| 1. |
- Desivyana, Nindya, 1997, et al.
(författare)
-
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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| 2. |
- 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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| 3. |
- Mathern, Alexandre, 1986
(författare)
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Addressing the complexity of sustainability-driven structural design: Computational design, optimization, and decision making
- 2021
-
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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| 4. |
- Mathern, Alexandre, 1986, et al.
(författare)
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Concrete Support Structures for Offshore Wind Turbines: Current Status, Challenges, and Future Trends
- 2021
-
Ingår i: Energies. - : MDPI AG. - 1996-1073 .- 1996-1073. ; 14:7
-
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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| 5. |
- Sundell, Jonas, 1984, et al.
(författare)
-
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
-
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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| 6. |
- Sundell, Jonas, 1984, et al.
(författare)
-
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. |
- Adam, Abderisak, 1988, et al.
(författare)
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How task heterogeneity and frequency relates to knowledge codification: Evaluating the Shared Construction Guidelines (SCG) of 24 Swedish Public Client Organizations
- 2017
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Ingår i: 9th Nordic Conference on Construction Economics and Organization. ; , s. 1-9
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Konferensbidrag (refereegranskat)abstract
- Over a sustained period of time, organizational theorists have argued that public sector organizationsare more inefficient than their private counterparts. Recent studies have explained these inefficienciesas the result of having to do with capabilities rather than resources thereby calling for an improvementof the capabilities of public organizations. A key mechanism for achieving such improvements is thearticulation and codification of knowledge. This study examines an attempt at codifying knowledge inthe form of a set of shared construction guidelines (SCG) employed by 24 large public clientorganizations in the Municipality of Gothenburg, Sweden. Specifically, these guidelines are viewedwith respect to the framework of Zollo and Winter (2002) in terms of how organizations with high taskheterogeneity and low task frequency can more effectively develop dynamic capabilities through thedeliberate learning mechanism of knowledge codification. Preliminary results indicate that taskfrequency and organizational size are stronger indicators than heterogeneity in deciding whether apublic client organization utilizes knowledge codification systems such as the SCG.
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| 8. |
- Adam, Abderisak, 1988
(författare)
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Managing construction challenges: Viability of a dynamic capabilities approach for the public client
- 2016
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Construction clients in the public sector face a large number of challenges in designing, procuring and managing construction projects in a manner that is conducive to the organization’s overall goals. In particular, clients have faced challenges in delivering projects that satisfied the projects’ goals with respect to cost overruns, delays and sustainable construction. The role of the client in managing these challenges has more recently been emphasized with a growing number of studies and governmental reports calling for the development of the client’s capabilities.This thesis examines the capabilities of the construction client through a dynamic capabilities framework, particularly with respect to the activities of sensing, seizing and transforming. Furthermore, the thesis explores whether the concept of dynamic capabilities is a viable approach for understanding how to manage the clients’ capabilities in a way that ensures that construction-related challenges are addressed. The thesis is based primarily on a case study of a large public construction client located in Sweden.Findings are presented in three appended papers. The thesis concludes with a discussion on the viability of using a dynamic capabilities framework in the specific case described in this thesis. It is argued that the concept of dynamic capabilities is inadequate for capturing the specific context in which public client organizations operate. Suggestions for alternative approaches to understanding the management and development of capabilities are then discussed.
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| 9. |
- Mathern, Alexandre, 1986, et al.
(författare)
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Lessons learned from the construction, inspection, and defect assessment of reinforced concrete foundations for wind turbines
- 2022
-
Ingår i: Applied Sciences (Switzerland). - : MDPI AG. - 2076-3417. ; 12:3
-
Tidskriftsartikel (refereegranskat)abstract
- Foundations of wind turbines are subject to challenging conditions during their service life as they support ever larger wind turbines under complex loading situations. There have been numerous reports of cracked concrete foundations of wind turbines. Cracking can impair the durability and serviceability of the foundations, thereby leading to very expensive repairs or even to premature failure of the structure. To avoid cracking-related problems and improve the quality of concrete foundations, it is important to gather information and experience from the production stage and its outcome. However, although problems and defects in the construction of wind turbine foundations are widespread, they have very seldom been documented and reported, in particular from a contractor’s perspective. This article analyses and critically reviews data collected during the production, inspection, diagnosis, and repair activities conducted in relation to the construction of foundations for a wind farm project in Sweden. The extent of defects observed on individual foundations is assessed and used to investigate the eventual relation between the observed deviations and different production aspects. Investigation methods to determine the importance of these defects and their consequences and possible remediation measures are also discussed. Finally, recommendations are proposed to improve the quality control of wind turbine foundations.
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| 10. |
- Williams Portal, Natalie, 1986, et al.
(författare)
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Bending behaviour of novel Textile Reinforced Concrete-foamed concrete (TRC-FC) sandwich elements
- 2017
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Ingår i: Composite Structures. - : Elsevier BV. - 0263-8223 .- 1879-1085. ; 177, s. 104-118
-
Tidskriftsartikel (refereegranskat)abstract
- A novel sandwich element design consisting of two facings made of carbon reinforced Textile Reinforced Concrete (TRC), a low density foamed concrete (FC) core and glass fibre reinforced polymer (GFRP) connecting devices was experimentally investigated according to quasi-static and cyclic quasi-static four-point bending. Optical measurements based on Digital Image Correlation (DIC) were taken during testing to enable a detailed analysis of the bending behaviour and level of composite action. A model, verified by the experiments, was developed based on non-linear finite element analysis (NLFEA) to gain further insight on the failure mechanisms. Under both loading conditions, the bending behaviour of the TRC-FC composite elements was characterized by favourable load bearing capacity, partial composite action, superior ductility and multiple fine cracking. The connecting devices were found to be the critical elements causing the initial failure mechanism in the form of localized pull-out within an element.
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| 11. |
- Rempling, Rasmus, 1976, et al.
(författare)
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Performance requirements for Swedish transport infrastructure - A pre-study of challenges and possibilities
- 2022
-
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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| 12. |
- Adl-Zarrabi, Bijan, 1959, et al.
(författare)
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Safe and Sustainable Coastal Highway Route E39
- 2016
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Ingår i: Transportation Research Procedia. - : Elsevier BV. - 2352-1465 .- 2352-1457. ; 14, s. 3350-3359
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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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| 13. |
- Dymitrow, Mirek, et al.
(författare)
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Crossing dichotomies and breaking mental patterns: Green business development when all else fails?
- 2017
-
Ingår i: 8th International Scientific Conference “Rural Development 2017: Bioeconomy Challenges”, 23–24 November, 2017 Kaunas, Lithuania.
-
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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| 14. |
- Crocetti, Roberto, et al.
(författare)
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Stress-laminated-timber decks: state of the art and design based on Swedish practice
- 2016
-
Ingår i: European Journal of Wood and Wood Products/Holz als Roh - und Werkstoff. - : Springer Science and Business Media LLC. - 1436-736X .- 0018-3768. ; 74:3, s. 453-461
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Tidskriftsartikel (refereegranskat)abstract
- Stress-laminated-timber (SLT) bridge decks area valid alternative to conventional short- and medium-spanbridges in terms of cost and performance. SLT decks aremade from a number of planks or glulam beams positionedside by side and stressed together using high-strength steelbars. A concentrated load can therefore be distributed fromthe loaded beams onto adjacent beams due to the resistingfriction caused by the pre-stressing of all beams in thedeck. This paper describes the state of the art of SLT bridgedecks, with special emphasis on Swedish practice. Theeffect of butt joints on deck deflection and solution appliedto accommodate the loss of pre-stress are shown. Simpledesign tools for the preliminary design of road bridges areillustrated. Best practice with regard to some detailing,water protection and durability is also discussed. Finally,possible developments of SLT bridges are discussed.
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| 15. |
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| 16. |
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| 17. |
- 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
-
Ingår i: Rock Mechanics and Rock Engineering. - : Springer. - 0723-2632 .- 1434-453X. ; 53:3, s. 1349-1358
-
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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| 18. |
- Desivyana, Nindya, 1997, et al.
(författare)
-
Sustainability Driven Procurement of Building Projects Incentives and Driving Factors from the Clients’ Perspective
- 2023
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The construction industry is reported as one of the biggest global industries which accounted 30% global greenhouse gas emissions. The challenge of the construction industry is not merely on the reduction of emissions, but also extended towards other aspects of sustainability, consisting of the environmental, social, and economic pillars of sustainability. Sweden took action to handle the environmental issues by targeting on being climate neutral by 2045. Hence, the Swedish National Board of Housing, Building, and Planning, commonly known as Boverket, took more detailed action by stipulating climate declaration for all new buildings. The property developers play a vital role to boost sustainability in Sweden, since they have an increased influence in the hierarchy of the construction industry. In this case, the drivers of sustainable development in the construction industry are partially reliant on the clients’ requirements requested in every project, as well as their ethics and initiatives. Therefore, this study investigates the state-of-the-art sustainable practices among property developers in Sweden to identify the main challenges in applying sustainable criteria during the procurement phase. This study was carried out by qualitative research which consists of a literature review and an empirical study of semi-structured interviews. This study resulted in the identification of several common sustainable criteria, covering the three pillars of sustainability and also emphasising the fact that currently the property developers have an increased interest in environmental and economic sustainability, rather than social sustainability. The results of the study also raised the notion of long-term perspective, how it affects the business strategy on sustainability and the different perceptions that exist. The study concludes that the market demand drives the implementation of the agenda on sustainability, among property developers in Sweden, while providing substantial information that could prove useful in the future development of the national agenda and its regulations.
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| 19. |
- 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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| 20. |
- Löfgren, Simon
(författare)
-
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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| 21. |
- 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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| 22. |
- Rempling, Rasmus, 1976, et al.
(författare)
-
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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| 23. |
- 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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| 24. |
- 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
-
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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| 25. |
- Täljsten, Björn, 1961-, et al.
(författare)
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Assessment of prestressed concrete bridges - challenges
- 2020
-
Ingår i: IABSE Symposium, Wroclaw 2020. - Zürich : International Association For Bridge And Structural Engineering (IABSE). ; , s. 487-494
-
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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| 26. |
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| 27. |
- Ståhle, Alexander, et al.
(författare)
-
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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| 28. |
- Adam, Abderisak, 1988, et al.
(författare)
-
Aggregation of factors causing cost overruns and time delays in large public construction projects: Trends and implications
- 2017
-
Ingår i: Engineering, Construction and Architectural Management. - 1365-232X .- 0969-9988. ; 24:3, s. 393-406
-
Tidskriftsartikel (refereegranskat)abstract
- PurposeThe purpose of this paper is to explore the impact that cost overruns and time delays exert on large public construction projects to clarify how past and current research regard factors causing cost overruns and time delays in large public construction projects.Design/methodology/approachThis paper, which is based on an analysis of a literature selection consisting of 40 journal articles, investigates and ranks the occurrence of and the explanations for cost overruns and time delays in large public construction projects. The study makes use of a kiviat diagram/radar chart in order to visualize multivariate data.FindingsAggregated rankings of important causes of cost overruns and time delays are reported. These show a strong emphasis on the management aspect as a primary cause of cost overruns and delays. Additionally, there seems to be a trend toward deemphasizing the role of financial considerations in explaining cost overruns and delays. It is argued that there needs to be a more rigorous assessment of the impact that each factor has on cost increases and delays based on factual observed data as opposed to retrospective accounts from questionnaire respondents.Research limitations/implicationsOnly public construction projects have been considered. The results will not be directly applicable to privately funded construction projects and/or projects of a smaller size.Originality/valueThe use of trend data, as illustrated in a kiviat diagram, showing how different ranking factors causing cost overruns and time delays has changed in importance over time.
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| 29. |
- Adam, Abderisak, 1988, et al.
(författare)
-
Applying the dynamic capabilities framework in the case of a large public construction client
- 2017
-
Ingår i: Construction Management and Economics. - : Informa UK Limited. - 1466-433X .- 0144-6193. ; 35:7, s. 1-12
-
Tidskriftsartikel (refereegranskat)abstract
- Public clients in the construction sector face a number of challenges in designing, procuring and managing major construction projects. The client’s role in bringing about project delivery has more recently been emphasized, particularly with respect to developing capabilities that facilitate the coordinating of projects through its different phases. In line with these developments, this paper sets out to examine the management of capabilities in a client organization through the lens of the dynamic capabilities framework. In particular, what is investigated is how the client organization senses, seizes and transforms opportunities. In pursuit of this objective, an exploratory case study approach is adopted which examines one of Sweden’s largest public client organizations. The study explores the concept of dynamic capabilities and its applicability to the public construction context. Although the usefulness of dynamic capabilities as an interpretive framework is recognized, it is suggested that the concept of dynamic capabilities is inadequate for addressing the specific context in which public client organizations operate. Particularly with respect to the project-based characteristic of these organizations and the difficulty in framing what constitutes “competitive advantage” for public organizations.
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| 30. |
- Haghani Dogaheh, Reza, 1979, et al.
(författare)
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Fatigue-Prone Details in Steel Bridges
- 2012
-
Ingår i: Buildings. - : MDPI AG. - 2075-5309. ; 2:4, s. 456-476
-
Tidskriftsartikel (refereegranskat)abstract
- This paper reviews the results of a comprehensive investigation including more than 100 fatigue damage cases, reported for steel and composite bridges. The damage cases are categorized according to types of detail. The mechanisms behind fatigue damage in each category are identified and studied. It was found that more than 90% of all reported damage cases are of deformation-induced type and generated by some kind of unintentional or otherwise overlooked interaction between different load-carrying members or systems in the bridge. Poor detailing, with unstiffened gaps and abrupt changes in stiffness at the connections between different members were also found to contribute to fatigue cracking in many details.
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| 31. |
- Lundgren, Karin, 1968, et al.
(författare)
-
Tests on anchorage of naturally corroded reinforcement in concrete
- 2015
-
Ingår i: Materials and Structures. - : Kluwer Academic Publishers. - 1359-5997 .- 1871-6873. ; 48:7, s. 2009-2022
-
Tidskriftsartikel (refereegranskat)abstract
- Many studies on the structural effects of corrosion in reinforcement have been conducted. However, most of them are based on artificially corroded test specimens. Thus, the knowledge available entails one major uncertainty, i.e. whether the results are reliable enough to be used for naturally corroded structures. The purpose of this study was to develop a test method and carry out experiments on naturally corroded specimens taken from an existing structure to investigate the anchorage capacity. Beam specimens were taken from the edge beams of a bridge at repair. The specimens showed corrosion-induced damage to a varying extent from no sign of corrosion to extensive cracking and spalling of the concrete cover. A four-point bending test indirectly supported by suspension hangers was chosen. The beams were strengthened with transverse reinforcement around the suspension hangers to avoid premature failure. Eight successful tests were carried out; in all these tests, diagonal shear cracks preceded a splitting induced pull-out failure; i.e. anchorage failure was achieved as intended. The results showed around 10 % lower capacity for the corroded specimens than for the reference ones. The average bond stress in the anchorage zone was estimated based on the applied load and available anchorage length. The stress was about 16 % lower in the beams with corrosion cracks, and 9 % lower in the beams with cover spalling compared to the reference specimens; there was also a larger variation among the damaged specimens than for the reference specimens. The results extend our knowledge concerning the structural behaviour of corroded reinforced concrete structures during field conditions.
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| 32. |
- 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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| 33. |
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| 34. |
- Robuschi, Samanta, 1991
(författare)
-
Natural corrosion in reinforced concrete structures
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Among the threats to the durability of concrete structures, corrosion of the reinforcement bars is undoubtedly the most common one. Corrosion damages impair safety and durability of infrastructure, and assessment of the safety is challenging due to the complex nature of the corrosion process. Furthermore, research on the topic often requires adapting results from short-time laboratory tests, where corrosion of the reinforcement bars is induced using impressed current, to the reality of existing structures. The use of impressed current results in differences in type and distribution of corrosion products. Naturally corroded specimens are hence the necessary bridge between the knowledge acquired from artificially corroded specimens and the application to real structures. This works investigates the structural effects of natural, chloride-induced corrosion in reinforced concrete structures. Specifically, three research questions were investigated. First, the bond and anchorage of naturally corroded plain bars was studied using 3-point bending and pull-out tests. The tests were designed to be applied to specimens taken from a decommissioned bridge from the 1930s. The bond capacity of plain bars was observed to be significantly higher than in results obtained from laboratory tests on similar bars. Significant factors influencing the effect of corrosion damages on the bond were casting position and presence of stirrups. Finite element analyses were used to further investigate the bond-slip behaviour of the tested specimens. The results highlighted the effect of the loss of bond at yielding on the structural behaviour of the specimens. The second question looked into the characteristics of the corrosion products and the surrounding concrete; this is relevant to assess corrosion damages in existing structures. Neutron imaging and X-ray computed tomography were used to obtain qualitative and quantitative data on corrosion damages in a naturally corroded specimens, including iron to rust ratio. Comparison with an artificially corroded specimen showed differences in distribution of the corrosion products. Finally, possible correlations between transversal cracks and corrosion damages was investigated. A dataset was compiled from experiments available in literature. In the selected studies, corrosion of the steel reinforcement resulted from exposing laboratory specimens, pre-cracked in 3-point bending, to chloride environments. No clear correlation between surface crack width and corrosion characteristics was found, but corrosion pits were shown to likely appear in the proximity of transveral cracks. To conclude, this work highlights the complexity of the corrosion process and argues that a thorough understanding of the material and environmental characteristics influencing this process is necessary to properly assess existing structures. Tests on naturally corroded structures are a fundamental step towards acquiring this knowledge.
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| 35. |
- Armesto Barros, Jesús, et al.
(författare)
-
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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| 36. |
- Bergenram, Felicia, et al.
(författare)
-
Parametric Optimization of Slab Frame Bridges Considering Investment Cost, Environmental Impact and Buildability
- 2023
-
Ingår i: Procedia Computer Science. - 1877-0509.
-
Konferensbidrag (refereegranskat)abstract
- This paper presents research performed on set-based multi-criteria optimization for the preliminary design of slab frame bridges. As a result of immense CO2 emissions emerging from concrete production, there is a need for optimization methods decreasing the volume of concrete without affecting the function of the structure. Previous research suggests a general correlation between CO2 footprint- and cost reduction, due to minimized material use. However, the aspect of buildability may conflict with lessened material, as optimized designs might simultaneously be less buildable. This research aimed to develop an optimization method with respect to the investment cost and environmental impact while also considering buildability cost aspects. The optimization algorithm shows the possibilities of reducing the environmental impact by up to 13.7% for a slightly increased cost of 2.3%. Thus, by implementing optimization procedures in the early stages of the planning process the holistic cost effects related to green solutions can be presented, favoring the choice of sustainable designs amongst clients during tendering procedures.
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| 37. |
- Ek, Kristine, 1975, et al.
(författare)
-
Multi-criteria decision analysis methods to support sustainable infrastructure construction
- 2019
-
Ingår i: IABSE Symposium, Guimaraes 2019: Towards a Resilient Built Environment Risk and Asset Management - Report. ; , s. 1084-1091
-
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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| 38. |
- 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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| 39. |
- Mathern, Alexandre, 1986, et al.
(författare)
-
Sustainability-driven structural design using artificial intelligence
- 2019
-
Ingår i: 20th Congress of IABSE, New York City 2019: The Evolving Metropolis - Report. ; , s. 1058-1065
-
Konferensbidrag (refereegranskat)abstract
- The construction industry is responsible for a large share of the global environmental impact. The need for addressing sustainability and increased competition calls for the development of innovative design methods that include sustainability in a transparent way. The aim of this work is to propose a framework to use machine learning and artificial intelligence (AI) for structural design optimization based on sustainability and buildability criteria. AI opens up new possibilities to optimize and assess structures early in the planning and design stages. In that way, it is possible to decrease the negative and enhance the positive environmental, economic and social impacts and create a more time‐ and cost‐effective design process. The work is meant to serve as a first step toward the development of AI‐based methods in the construction industry, which can bring digitalization in the construction industry to a new level and create new services and business models.
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| 40. |
- Rempling, Rasmus, 1976, et al.
(författare)
-
Automatic structural design by a set-based parametric design method
- 2019
-
Ingår i: Automation in Construction. - : Elsevier BV. - 0926-5805. ; 108:December
-
Tidskriftsartikel (refereegranskat)abstract
- Modern structural design faces new challenges, such as addressing the needs of several stakeholders and satisfying the criteria for achieving sustainability. The traditional design process does not allow resolution of these challenges. The purpose of this project was to investigate the applicability of a Set-Based Parametric Design method to the structural design process of bridges. The focus was on the early design stage, in which the design team evaluates design alternatives against a chosen set of criteria. The main challenge in this stage of design is that the process should be cost- and time-effective while allowing comparison of the different alternatives and their evaluation in terms of the different design criteria. Certainly, structural design is often performed by a discussion between the different stakeholders involved in this process, i.e. the client, contractor, and engineering team. An evaluation of alternatives against criteria requires a more detailed design, which is contradictory to the early design stage when information is scarce. The selected approach was to develop a script that can generate information for decision-making, automate the structural design process, perform common routine design tasks, and control the numerical analysis. The method combined Set-Based Design, Parametric Design, Finite Element Analysis and Multi-Criteria Decision Analysis. Three existing bridges were selected to demonstrate the applicability of the developed method. The method was successfully applied and it was observed that it resulted in bridges that were more efficient in terms of material costs and carbon dioxide equivalent emissions compared with existing bridges. By delaying the decisions and developing the sets of alternatives, various alternatives can be assessed and evaluated, in the design stage, against different sustainability criteria.
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| 41. |
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| 42. |
- Bannova, Olga, 1964
(författare)
-
Architectural approach to planning in the extreme arctic environment.
- 2016
-
Ingår i: archiDOCT: Transformable Architecture. - 2309-0103. ; 4:1, s. 53-67
-
Tidskriftsartikel (refereegranskat)abstract
- Extreme environments in Polar Regions share similar facilities and operations, design and planning challenges: extreme cold temperatures, structural problems, high standards for materials, resources limitations (including people), transportation and logistics. Nevertheless, they differ depending on local cultural and social traditions and climate challenges specific to a particular region. Environmental hardships create challenges that reflect on sets of architectural requirements. The paper discusses these challenges and their influences on form developing factors, site orientation and circulation, - factors that affect budget considerations as well. The paper also discusses criticality of addressing such impacts at the programming design stage especially in challenging environments, in order to avoid costly adjustments at later development stages.The paper argues that integrating an architectural approach into planning of construction and related to it activities in Polar Regions is critical for enabling sustainability and resilient strategies there. The importance of such integration comes from the fact that engineering-oriented developers follow strictly industry-specific technical regulations and standards. Simultaneously, planning construction work and design in extreme conditions becomes a more complex process that calls for a new methodology, which would differ from common regulatory “checklists” that most companies implement in their practices there.This paper outlines and categorizes recurrent and specific to extreme environment and conditions events based on select research methods that include verbal data collection and case studies analysis. Figures Of Merit method employed for identification of important lessons that can be applied across different settings; and the ‘HSB Sustainable Living Lab’ project is suggested for effectiveness and verification purposes.Understanding of relationships and influences between different facets of human society and architecture can help to find a design approach and optimize needs and requirements for various types of people living and working in extreme environments of Polar Regions, their societies and cultures.
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| 43. |
- Rempling, Rasmus, 1976, et al.
(författare)
-
Aspects of Integrated Design of Structures: Parametric Models, Creative Space and Linked Knowledge
- 2015
-
Ingår i: Civil Engineering and Architecture. - 2332-1121. ; 3, s. 143-152
-
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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| 44. |
- Adam, Abderisak, 1988, et al.
(författare)
-
Take a Chance on Me? Construction Clients' Perspectives on Risk Management
- 2015
-
Ingår i: Procedia Economics and Finance. - 2212-5671. ; 21, s. 548-554
-
Konferensbidrag (refereegranskat)abstract
- Having been overwhelmed with a strikingly large list of things that can go wrong, public clients have consistently found themselves subjected to many risks associated with construction projects. As the scale of projects increases, the severity of risks intensifies. This study sets out to highlight a particular set of risks associated with strategic decision making in public construction projects. Of particular importance stands the client organizations’ capacity to properly manage risks rooted in poor decision making that leads to many types of project failure. To curb the negative effects of poor decision making, varying organisational configurations have been adopted by clients. This paper investigates the six Swedish public client organizations’ risk management procedures, the risk types and the frequency by which they reference risk management in their internal documents. The purpose is to explore how organisational measures influence a client's ability to undertake major construction projects in a manner that is conducive to effective project delivery. The present study is part of an ongoing research project concerning the capabilities of public clients in managing large scale construction projects.
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| 45. |
- Baba Ahmadi, Arezou, 1985, et al.
(författare)
-
Utilization of Bio Ashes in Cement-based Materials: A Case Study in Cooperation with Pulp and Paper and Energy Production Industries in Sweden
- 2020
-
Ingår i: Nordic Concrete Research. - : Walter de Gruyter GmbH. - 0800-6377 .- 2545-2819. ; 63:2, s. 63-78
-
Tidskriftsartikel (refereegranskat)abstract
- Worldwide increased concern of the CO2 emissions has led to the replacement of coal by biomass in combustion-based power plants. However, this would cause the scarcity of fly ash, one of the most well-known rest products from coal combustion, which is used as supplementary cementitious materials (SCM) in construction sector to reduce the large environmental footprint of cement production. Seeking to find alternative SCMs, this article aims to demonstrate the viability of using bio ashes in Sweden as SCM, which, due to lack of studies validating their value, are landfilled today. According to the obtained results, bio ashes produced at pulp and paper industries have a considerably consistent chemical composition and exhibit a satisfactory pozzolanic behaviour. Nevertheless, according to the conclusions of this study, the pozzolanicity of these alternative binders is not reflected equally with respect to the most known reactivity tests for common SCMs. The results imply that although “R3” tests method infers the pozzolanic characteristics of the bio ashes in focus of this study, the “activity index test” as well as “calcium consumption test” indicate otherwise.
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| 46. |
- Blomfors, Mattias, 1990, et al.
(författare)
-
Evaluation of safety formats for non-linear finite element analyses of statically indeterminate concrete structures subjected to different load paths
- 2016
-
Ingår i: Structural Concrete. - : Wiley. - 1751-7648 .- 1464-4177. ; 17:1, s. 44-51
-
Tidskriftsartikel (refereegranskat)abstract
- To increase the efficiency of new structures and perform safety evaluations of existing structures, it is necessary to model and analyse the non-linear behaviour of reinforced concrete. The applicability of the safety formats in present design codes is unclear for indeterminate structures subjected to loading in several directions. The safety formats in fib Model Code 2010 have been evaluated for a reinforced concrete frame subjected to vertical and horizontal loading and the influence of load history studied. Basic reliability methods were used together with response surfaces to assess the failure probabilities and one safety format did not meet the intended safety level. The results indicate the importance of load history and it is concluded that more research is required regarding how load history influences the safety level of complex structures.
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| 47. |
- Blomfors, Mattias, 1990, et al.
(författare)
-
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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| 48. |
- Coronelli, Dario, et al.
(författare)
-
FIB model code 2020 - Structural models for existing concrete structures
- 2018
-
Ingår i: FIB 2018 - Proceedings for the 2018 fib Congress: Better, Smarter, Stronger. - 2617-4820. ; , s. 3019-3040
-
Konferensbidrag (refereegranskat)abstract
- The paper gives an overview of this ambitious project, which builds upon the achievements of fib MC2010, the previous edition of the fib Model Code. MC2020 will deal with both the design of new structures and all the activities associated with the through-life management and care of existing concrete structures, including matters such as inservice assessment and interventions to extend the life / improve the performance of these structures. Particular attention will be paid to issues specific to existing structures. Relevant structural models are planned for the determination of their load capacity / structural reliability, serviceability, remaining service life etc taking account of: • Load-carrying behaviour not considered in design, such as compressive membrane action and the increase in concrete compressive strength with time due to ongoing hydration effects. • Load-carrying behaviour in deteriorated members and structures, which is different to those members which have not experienced deterioration. The paper gives consideration to corrosion of reinforced concrete members and prestressed concrete members, as well as to the effects of other forms of deterioration such as alkali-aggregate reactions and frost damage. The paper also notes some of the differences between the approaches employed for Life Cycle Assessment and Design (LCA / LCD) based on deterioration models, and the assessment of the present condition of the structure (i.e. at a given moment in time) which utilise mechanical models to represent the influences of the deterioration processes which are active.
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| 49. |
- Fernandez, Ignasi, 1984, et al.
(författare)
-
Structural effects of steel reinforcement corrosion on statically indeterminate reinforced concrete members
- 2016
-
Ingår i: Materials and Structures/Materiaux et Constructions. - : Springer Science and Business Media LLC. - 1359-5997. ; 49, s. 4959-4973
-
Tidskriftsartikel (refereegranskat)abstract
- Steel corrosion in reinforced concrete structures produces loss of reinforcement area and damage in the surrounding concrete. As a consequence, increases in deflections, crack widths and stresses may take place, as well as a reduction of the bearing capacity, which depends on the structural scheme and redundancy. In this paper an experimental study of twelve statically indeterminate beams subjected to different levels of forced reinforcement corrosion is presented. Different sustained loads were applied during the corrosion phase to assess their influence on the effects of corrosion. An important increase in deflections was registered in all corroded beams, especially in those subject to higher load levels. It was also found that the rate of corrosion was affected by the load level. Internal forces redistributions due to induced damage were measured. Finally, the experimental results were compared with those predicted by a non-linear time-dependent segmental analysis model developed by the authors, obtaining in general good agreement. © 2016, RILEM.
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| 50. |
- Gil Berrocal, Carlos, 1986, et al.
(författare)
-
Analytisk beräkningsmodell för tvångsprickor hos kombinationsarmerade konstruktionselement
- 2018
-
Ingår i: Bygg och teknik. - 0281-658X. ; 2018:7, s. 30-33
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Kombinationsarmering kan vara en effektiv lösning för att begränsa sprickbildning orsakad av tvångskrafter och samtidig minska arbetsinsatsen som armeringen medför. Befintliga modeller som beaktar sprickor orsakade av tvångkrafter saknas dock för kombinationsarmerade betongelement. I ett nyligen avslutat SBUF-projekt som har genomförts på Thomas Concrete Group i samarbete med Chalmers tekniska högskola har en befintlig analytisk beräkningsmodell för tvångsprickor vidareutvecklats och beräkningar har jämförts med resultat från experiment. I den här artikeln beskrivas modellen och dess förmåga att prediktera antalet sprickor och sprickbredd i betongelement utsatta för förhindrad krympningsdeformation.
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