex processes, which are affected by many factors, both static (e.g., pipe material, size, age, and soil type) and dynamic (e.g., traffic load, pressure zone changes, and environmental impacts). These failures have serious impacts on public due to safety, disruption of traffic, inconvenience to society, environmental impacts and shortage of resources. Therefore, continuous and accurate condition assessment is critical for the effective management and maintenance of pipeline networks within transportation infrastructure. The aim of this study is to identify failure modes and consequences related to the crossing of pipelines in railway corridors. Expert opinion have been collected through two set of questionnaires which have been distributed to the 291 municipalities in the whole Sweden. The failure analysis revealed that pipe deformation has higher impact followed by pipe rupture at cross-section with railway infrastructure. For underground pipeline under railway infrastructure, aging and external load gets higher ranks among different potential failure causes to the pipeline.
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| 42. |
- Shu, Jiangpeng, 1987, et al.
(författare)
-
Field Destructive Testing of a Reinforced Concrete Bridge Deck Slab
- 2020
-
Ingår i: Journal of Bridge Engineering. - : American Society of Civil Engineers (ASCE). - 1084-0702 .- 1943-5592. ; 25:9
-
Tidskriftsartikel (refereegranskat)abstract
- Many bridge deck slabs in Europe are rated insufficient load-carrying capacity in shear and punching according to the Eurocodes. In the past, assessment models have mainly been developed from laboratory studies that simplified real-world conditions. Large-scale or full-scale field experiments are needed to validate more recent improved models. The goal of this study is to calibrate improved models using data obtained from a full-scale bridge deck slab shear test; the objective is to exploit and share our findings and to make recommendations for the planning, design, and implementation of such a complex experiment. Full-scale destructive tests of a 55-year-old reinforced concrete bridge deck slab on prestressed concrete girders were conducted to calibrate a model used to assess existing bridges. Concrete properties were also tested to evaluate the condition of the bridge. Results show that both the load-carrying capacity of the bridge deck slab and the strength of the concrete were much greater than were assumed in design. Finite-element analysis of the parameters governing loading positions and prestress in the girders showed that arch action and boundary condition simplification had important effects on shear distribution.
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| 43. |
- Adl-Zarrabi, Bijan, 1959, et al.
(författare)
-
Safe and Sustainable Coastal Highway Route E39
- 2016
-
Ingår i: Transportation Research Procedia. - : Elsevier BV. - 2352-1465 .- 2352-1457. ; 14, s. 3350-3359
-
Konferensbidrag (refereegranskat)abstract
- The project “Coastal Highway Route E39” have a mandate to, investigate how infrastructure can exploit renewable energy to reduce environmental footprint. Three PhD projects were initiated on this subject at Chalmers University of Technology by Norwegian public road administration. Results in this paper conclude that (1) Life Cycle Assessment should have a geographical dimension with respect to assumptions and input data, (2) there are substantial potential to reduce the CO2 emissions from the E39, especially when considering an electrification, and (3) the harvested energy from hydronic pavement system can be enough for maintaining ice-free roads in Nordic countries.
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| 44. |
- Berghauser Pont, Meta, 1972, et al.
(författare)
-
INTEGRATED URBAN ENVIRONMENT EFFECT ANALYSIS OF INFRASTRUCTURAL TRANSFORMATIONS
- 2022
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The report presents the method developed within the research project ‘Stadsmiljöanalys- Analys av tätbebyggda miljöer i infrastrukturprojekt’, funded by Trafikverket (Swedish Transport Authority). This project sets up an integrated methodology for analysing and estimating the local impact of road and rail infrastructure projects in urban environments, either by way of new infrastructure or by way of retrofits, focusing on socioeconomic, environmental, and cultural-historical effects. While the focus is on national transport infrastructure investments, the method addresses local effects. This stems from the acknowledgement that each infrastructure investments results in a redistribution of accessibility where increasing accessibility on a regional and interurban scale might create encroachments on a local scale including the reduction of the usability of areas near to the infrastructure due to emissions and noise, risk of accidents, negative impacts on wildlife as well as barrier effects. It is these encroachments this method aims to highlight with the aim to reduce negative trade-offs of new or transformed transport infrastructure and recognize both local opportunities and sensitivities. In this project the direct effects of infrastructure projects in relation to the three perspectives (socioeconomic, environmental, and cultural-historical are described and measured in a precise manner through a series of spatial analyses. The cumulative, indirect, effects and broader consequences are also assessed, in relation to the sustainable development goals. The overall assessment methodology is based on a before-and-after analysis workflow, systematically comparing the existing situation (how it is, how it functions, how it affects people) to the future scenarios proposed by planning. The methodology is showcased using two infrastructural transformations projects in Söderköping and Mölndal, Sweden, as case studies. The overarching goal of the research project is to contribute to an improved integration between infrastructure and local urban areas and communities in projects initiated and developed by the Swedish Transport Authority, Trafikverket. The presented methodology builds on the ILKA (Integrerad landskapskaraktärsanalys) method, currently used by the Swedish Transport Authority. While ILKA focuses mainly on the inventory of the current landscape on a regional scale, this project widens the scope to also address urban areas and to include, besides the ecological descriptions, also socio-economic and cultural-historical analysis that are currently less emphasized. Such an integrated method can improve the ability of the Swedish Transport Authority to develop projects that contribute to sustainable urban development and, furthermore, create a unified work procedure in the organization.
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| 45. |
- Gschösser, Florian, et al.
(författare)
-
Environmental analysis of new construction and maintenance processesof road pavements in Switzerland
- 2012
-
Ingår i: Structure and Infrastructure Engineering. - : Informa UK Limited. - 1573-2479 .- 1744-8980. ; 10:1, s. 1-24
-
Tidskriftsartikel (refereegranskat)abstract
- The subject of this paper is an environmental analysis of processes needed to construct (material production,pavement construction, transport) and maintain (pavement deconstruction, recycling, material production,pavement construction, transport) representative Swiss asphalt, concrete and composite pavements (includingsubbase layers). The analysed environmental indicators are the IPCC Global Warming Potential indicator, theEcological Scarcity Indicator and the Non-renewable Cumulative Energy Demand indicator. It is shown thatmaterial production processes have the largest impact on the values of the analysed indicators, and that pavementconstruction and deconstruction processes have a marginal impact on the analysed indicators in comparison tomaterial production, transport and recycling processes. It is also demonstrated that the values of the IPCC GlobalWarming Potential indicator and the Ecological Scarcity indicator for the processes needed to construct andmaintain concrete and composite pavements are higher than those for all processes required to construct andmaintain asphalt pavements, due to the greater thickness of concrete and composite pavements. The values of theNon-Renewable Cumulative Energy Demand indicator are higher for processes applied to construct and maintainasphalt pavements than for concrete pavements, due to the use of bitumen within asphalt pavements, which causes adepletion of fossil energy resources.
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| 46. |
-
European Energy Pathways - Pathways to sustainable european energy systems
- 2011
-
Samlingsverk (redaktörskap) (refereegranskat)abstract
- To meet the challenge of climate change, the world must substaintially reduce emissions of greenhouse gases (GHGs). this must be accomplished in a way that maintains security of supply and competitiveness.This book presents to pathways towards sustainable European energy systems - the "Policy Pathway" and the "Market Pathway". These to pathways differ with respect to where the main responsability lies for transforming the energy system in following the pathway. The Policy pathway takes its departure from the EU Energy and Climate Package, and has a strong focus on targeted policies that promote energy efficiency and energy from renewable sources. The Market Pathway relies more on the market to transform the energy system, and presents a future in which the cost associated with emitting CO2 (and other GHGs) is the dominating policy measure.This book describes the research that has been carried out during the first period (2006-2010) of the AGS project "Pathways to Sustsainable Energy Systems". This interdisciplinary project involved more than 40 researchers and addressed various aspects of the challenges faced in transforming the European energy system. The chapters in this book cover more than 30 topics and presents an overall picture of the results obtained to date from various activities in the Pathways project.
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| 47. |
- Rempling, Rasmus, 1976, et al.
(författare)
-
Research Roadmap - Information Integration in Construction
- 2019
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This Roadmap is developed for a challenging Global environment where fundamental paradigms such as data generation and analysis, are shifting at a seismic rate, while change in Construction Industries across the Globe is, in the main, confined to large-scale projects and slow. Against this background, the authors set out to also give a ‘voice’ to small-to-medium scale projects through which the construction output Worldwide is delivered. Hence, project scale was one of the key considerations throughout this Roadmap. Moreover, the authors conceptualized data integration by taking the realities of doing business’ in construction into consideration. The emergent framework facilitates the discussion of knowledge and data integration at organisational, team, operational and technical levels across key project phases. This approach recognizes that business is done through projects but change can only come about if appropriate organizational structures and processes are put in place. Last, but not least, the authors strived to ensure that data integration was not considered solely from a technical perspective. Organisational, team and individual aspects of data integration were integrated in the research framework. Through our work the individual’s willingness to collaborate emerged as a critical driver for high levels of integration, while our survey did identify “Reluctance to work across professional boundaries” as a major barrier to integration. Hence, we conclude that research on integration should pay due attention to the individual.
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| 48. |
- Gschösser, Florian, et al.
(författare)
-
Hidden Ecological Potentials in the Production of Materials for Swiss Road Pavements
- 2012
-
Ingår i: Journal of Management in Engineering - ASCE. - 0742-597X. ; 27:1, s. 13-21
-
Tidskriftsartikel (refereegranskat)abstract
- Sustainability has become a major concern in the field of civil infrastructures in recent years. Developing road construction projects with lower ecological impacts over a project’s entire life cycle can help in making road infrastructure contribute to sustainable development. This study focuses on the ecological potentials in the production of road materials used in Swiss road pavements. The environmental assessment was performed using a cradle-to-gate life-cycle assessment (LCA) approach in which all processes from the raw material extraction to the finished product were considered. The comparison of the results of the best-case asphalt pavement and the standard asphalt pavement for Swiss highway construction shows ecological potentials of up to 55%. Use of the best-case concrete pavement lowers the environmental impact by up to 53% in comparison to the worst-case concrete pavement for Swiss highways. Concerning composite pavements, the best-case variant offers an ecological potential 38% higher than the standard pavement.
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| 49. |
- Heshmati, Mohsen, 1987, et al.
(författare)
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On the strength prediction of adhesively bonded FRP-steel joints using cohesive zone modelling
- 2018
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Ingår i: Theoretical and applied fracture mechanics (Print). - : Elsevier BV. - 0167-8442 .- 1872-7638. ; 93, s. 64-78
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Tidskriftsartikel (refereegranskat)abstract
- The variety of failure modes that are likely to occur in fibre-reinforced polymer (FRP)/steel joints used in the construction industry adds to the complexity associated with the design of these joints. This variation in possible failure modes is mainly attributed to the lack of a controlled application environment and to rather insufficient quality assurance protocols and procedures. The use of energy-based methods such as, cohesive zone modelling (CZM), can be a solution to circumvent such complexities. This paper investigates a number of issues related to CZM analyses of FRP/steel adhesive joints using various test configurations and a comprehensive numerical study. Parameters such as the effect of shape and type of cohesive law, crack path location, length of damage process zone, variations of adhesive and FRP properties, and different failure modes including cohesive, interfacial debonding and FRP failure on the strength of joints are investigated. The results show that the behaviour of the tested joints is accurately predicted provided that the variation of failure modes are taken into account. Moreover, it is shown that the damage process zone in adhesive layer is directly proportional to the shape of cohesive laws. This feature can be employed in the design phase to ensure sufficient overlap length and to account for important in-service parameters such as temperature and moisture.
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| 50. |
- Li, Ying Zhen
(författare)
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Study of fire and explosion hazards of alternative fuel vehicles in tunnels
- 2018
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- An investigation of fire and explosion hazards of different types of alternativefuel vehicles in tunnels is presented. The different fuels are divided into four types:liquid fuels, liquefied fuels, compressed gases, and electricity, and detailed parameters are obtained. Three types offire hazards for the alternativefuel vehicles: pool fires, jet fires and fireballs are identified andinvestigated in detail. Fromthe perspective of pool fire size, the liquid fuels pose equivalent or evenmuch lower fire hazards compared to the traditionally used fuels, but theliquefied fuels may pose higher hazards. For pressurized tanks, the fires are generally much larger in size butshorter in duration. The gas releases from pressure relief devices and the resulting jet firesare highly transient. Forhydrogen vehicles, the fire sizes are significantly higher compared to CNGtanks, while flame lengths only slighter longer. Investigation of the peakoverpressure in case of an explosion in a tunnel was also carried out. Theresults showed that, for the vehicles investigated, the peak overpressure of tankrupture and BLEVE are mostly in a range of 0.1 to 0.36 bar at 50 m away. Thesituations in case of cloud explosion are mostly much more severe andintolerable. These hazards need to be carefully considered in both vehiclesafety design and tunnel fire safety design. Further researches on thesehazards are in urgent need.
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