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Lagerqvist, Ove
Publications (10 of 58) Show all publications
Sabau, G., Koltsakis, E. & Lagerqvist, O. (2018). Stability analysis of newly developed polygonal cross-sections for lattice wind towers. Paper presented at WINERCOST'17 – International Conference On Wind Energy Harvesting 2017, Coimbra, Portugal, 20-21 april, 2017. Wind Engineering: The International Journal of Wind Power, 42(4), 353-363
Open this publication in new window or tab >>Stability analysis of newly developed polygonal cross-sections for lattice wind towers
2018 (English)In: Wind Engineering: The International Journal of Wind Power, ISSN 0309-524X, E-ISSN 2048-402X, Vol. 42, no 4, p. 353-363Article in journal (Refereed) Published
Abstract [en]

The pursuit for cheaper energy is leading the current wind tower design to increased heights. Common wind turbine tower designs would generate unjustified costs for transportation and erection leading to inefficient use of materials. In order to reduce these costs, several simplified erection methods have been proposed. One of such is the hybrid lattice-tubular steel tower. For economic feasibility, built-up cold-formed polygonal cross-sections have been proposed for the lattice part. This article presents a numerical investigation of the failure modes of closed polygonal cross-sections. The first part contains a presentation of structural systems which incorporate elements composed of plates and cold-formed members. The evaluation of the polygonal sections is done by means of finite element analysis considering local and global geometrical imperfections and residual stresses generated in the fabrication procedure. A comparative study is performed between several finite element models to propose a corresponding European buckling curve for calculating the flexural buckling resistance. The results show that the design of polygonal sections can be done according to European buckling curves methodology.

Place, publisher, year, edition, pages
Sage Publications, 2018
Keywords
Cold-formed, finite element simulation, flexural buckling, lattice wind tower, polygonal sections
National Category
Building Technologies
Research subject
Steel Structures
Identifiers
urn:nbn:se:ltu:diva-70193 (URN)10.1177/0309524X18777366 (DOI)2-s2.0-85049948088 (Scopus ID)
Conference
WINERCOST'17 – International Conference On Wind Energy Harvesting 2017, Coimbra, Portugal, 20-21 april, 2017
Note

2018-08-02 (rokbeg);konferensartikel i tidskrift

Available from: 2018-08-01 Created: 2018-08-01 Last updated: 2018-08-08Bibliographically approved
Sabau, G., Koltsakis, E. & Lagerqvist, O. (2017). Cylindrical shell buckling under a hydraulic constraint: Numerical study. Paper presented at EUROSTEEL 2017, Copenhagen, Denmark, September 13–15, 2017. ce/papers, 1(2-3), 970-979
Open this publication in new window or tab >>Cylindrical shell buckling under a hydraulic constraint: Numerical study
2017 (English)In: ce/papers, E-ISSN 2509-7075, Vol. 1, no 2-3, p. 970-979Article in journal (Refereed) Published
Abstract [en]

Steel cylindrical shell structures are used in a large variety of civil engineering applications such as off- shore platforms, tanks, silos, wind turbine towers, etc. The local stability of such structures and their sensitivity to imperfections is a well-known problem. In current engineering practice the design method is based on the selection of an imperfection class for the shell and subsequently calculating a reduction factor,χ, to the resistance of the shell. One such methodology is supplied by the EN1993-1-6; special conditions are given to pressurized tubes subjected to meridional compression.

Past studies have focused on the stability of cylindrical shells with internal pressure. The stability problem of a long cylinder considering the internal pressure as a simple static load was addressed. Thus, the approaches considered the fluid as compressible.

The purpose of the present work is to investigate numerically the potential benefit of using an incompressible fluid fully enclosed in a circular cylindrical shell. The constraint imposed by the presence of the liquid in the interior of a shell will be referred to as “hydraulic constraint”. As liquids are nearly incompressible, the buckling of a liquid-filled shell has to satisfy the condition that the integral of all the displacements normal to the shell surface is equal to the volume variation of the contained liquid. The volume variation of the shell interior has to be equal to the dilation of the shell due to liquid pressure increments associated to the onset of geometrical instability. Additionally, the weight of the contained liquid causes additional circumferential tension in the cases of vertically placed cylinders.

The methodology followed is the numerical analysis of cylindrical shells by means of the ABAQUS Finite Element code and a comparison with the methods given in the Eurocode.

Place, publisher, year, edition, pages
Ernst & Sohn Verlag, 2017
National Category
Building Technologies
Research subject
Steel Structures
Identifiers
urn:nbn:se:ltu:diva-65654 (URN)10.1002/cepa.137 (DOI)
Conference
EUROSTEEL 2017, Copenhagen, Denmark, September 13–15, 2017
Note

Konferensartikel i tidskrift

Available from: 2017-09-15 Created: 2017-09-15 Last updated: 2017-11-24Bibliographically approved
Andrade, P., Lagerqvist, O., Simões, R. & Veljkovic, M. (2017). Structural assessment of a column splice with opened slotted holes: Finger Connection. Paper presented at EUROSTEEL 2017, Copenhagen, Denmark, September 13–15, 2017. ce/papers, 1(2-3), 514-521
Open this publication in new window or tab >>Structural assessment of a column splice with opened slotted holes: Finger Connection
2017 (English)In: ce/papers, E-ISSN 2509-7075, Vol. 1, no 2-3, p. 514-521Article in journal (Refereed) Published
Abstract [en]

This paper introduces a novel joint based on a friction connection designed for column-splices. The jointwas developed within the scope of modular construction to improve the fast assembly of prefabricatedframes and to accommodate eventual misalignments. Gaps at the connection are considered on the jointhorizontal and vertical axis to accommodate misalignments whether they are rotations and/ordisplacements and so to allow for the easy fit of the columns. The efficiency of the joint resistance basedon different connection gaps subjected to uniform compression is assessed.

Place, publisher, year, edition, pages
Ernst & Sohn Verlag, 2017
National Category
Building Technologies
Research subject
Steel Structures
Identifiers
urn:nbn:se:ltu:diva-65645 (URN)10.1002/cepa.88 (DOI)
Conference
EUROSTEEL 2017, Copenhagen, Denmark, September 13–15, 2017
Note

Konferensartikel i tidskrift

Available from: 2017-09-14 Created: 2017-09-14 Last updated: 2017-11-24Bibliographically approved
Sandström, J., Wickström, U., Thelandersson, S. & Lagerqvist, O. (2017). The Life Safety Objective in Performance-Based Design for Structural Fire Safety. In: : . Paper presented at 2nd international conference on structural safety under fire & blast loading, CONFAB 2017, London, 10-12 september 2017.
Open this publication in new window or tab >>The Life Safety Objective in Performance-Based Design for Structural Fire Safety
2017 (English)Conference paper, Published paper (Refereed)
Abstract [en]

Structural stability is not necessarily required for buildings where life safety is the sole structural fire safety objective. However, a structural collapse is only acceptable in an area where lethal fire conditions have developed. Therefore, structural failures due to fire resulting in risks of progressing outside of the area of lethal fire conditions need to be addressed. Thus, a new type of design principles for the life safety objectives is presented here which enables an evaluation of more precise risk assessments and more cost-efficient solutions without compromising human safety.

National Category
Building Technologies
Research subject
Steel Structures
Identifiers
urn:nbn:se:ltu:diva-70093 (URN)
Conference
2nd international conference on structural safety under fire & blast loading, CONFAB 2017, London, 10-12 september 2017
Funder
SBUF - Sveriges Byggindustriers Utvecklingsfond, 13330
Available from: 2018-07-09 Created: 2018-07-09 Last updated: 2018-08-15Bibliographically approved
Bröchner, J. & Lagerqvist, O. (2016). From ideas to construction innovations: Firms and universities collaborating (ed.). Construction Economics and Building, 16(1), 76-89
Open this publication in new window or tab >>From ideas to construction innovations: Firms and universities collaborating
2016 (English)In: Construction Economics and Building, ISSN 2204-9029, Vol. 16, no 1, p. 76-89Article in journal (Refereed) Published
Abstract [en]

The purpose here is to study patterns of project collaboration found in one government supported programme for construction innovation. Preferred types of interaction were identified using data from two questionnaire surveys, one with experienced construction sector respondents and one aimed at construction researchers. All sixteen development projects within the Swedish Bygginnovationen programme were investigated, relying on documents and a survey of project managers. Important types of interaction, according to construction respondents, are informal contacts, joint research projects and staff mobility. For university respondents, informal contacts is also seen as the most important type of interaction, followed by MSc thesis work in firms and industrial PhD candidates. Grant applicants from manufacturing depended more on university laboratories and were less sensitive to firm/university distance. Laboratory use was also more frequent for projects relying on the field of materials engineering. In conclusion, there is a consensus about which types of collaboration are valuable. The broadness of participation in the programme, ranging over many industries, both as to origin of ideas and ultimate applications, reaches beyond narrow interpretations of the construction industry. Policy makers should recognize the innovation importance of university laboratory facilities and field testing, rather than seeing researchers as sources of ideas.

National Category
Construction Management Building Technologies
Research subject
Construction Engineering and Management; Steel Structures
Identifiers
urn:nbn:se:ltu:diva-6919 (URN)10.5130/AJCEB.v16i1.4668 (DOI)000372073600006 ()540842d5-fb7d-4e41-835e-365ca4909e88 (Local ID)540842d5-fb7d-4e41-835e-365ca4909e88 (Archive number)540842d5-fb7d-4e41-835e-365ca4909e88 (OAI)
Note

Validerad; 2016; Nivå 2; Bibliografisk uppgift: Construction Economics and Building (formerly known as the Australasian Journal of Construction Economics and Building [AJCEB]) ; 20160321 (andbra)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Andrade, P., Lagerqvist, O., Veljkovic, M., Simoes, R. & Lundholm, J. (2016). Innovative system for the construction and management of student resisdences: Frameup system. In: Lennart Elfgren, Johan Jonsson, Mats Karlsson, Lahja Rydberg-Forssbeck and Britt Sigfrid (Ed.), IABSE CONGRESS, STOCKHOLM, 2016: Challenges in Design and Construction of an Innovativeand Sustainable Built Environment. Paper presented at 9th IABSE Congress, Stockholm 2016, September 21-23 (pp. 1364-1370). CH - 8093 Zürich, Switzerland: International Association for Bridge and Structural Engineering
Open this publication in new window or tab >>Innovative system for the construction and management of student resisdences: Frameup system
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2016 (English)In: IABSE CONGRESS, STOCKHOLM, 2016: Challenges in Design and Construction of an Innovativeand Sustainable Built Environment / [ed] Lennart Elfgren, Johan Jonsson, Mats Karlsson, Lahja Rydberg-Forssbeck and Britt Sigfrid, CH - 8093 Zürich, Switzerland: International Association for Bridge and Structural Engineering, 2016, p. 1364-1370Conference paper, Oral presentation with published abstract (Refereed)
Abstract [en]

Sweden has a strong demand on the construction of student accommodations and consequently significant efforts have been taken to increase and streamline construction methods. In addition, the fluctuation on the number of students admitted at each year, in each university, lead to periods of house shortage or, in opposition to that, to eventual surplus on the housing market. For these reasons urges finding a fast execution process in construction to fulfil the market needs, together with a housing mechanism of control which balances the students’ needs with the housing availability. In this sense, the Frameup system arises as a solution to solve both problems by combining a modular construction with an innovative execution process.

The FRAMEUP buildings uses a steel frame in combination with prefabricated 3D modules - fully equipped and suitable for student accommodations – which are assembled by starting from the roof to the 1st floor. The existence of the lifting system permits the erection of the building, promoting each time the building is lifted, a clearance of one-floor-height, at ground level, for the assembly of a new floor. The procedure is repeated several times, according to the number of floors, until the 1st floor of the building, the last floor of the execution sequence, is assembled.

Alongside with its advantage on the fast execution, the Frameup system allows to efficiently increase or decrease the number of the floors and consequently its exchangeability with other buildings of same nature. Thus, assuming a net of FRAMEUP buildings at each university, its exchangeability system would create the necessary conditions so that the number of floors at each campus would follow the fluctuations of the students’ population among the different universities on different periods of time, so to suppress the needs for housing or to avoid the surplus on construction.

Place, publisher, year, edition, pages
CH - 8093 Zürich, Switzerland: International Association for Bridge and Structural Engineering, 2016
Series
IABSE Congress Reports
National Category
Building Technologies
Research subject
Steel Structures
Identifiers
urn:nbn:se:ltu:diva-62563 (URN)2-s2.0-85018952106 (Scopus ID)978-3-85748-144-4 (ISBN)
Conference
9th IABSE Congress, Stockholm 2016, September 21-23
Available from: 2017-03-20 Created: 2017-03-20 Last updated: 2017-11-24Bibliographically approved
Schade, J., Wallström, P., Olofsson, T. & Lagerqvist, O. (2013). A comparative study of the design and construction process of energy efficient buildings in Germany and Sweden (ed.). Paper presented at . Energy Policy, 58, 28-37
Open this publication in new window or tab >>A comparative study of the design and construction process of energy efficient buildings in Germany and Sweden
2013 (English)In: Energy Policy, ISSN 0301-4215, E-ISSN 1873-6777, Vol. 58, p. 28-37Article in journal (Refereed) Published
Abstract [en]

Reducing the energy consumption of buildings is an important goal for the European Union. However, it is therefore of interest to investigate how different member states address these goals. Countries like Sweden and Germany have developed different strategies for energy conservation within the building sector. A longitudinal comparison between implemented energy conservation key policy instruments in Sweden and Germany and a survey regarding the management of energy requirements in the building process shows that:– No evidence is found that energy consumption is of great importance for producing competitive offers, either for Swedish or German clients.– The Swedish market-driven policy has not been as successful as the German regulation policy in decreasing the energy consumption of new buildings.– Building standards and regulations regarding energy performance affects how professionals are educated and the way energy requirements and demands are managed throughout the building process.In conclusion, the client's demand will govern the development of energy efficient buildings. Therefore, in order to use market-driven policies, the desired parameters must be of concern for the customer to influence the majority of building projects to be more energy efficient than is specified in national standards and regulations.

National Category
Construction Management
Research subject
Construction Engineering and Management
Identifiers
urn:nbn:se:ltu:diva-13755 (URN)10.1016/j.enpol.2013.02.014 (DOI)000319177800004 ()2-s2.0-84877116040 (Scopus ID)d0c0b23c-7023-4255-b824-9451a57fd9c5 (Local ID)d0c0b23c-7023-4255-b824-9451a57fd9c5 (Archive number)d0c0b23c-7023-4255-b824-9451a57fd9c5 (OAI)
Note
Validerad; 2013; 20130402 (andbra)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Eriksson, P.-E., Szentes, H., Olofsson, T. & Lagerqvist, O. (2012). Hinder och drivkrafter för industriellt anläggningsbyggande: Underlagsrapport till Produktivitetskommittén, Näringsdepartementet (ed.). Paper presented at . : Näringsdepartementet
Open this publication in new window or tab >>Hinder och drivkrafter för industriellt anläggningsbyggande: Underlagsrapport till Produktivitetskommittén, Näringsdepartementet
2012 (Swedish)Report (Other academic)
Place, publisher, year, edition, pages
Näringsdepartementet, 2012
National Category
Other Engineering and Technologies not elsewhere specified Construction Management
Research subject
Entrepreneurship and Innovation; Construction Engineering and Management
Identifiers
urn:nbn:se:ltu:diva-23355 (URN)6a139312-28db-4e6b-a489-c4068145f0e4 (Local ID)6a139312-28db-4e6b-a489-c4068145f0e4 (Archive number)6a139312-28db-4e6b-a489-c4068145f0e4 (OAI)
Note
Godkänd; 2012; Bibliografisk uppgift: Statens offentliga utredningar 2012:39; 20130909 (pererik)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2017-11-24Bibliographically approved
Rwamamara, R., Lagerqvist, O., Olofsson, T., Johansson, B. & Kaminskas, K. A. (2010). Evidence-based prevention of work-related musculoskeletal injuries in construction industry (ed.). Paper presented at . Journal of Civil Engineering and Management, 16(4), 499-509
Open this publication in new window or tab >>Evidence-based prevention of work-related musculoskeletal injuries in construction industry
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2010 (English)In: Journal of Civil Engineering and Management, ISSN 1392-3730, E-ISSN 1822-3605, Vol. 16, no 4, p. 499-509Article in journal (Refereed) Published
Abstract [en]

(WMSDs) among construction workers is considerably higher than those in most other occupations. The aim ofthe study presented in this paper was to contribute to understanding a healthy construction site brought about by the bestpractices implemented by large construction sites to prevent WMSDs. A triangulation method made of interviews, site observationsand studies on company's documents was used to identify the best practices in 13 several construction projects.A range of the best practices both in the pre-construction and construction phases of the projects were identified in six differentareas of the balance of the construction workplace system; however, there seems to be a significant need for goodpractices in the management of a systematic work environment. It is now established that Swedish construction industryhas several best practices to protect work-related musculoskeletal health. However, inadequate worker participation andthe neglect of health and safety issues by designers in the planning process as well as the implications of some remunerationmethods on the production schedule were perceived as detrimental to the musculoskeletal health of construction workers.

National Category
Construction Management Production Engineering, Human Work Science and Ergonomics
Research subject
Construction Engineering and Management; Industrial Work Environment
Identifiers
urn:nbn:se:ltu:diva-10138 (URN)10.3846/jcem.2010.56 (DOI)000285648200006 ()2-s2.0-78651410785 (Scopus ID)8e2e2bc0-0755-11e0-b767-000ea68e967b (Local ID)8e2e2bc0-0755-11e0-b767-000ea68e967b (Archive number)8e2e2bc0-0755-11e0-b767-000ea68e967b (OAI)
Note
Validerad; 2010; 20101214 (andbra)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Rwamamara, R., Lagerqvist, O., Olofsson, T., Johansson, B. & Kaminskas, K. A. (2010). Prevention of work-related musculoskeletal injuries in construction industry (ed.). In: (Ed.), E.K. Zavadskas; P. Vainiunas (Ed.), 10th International Conference on Modern Building Materials, Structures and Techniques: Vilnius, Lithuania 19 - 21 May 2010. Paper presented at International Scientific Conference on Modern Building Materials, Structures and Techniques : 19/05/2010 - 21/05/2010 (pp. 1292-1296). Vilnius
Open this publication in new window or tab >>Prevention of work-related musculoskeletal injuries in construction industry
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2010 (English)In: 10th International Conference on Modern Building Materials, Structures and Techniques: Vilnius, Lithuania 19 - 21 May 2010 / [ed] E.K. Zavadskas; P. Vainiunas, Vilnius, 2010, p. 1292-1296Conference paper, Published paper (Refereed)
Abstract [en]

Many construction work tasks are physically very strenuous, and the incidence of work-related musculoskeletal disorders (WMSDs) among construction workers is considerably higher than that in most other occupations. The aim of the research project presented in this paper was to contribute to an understanding of a healthy construction workplace brought about by the best practices implemented by large construction sites. From a preventive perspective, a model for the construction workplace system balance was used to identify the successful strategies. To identify the successful strategies in the Swedish industry to prevent WMSDs, several construction projects were investigated through interviews, site observations and company's documents study. In every construction project, six areas, (i.e., planning, technology used, work organisation, physical work environment, work tasks and the individual worker) of the construction workplace system balance were investigated. Numerous successful strategies both in pre-production and production phases of construction projects were identified in the six different areas of the construction workplace system balance; however there seems to be a significant need for good practices in the systematic work environment management. Further, the implications of some remuneration methods on the production schedule were perceived as detrimental to musculoskeletal health of construction workers.

Place, publisher, year, edition, pages
Vilnius: , 2010
National Category
Construction Management Production Engineering, Human Work Science and Ergonomics
Research subject
Construction Engineering and Management; Human Work Science
Identifiers
urn:nbn:se:ltu:diva-35531 (URN)a17cbfb4-70ea-4b23-b0a4-3c52881f400f (Local ID)9789955285946 (ISBN)a17cbfb4-70ea-4b23-b0a4-3c52881f400f (Archive number)a17cbfb4-70ea-4b23-b0a4-3c52881f400f (OAI)
Conference
International Scientific Conference on Modern Building Materials, Structures and Techniques : 19/05/2010 - 21/05/2010
Note
Godkänd; 2010; 20141119 (andbra)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2017-11-25Bibliographically approved
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