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  • 1.
    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.

  • 2.
    Edskär, Ida
    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.
    Dynamic Properties of Cross-Laminated Timber and Timber Truss Building Systems2019Ingår i: Engineering structures, ISSN 0141-0296, E-ISSN 1873-7323, Vol. 186, s. 525-535Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Incorrect prediction of dynamic properties of tall buildings can lead to discomfort for humans. It is therefore important to understand the dynamic characteristics such as natural frequency, mode shape and damping and the influence they have on acceleration levels. The aim of this study is to compare two timber building system, one with cross laminated panels and one with post-and-beam elements with diagonals for stabilisation. Empirical formulae for predicting the natural frequency and mode shape are compared to measured and numerical results. Tall building assumptions such as ‘line-like’ behaviour and lumped mass at certain points were evaluated for both systems. The post-and-beam system showed a stiffer behaviour than the cross laminated system where more shear deformation occurred. Empirical formulae should be used with care until more data is collected.  For the post-and-beam systems an assumption of linearity may be appropriate, but for cross laminated systems the approximation can give results on the unsafe side. Finally, the relationship between stiffness and mass for cross laminated timber systems and its effect on dynamic properties needs to be further investigated.

  • 3.
    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.

  • 4.
    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.

  • 5.
    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.

  • 6.
    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.

  • 7.
    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.

  • 8.
    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)
  • 9.
    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.

  • 10.
    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

  • 11.
    Lidelöw, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Offsite construction in Sweden: From technology-driven to integrated processes2017Ingår i: Offsite Architecture: Constructing the future / [ed] Ryan E Smith; John D Quale, London: Taylor & Francis, 2017, s. 214-223Kapitel i bok, del av antologi (Refereegranskat)
  • 12.
    Lidelöw, Helena
    et al.
    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.
    The effect of pre-engineering on design management methods2017Ingår 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. 523-530Konferensbidrag (Refereegranskat)
    Abstract [en]

    Several methods exist for design management such as Agile project management, the Last Planner System®, and configuration in diverse variants. Construction can be realized using different degrees of pre-engineering i.e. different production strategies, which can affect the design management method. The research aim is to describe different design management methods and discuss their capacity to function in existing production strategies in construction. Data was collected as secondary data from earlier publications on Agile project management, the Last Planner® system, configuration, and visual planning. Agile project management has a strong focus on customer value and lends itself well to situations with little pre-engineering. The Last Planner System® in design has a strong focus on the co-creation of flow and coordination of actions. In industrialised housing a dialect of Last Planner System® named KI-VP is implemented drawing upon predefinition of design tasks through standardized work. Configuration is the ultimate predefined design stage, where everything can be automated based on product variants.

  • 13.
    Lidelöw, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    The ER design simulation game: Experience and reflect2017Ingår 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. 515-522Konferensbidrag (Refereegranskat)
    Abstract [en]

    Most simulation games that exist are targeted towards experiencing and reflecting on Lean principles such as tact time, pull, Kanban, continuous improvements etc. The design phase in construction is characterised by information not being available, iterative work, specialized work tasks, and high uncertainty. The research aim is to develop and test a design simulation game that explains the design principles: lack of information, iterative work, and specialized work in order to let inexperienced people experience and reflect (ER) on the design phase. The method to develop the ER design game was to alter an already existing production sequence simulation game developed to illustrate one-piece flow. Action cards were entered into the game, changing work tasks and their sequencing as the game progressed. The ER design game demonstrates the difficulties in characterising and improving the design flow, but it does not show any methods to improve it. Lack of information, iterative work, specialized work, stop-start effects, and tact time issues all surfaced during playing the ER design game. The time frame for the game set was 45 minutes, which makes it feasible to incorporate in Lean method training.

  • 14.
    Lidelöw, Helena
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Olofsson, Thomas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    The Structure and Predefinition of the Industrialized Construction Value Chain2017Ingår 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. 117-125Konferensbidrag (Refereegranskat)
    Abstract [en]

    Industrialized construction means predefinition of products and processes. The level of predefinition is balanced against the level of needed flexibility to create the desired customer value. There is a range from no predefinition up to complete predefinition. This pattern can be repeated in different dimensions defining several decoupling points in the value chain. The aim of this paper is to map different situations of predefinition in design, supply, and production dimensions in order to understand the structure of industrialized construction value chains. A multiple case study was organized using secondary data collection from earlier work of the authors originally collected through interviews with key actors in industrialized construction companies in Sweden. The results show that long-term supplier agreements and cooperations are important to sustain industrialization of construction. A high degree of predefinition in design is a prerequisite to succeed in construction industrialization. However, there is no coupling between a high degree of predefinition in design and a high degree of mechanization and automation in production

  • 15.
    Edskär, Ida
    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.
    Wind-Induced Vibrations in Timber Buildings-Parameter Study of Cross-Laminated Timber Residential Structures2017Ingår i: Structural Engineering International, ISSN 1016-8664, E-ISSN 1683-0350, Vol. 27, nr 2, s. 205-216Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A current trend (2016) to construct high-rise timber buildings is seen. In order to understand the limitations posed by the timber material, wind-induced dynamic behaviour causing vibrations in the serviceability limit state has to be studied. The aim of this research is to calculate the natural frequency and acceleration levels of timber buildings having a cross-laminated timber structure to further the understanding of its behaviour and how a change in parameters affects building performance as reflected against comfort criteria. The results were calculated through finite element modelling using commercial software and by performing a modal analysis. The parameters under scrutiny were material stiffness, wall density, damping ratio, building height, and building footprint. The results show that even at moderate building heights (12-14 storeys), the comfort criteria are not fulfilled. Furthermore, the interaction between stiffness and mass for timber buildings needs to be explored further. And since the change of building footprint has a strong influence on the dynamic behaviour, the interplay between architectural and structural design becomes more important. Finally, more data on measurements of damping in timber buildings need to be collected to further validate simulation models.

  • 16.
    Jansson, Gustav
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Viklund, Emma
    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.
    Design management using knowledge innovation and visual planning.2016Ingår i: Automation in Construction, ISSN 0926-5805, E-ISSN 1872-7891, Vol. 72, nr 3, s. 330-337Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An open platform used for industrialised house-building imposes restrictions on the flexibility of the product offering when developing design standardisation. How design process standardisation incorporates variations in products has not been widely studied. The aim of this research is to explain how design breakdown enables Lean Product Development Flow (LPDF) and look-ahead planning in an industrialised house-building context where an open platform is used. A case study was conducted of how one of the leading industrialised house-building companies in Sweden introduced the LPDF tool Knowledge Innovation/Visual Planning (KI-VP) into their design process. The implementation of KI-VP led to an increased cross-functional understanding of relationships between activities, which are an important factor in achieving flexibility and a synchronised workflow. By using design standardisation, look-ahead planning was implemented and used in the management of design flow. Standardisation through design breakdown provides a basis for knowledge innovation that enables improvement of the open platform using a bottom-up approach and increases the production flow. 

  • 17.
    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)
  • 18.
    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)
  • 19.
    Lidelöw, Helena
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Jansson, Gustav
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Viklund, Emma
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Design Breakdown in Industrialized Construction: Supporting Lean Manufacturing2015Ingår i: Proceedings of the 2015 Modular and Offsite Construction (MOC) Summit & 1st International Conference on the Industrialization of Construction (ICIC) / [ed] Mohammed Al-Hussein; Osama Moselhi; Sunkuk Kim; Ryan E. Smith, Edmonton, Canada: University of Alberta Press , 2015, s. 255-262Konferensbidrag (Refereegranskat)
    Abstract [en]

    A turn-key commitment towards the client compels the contractor to optimize the entire supply chain from design to delivery of the finished building. Industrialization of residential construction can be accomplished using either an open or a closed platform. In the case of an open platform, the client can greatly affect design solutions and the subsequent production phase. The aim of this research is to explain how design process breakdown into activities and deli-veries supports Lean manufacturing in an open platform situation. The most successful industria-lized contractor in Sweden was studied through mapping their design process of modular buildings using their visual planning display. Describing the improvement strategy, the visual content, and the standardization efforts in design revealed the support for Lean manufacturing. Analyzing each activity for repetitive elements identified the base for standardization. The conclusion is that design breakdown is a successful method that effectively supports Lean manufacturing and provides a base for standardization in an open platform context.

  • 20.
    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.

  • 21.
    Jensen, Patrik
    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.
    Olofsson, Thomas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Product Configuration in Construction2015Ingår i: International Journal of Mass Customisation, ISSN 1742-4208, Vol. 5, nr 1, s. 73-92Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Construction is traditionally a trade that produces unique, one-off products designed specifically for the project in an engineer-to-order process. However, the development of flexible product platforms, based on the theory of mass customization, can offer product flexibility with affordable costs. The degree of commonality can also be increased if applying the products-in-products concept. This study aims to conceptualize and test theories of mass customization through modularization for applications in the construction industry. This is examined for three cases, with different specification processes (modify-to-order, configure-to-order and select-variant) incorporating bothbuilding and infrastructure products. The results show that the products-in-products concept is useful for enabling mass customization in construction. While the design can be integral in the select-variant type of specification process, the architecture needs to have a modular structure to enable a modify-to-order or configure-to-order type of customization.

  • 22.
    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

  • 23.
    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.

  • 24.
    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.

  • 25.
    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

  • 26.
    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

  • 27.
    Jansson, 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.
    Engström, Dan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Platform use in systems building2014Ingår i: Construction Management and Economics, ISSN 0144-6193, E-ISSN 1466-433X, Vol. 32, nr 1-2, s. 70-82Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The practice of reusing processes and technical solutions leads to the formation of product platforms in house building. Product platforms originate from industries employing a make-to-order production strategy, e.g. the automotive industry. To test how the product platform concept is useful in engineer-to-order production strategies, a case study at two Swedish house-builders was made. Key factors that affect platform use in systems buildings were sought. The smaller company operates a supplier-led platform focusing on commonalities in process knowledge. There is less definition of the product itself to allow for distinctiveness in the product offer. The larger company has a decentralized business and operates a client-driven platform with fragmented standardization. Focus is put on creating commonality through defining the product and handling distinctiveness through an iterative design procedure. Product families were not in use at the case study companies. The companies transform standardized platform solutions into project uniqueness by using support methods. Four platform support methods emerged from the case studies: design planning, collaborative design, design optimization, and requirements iteration. The balance between commonality and distinctiveness in the platform is important to attend to in each house-building project. The engineer-to-order production strategy hinders the implementation of a fully parameterized platform. The product platform concept is therefore expanded with support methods to handle distinctiveness, i.e. project uniqueness. The product platform assets: components, processes, relationships and knowledge, are present also in platforms used in systems building

  • 28.
    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))
  • 29.
    Caprolu, Giuseppe
    et al.
    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.
    Källsner, Bo
    School of Engineering, Linnæus University, Växjö.
    Lidelöw, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Splitting Capacity of Bottom Rail in Partially Anchored Timber Frame Shear Walls with Single-Sided Sheathing2014Ingår i: The IES Journal Part A: Civil & Structural Engineering, ISSN 1937-3260, E-ISSN 1937-3279, Vol. 7, nr 2, s. 83-105Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Plastic design methods can be used for determining the load-carrying capacity of partially anchored shear walls, where hold-downs are not provided. In order to use these methods, a ductile behaviour of the sheathing-to-framing joints must be ensured. Since the forces in the anchor bolts and the sheathing-to-framing joints do not act in the same vertical plane, the bottom rail will be subjected to bending and shear in the cross-wise direction, and splitting of the bottom rail may occur. In this article, results of two experimental programmes on the splitting capacity of the bottom rail due to uplift in partially anchored shear walls are presented. Two brittle failure modes occurred during testing: (1) a crack opening from the bottom surface of the bottom rail and (2) a crack opening from the edge surface of the bottom rail along the line of the sheathing-to-framing joints. The results show that the distance between the edge of the washer and the loaded edge of the bottom rail has a decisive influence on the maximum load and the failure modes of the bottom rail.

  • 30.
    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)
  • 31.
    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.

  • 32.
    Johnsson, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Fånga det industriella byggandet2013Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Det industriella byggandet i Sverige har under senare år rönt ett ökande intresse. Fortfarande råder tveksamhet kring vad industriellt byggande egentligen innebär. I den här rapporten sammanställs intervjuer med personer som har lång erfarenhet av olika satsningar på industriellt byggande. Gemensamt kommunicerar intervjuerna ett par teman som sammanfattar vad industriellt byggande omfattar:‐ För att industriellt byggande skall fungera måste hela kedjan, frånmarknadssidan, över projektering, till produktion och montage samt logistikfungera och gå i takt. Det innebär att tekniska lösningar som väljs måste vararobusta och gångbara i alla led. Ofta leder det till att lösningen inte är heltoptimal för något led, men det fungerar i kedjan.‐ Kopplingen mellan det erbjudande företaget har mot marknaden och deprodukter man kan leverera måste vara helt i överensstämmelse med varandra.Säljarbetet i ett industriellt byggande skiljer sig avsevärt från säljarbetet itraditionellt byggande. I ett industriellt byggande handlar det om att arbetainom byggsystemet tillsammans med kunden och förklara vilka kostnader somuppkommer om man går utanför systemet. I ett traditionellt byggande handlarsäljarbetet om att fånga kundens behov och tillfredsställa dem, även om detinnebär nya produktionsmetoder.‐ Långsiktigheten i en satsning på industriellt byggande kan inte överskattas. Ett företag som satsar måste vara förberett på att de första åren visar sämre ekonomiska resultat. Där måste finnas en tålighet för att orka med utvecklingsinsatser samtidigt som full produktion pågår. Vägen fram till ett fungerande och etablerat koncept måste ske i mindre steg och i en takt så att likviditeten i företaget inte blir lidande.‐ Ett unikt erbjudande är inte en fördel för industriellt byggande. Det handlarsnarare om att erbjuda en vara som uppfyller alla funktionskrav enligt normenpå ett trovärdigt och verifierat sätt. Det unika ligger i själva processen där t.ex.korta tider på byggplats kan vara ett erbjudande.‐ Relationerna i värdekedjan är mycket långsiktiga i industriellt byggande. Avtalom samarbete skrivs ibland över flera år. Underleverantörerna, både konsulteroch materialleverantörer, är ovana att arbeta på detta sätt i byggbranschen.Särskilt konsulternas affärsmodell att ta betalt per timme krockar medlångsiktiga samarbeten som bygger på ständiga förbättringar och upprepning av lösningar.Tidigare modeller för industriellt byggande har lagt för lite fokus på marknadens betydelse, affärsmodeller och kundmöten. Byggare generellt är ovana att hantera marknadsfrågor och att ha kundrelationer som sträcker sig bortom inlämnande och diskussioner kring anbud. Denna ovana kommer sig av att det bara är under de senaste 20 åren som Sverige haft en avreglerad bostadsmarknad. För industriellt byggande är marknadskopplingen om möjligt ännu viktigare och detta område behöver utvecklas avsevärt framgent.

  • 33.
    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.

  • 34.
    Jansson, 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.
    Jensen, Patrik
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Modularization in a housing platform for mass customization2013Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    The problem of combining production efficiency with flexible product offers in housing design is well known. The platform concept is applied in housing to support design and production with predefined solutions. Modularization can be useful to meet both client demands on flexibility and production requirements on standardisation. To identify the module drivers in housing, ten projects at one off-site housing company were analysed. Furthermore, the cycle time for the modules was recorded. Client, design, purchasing, production and suppliers have different module drivers. When module drivers concur, modules are identified by; identifying clear and few interfaces, the availability of a supplier, and the cycle time for the design and production of the module in relation to the production pace. The results from the case study further show that fixed geometry on modules is a less successful concept than parameterised modules in housing. The ability to outsource technical solutions increased, when the module drivers were combined with a long term relationship with the supplier. Variant modules were successfully applied in the studied company to respond to client demands. Further research is needed on how to configure generic modules.

  • 35.
    Johnsson, Helena
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Parida, Gabriela
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Prediction model for the load-carrying capacity of nailed timber joints subjected to plug shear2013Ingår i: Materials and Structures, ISSN 1359-5997, E-ISSN 1871-6873, Vol. 46, nr 12, s. 1973-1985Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Timber joints can experience ductile failures as modeled by Johansen in the European Yield Model adapted in Eurocode 5, or they can fail in a brittle manner. In nailed or screwed joints where the fastener does not protrude through the timber, plug shear failure can occur where an entire plug defined by the perimeter of the joint is torn away from the timber. The brittle plug shear failure, which can occur in joints loaded in tension parallel to the grain, results in a lower joint resistance than the ductile failure modes. The aim of this study is to evaluate existing prediction formulas for plug shear failure in timber connections, compare them to test results and observations, and propose a new prediction formula. Test results from four different experimental studies are presented. Using hypothesis testing, a prediction formula for plug shear failure is proposed based on 92 experiments. The resistance of the tensile failure mode of plug shear failure is best modelled by the tensile resistance of the end face of the plug. The resistance of the shear failure mode of plug shear failure is best modelled by the shear resistance of the bottom area of the plug taking into account the volume effect on shear strength. The model currently in Annex A of Eurocode 5 is overestimating the plug shear resistance compared to the test results analysed in this research. To avoid plug shear failure, short and wide joints are preferred, minimising the number of fasteners in line with the load and grain direction

  • 36.
    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.

  • 37.
    Johnsson, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Production strategies for pre-engineering in house-building: Exploring product development platforms2013Ingår i: Construction Management and Economics, ISSN 0144-6193, E-ISSN 1466-433X, Vol. 31, nr 9, s. 941-958Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Construction is a trade where the dominating production strategy is engineer-to-order. House-builders can pre-engineer their design to different degrees, resulting in variations of the engineer-to-order strategy: design-to-order, adapt-to-order, and engineer-to-stock. This variation causes different settings for the use ofplatforms in house-building. The aim of this research is to diversify the engineer-to-order production strategy and its consequences for platform organization by studying its use in house-building. The multiple case study on four engineering/contractor firms reports the core capabilities for engineer-to-order firms: procurement and tendering, market knowledge, engineering, multi-skilled manufacturing, and coordination of sales and manufacturing. Design-to-order, adapt-to-order and engineer-to stock were shown to be production strategies in use in house-building. In design-to-order platforms parts of the platform are undefined while engineer-to-stock platforms are fully predefined. Coordination between market and manufacturing is a crucial capability when engaging in platform organization. When an engineering firm and a contractor collaborate to fulfil client needs, the coordination capability between market and manufacturing was shown to be low. The case study shows that specialized contractors who integrate the supply chain towards a specific market segment benefit fully from the platform concept, while contractors with a wider scope could focus on standardization of processes rather than products.

  • 38.
    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.

  • 39.
    Johnsson, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    The Daily Life of a Construction Contractor: Multiplicity in Production Strategies2013Ingår i: Proceedings from 7th Nordic Conference on Construction Economics and Organisation 2013: Green Urbanisation - Implications for value Creation : Trondheim June 12-14, 2013 / [ed] Ole Jonny Klakegg, Trondheim: Akademika forlag, 2013, s. 404-414Konferensbidrag (Refereegranskat)
    Abstract [en]

    For a contractor, two main contractual agreements are used to meet the client; open bidding or design-build contracts. Viewing construction as a production system, this implies different production strategies are active; engineer-to-order and make-to-order. Theory suggests that this is difficult to handle within the same firm. The research aims to identify concurrent production strategies at a contractor and to elaborate on the consequences for the internal capabilities when acting according to several strategies. The in-depth case study is performed at a large contractor, active on the construction market in several European countries. The core capabilities of the case firm are analysed using theory capturing needed capabilities in the engineer-to-order and make-to-order situations. Generalisation is made by describing the atypical capabilities and consequences. The case study firm operates four concurrent production strategies. To cope, manufacturing is organised in flexible, multi-skilled teams to optimise the manufacturing resource utilization. When introducing industrialization in construction, the manufacturing flexibility hinders streamlining of the supply chain.

  • 40.
    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.

  • 41.
    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.

  • 42.
    Jensen, Patrik
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Olofsson, Thomas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Johnsson, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Configuration through the parameterization of building components2012Ingår i: Automation in Construction, ISSN 0926-5805, E-ISSN 1872-7891, Vol. 23, s. 1-8Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Many construction companies have developed building systems, based on prefabrication strategies, to enhance productivity. Current practice coupled with the difficulties of introducing these systems early in the design process often leads to ad hoc solutions and problems downstream along the value chain. In 2008 a multi-storey timber building system based on modularization principles was developed. The customization process used in this system is illustrated herein using a configurable timber floor slab module. The downstream flow of design information and upstream flow of constraints on, and rules for, the building system are described from three product viewpoints: the customer view, the engineering view and the production view. Using a manufacturing CAD tool, design automation is implemented in the engineering view and connected to an architectural CAD tool. The demonstration software shows that manufacturing CAD tools can be used to create design automation alternatives for modularized building systems within the construction industry.

  • 43.
    Johnsson, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Construction Purchasing and Supply Chain Management2012Ingår i: Construction Management and Economics, ISSN 0144-6193, E-ISSN 1466-433X, Vol. 30, nr 12, s. 1105-1107Artikel i tidskrift (Övrigt vetenskapligt)
  • 44.
    Björnfot, Anders
    et al.
    Faculty of Technology, Economy and Management, Gjøvik University College.
    Johnsson, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Simonsson, Peter
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    'Find-think-write-publish': Lean thinking in scientific paper writing2012Konferensbidrag (Refereegranskat)
    Abstract [en]

    Construction research supports long-term development of the construction industry and the society. Thus it is important to evaluate research against existing knowledge and to constantly develop new knowledge. The main mechanism for doing so is publishing scientific papers. In Sweden, praxis has developed that a Ph.D. consists of a handful of scientific papers. The average time period for a Ph.D. is five years after which the funding situation changes drastically. Previously, the duration of Ph.D. studies at Luleå University of Technology, Sweden often exceeded the planned five years, disrupting the flow of Ph.D. examinations. To increase awareness and interest in paper writing, a method was sought to visualise and manage the writing process. This paper investigates how an Oobeya room can be implemented in construction research to support paper writing. Experiences of working with the Oobeya room in three separate research divisions prove that it is possible and fruitful to better manage knowledge in academic institutions. Even though research is creative, it can be properly managed without hampering scientific freedom. Evidence from managing scientific paper writing using the Oobeya room shows that proper management of research will actually create better research that is more publishable with shorter lead times!.

  • 45.
    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.

  • 46.
    Caprolu, Giuseppe
    et al.
    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.
    Källsner, Bo
    Linnaeus University, Växjö.
    Johnsson, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Test on the splitting failure capacity of the bottom rail due to uplift in partially anchored shear walls2012Ingår i: World Conference on Timber Engineering: Final Papers - Architecture and Engineering Case Studies / [ed] Pierre Quenneville, New Zealand Timber Design Society , 2012, s. 189-194Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Källsner and Girhammar have developed a new plastic design method for wood-frame shear walls at ultimate limit state. The method is capable of calculating the load-carrying capacity of partially anchored shear walls, where the leading stud is not necessarily anchored against uplift. In fully anchored shear walls, the leading stud needs to be anchored using some kind of hold-downs to resist uplift and the bottom rail needs to be fixed by anchor bolts to resist horizontal shear forces. In partially anchored shear walls, where hold-downs are not provided, the uplifting force is resisted by the sheathing-to-framing joints along the bottom rail. Hence, it is important that the bottom rail is anchored to the floor structure or foundation by anchor bolts and, therefore, able to transmit the forces to the structure below. Because of the eccentric load transfer, transverse bending is developed in the bottom rail and splitting of the bottom rail can occur. In order to use the plastic design method, a ductile behaviour of the sheathing-to-framing joints must be ensured. In this paper, results of tests on the splitting capacity of the bottom rail due to uplift in partially anchored shear walls are presented. Specimens with single-sided sheathing were tested, varying the size of washer, pith orientation of the bottom rails and anchor bolt position along the width of the bottom rail. The aim of the tests was to evaluate the influence of these parameters in order to avoid splitting failure of the bottom rail. Two types of brittle failure modes occurred during testing: (1) a crack opening from the bottom surface of the bottom rail and (2) a crack opening from the edge surface of the bottom rail along the line of sheathing-to-framing joints. These failure modes were mainly dependent on the washer size and the location of the anchor bolt. The results show that the distance between the edge of the washer and the loaded edge of the bottom rail has a decisive influence on the maximum load and the failure modes of the bottom rail.

  • 47.
    Johnsson, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    The building system as a strategic asset in industrialised construction2011Ingår i: Proceedings of the 6th Nordic Conference on Construction Management and Organisation: Shaping the Construction/Society Nexus / [ed] Kim Haugbølle; Stefan Christoffer Gottlieb; Kalle E. Kähkönen; Ole Jonny Klakegg; Göran A. Lindahl; Kristian Widén, Danish Building Research Institute, Aalborg University , 2011, Vol. 3 . Construction in Society, s. 541-552Konferensbidrag (Refereegranskat)
    Abstract [en]

    The growing industry segment within construction focusing on industrialisation, meet new challenges traditional construction firms never have encountered. The choice of a building system (technical and process platform) defines not only what resources and technology are needed, but also the organisation within the company, its market position, and possible growth. Using a resource-based view, the building system can be seen as a strategic asset for an industrialised construction company. In this paper, the characteristics of a strategic asset is identified and used to analyse two building systems as being a strategic asset at two industrialised construction companies in Sweden. Two companies participated in the case study, one specialised contractor and one more general contractor, both active in the housing segment. The building system is clearly a strategic asset in all aspects for the specialised contractor, while the asset for the general contractor lies more in the organisational power of the company than in the technical solutions. The company strategy should therefore differ. The specialised contractor should strive to clarify and strengthen their total offer to the client, while the more general contractor should continue to exploit its human resources, moving towards a more unique offer to their client.

  • 48.
    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.

  • 49.
    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.

  • 50.
    André, Alann
    et al.
    Swerea SICOMP AB.
    Johnsson, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Flax fibre-reinforced glued-laminated timber in tension perpendicular to the grain: experimental study and probabilistic analysis2010Ingår i: Journal of materials in civil engineering, ISSN 0899-1561, E-ISSN 1943-5533, Vol. 22, nr 9, s. 827-835Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The weak mechanical properties of wood in tension perpendicular to the grain are often the origin of catastrophic brittle failure. In order to enhance the tension strength perpendicular to the grain and achieve a more ductile failure, flax fibre and glass fibre reinforced polymer (FRP) composites were used to strengthen glued-laminated (glulam) timber specimens. Three series of specimen of glulam timber (flax fibre reinforced, glass fibre reinforced and unreinforced), with a grand total of 28 specimens, were tested in tension perpendicular to the grain. For an approximate amount of FRP reinforcement of 1.2- in volume (thickness ~ 0.7 mm), an increase of the tensile strength up to 74- was shown, with a stiffness increase up to 41-. For all reinforced specimens, semi-ductile failures were observed. A parametric study was carried out using both the Monte Carlo method (MC) and the First Order Second Moment method (FOSM). It is shown that the mean values obtained during experiments are in agreement with those from the MC simulation. However, the standard deviations from the MC simulation are larger. From the FOSM analysis, it is demonstrated that the variation in glulam stiffness perpendicular to the grain is not the first parameter driving the variation for the reinforced system. The variation in mechanical properties of the flax fibres appeared to be the driving parameters for the strength of the system.

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