| 41. |
- Löfgren, Simon
(författare)
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Set-Based Design of Frame Bridges - Development and Implementation
- 2020
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The traditional design process of bridges in structural engineering is based on the design approach called Point-Based design. To minimize environmental impact and industrialize the design process, the theory of Set-Based design (SBD) has been recognized as a promising approach. Since frame bridges is one of the most common bridge types in Sweden, the main objective of this thesis is to develop and implement a SBD tool for frame bridges. To be able to evaluate the different design alternatives generated by the design tool, evaluation criteria within buildability and sustainability are identified. Buildability is a concept within building industry that aims to improve productivity and safety within on-site production while also reducing the costs of the construction process. The building industry is one of the major contributors regarding impact on its surrounding. Therefore, there is a huge potential in improving the sustainability within the building industry. Sustainability is divided in Environment, Social and Economy aspects. The design tool allows performing an automated and iterative structural preliminary design of several frame bridge alternatives specified within ranges of design parameters. The design alternatives are analyzed with Finite Element Analysis (FEA) and evaluated according to predefined evaluation criteria. By scripting the design tool in programing language Python, it is possible to control an FEA program, such as Brigade Plus, from the design tool as well as performing a preliminary design of frame bridges. The preliminary design is performed according to requirements in national building codes, Eurocode. Finally, a case study is performed to investigate how a SBD tool can be implemented in an infrastructure project containing several frame bridges. In a large infrastructure project and with a SBD tool it is possible to find one optimum bridge solution that fulfills the need of several bridges in a set of bridges. The contractor can then industrialize parts of the construction of frame bridges, hopefully leading to a more sustainable and cost-effective building of frame bridges.
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| 42. |
- Mangold, Mikael, 1982, et al.
(författare)
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Who benefits? Effects and perceptions of residential volumetric water billing
- 2012
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Ingår i: 2nd Nordic Conference on Consumer Research, 29 May-1 June, 2012, Göteborg.
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Konferensbidrag (refereegranskat)abstract
- What are the effects and perceptions of increased installation of water metering and volumetric billing in residential areas in Sweden? An interview study was undertaken in a low-income suburb of Göteborg to explore residents’ experiences and opinions. Additionally, the interests of water and energy companies, social affairs committee, real estate owner and maintainer were investigated to contrast the added value of reduced water consumption. Stakeholders either benefit or are disadvantaged by the introduced system. Furthermore, the applied tariff structure fails to motivate all segments of the population to reduce water consumption, yet still inequitably burdens the most financially exposed groups.
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| 43. |
- 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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| 44. |
- Rempling, Rasmus, 1976, et al.
(författare)
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Research Roadmap - Information Integration in Construction
- 2019
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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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| 45. |
- Aygül, Mustafa, 1970, et al.
(författare)
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A comparative study of different fatigue failure assessments of welded bridge details
- 2013
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Ingår i: International Journal of Fatigue. - : Elsevier BV. - 0142-1123. ; 49:0, s. 62-72
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Tidskriftsartikel (refereegranskat)abstract
- Five different welded joints frequently used in steel bridges have been selected to investigate the accuracy and applicability of three fatigue assessment methods. The first method, also categorised as the global method, is the nominal stress method, while the more advanced methods are the hot spot and the effective notch stress methods. Solid element based finite element models for welded bridge details were created by following the modelling requirements of each fatigue assessment method. A statistical evaluation based on the results of the finite element analyses and the fatigue test data collected from the literature was performed to determine the mean and characteristic fatigue strength. In addition, the standard deviation for each data series was also determined to conclude how well each method describes the fatigue strength of each welded detail. A method with a lower standard deviation is regarded as more accurate. Moreover, the evaluated results from each method were compared with the recommended fatigue strength values in the Eurocode 3 (EN 1993-1-9:2005) and IIW codes. In the light of the test results in this study, it appears that the codes are in reasonable agreement with the test data, even though a few examples of the opposite occurred. The conclusion based on the revised results in this article indicates that the nominal stress method yields satisfactory results, despite its simplicity. When considering the effort involved in creating FE models for numerical analysis, it seems clear that the choice of the nominal method is fairly acceptable.
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| 46. |
- Blomfors, Martin, et al.
(författare)
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Reliability analysis of corroded reinforced concrete beam with regards to anchorage failure
- 2019
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Ingår i: Life-Cycle Analysis and Assessment in Civil Engineering. - : CRC Press/Balkema. - 9781138626331 - 9781351857574 ; , s. 337-344, s. 337-344
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Konferensbidrag (refereegranskat)abstract
- Reinforcement corrosion is a common problem in reinforced concrete infrastructure today, and it is expected to increase in the future. To simply replace the corroded structures with new ones requires large resources, both in financial and environmental terms. Therefore it is important that existing structures are used to their full potential, also after the onset of corrosion. This paper presents a reliability study of the anchorage capacity of a reinforced concrete beam including reinforcement corrosion. The sensitivity of the different input parameters is also studied. As expected, the results show that the reliability is reduced with corrosion; the magnitude depends to a large extent on the modelling uncertainty used for the bond model for corroded reinforcement. The sensitivity analysis shows an influence of corrosion also on the sensitivities of the input parameters, which is expected based on the properties of the underlying bond model. This paper demonstrates that probabilistic evaluations give valuable insight of the reliability, which can be used to prolong the service-life of existing infrastructure and save both money and the environment.
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| 47. |
- Jockwer, Robert, 1984, et al.
(författare)
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Design for adaption - making timber buildings ready for circular use and extended service life
- 2021
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Ingår i: World Conference on Timber Engineering 2021, WCTE 2021.
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Konferensbidrag (refereegranskat)abstract
- The use of timber and the implementation of the concept of circularity in the process of the construction of buildings potentially has a high sustainability impact, both from the perspective of material and construction technique. The three most effective ways to ensure the benefit of the circularity in the building sector in general are (1) maintain the service life of structures and buildings materials as long as possible to avoid unnecessary emissions and costs for demolition and reconstruction (2) conserve the quality of materials as long as possible to avoid unnecessary emissions and costs for the replacement and processing of new materials and (3) recycle and repurpose only the parts and materials which cannot function any more for technical and/or socio-cultural reasons. In this paper an approach is discussed towards a more sustainable built environment by making buildings adaptable to the changes of demands and requirements to building functions and thus leading to an extended use of buildings in a maximum of life cycles. This design for adaption may enhance economic, social and environmental benefits to various stakeholders and key players related to the building process, i.e. developers, building owners, users, municipality and others.
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| 48. |
- Thunberg, Micael, 1986-, et al.
(författare)
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Categorising on-site problems : A supply chain management perspective on construction projects
- 2017
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Ingår i: Construction Innovation. - : Emerald Group Publishing Limited. - 1471-4175 .- 1477-0857. ; 17:1, s. 90-111
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Tidskriftsartikel (refereegranskat)abstract
- Purpose - This study aims to identify and categorise common on-site problems from a supply chain management (SCM) perspective and to trace the origin of these problems in the construction project process, the supply chain or in the intersection between these processes. This allows for identification of how on-site problems affect SCM in construction projects and how they can be mitigated. Design/methodology/approach - A literature review in combination with semi-structured interviews was used to identify on-site problems. This enabled triangulation and strengthened both construct validity and internal validity. Findings - On-site problems can be categorised in one of the four following categories: material flows, internal communication, external communication or complexity. The first category has its origin in the supply chain, the second in the construction project process, the third in the supply chain-construction process intersection on site and the fourth in the construction project as a whole. The findings conclude that on-site problems often originate from construction companies' lack of supply chain orientation. Research limitations/implications - It is suggested that supply chain planning (SCP) can facilitate on-site problem mitigation in construction project management. This extends the body of knowledge of SCP in construction project management and supports the development of effective on-site construction project management. Practical implications - The results show that SCP can aid construction project management in handling on-site problems earlier in the project process. Originality/value - The main value lies in extending the body of knowledge in construction project management research by applying an SCM perspective and by introducing SCP to support more effective construction project management.
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| 49. |
- 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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| 50. |
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