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Björnfot, Anders
Publications (10 of 28) Show all publications
Turesson, J., Björnfot, A., Berg, S., Ekevad, M. & Tomasi, R. (2019). Picture frame and diagonal compression testing of cross-laminated timber. Materials and Structures, 52(4), Article ID 66.
Open this publication in new window or tab >>Picture frame and diagonal compression testing of cross-laminated timber
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2019 (English)In: Materials and Structures, ISSN 1359-5997, E-ISSN 1871-6873, Vol. 52, no 4, article id 66Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
Springer, 2019
Keywords
In-plane shear stiffness, Picture frame method, CLT, Shear modulus, Diagonal compression
National Category
Building Technologies Other Mechanical Engineering
Research subject
Wood Science and Engineering
Identifiers
urn:nbn:se:ltu:diva-74874 (URN)10.1617/s11527-019-1372-7 (DOI)000472221500001 ()2-s2.0-85067616889 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-06-24 (svasva)

Available from: 2019-06-23 Created: 2019-06-23 Last updated: 2019-07-10Bibliographically approved
Björnfot, A. & Torjussen, L. (2012). Extent and effect of horizontal supply chain collaboration among construction SME (ed.). Paper presented at . Journal of Engineering, Project, and Production Management, 2(1), 47-55
Open this publication in new window or tab >>Extent and effect of horizontal supply chain collaboration among construction SME
2012 (English)In: Journal of Engineering, Project, and Production Management, ISSN 2221-6529, E-ISSN 2223-8379, Vol. 2, no 1, p. 47-55Article in journal (Refereed) Published
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.

National Category
Building Technologies
Research subject
Timber Structures
Identifiers
urn:nbn:se:ltu:diva-12001 (URN)b0f4d3cb-d478-44f0-bcab-93ed87139401 (Local ID)b0f4d3cb-d478-44f0-bcab-93ed87139401 (Archive number)b0f4d3cb-d478-44f0-bcab-93ed87139401 (OAI)
Note
Validerad; 2012; 20120510 (ysko)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2017-11-24Bibliographically approved
Simonsson, P., Björnfot, A., Erikshammar, J. & Olofsson, T. (2012). 'Learning to see' the effects of improved workflow in civil engineering projects (ed.). Paper presented at . Lean Construction Journal, 35-48
Open this publication in new window or tab >>'Learning to see' the effects of improved workflow in civil engineering projects
2012 (English)In: Lean Construction Journal, ISSN 1555-1369, E-ISSN 1555-1369, p. 35-48Article in journal (Refereed) Published
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.

National Category
Infrastructure Engineering Building Technologies Construction Management
Research subject
Structural Engineering; Timber Structures; Construction Engineering and Management
Identifiers
urn:nbn:se:ltu:diva-5551 (URN)3adf831b-ea5c-4186-807f-9fdbcae83c3e (Local ID)3adf831b-ea5c-4186-807f-9fdbcae83c3e (Archive number)3adf831b-ea5c-4186-807f-9fdbcae83c3e (OAI)
Note
Validerad; 2012; 20120327 (ysko)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2017-11-24Bibliographically approved
Lennartsson, M. & Björnfot, A. (2012). Production resource management in the industrialised house-building supply chain (ed.). Paper presented at . Journal of Engineering, Project, and Production Management, 2(2), 78-87
Open this publication in new window or tab >>Production resource management in the industrialised house-building supply chain
2012 (English)In: Journal of Engineering, Project, and Production Management, ISSN 2221-6529, E-ISSN 2223-8379, Vol. 2, no 2, p. 78-87Article in journal (Refereed) Published
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.

Keywords
Industrialised house-building, Production system, Robustness, Supply Chain Management, Systematic Production Analysis, Civil engineering and architecture - Building engineering, Samhällsbyggnadsteknik och arkitektur - Byggnadsteknik
National Category
Building Technologies
Research subject
Timber Structures
Identifiers
urn:nbn:se:ltu:diva-5212 (URN)3415d377-cf0d-41fc-ba68-bf175b3ab882 (Local ID)3415d377-cf0d-41fc-ba68-bf175b3ab882 (Archive number)3415d377-cf0d-41fc-ba68-bf175b3ab882 (OAI)
Note
Validerad; 2012; 20120419 (marlen)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2017-11-24Bibliographically approved
Björnfot, A., Torjussen, L. & Erikshammar, J. (2011). Horizontal supply chain collaboration in Swedish and Norwegian SME networks (ed.). In: (Ed.), John Rooke; Dave Bhargav (Ed.), Proceedings of IGLC-19: 19th Conference of the International Group for Lean Construction. Paper presented at Annual Conference of the International Group for Lean Construction : 13/07/2011 - 15/07/2011 (pp. 678-688). Lima: Fondo Ed. Pontificia Universidad Católica del Peru
Open this publication in new window or tab >>Horizontal supply chain collaboration in Swedish and Norwegian SME networks
2011 (English)In: 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, p. 678-688Conference paper, Published paper (Other academic)
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.

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.

Place, publisher, year, edition, pages
Lima: Fondo Ed. Pontificia Universidad Católica del Peru, 2011
Keywords
Civil engineering and architecture - Building manufacturing engineering, Horizontal Sypply Chain Management, Construction Suppliers, Collaboration, SME, Samhällsbyggnadsteknik och arkitektur - Byggproduktionsteknik
National Category
Building Technologies
Research subject
Timber Structures
Identifiers
urn:nbn:se:ltu:diva-37940 (URN)c242ee20-935a-43b5-932a-b9037915aa63 (Local ID)9781622768233 (ISBN)c242ee20-935a-43b5-932a-b9037915aa63 (Archive number)c242ee20-935a-43b5-932a-b9037915aa63 (OAI)
Conference
Annual Conference of the International Group for Lean Construction : 13/07/2011 - 15/07/2011
Note
Godkänd; 2011; Bibliografisk uppgift: Conference Chair Jorge Luis Izquierdo Graña y Montero Pontificia Universidad Católica del Perú Lima, Peru July 13-15 2011; 20110719 (jarkko)Available from: 2016-10-03 Created: 2016-10-03 Last updated: 2017-11-25Bibliographically approved
(2011). Lean Wood Engineering goes Japan (ed.). Paper presented at . Luleå: Luleå tekniska universitet
Open this publication in new window or tab >>Lean Wood Engineering goes Japan
2011 (English)Report (Other academic)
Place, publisher, year, edition, pages
Luleå: Luleå tekniska universitet, 2011. p. 43
Series
Technical report / Luleå University of Technology, ISSN 1402-1536
National Category
Building Technologies
Research subject
Timber Structures
Identifiers
urn:nbn:se:ltu:diva-23441 (URN)70071928-49b9-42d4-beb9-53061c0d3a50 (Local ID)978-91-7439-226-5 (ISBN)70071928-49b9-42d4-beb9-53061c0d3a50 (Archive number)70071928-49b9-42d4-beb9-53061c0d3a50 (OAI)
Note
Godkänd; 2011; 20110228 (anbjo)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2017-11-24Bibliographically approved
Björnfot, A., Bildsten, L., Erikshammar, J., Haller, M. & Simonsson, P. (2011). Lessons learned from successful value stream mapping (VSM) (ed.). In: (Ed.), John Rooke; Dave Bhargav (Ed.), Proceedings of IGLC-19: 19th Conference of the International Group for Lean Construction. Paper presented at Annual Conference of the International Group for Lean Construction : 13/07/2011 - 15/07/2011 (pp. 163-173). Lima: Fondo Ed. Pontificia Universidad Católica del Peru
Open this publication in new window or tab >>Lessons learned from successful value stream mapping (VSM)
Show others...
2011 (English)In: 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, p. 163-173Conference paper, Published paper (Other academic)
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.

Place, publisher, year, edition, pages
Lima: Fondo Ed. Pontificia Universidad Católica del Peru, 2011
National Category
Building Technologies Infrastructure Engineering
Research subject
Timber Structures; Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-26981 (URN)043e9a8c-0c0e-46d5-acb4-aaee216fb06e (Local ID)9781622768233 (ISBN)043e9a8c-0c0e-46d5-acb4-aaee216fb06e (Archive number)043e9a8c-0c0e-46d5-acb4-aaee216fb06e (OAI)
Conference
Annual Conference of the International Group for Lean Construction : 13/07/2011 - 15/07/2011
Projects
Lean Wood Engineering
Note
Godkänd; 2011; Bibliografisk uppgift: Conference Chair Jorge Luis Izquierdo Graña y Montero Pontificia Universidad Católica del Perú Lima, Peru July 13-15 2011; 20110719 (jarkko)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2017-11-25Bibliographically approved
Björnfot, A. (2011). LWE goes Japan: En resa i hållbarhetens tecken (ed.). Paper presented at . Samhällsbyggaren (2), pp. 22-25
Open this publication in new window or tab >>LWE goes Japan: En resa i hållbarhetens tecken
2011 (Swedish)In: Samhällsbyggaren, ISSN 2000-2408, no 2, p. 22-25Article in journal, News item (Other (popular science, discussion, etc.)) Published
National Category
Building Technologies
Research subject
Timber Structures
Identifiers
urn:nbn:se:ltu:diva-9575 (URN)83909241-0494-4dd8-9a1b-d1eb0bff69b7 (Local ID)83909241-0494-4dd8-9a1b-d1eb0bff69b7 (Archive number)83909241-0494-4dd8-9a1b-d1eb0bff69b7 (OAI)
Note
Godkänd; 2011; 20120213 (ysko)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2017-11-24Bibliographically approved
Bildsten, L., Björnfot, A. & Sandberg, E. (2011). Value-driven purshasing of kitchen cabinets in industrialized housing (ed.). Paper presented at . Journal of Financial Management of Property and Construction, 16(1), 73-83
Open this publication in new window or tab >>Value-driven purshasing of kitchen cabinets in industrialized housing
2011 (English)In: Journal of Financial Management of Property and Construction, ISSN 1363-2175, Vol. 16, no 1, p. 73-83Article in journal (Refereed) Published
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

National Category
Building Technologies
Research subject
Timber Structures
Identifiers
urn:nbn:se:ltu:diva-12669 (URN)10.1108/13664381111116106 (DOI)2-s2.0-84896507499 (Scopus ID)bd5d8e6b-af82-4b0c-9604-2fda5c80b1cf (Local ID)bd5d8e6b-af82-4b0c-9604-2fda5c80b1cf (Archive number)bd5d8e6b-af82-4b0c-9604-2fda5c80b1cf (OAI)
Note
Validerad; 2011; 20110429 (anbjo)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Björnfot, A., Lennartsson, M., Stehn, L. & Lindbäck, H. (2010). Projekt: Installationssamordning. Paper presented at .
Open this publication in new window or tab >>Projekt: Installationssamordning
2010 (Swedish)Other (Other (popular science, discussion, etc.))
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

National Category
Building Technologies
Research subject
Timber Structures
Identifiers
urn:nbn:se:ltu:diva-36024 (URN)2d656bfc-a9d8-4273-8b38-a23227212120 (Local ID)2d656bfc-a9d8-4273-8b38-a23227212120 (Archive number)2d656bfc-a9d8-4273-8b38-a23227212120 (OAI)
Note

Medverkande parter: Universitet: Luleå tekniska universitet (LTU). Företag: Lindbäcks Bygg AB, Norvag Byggsystem AB, Moelven ByggModul AB, Setra Group AB, Martinsons Byggsystem AB; Status: Pågående; Period: 17/12/2010 → …

Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2017-11-25Bibliographically approved
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