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  • 51.
    Lidelöw, Helena
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Simu, Kajsa
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Lean construction as an emergent operations strategy2016Ingår i: IGLC 2016 - 24th Annual Conference of the International Group for Lean Construction, National Pingtung University of Science and Technology , 2016, s. 153-162Konferensbidrag (Refereegranskat)
  • 52.
    Lidelöw, Helena
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Simu, Kajsa
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Lean construction as an operations strategy2015Ingår i: Proceedings of IGLC 23: 23rd Annual Conference of the International Group for Lean Construction: Global Knowledge - Global Solutions, Perth, Australia, 28 - 31 July 2015 / [ed] P. Arroyo; O. Seppanen; V.A. Gonzalez, International group for lean construction , 2015, s. 486-495Konferensbidrag (Refereegranskat)
    Abstract [en]

    All companies have an operations strategy; a pattern of decisions made in operations with the purpose to support the business strategy. Lean Construction can be seen as an operations strategy. The aim of this research is to present the generic decision categories in an operations strategy and discuss their characteristics in contrast to the Lean Construction framework. A literature study identified ten decision categories: process technology, capacity, facilities, vertical integration, human resources, organization, quality, production control, product development, and performance measurement. Data was collected through in-depth interviews with managers on the tactical level at three construction companies with a Lean implementation. The results indicate that Lean construction companies emphasize quality, production planning, and vertical integration in their operations strategy. Facilities, process technology, capacity, and organization receive less attention. Quality, production planning, and vertical integration are keywords also in Lean Construction, while it is intriguing that organization receives little attention. Facilities, process technology, and capacity are ever changing between construction projects and are candidates for decision categories that could be less relevant for formulating an operations strategy in construction.

  • 53.
    Lidelöw, Helena
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Simu, Kajsa
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Project: Flow Efficiency in Construction2014Övrigt (Övrig (populärvetenskap, debatt, mm))
  • 54.
    Lidelöw, Helena
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Simu, Kajsa
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Understanding Construction Contractors and their Operations Strategies2015Ingår i: Procedia Economics and Finance, E-ISSN 2212-5671, Vol. 21, s. 48-56Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    All firms have an operations strategy, but it is not always explicit. The operations strategies of construction firms are poorly described as they receive less attention than those of project management, although operations strategies (and operations management) are important actions and processes on the permanent firm level. Within many construction contractors, there is a gap between the tactical and operational levels which, for example, is resulting in business strategies being poorly executed on the project level. In this paper, the operations strategies of construction contractors are compared with those reported in business school literature in terms of the prioritisation of decision categories. The findings based on the semi-structured interviews with the tactical level managers inside the three construction contractors clearly indicate that the priorities when forming an operations strategy in construction differ from patterns commonly specified in business school literature. It is initially recommended that construction contractors should plan their operations strategies with a focus on organisation, quality, human resources and planning.

  • 55.
    Lidelöw, Helena
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Ödéen, Henrik
    Moelven ByggModul AB, Sverige.
    Risberg, Wilhelm
    Lindbäcks Bygg AB.
    Projekt: Konstruktionsoptimering för trävolymbyggande2010Övrigt (Övrig (populärvetenskap, debatt, mm))
    Abstract [sv]

    Syfte  Högre träbyggnader som flerfamiljshus måste konstrueras för att möta ett antal byggnadstekniska funktionskrav såsom brandskydd, ljudisolering, tillräcklig stabilisering och fuktsäkerhet. Fler än 4 våningar innebär ökad problematik att klara stomstabiliseringen och dessutom tar brandkraven ett språng från REI60 till REI90 (en ökning med 50 % av den tid som byggnaden förväntas stå kvar vid brand)Idén med detta projekt är att ta fram en optimeringsmetod som medger att träbyggsystem kan utvecklas så att ett mer kostnadseffektivt och optimalt byggsystem erhålls.    Uppnådda resultat  Teknikutveckling för trävolymbyggnads-företagen. 2006 var man säkra på 4-våningshus, idag är man säker på 6-våningshus. Populärvetenskaplig presentation LWE-konferensen 2009; "Konstruktionsoptimering" 

  • 56. Lukaszewska, Elzbieta
    et al.
    Fragiacomo, Massimo
    Department of Architecture and Planning, University of Sassari, Alghero.
    Johnsson, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Laboratory tests and numerical analyses of prefabricated timber-concrete composite floors2010Ingår i: Journal of Structural Engineering, ISSN 0733-9445, E-ISSN 1943-541X, Vol. 136, nr 1, s. 46-55Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper describes tests on a novel composite floor system constructed by connecting prefabricated concrete slabs to timber joists. Seven types of shear connectors have been developed and tested: lag screws, either alone or combined with a notch cut from each timber joist; metal plates embedded in the concrete slab and either nailed or glued to the joists; dowels embedded in the concrete and glued to the timber; and toothed metal plates embedded in the concrete and pressed into the timber. Four-point bending tests to failure were performed on five, full-scale, 4.8 m long specimens connected with lag screws or metal plates nailed to the timber. Values of deflection and relative slip between the concrete slab and the timber obtained in these tests showed high correspondence with values obtained from a uniaxial finite element model developed for nonlinear analyses of composite beams. The model was also used to perform a numerical analysis to failure of composite beams with the other four connection systems that were developed but not tested on full-scale specimens. The outcomes of the experimental tests and numerical analyses show that the newly developed system can provide good structural performance, especially if connections with coach screws and notches in the timber are used. The economic advantages of prefabrication and the possibility to disassemble the structure and reuse the timber beams and concrete panels at the end of the service life make the proposed floor system very promising.

  • 57. Lukaszewska, Elzbieta
    et al.
    Johnsson, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Fragiacomo, Massimo
    Department of Architecture and Planning, University of Sassari, Alghero.
    Performance of connections for prefabricated timber-concrete composite floors2008Ingår i: Materials and Structures, ISSN 1359-5997, E-ISSN 1871-6873, Vol. 41, nr 9, s. 1533-1550Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Timber-concrete composite beams and slabs require interlayer connectors, which provide composite action in the cross-section. A range of mechanical connectors is available on the market with an extensive variety of stiffness and strength properties, which are fundamental design parameters for the composite structure. Another crucial parameter is the cost of the connector, including the labour cost, that if too high may prevent the use of the composite system. In order to reduce the construction cost and make timber-concrete structures more widespread on the market, it is believed that a high degree of prefabrication should be achieved. For a simple and cost effective construction process, the use of "dry" connections, which do not require the pouring and curing of concrete on site, may represent a possible solution. This paper reports the outcomes of an experimental programme aimed to investigate a number of different mechanical "dry-dry" connectors previously embedded into a prefabricated concrete slab. Direct shear tests on small blocks made of a glulam segment connected with a prefabricated concrete slab were performed. The shear force-relative slip relationships were measured and all the relevant mechanical properties such as slip moduli and shear strengths were calculated. It was found that some of the new developed connection systems for prefabricated concrete slab can perform as satisfactorily as those for cast-in-situ slabs, with the additional benefit of being relatively inexpensive.

  • 58.
    Lundberg, Mary
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Engström, Susanne
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Lidelöw, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Diffusion of innovation in a contractor company: the impact of the social system structure on the implementation process2019Ingår i: Construction Innovation, ISSN 1471-4175, E-ISSN 1477-0857, artikel-id 632762Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Purpose

    In the construction industry, it has proven difficult to implement and realize innovation efforts, for example in the development of industrialized construction and use of platform concepts. Thus, the purpose of this study is to characterize the innovation diffusion process in the social system of a large Swedish contractor company. Specifically, the diffusion of three innovative industrialized house-building (IHB) platforms and factors affecting their adoption and implementation (particularly effects of their perceived radicality in relation to the company's decentralized characteristics) are identified and discussed.

    Design/methodology/approach

    A case study approach was applied, using empirical material including semi-structured interviews and archival records (research reports from earlier studies at different points in time related to each innovation and annual corporate reports). The material was analyzed using Rogers' (2003) five-stage innovation process model, acknowledging the importance of social systems' structures.

    Findings

    Structural characteristics of the social system strongly affect innovation diffusion. In subsystems that had not been involved in initiation of the innovations, they were regarded as radical, which hindered their adoption and implementation.

    Research limitations/implications

    This study builds upon the recent findings that successful innovation implementation depends on a range of contingencies in the construction context. Although the diffusion of the innovations per se has been traced over a ten-year period, generalizability is limited because the results come from one construction company.

    Practical implications

    Contractors have invested substantially in the development of industrialized construction and use of platform concepts, but less in their implementation, so they have obtained little gain. How innovations are perceived and implemented in different subsystems affects the success of their implementation in the overarching social system.Originality/valueThis study adheres to previous calls for more research on firm level in the complex social system of construction companies by adopting a ten-year perspective on the diffusion of innovation at a large contractor addressing in particular the impact of the innovations perceived radicality in relation to the decentralized characteristics of the company.

  • 59.
    Lundberg, Mary
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Lidelöw, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Social Motivations for Knowledge Sharing in Construction Companies2015Ingår i: Procedia Economics and Finance, E-ISSN 2212-5671, Vol. 21, s. 224-230Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In 1965 a political initiative was taken launched to solve the lack of accommodation in Sweden, and during a ten- year period about one million new homes were built- the Million Homes programme. These buildings constitute about one fourth of the entire Swedish building stock and thus have a high societal value. Today they do not always meet current building standards and many are in need of refurbishment. The Million Homes programme incorporated a large variety of technical building solutions, andknowledge about former building practices is needed if refurbishment is to be successful. Industrialised builders in Sweden have recognized the use of a platform as one means of sharing knowledge. A platform is essentially the collection of assets that are shared by a set of products. In a platform for housing refurbishment the assets have knowledge and process content (as opposed to product content) and will probably also contain many relationships. The interview study carried out as part of the research shows that the main purpose of a platform concept is to standardize components and processes. To increase the possibility that a platform concept for refurbishment of buildings will beused for knowledge sharing the focus should be on the individuals who will actually be sharing their knowledge and especially on social motivations. It is important that managers and leaders demonstrate knowledge sharing behaviors as this will lead to the establishment of a culture where knowledge sharing is the norm; in the context of this study this is especially important for the creation of an efficient platform concept for refurbishment

  • 60.
    Lundberg, Mary
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Lidelöw, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Testing a Proposition for a Knowledge Management Method for Refurbishment2016Ingår i: Proceedings of the 32nd Annual ARCOM Conference: 5-7 September 2016, Manchester, UK / [ed] P.W Chan; C.J. Neilson, Association of Researchers in Construction Management , 2016, Vol. 2, s. 757-766Konferensbidrag (Refereegranskat)
  • 61.
    Lundberg, Mary
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Lidelöw, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Engström, Susanne
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Methods used for knowledge management and organizational learning in the practice of construction projects: a systematic literature review2017Ingår i: Proceedings of working papers from the ARCOM and BEAM Centre Early Career Researcher and Doctoral Workshop on Building Asset Management / [ed] Craig Thomson, 2017Konferensbidrag (Refereegranskat)
  • 62.
    Lundberg, Mary
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Lidelöw, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Engström, Susanne
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Methods used in the everyday practice of construction projects for knowledge sharing and knowledge transfer2017Konferensbidrag (Refereegranskat)
    Abstract [en]

    Many construction practitioners and researchers would agree that acquiring the knowledge created in construction projects is a prerequisite for organizational learning and improved practice. This applies also to continuous improvement by a lean strategy. Various technological tools and methods for knowledge acquisition have been proposed, but their success depends on acknowledging the involved individuals and on the interaction between project actors, i.e. embracing the principle of respect for people in a lean strategy. A systematic literature review to identify methods used in the everyday practice in construction projects for the sharing and transfer of tacit knowledge has been performed.

    Findings indicate that a combination of technological and social methods are used for knowledge sharing and knowledge transfer in construction projects. Social methods such as workshops, different kinds of often informal face-to-face meetings, various forms of reviews, mentorships, and site visits, are commonly used for sharing and transfer of tacit knowledge. Therefore, these methods which also often involve different actors should form part of a lean construction strategy.

  • 63.
    Meiling, John
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Backlund, Fredrik
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Johnsson, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Managing for continuous improvement in off-site construction: Evaluation of lean management principles2012Ingår i: Engineering Construction and Architectural Management, ISSN 0969-9988, E-ISSN 1365-232X, Vol. 19, nr 2, s. 141-158Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Purpose – Several off-site manufacturing companies in Sweden have attempted to apply lean management to improve process effectiveness and efficiency. A state of continuous improvement is a key goal of lean management, as described in, e.g. Likers 4P model. The aim of this study is to test a method to measure the degree to which lean management principles have been adopted by companies that base their production on off-site manufacturing, as a prerequisite for a sustainable approach to continuous improvement. Design/methodology/approach – A survey is applied as research method, using a questionnaire based on the authors' perceptions of best practices corresponding to each lean management principle. Two questionnaires were distributed to both management and factory production personnel in two off-site manufacturing firms in Sweden. Findings – The Likert scores regarding the degree to which lean principles have been applied in the two studied companies showed similar patterns (and similar differences between the management and production personnel's responses), indicating that the results can be generalised within an off-site construction context. The study shows that continuous improvements must emerge and evolve simultaneously with a focus on processes, people and long-term thinking. Research limitations/implications – In order to obtain more generalised and detailed results a more extensive survey covering several companies, as well as more detailed case studies and more questions regarding each principle, are needed. A multivariate analysis will also scan the material for further dependences. Originality/value – The paper highlights several aspects that are important for management to be aware of when aiming for continuous improvements in off-site manufacturing.

  • 64. Meiling, John
    et al.
    Johnsson, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Experience feedback at industrialised house builders2008Ingår i: IGLC 16 Proceedings: 16th Annual Conference of the International Group for Lean Construction / [ed] P. Tzortzopoulos; M. Kagioglou, University of Salford, U.K. , 2008, s. 553-564Konferensbidrag (Refereegranskat)
    Abstract [en]

    In lean theories as in quality management, the notion of continuous improvement is strong. Experience from an earlier production cycle should be fed into the next cycle. The framework of lean production offers a structure for experience feedback to take place. The industrialised house builders would benefit more from experience feedback than traditional construction firms would, since the degree of repetitiveness of their work is higher. The degree of prefabrication in industrialised housing ranges from manufacturing open walls and floors up to producing entire volume modules with complete interior cladding. The higher the degree of prefabrication, the stronger is the clash between construction and manufacturing, since the traditional construction process does not cater for the need for early design decisions that are rigid throughout the building process. This paper aims at exploring the production process at three industrialised housing companies seeking feedback opportunities and implications. An explorative research method is used where interviews with the participating companies show that initiatives and opportunities exist, but not in a consistent way. The transformation of information and knowledge into useful design input could be seen as a bottleneck in production process.

  • 65. Meiling, John
    et al.
    Johnsson, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Feedback in industrialised housing, why does it not happen?2008Ingår i: Proceedings 24th Annual ARCOM Conference: 1-3 September 2008, Cardiff, UK, Association of Researchers in Construction / [ed] Andrew Dainty, Reading: Association of Researchers in Construction Management , 2008, Vol. 1, s. 145-54Konferensbidrag (Refereegranskat)
    Abstract [en]

    The construction industry is based on craftsmanship and the construction hero is someone who handles every appearing situation with a somewhat good result. Quality work in manufacturing relies on repetitiveness, standardisation and follow-up, whereas construction is about uniqueness, responsiveness to problems and flexibility in solutions. A category of construction companies have met the contradiction between construction and manufacturing - industrialised house builders. This category of companies work with the prefabrication of building parts for later assembly at the building site. The degree of prefabrication ranges from manufacturing open walls and floors up to producing entire volume modules with complete interior cladding. In lean theories as well as quality management, the notion of continuous improvement and experience feedback is strong. Yet, why is this mechanism almost non-existent with traditional construction companies? Industrial house builders benefit more from experience feedback than traditional construction firms, since the repetitiveness is higher. This paper aims to explore why experience feedback, in Sweden, does not function in today's industrialised building process. The manufacturing process of four industrial house builders in Sweden was studied and mapped. The results show that much focus was put on streamlining the production process at the factory, but that experience feedback between departments at the company was small and non-existent from quality audits within the company. A change in company culture and leadership is needed to start addressing this problem.

  • 66.
    Meiling, John
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Sandberg, Marcus
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Johnsson, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    A study of a plan-do-check-act method used in less industrialized activities: two cases from industrialized housebuilding2014Ingår i: Construction Management and Economics, ISSN 0144-6193, E-ISSN 1466-433X, Vol. 32, nr 1-2, s. 109-125Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In construction projects, a large number of deviations are usually found during inspections and adjusted in a reactive manner. For projects to become proactive, root causes need to be identified and eliminated as a part of a process of continuous improvement (CI). Plan-do-check-act (PDCA) methods are part of CI and have been used with success within the manufacturing industry for decades. Research studies of PDCA in construction are less common, which could be explained by the past dominance of the project-based nature of construction compared to the process-based nature of manufacture. Industrialized construction, however, has changed this picture somewhat, and it is of interest to find out how well it works for less industrialized activities in construction. A PDCA method was tested in two cases selected from one medium-sized Swedish industrialized housebuilder, which uses a building system based on offsite manufactured modules. Empirical results are based on systematic data gathered through interviews and participant observations. Results from the two cases show that the PDCA method worked even when processes were divided into industrialized parts within a factory and non-industrial parts at the construction site although this might lead to temporary corrective actions rather than permanent process actions

  • 67.
    Nordström, Gustav
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Johnsson, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Lidelöw, Sofia
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    HRV-Systems in the Energy-Signature method2013Ingår i: Proceedings of SB13 Dubai Conference: Advancing the Green Agenda, 2013Konferensbidrag (Refereegranskat)
    Abstract [en]

    The energy use for the residential sector in Sweden is about 40% of Sweden’s total energy use. European Union has specified that al new buildings by the year 2020 shall be close to zero energy buildings. But what happens in a house when heating comes from non-measurable or hard to measure sources such as heat from household electricity, people, sun or HRV-systems. All these sources are becoming more and more important in standard houses of today and especially in low energy houses of today and the future. This paper deals with a Data-driven technique based on an Energy-Signature model to investigate how single family houses with HRV systems installed preforms by comparing the Effective U-value based on the heat loss factor and envelope area for each house. The results show that no distinct difference between the HRV and non-HRV houses can be seen in this study by using an energy signature method as presented in this paper which is surprising.

  • 68.
    Nordström, Gustav
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Johnsson, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Lidelöw, Sofia
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Using the energy signature method to estimate the effective U-value of buildings2013Ingår i: Sustainability in Energy and Buildings: Proceedings of the 4th International Conference in Sustainability in Energy and Buildings (SEB´12), Berlin: Encyclopedia of Global Archaeology/Springer Verlag, 2013, s. 35-44Konferensbidrag (Refereegranskat)
    Abstract [en]

    The oil crisis of the 1970s and the growing concern about global warming have created an urge to increase the energy efficiency of residential buildings.Space heating and domestic hot water production account for approximately 20% of Sweden’s total energy use. This study examines the energy performance of existing building stock by estimating effective U-values for six single-family houses built between 1962 and 2006. A static energy signature model for estimating effective U-values was tested, in which the energy signature was based on measurements of the total power used for heating and the indoor and outdoor temperatures for each studied house during three winter months in northern Sweden. Theoretical U-values for hypothetical houses built to the specifications of the Swedish building codes in force between 1960 and 2011 were calculated and compared to the U-values calculated for the studied real-world houses. The results show that the increasingly strict U-value requirements of more recent building codes have resulted in lower U-values for newer buildings, and that static energy signature models can be used to estimate the effective U-value of buildings provided that the differences between the indoor and outdoor temperatures are sufficiently large.

  • 69.
    Nordström, Gustav
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Lidelöw, Sofia
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Johnsson, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Comparing energy signature analysis to calculated U-values in wooden houses in cold climate2012Ingår i: Eco-Architecture IV, WIT Press, 2012, s. 411-419Konferensbidrag (Refereegranskat)
    Abstract [en]

    In Sweden the housing sector stands for about 40% of the energy usage. About 20% of total energy usage goes to heating and hot tap water. Since 1920, the dominant building technology for single family houses in Sweden is a light timber-frame structure with studs at even spacing. This study aims to investigate how the static energy signature model can be used to estimate the effective U-values in existing wooden buildings and compare them to calculated U-values based on the thermal properties of the building parts. The results show that the energy signature model gives reasonable estimates of the U-value in a building. It is important though that a large difference in temperature can be achieved.

  • 70.
    Näslund, Ida
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Johnsson, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Horizontal Displacements in Medium-Rise Timber Buildings: Basic FE Modeling in Serviceability Limit State2014Ingår i: Materials and Joints in Timber Structures: Recent Developments of Technology, Dordrecht: Encyclopedia of Global Archaeology/Springer Verlag, 2014, s. 3-12Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    Higher and larger timber buildings are built today. The building is exposed to static lateral wind loads that cause displacements that might lead to discomfort and non-function of the building. To determine the size and behavior of horizontal displacements, two timber systems has been studied, a light frame system with shear walls and a post and beam system with diagonal bracing. The stabilizing wall segments have been analyzed with a FE model and subjected to static lateral wind load and vertical dead load in serviceability limit state. Both plywood and particle board were used as sheet materials. To reduce flanking transmission Sylomer® is applied in the light frame system. The total lateral displacement varies between 4 to 125 mm in the light frame system and 2 to 5 mm in the post and beam system. Removing the Sylomer® damping material from the light-frame system would decrease the lateral displacements with 1.5-3 times, which needs to be further investigated

  • 71.
    Näslund, Ida
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Lidelöw, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Stiffness of sheathing-to-framing connections in timber shear walls: In serviceability limit state2014Konferensbidrag (Refereegranskat)
  • 72.
    Olofsson, Thomas
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Jensen, Patrik
    Lidelöw, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Alsmarker, Tomas
    Tyréns, Sverige.
    Projekt: Konfigurationssystem för teknikplattformar2010Övrigt (Övrig (populärvetenskap, debatt, mm))
    Abstract [sv]

    Syfte  Syftet med projektet är att utreda hur utveckling och uppdateringar av tekniska plattformar skall åstadkommas och utformas. I en industriell process är återkopplingen och uppdateringen av de system man använder av stor vikt för att utveckla och förbättra lönsamheten, vilket ligger nära tillhands med dagens konsultroll inom byggprojektering där många års erfarenheter kan tillvaratas. Tyréns AB har som konsultföretag för avsikt att utöka sin projekteringsroll och vända sig mot nya kunder inom den prefabricerande industrin och erbjuda helhetslösningar inom återkoppling och uppdatering av befintliga tekniska plattformar.

  • 73.
    Parida, Gabriela
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Fragiacomo, Massimo
    Department of Architecture, Design and Urban Planning, Faculty of Architecture, University of Sassari.
    Johnsson, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Prefabricated timber walls anchored with glued-in rod connections: racking tests and preliminary design2013Ingår i: European Journal of Wood and Wood Products, ISSN 0018-3768, E-ISSN 1436-736X, Vol. 71, nr 5, s. 635-646Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A new beam and post system for multi-storey timber buildings is being developed in Sweden. The stabilising walls are constructed from two Kerto-Q LVL boards glued and screwed onto a glulam skeleton. The walls are prefabricated off-site and connected to the foundation using either glued-in rods or nail plates.An introductory racking test of a full scale stabilising wall anchored with glued-in rods was performed. The paper presents the results of the experimental test and evaluates them using the transformed section method. To evaluate the strength of the glued-in rods, two newly proposed models were employed. A theoretical examination was conducted to investigate the role of the sheathing in the racking load carrying capacity. An analysis was also performed to quantify the contribution of the axial force on the racking capacity of the wall, which was conservatively ignored in the experiment. Generally, the stabilising wall panels tested in this experimental programme showed high strength and stiffness. The anchoring joints with glued-in rods demonstrated a high load-carrying capacity, however, with a large scatter and a brittle failure mode characterized by pull-out from the timber member. The transformed section method is recommended as a method for designing stabilising walls anchored with glued-in rods.

  • 74.
    Parida, Gabriela
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Johnsson, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Fragiacomo, Massimo
    Department of Architecture, Design and Urban Planning, University of Sassari.
    Provisions for ductile behavior of timber-steel connections with multiple glued-in rods2013Ingår i: Journal of Structural Engineering, ISSN 0733-9445, E-ISSN 1943-541X, Vol. 139, nr 9, s. 1468-1477Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Connections with glued-in rods are very efficient and high strength joints, and can be successfully used for e.g. anchorage of vertical timber elements to the foundation. Although extensive research was done on the pull-out strength of single rods, few references can be found on the behavior of multiple glued-in rods. This paper presents the results of an experimental program carried out on timber-to-steel connections with multiple glued-in rods. Two series of ten specimens with four large-diameter glued-in rods made from mild steel (series GB) and ten specimens with twelve small diameter high grade glued-in rods (series GS) were tested to failure under monotonic tensile load. Both types of connections failed ultimately in a brittle manner, however series GB developed some plastic deformations prior to failure by pull-out of two rods and longitudinal splitting of the timber member. By comparing the experimental results with the analytical predictions, no significant group effect could be detected in test series GB, and an overall acceptable approximation was found. In test series GS, no final conclusion on group effect could be drawn as several rods failed by nut stripping. A parametric study using analytical formulas was carried out to investigate the effect of rod strength, rod diameter, glued length, and timber density on the connection performance. Based on the results of the parametric study and experimental tests, it can be concluded that the use of mild steel as well as more rods of larger diameter properly spaced from each other and from the edges are all effective measures to increase the connection ductility. Furthermore, by leaving a suitable length of rod unbonded between the steel plate and the glued length, it is possible to control ductility, providing all brittle failure modes have higher strength capacity than the rod yielding force. Special care should be taken during the manufacturing process to ensure good quality of gluing (required glued length and amount of adhesive) and rod alignment.

  • 75.
    Persson, Stefan
    et al.
    Tyréns IT.
    Malmgren, Linus
    Lund Institute of Technology.
    Johnsson, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Information management in industrial housing design and manufacture2009Ingår i: Journal of Information Technology in Construction (ITcon), ISSN 1874-4753, E-ISSN 1874-4753, Vol. 14, s. 110-122Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Industrialized production of building components, or entire houses, reduces activities at the construction site to the assembly of parts and has the potential to increase productivity and reduce the design effort invested in every project. However, in order to realize all of the potential efficiency gains that use of predefined components could deliver effective, interoperable information management systems are required. This article presents a multiple case study investigating the processes, products and ICT environment involved in industrialized house construction from an information management perspective, focusing on six Swedish companies that manufacture timber frame elements and one that makes precast concrete elements. The aim of the study was to identify critical aspects of information management related to industrialization in the sector. The findings show that companies aiming to enhance control and productivity by improving information management need a better understanding of the requisites for efficient industrialized construction in terms of ICT support. Changes in the perspectives of the construction companies appear to be needed in terms of not only the manufacturing processes, but also information management. Three main areas are identified that should be prioritized before any investments in ICT can be implemented effectively: formal description of the relevant processes, detailed description of the product range and its full variety, and creation of an appropriate information systems strategy.

  • 76.
    Sandberg, Marcus
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Innovation och Design.
    Johnsson, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Larsson, Tobias
    Knowledge-based engineering in construction: the prefabricated timber housing case2008Ingår i: Journal of Information Technology in Construction (ITcon), ISSN 1874-4753, E-ISSN 1874-4753, Vol. 13, s. 408-420Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Swedish prefabricators of domestic buildings need to become more effective and efficient; the aim of this paper is to investigate the usefulness of rule-based IT support tools for this purpose. The current sales and design process at a Swedish timber volume element prefabricator is presented. The process was mapped and the early design phase was evaluated regarding information management and standardisation. It was found that information management during early design is often ad hoc and person dependent; therefore searching for information that could lead to reuse of past solutions is rather time demanding. There is a need for standardisation to promote reuse due to a mentality of designing one-of-a-kind buildings. Knowledge-based engineering is seen as an enabler to enhance the current situation and an IT support approach is suggested. A demonstrator stair tool is tested, which lets the seller discuss needs with the customer and then use the tool to assess cost and manufacturability. If design flaws can be found early on, waste activities downstream can be reduced. Standardisation could be realised through modularisation, which the implementation of an IT support tool could gain from.

  • 77.
    Simu, Kajsa
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Lidelöw, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Middle managers’ perceptions of operations strategies at construction contractors2019Ingår i: Construction Management and Economics, ISSN 0144-6193, E-ISSN 1466-433X, Vol. 37, nr 6, s. 351-366Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Operations strategies focus on how a firm delivers value, while business strategies focus on what to deliver and where. Lean is an operations strategy prioritizing flow efficiency. In construction, empirical underpinning of operations strategies has been limited. The aim is to capture how perceptions of operations strategy in construction practice aligns with existing theories of operations strategy organized in decision categories. Nine in-depth interviews with contractor middle managers were transcribed and analyzed to capture their perceptions of operations strategies. Results show: (1) decision categories in construction differ from manufacturing, and (2) differences between resource and flow efficient operations strategies exist. A resource efficient strategy focuses cost and delivery as competitive criteria, while customer value is targeted in a flow efficient strategy. Proposed structural decision categories are standardization, organization and production planning, supply chain, and infrastructural decision categories are human resources, continuous improvement, long-term perspective, process vs. project, and performance measurements. Infrastructural categories are more difficult to replicate and render competitive advantage if successfully aligned with business strategy. An operations strategy strictly focused on project delivery, such as lean construction, is not automatically aligned with the business strategy, but can achieve satisfactory project performance.

  • 78.
    Simu, Kajsa
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Lidelöw, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    The effect of economic variation in construction projects on contractor firms2014Ingår i: Annual conference of the international group for lean construction, International group for lean construction , 2014, s. 221-232Konferensbidrag (Refereegranskat)
    Abstract [en]

    Lean is about finding a flow efficient way to deliver value to the client. To do so reducing variation is vital. The construction industry is project-based and variation in project deliveries is more the rule than the exception. Being able to predict economic variation in projects is important for contractors and other project-oriented firms since it affects the total turnover for the firm. The aim of this research is to capture the variation in economic profit in a project, estimate the effect this variation has on the aggregated firm level, and discuss the implications for flow efficient operational strategies to adhere. Economic reports were collected from 1000 projects, throughout 2 years at a large Swedish contractor. The data contains quarterly economic prognoses and results per project. From the data, the variation in profit was deducted. The variation was used in a statistical model of the firm, reflecting five levels of financially liable units. The results show that variations in the economic results on the project level are evened out on the firm level. Thus, the reduction of variation sought in Lean implementation does not emerge as positive in accounting. Measuring economic results on the project level drives a focus on resources in the value chain. This is a hindrance for implementation of a flow efficient operational strategy as Lean. Therefore, key performance indicators capturing flow efficient strategies for control on project and firm levels need to be developed.

  • 79.
    Stehn, Lars
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Engström, Susanne
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Lidelöw, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Serrander, Peter
    AB Fristad Bygg, Sverige.
    Projekt: Beställarrollen i ett industriellt byggande i trä2010Övrigt (Övrig (populärvetenskap, debatt, mm))
    Abstract [sv]

    Att reducera beställarens osäkerhet vid beslut om att initiera byggprojekt genom att ta fram förslag på styrmedel anpassade för den industriella byggprocessen. För att utveckla dessa nya styrmedel avser projektet attstudera beställarnas nuvarande styrmedel, vilka huvudsakligen är utvecklade med utgångspunkt från det traditionella byggandet och därför anpassade efter detta, studera de specifika krav som en industriell byggprocess ställer, och jämföra beställarnas styrmedel med dessa krav för att identifiera eventuella gap och hinder för beställare att, vid beslut om att initiera byggprojekt, kunna beakta industriella byggalternativ tillsammans med mer traditionella.  

  • 80.
    Stehn, Lars
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Johnsson, Helena
    Ductility aspects in nailed glue laminated timber connection design2002Ingår i: Journal of Structural Engineering, ISSN 0733-9445, E-ISSN 1943-541X, Vol. 128, nr 3, s. 382-389Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A nailed joint system, comprising of two slotted-in steel plates with shot-through smooth round steel nails in glulam, was analyzed from the viewpoint of an engineering description of the ductility behavior. Experiments on 15 specimens, with 10 nails in each specimen, were performed. Based on the results, a model describing the ductility behavior is proposed. Ductility is defined as the ratio of ultimate-to-elastic deformations with the ultimate deformation defined as the first load drop corresponding to wood splitting. The model is based on "engineering" parameters and estimates the engineering ductility from the slenderness ratio, timber density, and the fastener yield strength in bending. The model is compared with similar experiments in the literature and the validation shows correlation. The method of solution, based on the plastic theory of the European yield model for dowels, is general, and is applicable to other timber-to-timber or timber-to-steel dowel-type connections. The engineering ductility philosophy can give engineers a tool to assess ductility for connections in timber structures.

  • 81.
    Stehn, Lars
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Johnsson, Helena
    Engineering ductility assessment for a nailed slotted-in steel connection in glulam2000Ingår i: CIB-W18 meeting thirty-three: Delft, the Netherlands, August 2000, Karlsruhe: Lehrstuhl für Ingenieurholzbau und Baukonstruktionen, Univ. Karlsruhe , 2000, s. 33-7Konferensbidrag (Refereegranskat)
  • 82.
    Stehn, Lars
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Lidelöw, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Larsson, Tobias
    Sandberg, Marcus
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Project: Lean Wood Engineering2007Övrigt (Övrig (populärvetenskap, debatt, mm))
    Abstract [sv]

    LWE är ett kompetenscenter för forskning och utveckling inom - industriellt träbyggande, - trämanufaktur samt - interiöra lösningar. LWE är ett samarbete mellan Luleå tekniska universitet (koordinator), Linköpings tekniska högskola, Lunds tekniska högskola, VINNOVA och tolv företag inom bygg- och trämanufaktursektorn. Kompetenscentret involverar ett trettiotal seniora forskare och doktorander.

  • 83.
    Stehn, Lars
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Söderholm, Erik
    Lidelöw, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Sandberg, Marcus
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Samuelsson, Johan
    Moelven ByggModul, Sverige.
    Projekt: Standardiserad projekteringsprocess2010Övrigt (Övrig (populärvetenskap, debatt, mm))
    Abstract [sv]

    Syfte  Moelven ByggModul AB har för avsikt att vara en av Nordens ledande producenter av industriframställda byggmoduler i trä, med hög färdigställandegrad från fabrik. För ett företag som strävar efter en industriell process är likformighet och standardisering nyckelord för att säkerställa kvalitet och kontroll på arbetet. En process som har olika utseende beroende på beställare är inte önskvärd. En möjlig väg att hantera problematiken är att arbeta med varianter på processen, analogt till metoden att arbeta med varianter på produkter (t.ex. SCANIA). För att komma dit måste dock den nuvarande processen standardiseras och återkommande moment rationaliseras och eventuellt automatiseras.  

  • 84.
    Sundkvist, Jenny
    et al.
    Mittuniversitetet.
    Johnsson, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Tre bygger i trä2008Ingår i: V-byggaren : väg- och vattenbyggaren, ISSN 0283-5363, nr 5, s. 14-16Artikel i tidskrift (Övrigt vetenskapligt)
  • 85.
    Söderholm, Erik
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Johnsson, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Housing design performance - how is it measured?2009Ingår i: Twenty-Fifth Annual Conference, 2009, September 7-9, Albert Hall, Nottingham / [ed] Andrew Dainty, Reading: Association of Researchers in Construction Management , 2009, s. 281-290Konferensbidrag (Refereegranskat)
    Abstract [en]

    Industrialisation involves reoccurring tasks and interfaces, which enables companies to work with continuous improvements of the process. In order to determine the effects of undertaken measures as well as enhance the manageability of the process, it is important to find measurements for effectiveness and efficiency of the construction design process. The aim of this paper is to serve as a gap analysis regarding the differences between current practice and the characteristics of performance measurement found in literature. This study is based on interviews with middle-managers at six industrial housing companies and four construction engineering consultant firms in Sweden, in order to explore the current methods of performance measuring in the construction design phase. The result shows that the studied companies currently have a limited use of measures and that the present measurements do not serve as a means of control for the design process or enable follow ups of undertaken improvements. For extended control and continuous improvement of the design process additional methods for measuring are required.

  • 86.
    Tlustochowicz, Gabriela
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Johnsson, Helena
    Displacements in the stabilizing system of a glulam beam-and-post system2008Ingår i: Proceedings of the 10th World Conference on Timber Engineering: WCTE 2008 : Miyazaki, Japan, June 2-5, 2008, 2008, Vol. 3, s. 1573-1580Konferensbidrag (Refereegranskat)
    Abstract [en]

    The provisions for developing a beam-and-post building system of glulam are examined for the Swedish market. The building system should provide open spaces through long-span floors combined with apartment floors, reaching a total height of 5-6 stories. Building multi-storey houses in timber requires a strong and stiff stabilizing system assuring safety and comfort for their users. Large movements are unacceptable risking damage on interior claddings and even nausea with the inhabitants on the upper floors. Stabilization can be achieved through diagonal bracing, moment stiff connections or diaphragm action. In this work a special stabilizing element based on diaphragm action is proposed. A parametric study of the stabilization system against lateral loads for a beam-and-post building system is presented based on traditional and numerical analyses. The aim of the paper is to establish the limitations for the stabilizing element to function within a multi-storey beam-and-post system. The study is a first step towards introducing an optimized beam-and-post building system in timber to the Swedish market.

  • 87.
    Tlustochowicz, Gabriela
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Johnsson, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Girhammar, Ulf Arne
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Beam and post system for non-residential multi-storey timber buildings: horizontal stabilising system2010Ingår i: 11th World Conference on Timber Engineering 2010, Red Hook: Curran Associates, Inc., 2010, Vol. 4, s. 3426-3433Konferensbidrag (Refereegranskat)
    Abstract [en]

    Due to changes in the Swedish design code in 1994, timber construction is no longer limited to two-storey buildings. This change has created an attractive market for multi-storey timber structures. A Scandinavian glulam manufacturer, Moelven Töreboda, started in 2007 to develop a new beam and post building system in timber for multi-storey buildings with the Swedish commercial name, “trä8”. For “trä8”, the stabilising system is based on prefabricated wall panels placed at a few locations in the building. The stabilising elements consist of double sheathing of LVL Kerto-Q boards glued and screwed to a glulam frame. The panels are typically of 2.4 m width and continuous up to four storey height. The elements are fixed to the foundation by using special anchoring devices, which include threaded rods glued-in lengthwise in the timber member. In this paper, an introductory experimental study of the efficiency of this prefabricated wall panel used as a stabilising element is reported. Experimental results from full-scale testing of the racking performance of the stabilising element including the anchoring device are presented. The study, which focuses on the stiffness and the serviceability state, demonstrates that the presented wall panel elements, as part of a beam and post system for multi-storey buildings, have the potential to provide the necessary horizontal stability for the building.

  • 88.
    Tlustochowicz, Gabriela
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Kermani, Abdy
    Centre for Timber Engineering, Edinburgh Napier University.
    Johnsson, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Beam and post system for non-residential multi-storey timber buildings: conceptual framework and key issues2010Ingår i: 11th World Conference on Timber Engineering 2010, Red Hook: Curran Associates, Inc., 2010, Vol. 3, s. 2032-2037Konferensbidrag (Refereegranskat)
    Abstract [en]

    In Sweden, there has been a long tradition of using timber in the construction of housing and in recent years, timber structural systems are increasingly used in multi-storey and large span buildings. The main focus of the majority of timber construction industries has been the development and utilisation of components, systems and construction techniques for the large market of residential buildings. Moelven Töreboda AB, a Scandinavian glulam manufacturer, has developed a beam and post system named “trä8” with the intention of filling the gap in the market for non-residential multi-storey buildings in timber. The developed timber beam and post system offers many advantages over other construction systems as well as being an attractive and versatile system for meeting clients’ and users’ expectations. This paper examines and provides guidelines on key issues in the development of the timber beam and post system for multi-storey non-residential buildings and deals with its structural system, assembly method and weather protection.

  • 89.
    Tsao, Cynthia
    et al.
    Consigli Construction Co.
    Lidelöw, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Development of a materials management strategy to enable continuous work flow on-site2017Ingår i: IGLC 2017: Proceedings of the 25th Annual Conference of the International Group for Lean Construction 2017 / [ed] Brilakis I.,Walsh K.,Sacks R., The International Group for Lean Construction , 2017, s. 853-860Konferensbidrag (Refereegranskat)
    Abstract [en]

    When project teams are pressured to limit internal or external Lean coaching due to budgetary concerns, Lean coaches may not have sufficient time to guide project teams in materials management to support milestones. Consequently, while organized project teams will make the time to develop a strategy for managing key materials that impact the critical path, disorganized project teams will more likely manage most materials on an ad-hoc basis. This lack of a materials management strategy then leads to unrealized profits and hidden wastes on projects. As a result, this research seeks to investigate how to develop a basic materials management framework to help project teams begin determining which bulky materials should be: (1) Using a pull system (e.g., through the use of Kanban cards or milk runs) to coordinate deliveries, (2) Kitted off-site vs. on-site, and (3) Organized into prefabricated assemblies. Specifically, this paper will identify various questions, calculations, and artefacts (e.g., equipment for handling and staging materials, signage used to make the materials management strategy transparent to all project participants) that contribute to establishing a comprehensive materials management strategy. In particular, space management emerges as an important tool to organize the flow of materials to match job-site installation rates.

  • 90.
    Uusitalo, Petri
    et al.
    Stora Enso Plc, FI-94800, Kemi.
    Lidelöw, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    The Struggle of Multiple Supply Chain Structures: Theoretical Overview2015Ingår i: Procedia Economics and Finance, E-ISSN 2212-5671, Vol. 21, s. 185-192Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Supplier firms are integrating downstream closer to the construction client. Sawmills have tried for decades to start producing timber buildings in order to capitalise on their core product; sawn timber. Their efforts have often failed, which is attributed to the different business logics between sawing timber and constructing buildings. This research identifies the supply chain structure as an important classification of production and business logic. Many firms operate make-to-stock, make-to-order and even engineer-to-order within the same firm, thus utilising the same or overlapping resources. From a theoretical viewpoint, this paper explores the problem of multiplicity in supply chains within construction and construction supplier firms. Literature on operations strategies, operations management, and supply chain structures is covered and put into perspective. It is an important capability to handle diversity in supply chain structures, not only when expanding business, but also in balancing different product categories internally e.g. to handle variations in market demand. The effect on internal resource utilisation can be vast. Operations management must take the differences in supply chain structures into account when developing key performance indicators and operations management strategies.

  • 91.
    Viklund, Emma
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Sandberg, Marcus
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Lidelöw, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Jansson, Gustav
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Modularization based on commonalities in house-building requirements2017Ingår i: ICCREM 2016: BIM Application and Offsite Construction - Proceedings of the 2016 International Conference on Construction and Real Estate Management 2016 / [ed] Wang Y.,Al-Hussein M.,Shen G.Q.P.,Zhu Y., Reston, VA: American Society of Civil Engineers (ASCE), 2017, s. 126-134Konferensbidrag (Refereegranskat)
    Abstract [en]

    Some of the requirements governing the design of houses are common between projects. This opens up for using modularization based on product commonalities. Though modularization is well known in the manufacturing industry, its use in house-building contexts is less studied. Even more scarce is research focusing on how requirement commonalities between one-of-a-kind products are found and managed in a modularization process. In this research, modularization from a requirements management perspective is empirically explored using a case study approach. Though the studied modularization process can be described as sequential, the process steps are highly interrelated, with overlaps and iterations. Commonalities are found by functional decomposition of the customer's portfolio projects, tracing technical solutions back to their initial requirements. These are balanced with the customer's requirements on the product and on the design automation tool. The requirement list is continuously updated based on portfolio analysis and communication of modularization results to the customer

  • 92.
    Wernicke, Brian
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Lidelöw, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Foundation for Balancing Resources and Flow Efficiency in Industrialized Construction2017Ingår i: ICCREM 2016: BIM Application and Offsite Construction - Proceedings of the 2016 International Conference on Construction and Real Estate Management 2016 / [ed] Wang Y.,Al-Hussein M.,Shen G.Q.P.,Zhu Y., Reston, VA: American Society of Civil Engineers (ASCE), 2017, s. 103-110Konferensbidrag (Refereegranskat)
    Abstract [en]

    Construction companies traditionally try to optimize their resource efficiency to minimize costs. Today's demand for value stream optimization along the whole supply chain cannot be resolved by that approach. To be able to strengthen the performance of the fragmented construction, supply chain measuring flow efficiency is essential to meet the customer's demand of shorter lead times. A literature study and an exploratory case study on a construction company and its supplier have been done to map existing key performance indicators (KPIs) for measuring both resource and flow efficiency. The outcomes from the literature study show possible KPIs and the connections between them. Results from the case study indicate that basic data for flow efficiency measurements exist in companies but these are underutilized. Balancing resource and flow efficiency is a challenge for all companies. Decisions made on how to manage production and construction affect this balance, thus creating a dynamic situation where the balance is different between building projects.

  • 93.
    Wernicke, Brian
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Lidelöw, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande. Lindbäcks bygg.
    Simu, Kajsa
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Flow Dimensions at Swedish Construction Contractors2019Ingår i: Lean Construction Journal, ISSN 1555-1369, E-ISSN 1555-1369, Vol. 2019, s. 24-46Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Research Question: How do different flow dimensions and their interrelations appear in Swedish construction settings?

    Purpose: To contribute to the ongoing discussion on flow in construction by providing empirical data to a proposed flow model and widening the current understanding within Lean Construction with theory from industrialized construction and operations management.

    Research Design: Transcriptions of nine in-depth interviews with managers at different Swedish contractors were utilized to identify different flow dimensions.

    Findings: Results show different patterns which describe contractors’ focus on different flow dimensions.

    Limitations: The study is performed in Swedish construction companies with limited generalizability to construction in general. Data collection based on interviews might struggle with objectivity and multi-case studies do not coincide with in-depth research in each single case.

    Implications: Different flow dimensions are relevant within construction contractors and should be addressed by either management activities or an operations strategy.

    Value for practitioners: Increased understanding of flow in construction based on empirical data enables management of different flow dimensions to evolve contractors’ operations strategies towards Lean Construction or industrialized construction.

  • 94.
    Wernicke, Brian
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Lidelöw, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Stehn, Lars
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Flow and resource efficiency measurement method in off-site production2017Ingår i: IGLC 2017: Proceedings of the 25th Annual Conference of the International Group for Lean Construction 2017 / [ed] Brilakis I.,Walsh K.,Sacks R., The International Group for Lean Construction , 2017, s. 861-868Konferensbidrag (Refereegranskat)
    Abstract [en]

    Although the focus remains primarily on high resource efficiency, the significance of flow efficiency in construction is continuously increasing. Flow and resource efficiency describe two competing target viewpoints, which focus on reducing non-value adding activities and maximizing resource utilization, respectively. Recent research has shown that balancing both perspectives provides a viable solution. However, the exact measurement of flow and resource efficiency in construction remains unclear. Therefore, the aim of this work is to evaluate a possible flow and resource efficiency measurement method in the off-site production context of volumetric element construction, and assess the industrial relevance thereof. Work sampling has been used to collect data from a building project flowing through the off-site production system. The validity of the method has been checked statistically, through a focus-group workshop and with calculation figures from the case company. Work sampling allows flow and resource efficiency measurements in an off-site production system. The method delivers current status figures of companies, yielding a balance between flow and resource efficiency.

  • 95. Johnsson, Helena (Redaktör)
    Proceedings from the Nordic Workshop in Wood Engineering: Skellefteå, February 21 20072007Rapport (Övrigt vetenskapligt)
    Abstract [en]

    On February 21st 2007 the Nordic Workshop in Wood Engineering was held in Skellefteå as part of Woodtech Sweden Research School. The proceedings contain seven original research papers presented by Ph.D. students in the field of wood material science, wood physics and timber engineering.

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