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  • 1.
    Bildsten, Louise
    et al.
    Industrial Marketing, Department of Management and Engineering, Linköping Institute of Technology.
    Björnfot, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Sandberg, Erik
    Logistics Management, Department of Management and Engineering, Linköping Institute of Technology.
    Value-driven purshasing of kitchen cabinets in industrialized housing2011Inngår i: Journal of Financial Management of Property and Construction, ISSN 1363-2175, Vol. 16, nr 1, s. 73-83Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Purpose – The purpose of this paper is to hypothesize that value-driven purchasing of customized kitchen cabinets is more profitable than market-driven purchasing in industrialised housing construction. The hypothesis is examined through a case study of kitchen carpentry at one of the Sweden's largest producers of industrialised prefabricated multi-storey housing. By comparing characteristics of market- vs value-driven purchasing, this paper aims to further clarify the benefits and drawbacks of these two strategies. Design/methodology/approach – By comparing characteristics of market- vs value-driven purchasing, a theoretical framework is proposed that clarifies the benefits and drawbacks of the two strategies. An explorative case study of kitchen carpentry at a house manufacturer illustrates purchasing of kitchen cabinets in the industrialised housing industry in relation to the proposed framework. Findings – The case study results indicate that, from a value perspective, a long-term relationship with a dedicated local smaller supplier is a preferable choice over a short-term relationship with a low-price mass producer. Research limitations/implications – This is a single case study that should be verified by further empirical work of a test delivery from the local sub-system manufacturer. Such a study would provide more insights into this area of work and make it possible to thoroughly evaluate potential risks. The indicative results in this paper can be made conclusive through quantification of the proposed lean purchasing characteristics. Originality/value – A comparison of value- and market-driven purchasing is carried out in theory and applied to a real case study that brings new perspectives to purchasing. In this way, the paper proposes alternative purchasing strategies to the construction industry

  • 2.
    Bildsten, Louise
    et al.
    Linköping University.
    Björnfot, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Sandberg, Erik
    Linköping University.
    Value-driven vs. market-driven purchasing of kitchen cabinets2010Inngår i: Proceedings IGLC-18: 18th Conference of the International Group for Lean Construction / [ed] Ken Walsh; Thais Alves, Haifa: Technion-Israel Institute of Technology , 2010, s. 202-211Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In economic and management literature, the relationship between supplier and buyer can be more or less intimate. It can vary from market-driven with a constant change of suppliers to a value-driven relationship with one sole supplier. Purchasing strategies of construction companies have often been described as short-sighted, where price is the most considered aspect. Recent lean management literature promote value-driven purchasing, since it provides benefits such as just-in-time delivery, zero defects and customized products through close technical collaboration. This article hypothesises that value-driven purchasing of customized kitchen cabinets is more profitable than market-driven purchasing in industrialized housing construction. The hypothesis is examined through a case study of kitchen carpentry at one of Sweden‘s largest producers of industrialized prefabricated multi-storey housing. By comparing characteristics of market-driven vs. value-driven purchasing, this article aims to further clarify the benefits and drawbacks of these two strategies. At the case company, kitchens are ordered cabinet-by-cabinet and then installed inside the factory. The company is considering the possibility of a long-term relationship with a smaller local supplier that can deliver a new kind of innovative kitchen cabinet solution that is prefabricated. If the local supplier can meet the expectations of just-in-time delivery, zero defects and a product -tailor-made‖ for the housing company, there is much to gain.

  • 3.
    Björnfot, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    An engineering perspective on lean construction theory2008Inngår i: IGLC 16 Proceedings: 16th Annual Conference of the International Group for Lean Construction / [ed] Patricia Tzortzopoulos; Mike Kagioglou, University of Salford, U.K. , 2008, s. 15-26Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The diversity of Lean Construction research and applications is extensive. Due to this diversity, it can be argued that Lean Construction theory has been overextended and lost some of its fundamental ideas. Even though much theoretical progress has been achieved, theoretical development shows inadequate relation to practical construction. Therefore, theory development is of limited interest for the construction community. The aim of this paper is to make Lean Construction more accessible for construction participants who are interested in learning more about the advances of Lean Construction theory, but are unable to do so due to the vast availability of associated theories. The view of the engineer, representing such a construction participant, is used to revivify and organise Lean Construction theory  through a classic structural engineering problem, the column-buckling case. Similar to the engineering case, the delivery team should consider four dimensions when designing a stable production system; these dimensions are product standardisation, process standardisation, workload reduction, and organisation strength. Application of these aspects in a systematic manner has potential to reduce variation while improving system stability and control.

  • 4.
    Björnfot, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    An exploration of lean thinking for multi-storey timber housing construction: contemporary Swedish practices and future opportunities2006Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Construction is affected by a large amount of waste (up to 35% of production costs in Sweden) and adverse relationships which lead to low quality and profitability. In Sweden, industrialized construction is viewed as one solution to the issues of construction which has led to a number of development efforts. Based on the success of Lean Production in manufacturing and the development of Lean Construction in countries such as Denmark, England and USA, the application of Lean Construction is currently debated in Sweden. However, Lean Construction theory seems unable to explain the development of industrialization in Swedish construction. Consequently, there is need of further research on how to better match industrialized construction with Lean Construction theory. The aim of this research is twofold; 1) explore how Lean Construction theory can be used to gain a deeper understanding of Swedish multi-storey timber housing construction and 2) explore how an understanding of contemporary practices can help extend the theory of Lean Construction to better facilitate research on industrialized construction. Currently, there is a Swedish governmental investment campaign supporting development of timber housing construction. Consequently, this is a good opportunity to explore the applicability of Lean Construction. Based on an understanding of the Lean philosophy, contemporary Swedish timber construction practices are analysed through three case studies; element prefabrication, volume prefabrication, and an initiative combining volumes and elements. The driving force in the development of applications for Lean Construction is production system design for increased control over construction events - stability (reliability) and better control (predictability) are sought through the reduction of variety in working practices, supply chains, etc. Consequently, improving work flow is the primary target of Lean Construction. An analysis of the contemporary timber element prefabrication reveals three main issues; 1) complicated design decisions, 2) poor design documentation, and 3) deficient production planning which, from a Lean Construction perspective, obstruct work flow. However, the root cause of work flow issues is identified as a lack of value management which causes ripples all through the production system resulting in variety and poor control. Results from volume and volume/element prefabrication indicate that value management greatly improves production system design. These well-defined technical platforms, so called ‘product offers', represent a new way of thinking in the delivery of value for multi-storey housing construction. The Lean characteristics of the ‘product offer' are product specifications based on customer value, value stream management through specific resources and activities, management of value-adding activities for flow, flexibility to customer demands enabling pull, and transparency for continuous improvements (perfection). Based on these characteristics, the ‘product offer' is viewed as one possible change-agent in the adoption of Lean Construction for Swedish multi-storey housing construction.

  • 5.
    Björnfot, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Industrialiserat byggande möter Leant byggande2007Inngår i: V-byggaren : väg- och vattenbyggaren, ISSN 0283-5363, nr 2, s. 12-16Artikkel i tidsskrift (Annet vitenskapelig)
  • 6.
    Björnfot, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    LWE goes Japan: En resa i hållbarhetens tecken2011Inngår i: Samhällsbyggaren, ISSN 2000-2408, nr 2, s. 22-25Artikkel i tidsskrift (Annet (populærvitenskap, debatt, mm))
  • 7.
    Björnfot, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Modular long-span timber structures: a systematic framework for buildable construction2004Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    One of the identified reasons for the low amount of timber construction in Sweden is a general lack of knowledge about timber engineering and how timber can be used to its full advantage. One way for increased timber construction is the development of a cost-efficient and easy to comprehend building system. Efficiency in construction has recently been under hot debate following the success of lean production in the manufacturing industry. Therefore, the attention of construction has been directed towards the manufacturing industry in an attempt to learn successful methods. Three main principles, modularity, lean construction, and buildability, emerge as potentially useful in order to streamline construction. The aim of this research project is to create a knowledge- based framework for long-span timber construction. This framework should be able to store knowledge and experience about timber construction as well as aid in the design and production of buildable timber structures. A buildable structure is here defined as a structure constructed in competition with all other materials and sub-system choices, i.e., by this definition a constructed structure is buildable and therefore competitive. The research is based on a case study of the design and production of long- span timber structures performed at a Swedish design company. The case study includes interviews, and a survey of 60 constructed long-span timber structures. A literature review of the industrialisation principles reveals that modularity has been a key concept in the evolution of the manufacturing industry. Therefore, the long-span timber construction industry should emit a bottom-up view where product modularity guides the construction processes. A systematic framework, Experience Feedback System (EFS), is created to store buildable construction knowledge based on modularity. The EFS is based on two distinct systems; Experience Based System (EBS), and Construction Knowledge Database (CKD), connected by a feedback loop for buildable construction feedback. The EBS utilises neural network theory containing competitive knowledge and experience of long-span timber structures, providing aid in early design. The CKS is based on the Design Structure Matrix (DSM), providing management of innovative construction and aid in detailed design. Due to the adaptability of neural networks and the developed 3-D DSM hierarchy representing the structural system, the systematic framework is potentially useful for the design and development of other types of structures and materials choices in the future.

  • 8.
    Björnfot, Anders
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Bildsten, Louise
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Erikshammar, Jarkko
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Haller, Martin
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Simonsson, Peter
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Lessons learned from successful value stream mapping (VSM)2011Inngår i: Proceedings of IGLC-19: 19th Conference of the International Group for Lean Construction / [ed] John Rooke; Dave Bhargav, Lima: Fondo Ed. Pontificia Universidad Católica del Peru , 2011, s. 163-173Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    To improve, it’s crucial to see! Vital characteristics of Lean are visualisation and transparency, i.e. allowing everyone to see all what occurs in production. A common tool for this purpose is Value Stream Mapping (VSM). Due to varying flows, performing a successful VSM in construction confers additional challenges. In this paper, lessons learned from successful VSM studies in construction are provided.Three VSM case studies were performed at different companies ranging from patio door manufacturing to kitchen cabinet assembly. Lessons learned can be structured into three phases; preparing the VSM (selecting “value stream leaders” and VSM team, clarifying values, etc.), performing the VSM (use of mapping tools, approximation of key indicators, waste identification, etc.), and following-up the VSM (Plan-Do-Check-Act, evaluating customer values, etc.).For the involved companies, the lessons learned imply the start of a “Lean journey” even though the involved companies found it difficult to relate VSM improvements to business strategies. Consequently, there are opportunities to further improve the application of VSM. However, it’s important to remember that VSM is about the straight-forward visualisation of flows and that these flows are made transparent for the whole organisation.

  • 9.
    Björnfot, Anders
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Jongeling, Rogier
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Application of line-of-balance and 4D CAD for lean planning2007Inngår i: Construction Innovation, ISSN 1471-4175, E-ISSN 1477-0857, Vol. 7, nr 2, s. 200-211Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Purpose - The purpose of this paper is to suggest the application of the line-of-balance (LoB) scheduling technique in combination with a 4D CAD workspace model as a method to improve the management of the flow of resources through locations in construction projects, defined as work flow. Current scheduling methods fail to consistently manage work flow, which can disrupt the construction process, leading to waste such as conflicts in time and space by construction crews. Design/methodology/approach - LoB and 4D CAD are applied to a case study of multi-story timber housing project involving the construction of 95 apartments in five six-storey buildings. Based on the case study results, the benefits and limitations of the combined use of both methods are discussed. Findings - The majority of the problems experienced during the actual construction process quickly become evident from an analysis of a relatively simple LoB diagram. Furthermore, the 4D CAD workspace model provides additional insights in the scheduling of construction activities, such as workspace availability, the spatial context of workspaces and partial overlap of workspaces. Practical implications - Virtual design and construction methods based on principles from lean construction can contribute significantly to the value of the product and the elimination of waste in any construction project. Originality/value - The paper refers to the guiding principles from lean construction in relation to virtual design and construction methods, such as simulations with 4D CAD. Additional research and studies of practical applications are suggested to facilitate the combination of principles from lean construction with virtual design and construction methods.

  • 10. Björnfot, Anders
    et al.
    Lennartsson, Martin
    Stehn, Lars
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Lindbäck, Hans
    Lindbäcks Bygg, Sverige.
    Projekt: Installationssamordning2010Annet (Annet (populærvitenskap, debatt, mm))
    Abstract [sv]

    Projektet syftar till att arbeta fram en modell för hur modularisering kan utnyttjas praktiskt i byggsammanhang. Specifikt handlar det om att definiera och avgränsa moduler samt att redogöra för hur en teknisk plattform kan skapas som stöds av en individuell utveckling av moduler för tekniska installationer. Medverkande parter Universitet: Luleå tekniska universitet (LTU) Företag: Lindbäcks Bygg AB Norvag Byggsystem AB Moelven ByggModul AB Setra Group AB Martinsons Byggsystem AB

  • 11.
    Björnfot, Anders
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Sardén, Ylva
    Prefabrication: a lean strategy for value generation in construction2006Inngår i: Understanding and Managing the Construction Process: Theory and Practice: Proceedings of the 14th Conference of the International Group for Lean Construction / [ed] R. Sacks; S. Bertelsen, Catholic University of Chile, School of Engineering , 2006, s. 265-277Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Despite a number of attempts to establish prefabrication as a Lean Construction method, there is still confusion of what prefabrication provides to the management of the construction process. It seems as if prefabrication can provide a means of dealing with value stream fluctuations in highly complex situations, such as a traditional construction project where it is difficult to define client value accurately. The prefabrication decision and the strategies for meeting customer demands have been studied for three Swedish producers of prefabricated timber components for multi-storey housing construction.The case study results indicate that the Swedish construction industry is slowly changing from a traditional project based generation of customer value to offering specific products, adaptable by the customer to suit their own view on value. A prefabrication strategy where a well defined and tested product is offered to customers has the effect of redistributing resources from the design process to the value stream. Such redistribution enables companies with a well developed prefabrication strategy to better control the value stream and to implement new and better ways of meeting customer requirements while continuously improving their work and eliminating waste.

  • 12.
    Björnfot, Anders
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Stehn, Lars
    A design structural matrix approach displaying structural and assembly requirements in construction: a timber case study2007Inngår i: Journal of engineering design (Print), ISSN 0954-4828, E-ISSN 1466-1837, Vol. 18, nr 2, s. 113-124Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A fundamental demand of construction design is human safety from structural failure. As a consequence, buildings generally tend to be structurally optimized with cost as the main target parameter. However, a cost-suboptimized structural design often leads to poor constructability decisions with subsequent waste. This paper presents initial research in the development of a design structural matrix (DSM) method able to identify constructability obstacles between structural design and assembly and thus eliminate waste. Empirical data based on a case study of long-span timber structures is used in the development and analysis of the method. The DSM was found to be a holistic tool for systematic consideration of structural design and constructability requirements by providing a standardized system view, a detailed element view, and physical and functional interactions among elements and modules. The DSM was also shown to aid in detailed design and production management through the use of simple matrix tools.

  • 13.
    Björnfot, Anders
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Stehn, Lars
    A systematic framework for long-span timber structures2004Inngår i: Proceedings, The 8th World Conference on Timber Engineering: WCTE 2004, 2004, Vol. 1, s. 93-98Konferansepaper (Fagfellevurdert)
  • 14.
    Björnfot, Anders
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Stehn, Lars
    Industrialization of construction: a lean modular approach2004Inngår i: 12th Conference of the International Group for Lean Construction: proceedings of IGLC-12 : Helsingør, Denmark, August, 3-5, 2004 / [ed] Sven Bertelsen; Carlos T. Formoso, 2004Konferansepaper (Fagfellevurdert)
  • 15.
    Björnfot, Anders
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Stehn, Lars
    Product design for improved material flow: a multi-storey timber housing project2005Inngår i: Proceedings: 13th Conference of the International Group for Lean Construction / [ed] Russell Kenely, Sydney: International group for lean construction , 2005, s. 297-306Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Understanding of construction has evolved to include a deeper understanding of its mechanics; in addition to traditional on-site work involving the manufacturing of building products - industrial construction. One of the most important aspects of any industrial process is flow of materials and resources. Using empirical data from a unique multi-storey timber housing project, this paper aims at building a better understanding of how product design affects flow of materials in housing construction. Even though a high degree of prefabrication was used in the project, the amount of complementary site work caused delays, complaints, and a slow learning cycle. A standardization process was used to shift product 'know-how' from person to product, resulting in increased flow and a reduction of errors. Prefabrication was not the sole solution to the encountered problems, but the controlled and ordered environment in prefabrication provided solutions at early stages. Instead of working towards solving the main production issues, the management was instead observed working with minor changes (first-aid solutions) to control flow. If industrialized multistorey timber housing construction is to be successful, product design decisions should be thought through, thoroughly, from start to finish using standardization as a guiding star

  • 16.
    Björnfot, Anders
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Stehn, Lars
    Value delivery through product offers: a lean leap in multi-storey timber housing construction2007Inngår i: Lean Construction Journal, ISSN 1555-1369, E-ISSN 1555-1369, Vol. 3, nr 1, s. 33-45Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Among large Swedish contractors there is currently a specialization trend towards an increased use of prefabrication and complete systems in housing construction. The Lean Construction development up to date has focused on the management of value delivery for complex construction projects. Typical Swedish housing projects do not experience this broad complexity; instead the main challenge seems to be to better specify and deliver customer value. Currently, the Lean Construction methods available are not by themselves enough for the generation of value in Swedish multi-storey housing construction. The aim of this paper is to examine the potential of the product offer (a well-defined and highly standardized building system developed from the value views of specific customers) as an aid in the generation and delivery of value for multi-storey timber housing construction.From the point of view of manufacturing and customer value, the product offer is considered a Lean strategy for integrated consideration of internal and external value. Case study experiences indicate that the product offer strategy provides stability and continuity for producers that in turn provides with Lean practices in marketing, design and manufacturing. Approaching Lean, small- to medium-sized Swedish producers should focus on improvements through Lean Manufacturing. However, since an emerging demand from the Swedish construction industry forces these producers to take a larger role in the construction process, more construction related Lean improvements must also be considered. In this regard, the product offer is demonstrated to be a promising Lean strategy for the Swedish housing industry.

  • 17.
    Björnfot, Anders
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Torjussen, Liv
    Gjövik University College.
    Extent and effect of horizontal supply chain collaboration among construction SME2012Inngår i: Journal of Engineering, Project, and Production Management, ISSN 2221-6529, E-ISSN 2223-8379, Vol. 2, nr 1, s. 47-55Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The majority of companies involved in value delivery in the Swedish housing industry are Small- and Medium-sized Enterprises (SME). An SME is often managed in an informal way with focus on sales and production. Many SME are also financially vulnerable as they are strongly dependent on a few key customers and key products. As variation will always exist, SME should learn to deal with variation instead of try eliminating it. This paper hypothesises that structural flexibility in SME supply chains through horizontal collaboration leads to a regional environment of economical growth from which all active SME will benefit. The hypothesis is examined through two case studies; a Swedish supplier network that has worked together six years and a four year old Norwegian supplier network. A benefit of collaboration is knowledge sharing that lessens the economical strain of keeping up with the “latest”. Other examples of collaboration are shared production resources in case of low capacity. Collaboration within supplier tier networks is considered to mark the emergence of a “collective strength” that improves individual suppliers bargaining position towards their customers. This evolution is considered an indication of the emergence of a “Lean Enterprise” within the house building sector.

  • 18.
    Björnfot, Anders
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Torjussen, Liv
    Gjövik University College.
    Erikshammar, Jarkko
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Horizontal supply chain collaboration in Swedish and Norwegian SME networks2011Inngår i: Proceedings of IGLC-19: 19th Conference of the International Group for Lean Construction / [ed] John Rooke; Dave Bhargav, Lima: Fondo Ed. Pontificia Universidad Católica del Peru , 2011, s. 678-688Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    An SME is often managed in an informal way with focus on sales and production. Many SME are also financially vulnerable as they are strongly dependent on a few key customers and key products. As variation will always exist, SME should learn to deal with variation instead of try eliminating it. This paper hypothesises that structural flexibility in SME supply chains through horizontal collaboration leads to a regional environment of economical growth from which all active SME will benefit The hypothesis is examined through two case studies; a Swedish supplier network that has worked together six year and a freshly started Norwegian supplier network. The Swedish suppliers are cooperating; e.g. in case of low capacity, they are sharing production resources. Another benefit of cooperation, supported by Norwegian findings, is the sharing of knowledge amongst each other that lessens the economical strain of keeping up with the “latest”. Cooperation within supplier tier networks marks the emergence of a “collective strength” improving individual suppliers bargaining position towards their customers, e.g. when obtaining new orders, when lobbying for changes in regulations, or when developing and verifying new products. This evolution indicates the emergence of a “Lean Enterprise” within the house building sector.

  • 19.
    Erikshammar, Jarkko
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Björnfot, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Gardelli, Viktor
    Luleå tekniska universitet, Institutionen för konst, kommunikation och lärande, Pedagogik språk och Ämnesdidaktik.
    The ambiguity of value2010Inngår i: Proceedings IGLC-18: 18th Conference of the International Group for Lean Construction / [ed] Ken Walsh; Thais Alves, Haifa: Technion-Israel Institute of Technology , 2010, s. 42-51Konferansepaper (Fagfellevurdert)
    Abstract [en]

    'Value' is a central concept in all of the principles and methods applied in Lean Construction, but it is rather difficult to provide a precise definition of the term. The problem lies in the word value itself: its ambiguity and vagueness make theorization difficult. This paper investigates the philosophical concept of value from a Lean Construction perspective. Several elements that contribute to value are considered, including objective elements such as waste reduction, quality, price and functionality, and more subjective elements such as design. The hypothesis of this paper is that the reduction or removal of elements that detract from value, such as waste and costs, is not the only means by which value may be increased. The Sorites paradox is used to form a cohesive perspective on some different meanings of the word ‗value‘. One of the known ‗solutions‘ of the paradox, utilization theory, is then explored through a case study in off-site construction that illustrates how different actors in the construction process view value, and how utility theory can be used to provide a consensus on value that is acceptable. In practice, ‗value‘ is ambiguous because actors generally value different things and these views seldom converge during projects. Our results indicate that the actors involved strive for value individually. Analysis using utility theory allows the actors to establish a shared conceptualization of value, expressed in monetary terms. The work described in this paper aims to improve our understanding of value and of how to design products in construction to improve value for clients of industrialized housing.

  • 20.
    Lennartsson, Martin
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Björnfot, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Production resource management in the industrialised house-building supply chain2012Inngår i: Journal of Engineering, Project, and Production Management, ISSN 2221-6529, E-ISSN 2223-8379, Vol. 2, nr 2, s. 78-87Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Industrialised house-building suppliers must learn to see how the lack of resource management disrupt the synchronisation of their production processes both upstream (e.g. capability to forecast material consumption) and downstream (e.g. order delivery Just-in-Time). In contrast to focus on workflow as is more common in construction, Systematic Production Analysis (SPA) is a tool capable of providing a more robust production process in terms of better resource characterisation and predictability. A roadmap model, composed of six steps, has been developed for simple introduction of SPA. The model is a straightforward way of classifying the production system in terms of impacting resource and parameters attributing to production loss (scrap or downtime). The applicability of SPA is analysed through a pilot case study at a patio door manufacturer. Two main response parameters emerged related to scrap; surface and dimension errors of the work piece material (wood). An objective function was formulated to reduce the scrap without increasing the total cost of the work piece material. It was suggested that the case company evaluates Engineering Wood Products (EWP) leading to a more robust production process (less scrap), but in turn increasing the initial cost of the work piece material. Other potential measures are purchasing new processing tools, investing in new machinery or educating workers which all, directly or indirectly, lead to reduced scrap. Consequently, proper management of production resources will improve their predictability and in turn improve production control.

  • 21.
    Lennartsson, Martin
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Björnfot, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Step-by-step modularity: a roadmap for building service development2010Inngår i: Lean Construction Journal, ISSN 1555-1369, E-ISSN 1555-1369, Vol. 2010, nr 1, s. 17-29Artikkel i tidsskrift (Fagfellevurdert)
  • 22. Lennartsson, Martin
    et al.
    Björnfot, Anders
    Stehn, Lars
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Lean modular design: value-based progress of industrialised housing2008Inngår i: IGLC 16 Proceedings: 16th Annual Conference of the International Group for Lean Construction / [ed] Patricia Tzortzopoulos; Mike Kagioglou, University of Salford, U.K. , 2008, s. 541-551Konferansepaper (Fagfellevurdert)
    Abstract [en]

    One of the core ideas of Lean Construction is that the process of designing and producing a construction product should progress continuously and create value for both the customer and the delivery team. The hypothesis in this paper is that modularisation has potential as a method for value management. The aim is to describe how modularisation, in a lean context, can be used as a tool to facilitate the management of internal and external values in industrialised housing. The paper will explore the theory of modularisation and its drivers and examine how the method can promote value management. Modularisation is then explored in practice, using empirical knowledge from the building service systems (HVAC, electricity, etc.) development process at five Swedish multi-storey timber housing producers. The analysis point out the importance of decomposing the modularisation process into a jointly performed industry phase where modules are designed, followed by a company internal product development process that complies to the modules. This paper concludes that it is not the product decomposition into modules that is of importance, rather the process that strives to balance internal and external values.

  • 23.
    Lennartsson, Martin
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Björnfot, Anders
    Stehn, Lars
    Production control through modularisation2009Inngår i: Proceedings IGLC 17: 17th Annual Conference of the International Group for Lean Construction, 2009, s. 453-464Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In Sweden, the industrial housing trade has developed for many years with the salient idea of improving production control through an increased level of prefabrication. However, production variability is a consistent issue as work is still sub-optimised, resulting in a fragmented production process. Consequently, problems arise when prefabricated parts and components are assembled. The building services are often a source of high variability (many different components and subcontractors), leading to reduced production control. The aim of this paper is to present how modularisations can provide prerequisites for production control in service system design.So far, modularisation has only rendered little attention in Lean construction. In this paper, a modularisation development effort of five Swedish industrial housing ompanies is reported. To generate a relevant set of modules, several workshops were held together with company representatives and building service consultants. The Design Structure Matrix (DSM) was used to detect the lowest common geometrical denominator of the building service systems as well as crucial connection points and interfaces. Combining the DSM with qualitative module drivers generates a design for service system modules facilitating improved production control.

  • 24.
    Simonsson, Peter
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Björnfot, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Erikshammar, Jarkko
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Olofsson, Thomas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    'Learning to see' the effects of improved workflow in civil engineering projects2012Inngår i: Lean Construction Journal, ISSN 1555-1369, E-ISSN 1555-1369, s. 35-48Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Research Question/Hypothesis: Value Stream Mapping (VSM) can, independent of work repetition, improve the performance of civil engineering projects by allowing the site management to visualize the flows of materials, resources and information.Purpose: The purpose is to show how VSM can be used by on-site practitioners to see the day-to-day flow of work, to understand the effect of straight-forward improvements to workflow, and to see the effect of applying industrialized working methods.Research Method: Applicability of VSM to civil engineering is examined through the fixing of reinforcement in two bridge construction projects. A traditional bridge was used to map (current state) and improve (future state) workflow. The potential of modern production methods are then analyzed in a second bridge project (ideal state).Findings: Allowing the site management to visualize and to see workflow improves the work performance of the two studied bridges. Addition of easy to understand and calculable metrics for lead time, inventory level and manufacturing costs, emphasize the potential savings of reactive and proactive workflow measures (≈ 80-90 %).Limitations: The paper considers fixing of reinforcement in two bridge construction projects. Additionally, the so-called future state bridge was not actually constructed, i.e. the savings stated for the future state, even if reasonable, are an approximation.Implications: The framework to visualize current, future and ideal workflow provides a framework to extend the VSM methodology to civil engineering projects.Value for practitioners: To overcome the sub-optimized mindset in civil engineering that repeatedly leads to the same practice, the paper proposes a straightforward and easy to use framework to visualize and analyze effects of workflow improvements.

  • 25.
    Stehn, Lars
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Björnfot, Anders
    Comparison of different ductility measures for a nailed steel-to-timber connection2002Inngår i: 7th World conference on timber engineering: WCTE 2002, Penerbitan Publications , 2002, Vol. 2, s. 155-162, artikkel-id 4.4.2Konferansepaper (Fagfellevurdert)
  • 26.
    Stehn, Lars
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Björnfot, Anders
    Temperaturen på det industriella trähusbyggandet2008Inngår i: V-byggaren : väg- och vattenbyggaren, ISSN 0283-5363, nr 5, s. 8-10Artikkel i tidsskrift (Annet vitenskapelig)
  • 27.
    Turesson, Jonas
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknik.
    Björnfot, Anders
    Department of Manufacturing and Civil Engineering, Faculty of EngineeringNorwegian University of Science and TechnologyGjøvikNorway.
    Berg, Sven
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknik.
    Ekevad, Mats
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknik.
    Tomasi, Roberto
    Faculty of Science and Technology, Division of Buildings, Architecture, and Environmental EngineeringNorwegian University of Life SciencesÅsNorway.
    Picture frame and diagonal compression testing of cross-laminated timber2019Inngår i: Materials and Structures, ISSN 1359-5997, E-ISSN 1871-6873, Vol. 52, nr 4, artikkel-id 66Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Currently, no appropriate standard exists that describes how to determine the in-plane shear stiffness for cross-laminated timber (CLT) panels, meaning that, there is a lack of appropriate and reliable test methods. In this paper, two gross shear test methods are evaluated: a picture frame test and a diagonal compression test, which are intended to measure the shear stiffness of a whole CLT panel. This evaluation aimed to compare the shear modulus, the amount of compression/tension in the diagonal directions of the panels and the deformations of both sides of the panels. The picture frame test and diagonal compression test provides a bi- and uniaxial pre-stress, respectively. A total of 30 non-edge glued CLT panels were tested, 17 3-layer and 13 5-layer panels. The shear modulus for the 3- and 5-layer non-edge-glued panels were measured as 418 and 466 MPa, respectively, in the picture frame test. In the diagonal compression test, the shear modulus was measured to substantially higher values of 530 and 626 MPa for the 3- and 5-layer panels, respectively. In the picture frame test, panels were equally stretched along one of the diagonals as they were compressed along the other diagonal, which was not the case for panels in the diagonal compression test. The test results also showed that measuring only one side incurs a risk of over- or under-estimating the in-plane shear modulus. Compared with results from the literature, the picture frame test seems to be a more reliable test method than the diagonal compression test.

  • 28. Björnfot, Anders ()
    Lean Wood Engineering goes Japan2011Rapport (Annet vitenskapelig)
1 - 28 of 28
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