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  • 101.
    Olsson, Anders
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Oscarsson, Jan
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Strength grading on the basis of high resolution laser scanning and dynamic excitation: a full scale investigation of performance2017In: European Journal of Wood and Wood Products, ISSN 0018-3768, E-ISSN 1436-736X, Vol. 75, no 1, p. 17-31Article in journal (Refereed)
    Abstract [en]

    Effective utilization of structural timber requires grading and indicating properties (IPs) that are able to predict strength with high accuracy, and machines that are able to measure the underlying board properties at a speed that corresponds to the production speed of sawmills. The aim of this research is to assess the performance of a new machine strength grading method/procedure which was recently approved for the European market and to compare the performance of it with the performance of other available techniques. The novel method is based on laser scanning utilizing the tracheid effect, in combination with data from dynamic excitation and weighing. Applied indicating properties are defined in detail and results presented include assessment of the repeatability, coefficients of determination between IPs and grade determining properties, and examples of the yield achieved in different strength classes and combinations of strength classes. The investigated sample comprised more than 900 pieces of timber of Norway spruce (Picea abies) from Sweden, Norway and Finland. For this sample the coefficient of determination between the IP to bending strength and the measured bending strength was as high as R2 = 0.69, while the coefficient of determination between dynamic modulus of elasticity (MOE) and measured bending strength was R2 = 0.53. The yield in high strength classes, C35 and above, become about twice as high using the new method/procedure compared to machines using dynamic MOE as IP. A comparison of the performance with what have been presented for machines that are based on X-ray in combination with dynamic excitation indicates that the new method/procedure will surpass such machines as well. 

  • 102.
    Olsson, Jörgen
    et al.
    SP Technical Research Institute.
    Linderholt, Andreas
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Nilsson, Börje
    Linnaeus University, Faculty of Technology, Department of Mathematics.
    Impact evaluation of a thin hybrid wood based joist floor2016In: Proceedings of ISMA 2016, presented at the International Conference on Noise andVibration Engineering (ISMA) / [ed] Sas, P; Moens, D; VanDeWalle, A, Leuven, Belgium: Katholieke University Leuven , 2016, p. 589-602Conference paper (Refereed)
    Abstract [en]

    The purpose of this paper is twofold. The first aim is to develop a numericalanalysis procedure, by combining FRFs from FE-models with analyticalformulas for sound emission and transmission from the ceiling anddownwards within a room with four walls. The aim is to, by applying thisapproach; accomplish a tool which calculates the relative impact soundbetween different joist floors, in the low frequency range. The second aim is tobenchmark a thin hybrid wooden based joist floor with similar thickness,surface weight and global bending stiffness as a concrete hollow core floorstructure. What will be the difference in sound transmission? The question isrelevant since it may be necessary to make thinner wood based joist floors inhigh rise buildings, if wood should stay competitive against concrete. Theresults show that the direct transmissions of impact sound are very similararound the first bending mode. As the frequency increases, the modes in thestructures differ significantly. Below 100 Hz, the concrete floor has 4 modes,while the hybrid joist floor has 9 modes. As the frequency increases the soundradiation characteristics differs. The results show that it is possible to havesimilar sound transmission properties around the first bending modes for ahybrid based joist floor and a hollow core concrete floor structure with similar thicknesses. At the first modes of the structure, the information about thesurface weight and global bending stiffness are useful for prediction of soundtransmission properties but for higher modes, they are not sufficient.

  • 103.
    Olsson, Jörgen
    et al.
    Byggande och boende (TRb).
    Sjökvist, Lars-Göran
    SP- Sveriges Tekniska Forskningsinstitut, Trätek.
    Jarnerö, Kirsi
    SP- Sveriges Tekniska Forskningsinstitut, Trätek.
    Low frequency measurements of impact sound performance in light weight timber frame office buildings2012In: Proceedings of EURONOISE 2012, European Acoustics Association, European Acoustics Association (EAA), 2012Conference paper (Refereed)
  • 104.
    Ormarsson, Sigurdur
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Parameterized and adaptive modelling of structural behaviour of innovative modular-based multi-storey timber buildings of wood2018In: Presented at EMI 2018, Engineering Mechanics Institute Conference, May 29 - June 1, 2018, MIT, Cambridge, USA, 2018Conference paper (Refereed)
  • 105.
    Ormarsson, Sigurdur
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Dahlblom, Ola
    An extended beam model for simulation of hygro-mechanical and visco elastic deformations in inhomogeneous timber structures2014In: 11th World Congress on Computational Mechanics - 2014, Barcelona: Spanish Association for Numerical Methods in Engineering , 2014Conference paper (Refereed)
    Abstract [en]

    Due to numbers of failures of large glue laminated (glulam) timber structures there seems to be a need for better design tools for wood applications. In EC5 and in many textbooks on timber design it is stated that the moisture sensitivity of the wood material needs to be taken into account in the design process. But the fact is that in stress calculations associated with ordinary timber design, these matters are not dealt with properly. The problem is that it is very difficult to predict the variation of moisture-related stresses during the service life of the timber structure as a whole. A proper prediction requires that material inhomogeneity, mechano-sorption effect and visco-elastic behaviour are taken into account. The paper presents a finite element implementation of a new beam element able to simulate hygro-mechanical and visco-elastic behaviours in inhomogeneous timber structures.

  • 106.
    Ormarsson, Sigurdur
    et al.
    Lund University.
    Dahlblom, Ola
    Lund University.
    Petersson, Hans
    Chalmers University of Technology.
    A numerical study of the shape stability of sawn timber subjected to moisture variation: Part 2: Simulation of drying board1999In: Wood Science and Technology, ISSN 0043-7719, E-ISSN 1432-5225, Vol. 33, no 5, p. 407-423Article in journal (Refereed)
    Abstract [en]

    A theory for analysing the shape stability of sawn timber was implemented in a finite element program. To illustrate the types of results that can be obtained, the behaviour of a board during drying was simulated. The simulation yields information about unfavourable deformations and stresses during the drying process. To investigate factors that influence drying deformations, a parameter study was performed in which the influence of different constitutive models and different material parameters was studied. In addition, the influence of the spiral grain angle was examined.

  • 107.
    Ormarsson, Sigurdur
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Johansson, Marie
    RISE Research Institute of Sweden, Sweden.
    Finite element simulation of global structural behaviour of multifamily timber buildings using prefabricated volume modules2018In: WCTE 2018 - World Conference on Timber Engineering, World Conference on Timber Engineering (WCTE) , 2018Conference paper (Refereed)
    Abstract [en]

    The potential of building multi-storey timber buildings has changed in recent decades. The building of apartment houses with fully prefabricated volume modules in wood is an industry sector that is rapidly increasing its capacity. A number of house manufacturers that have delivered volume modules, primarily for single family homes, are now expanding their production to multi-storey buildings up to 6-8 floors. This is a challenging task for producers, since the available design procedures for timber buildings have not yet been fully implemented for these types of buildings.The aim of the work is to develop an efficient and flexible finite element model to analyse the three-dimensional structural behaviour of multi-storey buildings using prefabricated volume modules made by wooden stud-and-rail structure. The model will be used to study the global structural behaviour of various timber walls, volume modulus and modular-based multi-storey buildings when subjected to different types of loading. The model will also be used for detailed analysis and design (using so-called adaptive modelling) of the most critical (weak) parts of the structure.

  • 108.
    Ormarsson, Sigurdur
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Steinnes, Jan Roar
    Norcunsult AS, Norway.
    An enhanced beam model for glued laminated structures that takes moisture, mechano-sorption and time effects into account2014In: WCTE 2014 World Conference on Timber Engineering, Quebec City, Canada, August 10-14, 2014 / [ed] Alexander Salenikovich, Quebec City: Université Laval , 2014Conference paper (Refereed)
    Abstract [en]

    There is a need of more advanced analysis for studying how the long-term behaviour of glued laminated timber structures is affected by creep and by cyclic variations in climate. A beam theory is presented able to simulate the overall hygro-mechanical and visco-elastic behaviour of (inhomogeneous) glulam structures. Two frame structures subjected to both mechanical and cyclic environmental loading are analysed to illustrate the advantages the model involved can provide. The results indicate clearly both the (discontinuous) inhomogeneity of the glulam products and the variable moisture-load action that occurs to have a significant effect on deformations, section forces and stress distributions within the frame structures that were studied.

  • 109.
    Ormarsson, Sigurdur
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Vessby, Johan
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Källsner, Bo
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Filchev, Ivan
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Numerical analysis of failure modes and force distribution in a pitched roof structure of wood2016In: Proceedings of the 2016 World Conference on Timber Engineering (WCTE) / [ed] J. Eberhardsteiner, W. Winter, A. Fadai, M. Pöll, Vienna: Vienna University of Technology , 2016Conference paper (Refereed)
    Abstract [en]

    Instability failures of timber elements and timber structures are reported relatively frequently although there are some suggestions available how to prevent such failures. These types of failures are characterized by sudden deformations that typically lead to failure in a single loadbearing element or collapse of the entire structure. This paper deals with buckling analysis and geometric nonlinear stress analysis of pitched roof structures of wood. A FE- model has been developed and used to study how different parameters influence the buckling modes and force distribution in the lateral bracing system of the roof structure. The simulated forces in the bracing system are also compared with results based on a simple design method given in Eurocode 5 (EC5) and a method where the compressed top chord is treated as a beam on a continuous elastic foundation. The buckling simulations showed the out-of-plane buckling to be the critical failure mode for the truss structure studied and the geometric nonlinear analysis showed the bracing stiffness and the bracing forces to be significant lower than those calculated by hand according to EC5.

  • 110.
    Pardalis, Georgios
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Mahapatra, Krushna
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Mainali, Brijesh
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Swedish construction MSEs: simply renovators or renovation service innovators?2019In: Building Research & Information, ISSN 0961-3218, E-ISSN 1466-4321, Vol. 48, no 1, p. 67-83Article in journal (Refereed)
    Abstract [en]

    To address the renovation needs of detached house stock in Sweden, micro and small-sized enterprises (MSEs), a subgroup of small and medium-sized enterprises, are expected to introduce more comprehensive house renovation solutions. One-stop-shop (OSS) is an innovative Product-Service System model that can enable MSEs to offer comprehensive renovation packages instead of existing fragmented solutions. We have applied a conceptual framework for innovation adoption in organizations and conducted an interview of 21 construction MSEs in three different geographical areas in Sweden to examine their perceptions and preparedness to adopt the OSS business concept. Findings showed that the examined MSEs are positive towards OSS as it could address the needs for the comprehensive renovation of detached houses. However, presently, are not prepared to take the coordinator’s role in such a concept mainly due to the perceived business risks, the lack of flexibility to organizational restructuring, and lack of resources and management competency to coordinate multiple tasks and actors. Those organizations lacked awareness of existing policy support and access to funding mechanisms to try new business models. As a solution, they proposed an external coordinator to be the provider of OSS, on the trial phase, whose role and characteristics need to be further examined.

  • 111.
    Pardalis, Georgios
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Mainali, Brijesh
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Mahapatra, Krushna
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    One-stop-shop as an innovation, and construction SMEs: a Swedish perspective2019In: Innovative Solutions for Energy Transitions: Proceedings of the 10th International Conference on Applied Energy (ICAE2018) / [ed] Prof. J.Yanab, Prof. H.Yangc, Dr. H.Lid, Dr. X.Chene, Elsevier, 2019, Vol. 158, p. 2737-2743Conference paper (Refereed)
    Abstract [en]

    This paper examines the views of construction SMEs in Sweden regarding innovations, in particular the one-stop-shop business concept,and its adoption for renovation of detached house. The investigation is based on interviews with 10 construction SMEs and by applying aconceptual framework for organizational innovation adoption. The results suggest that, even though the one-stop-shop businessconcept is perceived as a means for growth, at present, construction SMEs in Sweden are unlikely to adopt it at present. This lackof interest is mostly related to the perceived complexity of this model and the underlying risks and uncertainties. That complexity isseen as a preventing factor as it puts at stake their current business. The interviewees proposed that there should be an entrepreneur to coordinate the actors involved in the renovation process, whose role can be further studied.

  • 112.
    Pardalis, Georgios
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Mainali, Brijesh
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Mahapatra, Krushna
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    One-stop-shop as an innovation, and preparedness to adopt it: A study on house renovation stakeholders in Sweden2018Conference paper (Other academic)
    Abstract [en]

    This study examines the views of stakeholders involved in house renovations regarding the one-stop-shopbusiness concept innovation, and assesses their level of preparedness to adopt such a concept in order toenter the promising market of detached house renovations. The investigation is based on 25 interviews withconstruction SMEs owners, real estate agents and loan consultants, and on a conceptual framework fororganizational innovation adoption. The results suggest that for the nonce, none of the examined stakeholdersis likely to adopt a one-stop-shop business model to enter the market of detached house renovations, eventhough this concept is seen as one with great potential. This mostly happens due to their individualcharacteristics, the complexity of one-stop-shop model related to their way of doing business and theuncertainties deriving from the adoption of such a model. Furthermore, the participation of an entrepreneur isproposed, who would coordinate all the different actors involved in the renovation process, and whose rolecan be further examined.

  • 113.
    Paz-Garcia, Juan Manuel
    et al.
    Technical University of Denmark, Denmark.
    Johannesson, Björn
    Technical University of Denmark, Denmark.
    Ottosen, Lisbeth M.
    Technical University of Denmark, Denmark.
    Numerical Simulations of Electrokinetic Processes Comparing the Use of a Constant Voltage Difference or a Constant Current as Driving Force2010In: Conference on Electrochemical Science and Technology: 30th Sept. - 1st Oct. 2010. Technical University of Denmark, Kgs. Lyngby, Denmark, 2010Conference paper (Refereed)
    Abstract [en]

    Electrokinetic techniques are characterized by the use of a DC current for the removal of contaminants from porous materials. The method can be applied for several purposes, such as the recuperation of soil contaminated by heavy metals or organic compounds, the desalination of construction materials and the prevention of the reinforced concrete corrosion. The electrical energy applied in an electrokinetic process produces electrochemical reactions at the electrodes. Different electrode processes can occur. When considering inert electrodes in aqueous solutions, the reduction of water at the cathode is usually the dominant in the process. On the other hand, the electrode processes at the anode depend on the ions present in its vicinity. Oxidation of water and chloride are typically assumed to be the most common processes taking place. Electrons produced in the electrode processes are transported from the anode to the cathode through the closed electrical circuit of the cell. In the solution, the electrical current is carried by the ions, which move towards the electrode with different charge. Therefore, different authors have studied the system using the circuit theory. Assuming that it is possible to study the region limited by the electrodes as a one-dimensional problem, the system consisting of electrolyte, electrodes, conductors and power supply can be considered as an electrical circuit connected in series. According to the Ohm’s law, the voltage and the electrical current would be related to the conductivity of the media. This conductivity will vary as the electrokinetic process proceeds. For a better control of the electrokinetic process, a constant difference of voltage or a constant current density between the electrodes is typically used. Most authors argued that fixing the current density results in more efficient electrokinetic experiments with less operative problems. Nevertheless, in long term treatments, maintaining a constant current density can be difficult due to limitations of the power supply.

  • 114.
    Paz-Garcia, Juan Manuel
    et al.
    Lund University ; Wetsus, centre of excellence for sustainable water technology, The Netherlands ; Technical University of Denmark, Denmark.
    Johannesson, Björn
    Technical University of Denmark, Denmark.
    Ottosen, Lisbeth M.
    Technical University of Denmark, Denmark.
    Ribeiro, A. B.
    Universidade Nova de Lisboa, Portugal.
    Rodriguez-Marotoe, J.M.
    Universidad de Málaga, Spain.
    Modeling Electric Double-Layers Including Chemical Reaction Effects2014In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 150, p. 263-268Article in journal (Refereed)
    Abstract [en]

    A physicochemical and numerical model for the transient formation of an electric double-layer between an electrolyte and a chemically-active flat surface is presented, based on a finite elements integration of the nonlinear Nernst-Planck-Poisson model including chemical reactions. The model works for symmetric and asymmetric multi-species electrolytes and is not limited to a range of<br/>surface potentials. Numerical simulations are presented, for the case of a CaCO3 electrolyte solution in contact with a surface with rate-controlled protonation/deprotonation reactions. The surface charge and potential are determined by the surface reactions, and therefore they depends on the<br/>bulk solution composition and concentration

  • 115.
    Paz-Garcia, Juan Manuel
    et al.
    Technical University of Denmark, Denmark.
    Johannesson, Björn
    Technical University of Denmark, Denmark.
    Ottosen, Lisbeth M.
    Technical University of Denmark, Denmark.
    Rodriguez-Maroto, J. M.
    University of Málaga, Spain.
    Ribeiro, A. B.
    New University of Lisbon, Portugal.
    Modelling of Electrokinetic Processes in Civil and Environmental Engineering Applications2011In: Proceeding of the thirteenth international conference on civil, structural and environmental engineering computing / [ed] B.H.V. Topping, Y. Tsompanakis, Civil-Comp Press , 2011, p. 128-Conference paper (Other academic)
    Abstract [en]

    A mathematical model for the electrokinetic phenomena is described. Numerical simulations of different applications of electrokinetic techniques to the fields of civil and environmental engineering are included, showing the versatility and consistency of the model. The electrokinetics phenomena consist of the mobilization of species within the pore solution of porous materials induced by an externally applied electric field. Many physicochemical aspects have to be taken into account when modeling this strongly coupled reactive transport process. A finite element integration of the Poisson-Nernst-Planck system of equations, accounting for ionic migration, chemical diffusion and advection is used for modeling the transport process. The advection term contributor is studied by including in the system the water transport through the porous media, mainly due to electroosmosis. The pore solution filling the porous materials undergoes an electroosmotic flow subject to externally applied electric fields. Electroosmotic transport makes electrokinetic techniques suitable for the mobilization of non-charged particles within the pore structure, such as the organic contaminants in soil. Chemical equilibrium conditions are assumed between the aqueous species and the solid matrix for a set of feasible chemical equilibrium reactions defined for each specific application. A module for re-establishing the chemical equilibrium has been developed and included in the system for this purpose. Changes in the porosity along the domain arising from the reactivity of the solid matrix have been taken into account. These changes affect significantly to the transport process of both aqueous species and the water, since the effective transport coefficients depends on the porosity of the media. The model described here gives good estimations of the results obtained from laboratory and pilot scale electrokinetic treatments. The model can be easily adapted to simulate different enhanced techniques and different chemical systems. Apart from the prediction ability, the detailed definition of the transport process increases the understanding of the main physicochemical aspects affecting the process. Results from simulations of some test examples are presented, showing the versatility of the model. Two types of enhanced methods are compared: The electrokinetic desalination of a brick sample, using carbonated clay to hinder the acid penetration; and an acid-enhanced electrokinetic soil remediation process, where the basic front is neutralized in order to avoid the precipitation of hydroxides of the target heavy metal.

  • 116.
    Paz-Garcia, Juan Manuel
    et al.
    Technical University of Denmark, Denmark.
    Johannesson, Björn
    Technical University of Denmark, Denmark.
    Ottosen, Lisbeth M.
    Technical University of Denmark, Denmark.
    Rodriguez-Maroto, José Miguel
    University of Malaga, Spain.
    Ribeiro, Alexandra B.
    New University of Lisbon, Portugal.
    Modeling of Electrokinetic Processes Using the Nernst-Plank-Poisson System2010In: The 8th fib international PhD Symposium in Civil Engineering, Technical University of Denmark , 2010, p. 449-454Conference paper (Other academic)
    Abstract [en]

    Electrokinetic processes are known as the mobilization of species within the pore solution of porous materials under the effect of an external electric field. A finite elements model was implemented and used for the integration of the coupled Nernst-Plank-Poisson system of equations in order to simulate the transport process of ionic species and the modeling of electrokinetic remediation techniques. The electrode half-reactions were included in the model. The charge unbalance produced was used for satisfying the voltage differences applied as boundary conditions in the system. In addition to this, water equilibrium was continuously assured and the pH value monitored. Results from a test example simulation of the desalination of a sample of porous material contaminated with NaCl are shown.

  • 117.
    Paz-Garcia, Juan Manuel
    et al.
    Technical University of Denmark, Denmark.
    Ottosen, Lisbeth M.
    Technical University of Denmark, Denmark.
    Johannesson, Björn
    Technical University of Denmark, Denmark.
    Alshawabkeh, A. N.
    Northeastern University, USA.
    Ribeiro, A. B.
    New University of Lisbon, Portugal.
    Rodríguez-Maroto, J. M.
    University of Málaga, Spain.
    Coupling the transport of water and aqueous species in finite element modeling of electrokinetics2011In: Abstracts. 12th Mediterranean Congress of Chemical Engineering, SEQUI , 2011Conference paper (Refereed)
    Abstract [en]

    The electrokinetic transport of ionic and non-ionic species through a porous media under the effect of an external electric field can be mathematically described by the Nernst-Planck-Poisson (NPP) system of equations. The Nernst-Planck mass balance equation describes the transport of aqueous species by a combination of the diffusion and electromigration terms. Since the ions themselves contribute to the local electric potential, Poisson’s equation of electrostatics, that relates the electrostatic potential to local ion concentrations, is solved simultaneously to describe this effect. This strongly coupled non-linear system has been satisfactory solved by finite element integration, and combined to additional physicochemical aspects such as the electrode processes and the chemical interaction between the species in the system for modeling of electrokinetic transport processes. Proper models of the electrokinetic phenomena have to take into account the transport of the pore solution itself. Water is suggested to electroosmotic flow under electric fields. Electroosmotic advection is of mayor importance when considering the transport of non-charged particles such as organic contaminants from soil. The transport of water may dry the material at the anode surroundings, what may interrupt the ionic current and stop the process. Capillary forces and hydraulic gradient, between others, can also affects to the transport of water in the porous media. In the present work, the NPP system has been extended in order to include the water transport equation, and to calculate the advective flow contribution on the ionic transport. In this model, the transport of water is assumed to be a combination of hydraulic gradient, capillary suction forces and electroosmotic flow. In the model presented here, the advective term has been implicitly included in the Nernst-Planck equation of each individual aqueous species. Thus, this coupling strategy between the water and the ionic transport together with a numerical procedure for solving the non-linearity character, allows a simplified finite element analysis.

  • 118. Pearson, Hamish
    et al.
    Gabbitas, Brian
    Ormarsson, Sigurdur
    Instantaneous Wood Distortion under High Temperature Drying2011In: COST Action FP0904: Thermo-Hydro-Mechanical Wood Behaviour and Processing, 2011Conference paper (Refereed)
    Abstract [en]

    Internal stresses develop in wood during moisture conditioning because of its hygroscopic properties and unequal shrinkage behaviour in the three grain directions. However, such stresses can be inherently difficult to detect. External wood distortion usually indicates the presence of internal stress but all stress may have been relieved through such distortion. Conversely, wood, which shows no external distortion, may still exhibit an internal stress imbalance which can lead to distortion after sawing. Stress effects associated with kiln drying can result in significant sawn lumber product degrade as a result of warping and checking.

    Two methods exist to assess internal stress in wood as a result of moisture change. The first method is direct measurement, as with prong and slices tests, and the second method is to model internal stress. Direct measurement assessments are usually unable to be performed during moisture conditioning and are invasive in that they lead to sample destruction. Conversely stress modeling is predictive and requires fundamental wood material properties and complex software to solve the mechanical equations in space and time.

    A work programme was initiated at Scion, New Zealand, with the overall goal of collecting high temperature (70 to 150ºC) material properties for use in modeling the stress developed in radiata pine during high temperature kiln drying. A key focus was also to design and develop equipment to accurately measure fundamental material properties required for such modeling. The study was designed to extend an earlier three dimensional distortion model developed by Ormarsson (2000) to predict drying stress in wood up to a temperature of 70°C where the total strain equation was assumed to consist of the summation of elastic, moisture-induced shrinkage, mechanosorptive and creep deformations. Each component of the total strain equation was studied separately with respect to the variables stress, time, temperature and moisture content using purpose designed equipment and the results combined in a finite element stress model.

    Experimental material property results for tangential grain, tensile, radiata pine (Pinus radiata D.Don) sapwood samples were combined into an instantaneous distortion model to predict stress or distortion as a function of temperature, moisture content and either external load or distortion. All samples were taken from one representative plantation tree from which wood quality information was obtained for a covariate analysis of the results. This included basic wood density, spiral grain, conic angle, and cardinal point mean microfibril angle which was obtained using SilviScan. Poissons' ratios were estimated from digital speckle photography experiments perfomed using an Aramis system at 20°C whilst the remaining compliance matrix variables such as shear moduli and moduli of elasticity for longitudinal and radial grain directions were estimated from published ratios.

    The distortion model architecture involved Python code for use as an input into Abaqus software with Fortran subroutines. For each study a moisture field output file, based upon the chosen constant temperature, was obtained for each geometric sample element and the results used as an input into the stress model. Stress model results were compared with representative experimental results from instantaneous, free shrinkage and mechanosorption studies.

    Results showed good agreement between the model and instantaneous elastic, free shrinkage and mechanosorption experimental results for tensile sample geometries, provided a 'thermo-sorptive-aging' effect was used to compensate for reduced hygroscopicity, if wood was alternately wet and re-wet in a cyclic fashion. A full board distortion model was then used to test the resultant stresses associated with wood that was dried to 5% moisture content followed by steaming to simulate final stress relief as implemented by industry. As expected, full board model results revealed the average stress in the longitudinal, radial and tangential directions to decrease after steaming, compared to drying with no steaming. Even though internal stresses from modelling were higher after steaming compared to only drying, total stress was improved. This theoretically caused less external distortion in a simple geometry like a board, although creep was not included in the simulations and may help to equalise internal stress further over time. Stress result profiles within the board agreed with earlier studies for two dimensional distortion by Chen et al (1997b).

    The three dimensional high temperature distortion model that was developed as part of this work is a valuable tool for distortion assessment compared to one- or two-dimensional models that are limited to a single plane. Future work will seek to optimise moisture conditioning schedules and thermo-hygro-mechanical treatments using the full board distortion model with full mechano-sorptive-creep analysis.

  • 119.
    Petersson, Viktor
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Gustafsson, Johan
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Beräkningsmetoder för verifiering av svetsar med inriktning på PWT2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Steel is a material used in various building structures. Fatigue can occur in the material if building structures is exposed for repeated loads. Fatigue leads to permanent damages such as crack initiations and fracture. It is common that welds in welded structures have the lowest fatigue strength. A welds fatigue strength can be improved with treatments termed Post Weld Treatment (PWT).

    Today a welds fatigue strength is verified with a method described in Eurocode. The calculation method is simplified which can underestimate the objects number of lifecycles regarding fatigue. The purpose with this essay is to study different structural design methods for fatigue exposed welds and how many lifecycles a typeweld will increase when applying PWT. The goal with this essay is to study a typeweld and calculate the number of lifecycles between the calculation methods and to show how many lifecycles the same type weld will increase when applying PWT.

    The results and theory are based on scientific articles, literature studies and a casestudy which both contains a through welded butt weld and a fillet weld placed on an I-beam. The results points at that the calculation method that is used today underestimates the number of lifecycles and that the number of lifecycles increased significant after PWT.

  • 120.
    Pettersson, Jenny
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Wiberg, Sara
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Tidseffektivisering av materialleveranser på byggprojekt med radiofrekvensidentifikation, RFID2015Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Studien undersöker möjligheten för tidseffektivisering av materialleveranser med hjälp av RFID, radiofrekvensidentifikation. RFID är en trådlös teknik som används för att identifiera föremål.

    För att ta reda på vilka problem som uppkommer på dagens byggarbetsplatser genomfördes intervjuer på fyra olika projekt där Skanska Sverige AB är entreprenör. Genom sammanställning av intervjuerna gjordes en kartläggning av materialflöden och materialhantering på samtliga projekt. Dessa problem diskuterades därefter med en sakkunnig inom RFID och resultatet visar förslag på hur RFID kan användas för att uppnå en effektivare materialhantering.

    Huvudförslaget som analysen redovisar är tidseffektivisering av mottagandekontroller vid materialleveranser. Genom att använda RFID finns möjlighet att automatisera mottagningskontroller. Företaget kan redan vid avlastning upptäcka om material saknas och på så sätt tidseffektivisera byggprojekt. Dock är denna lösning svår att genomföra då mycket behöver förändras i materialflödesprocessen innan RFID införskaffas.

  • 121.
    Pettersson, Sara
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Granskning av kvalitets- och miljöledningssystemet hos Skanska Hus Sydost Linköping : “Vårt sätt att arbeta”2010Independent thesis Basic level (university diploma), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [sv]

    För att effektivisera och uppnå de krav som ställs på företaget har Skanskas Sverige AB, i likhet med många andra företag, lagt upp ett kvalitets- och miljöledningssystem som Skanska kallar ”Vårt sätt att arbeta”. Det råder idag osäkerhet om i hur stor utsträckning systemet tillämpas och förenklar arbetet. Samt om det finns en gemensam bild av systemet bland de anställda.

    I denna uppsats kommer endast produktionsförberedelsefasen och produktionsstyrningsfasen behandlas. Uppsatsen består av en kortfattad beskrivning av ”Vårt sätt att arbeta”, byggprocessen och ISO. Den utredande delen av rapporten innehåller data från intervjuer och enkäter.

    Skanska har utvecklat ett mycket bra system för att hjälpa sina anställda i sitt arbete. Utifrån svaren i intervjuerna kan man tydligt se att det finns en gemensam bild av ”Vårt sätt att arbeta” och att det används och uppskattas i stor utsträckning. Men det finns alltid saker som kan förbättrs för att göra systemet ännu mer funktionellt. Det efterfrågas till exempel någon slags uppdelning i systemet.

  • 122.
    Piccardo, Chiara
    et al.
    University of Genoa, Italy.
    Dodoo, Ambrose
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Gustavsson, Leif
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Tettey, Uniben Yao Ayikoe
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Comparative Life-Cycle Analysis of Building Materials for the Thermal Upgrade of an Existing Building2019In: SBE19 Brussels - BAMB-CIRCPATH "Buildings as Material Banks - A Pathway For A Circular Future"5–7 February 2019, Brussels, Belgium, Institute of Physics Publishing (IOPP), 2019, Vol. 225, article id 012044Conference paper (Refereed)
    Abstract [en]

    The existing building stock is estimated to need major renovations in the near future. At the same time, the EU energy-efficiency strategy entails upgrading the energy performance of renovated buildings to meet the nearly-zero energy standard. To upgrade existing buildings, two main groups of measures can be adopted: thermally-improved building envelope and energy-efficient technical devices. The first measure usually involves additional building materials for thermal insulation and new building cladding, as well as new windows and doors. A number of commercially-available materials can be used to renovate thermal building envelopes. This study compares the life-cycle primary energy use and CO2 emission when renovating an existing building using different materials, commonly used in renovated buildings. A Swedish building constructed in 1972 is used as a case-study building. The building's envelope is assumed to be renovated to meet the Swedish passive house standard. The entire life cycle of the building envelope renovation is taken into account. The results show that the selection of building materials can significantly reduce the production primary energy and associated CO2 emissions by up to 62% and 77%, respectively. The results suggest that a careful material choice can significantly contribute to reduce primary energy use and CO2 emissions associated with energy renovation of buildings, especially when renewable-based materials are used.

  • 123.
    Piccardo, Chiara
    et al.
    University of Genoa, Italy.
    Dodoo, Ambrose
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Gustavsson, Leif
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Tettey, Uniben Yao Ayikoe
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Energy and carbon balance of materials used in a building envelope renovation2019In: SBE19 Brussels - BAMB-CIRCPATH "Buildings as Material Banks - A Pathway For A Circular Future"5–7 February 2019, Brussels, Belgium, Institute of Physics Publishing (IOPP), 2019, Vol. 225, article id 012045Conference paper (Refereed)
    Abstract [en]

    Construction and demolition waste (CDW) are a priority waste stream in EU's polices, accounting for about 30% of all waste generated. At the same time, according to the EU energy-efficiency directive, existing buildings subject to significant renovation need to be upgraded in their thermal building envelope in order to meet higher energy performance standard. This involves additional building materials and hence increases the CDW generation. This study investigates the energy and CO2 emission balance of building envelope renovation when using different building materials, taking into account the production and end-of-life stages. The study is based on a Swedish case-study building assumed to be upgraded to the passive house standard. Benefits from waste recovering are considered, including construction and demolition wastes. The results show that the selection of building materials can significantly affect the primary energy and CO2 emission balances. Depending on the material alternative the end-of-life primary energy use and net CO2 emission can be reduced by 5%-21% and 2%-24%, respectively, compared to the initial primary energy use and net CO2 emission. Therefore, a careful material choice at the design stage, as well as an efficient waste management, can contribute to reduce primary energy use and CO2 emission associated with energy renovation of existing buildings.

  • 124.
    Rubenson, Sarah
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Utformning av ett flerbostadshus enligt detaljplan2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Arbetet grundar sig på en fastighetsägares insikt om att nuvarande bebyggelse inte följer detaljplan och hennes nyfikenhet kring hur tomten skulle kunna disponeras och ett flerbostadshus utformas på så sätt att detaljplan följs. På vägen passeras huvudpunkterna utformning enligt detaljplan, godkända energikrav enligt Boverket och skapandet av en solstudie. 

    Tomten som behandlas är en del av en kvartersbebyggelse i centrala Ängelholm. Staden som närmar sig femhundra år bär på en lång historia och byggnaderna inom kvarteret är klassade som värdefull bebyggelse eller särskilt värdefull bebyggelse enligt plan- och bygglagen (8 kap. § 13). Detaljplanen har i sin tur stämplat hela området som lagskyddade kulturlager vilket kräver ytterligare försiktighetsåtgärder. Stadens historia har tillsammans med dessa bemärkelser kraftigt kommit att påverka utformningen av ett nytt flerbostadshus.

  • 125.
    Santos, Graziely Cristina
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology. Univ. Estadual Paulista, Brazil.
    Forss, Jörgen
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Welander, Ulrika
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Corso, Carlos Renato
    Univ. Estadual Paulista, Brazil.
    Redox mediator evaluation in the azo dye biodegradation2015Conference paper (Refereed)
    Abstract [en]

    Azo dye degradation occurs by means of the oxidation–reduction reactions which have the azo dye acting as final electron acceptor. Some carbon sources can act as electron donors because the products of their metabolism act as redox mediators. In order to enhance the dye biodegradation process, the present study aims to evaluate the decolorization of an artificial wastewater, containing the azo dye Direct Red 75 (DR75), led by a microbial consortium from rice husks, testing the effect in the process of glucose and yeast extract as carbon sources. Samples with and without 0.1 M Sodium phosphate buffer were also analysed. The decolorization was measured by means UV-VIS spectrophotometry. The percentage of decolorization of the samples over the time indicates that the sample with yeast extract, rinse water of rice husks and without buffer presented the best decolorization rate, about 80%. Therefore, the results presented in this study may also suggest that yeast extract is a better carbon source for dye biodegradation than glucose.

  • 126.
    Saxbo, André
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Underlag för mest fördelaktiga upphandling av stomkomplettering i mindre bostadshus:  2012Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Examensarbetets syfte var att skapa och jämföra två alternativa underlag för upphandling av stomkomplement i JSBs typhus ”Trygga Boendet”. Typhusets stomme är av betong och har hög prefabriceringsgrad, det utsågs till vinnare i en tävling SABO anordnade i strävan efter billiga hyresrätter, som grund till tävlingen låg en undersökning som visade att 70 % av Sveriges kommuner har brist på billiga hyresrätter.

    Undersökningen avgränsades till en jämförelse av två alternativvid uppförande av stomkomplement, ett alternativ var att ta fram upphandlingsunderlag till en så kallad stomkomplementsentreprenör som utförde samtliga stomkomplement, ett andra alternativ var att ta fram underlag för upphandling av separata entreprenörer för varje stomkomplement.

  • 127.
    Schauerte, Tobias
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Editorial: Special Issue: Forum Wood Building Nordis 20152015In: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 10, no 3, p. 215-Article in journal (Other academic)
  • 128.
    Schauerte, Tobias
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Identifying Product Attributes for Quality Function Deployment: Consumer Perceptions in the Case of Wooden Multi-Storey Houses2013In: Pro Ligno, ISSN 1841-4737, E-ISSN 2069-7430, Vol. 9, no 4, p. 773-779Article in journal (Refereed)
    Abstract [en]

    In order to bridge the gap between external consumer value and internal production quality, an understanding of consumers’ needs is vital. Consumers’ needs have to be translated through a firms’ internal value chain to improve production quality. The Means-End Chain approach elicits consumers’ needs in terms of product attributes, which further can be translated into engineering characteristics by using the House of Quality concept as the first step in Quality Function Deployment. Here, the relative importance of the attributes plays an important role for further processing. This paper’ aims at identifying product attributes and their relative importance, as an input into the House of Quality within Quality Function Deployment. This is done in the case of wooden multi-storey houses in Sweden, since there is a documented gap between the external consumer value and the internal production quality. Based on the Means-End Chain approach, the Extended Association Pattern Technique was used for a two stage study to elicit product attributes. Results from 34 interviews and 503 returned questionnaires revealed ten product attributes ranked by importance, to be further translated into engineering characteristics within Quality Function Deployment.

  • 129.
    Schauerte, Tobias
    et al.
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Johansson, Jimmy
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Gustafsson, Åsa
    Linnaeus University, School of Business and Economics, Department of Management Accounting and Logistics.
    From Customer Values to Production Requirements: Improving the Quality of Wooden Housing2013In: Pro Ligno, ISSN 1841-4737, E-ISSN 2069-7430, Vol. 9, no 4, p. 780-787Article in journal (Refereed)
    Abstract [en]

    The industry of wooden single-family houses in Sweden faces several challenges; both with regards to production but also with regards to the market conditions. In order to avoid uncontrolled price increases of wooden single-family houses, an act regulating the cash contribution when purchasing a house has been introduced. This has led to an increased focus of the house price as well as on the individual producers to control its processes and thereby its costs. The purpose of this paper is to give an overview of existing research related to product and production developments related to the industry, identifying research gaps, and suggest research activities. This research has been carried out as a literature study focusing on these concepts. It concludes that existing research is fragmented and that the linkage between the consumer and the product is neglected as well as the holistic approach is missing in development activities. The authors propose that in order to study how the industry could come closer to their consumer markets and the aligned requirements as well as to facilitate product development, the Means-End Chain approach may be of use and that the approach could further be linked to Quality Function Deployment.

  • 130.
    Schauerte, Tobias
    et al.
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Lindblad, Fredrik
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Improving Profitability by Improving the Material and Production Flow: 3 case studies of Swedish Wooden Single-Family House Producers2015In: Forum Wood Building Nordic Växjö 2015: Competition and competence: how can we reach a higher level?, Linnaeus Univeristy , 2015Conference paper (Other academic)
  • 131.
    Schauerte, Tobias
    et al.
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Lindblad, Fredrik
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Flinkman, Matti
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Critical success factors determining economic health of firms producing wooden single-family houses2017In: Arkitektur N, ISSN 1504-7628Article in journal (Refereed)
    Abstract [en]

    Firms in the Swedish industry for wooden single-family houses operate on a highly competitive market. Products are relatively homogenous, easily substitutional and firms mainly compete by prices. Since 2005, the accumulated market share for the five largest firms decreased from 53 % to 39 %, whilst the number of firms in the industry increased by almost 60 %. In addition to these internal issues on industry structure, construction firms are generally sensitive to external impacts, like the current changes in bank loan policy for the customer. Nonetheless, the number of produced single-family houses in Sweden increased by almost 130 % since 2012. Contributing to reducing the existing housing shortage in Sweden, wooden single-family house producers play an important role.

    However, earlier studies show that around 40 % of these firms are economically distressed, or in a situation, where they need to take appropriate strategic action to avoid economic distress in the near future. Yet, what actions are appropriate?

    This study is aiming at identifying current critical success factors determining economic health of Swedish firms producing wooden single-family houses. By means of these factors, conclusions about appropriate strategic actions might be drawn to avoid economic distress. Data from the 2015 annual reports of 50 relevant firms were collected and processed by means of the Altman’s Z´-score model and regression analysis.

    The results show that two factors accumulate to 99 % explanatory power (adj. R2) of financial health: (1) the manufacturing capacity of the firms’ assets and (2) the firms’ equity ratio. These are the current critical success factors for economic health of Swedish firms producing single-family houses. (1) matches todays’ debate about automated prefabrication and (2) can be seen as the way of financing such assets. Thus, these issues should guide the strategic agenda of firms in the industry.

  • 132.
    Sejkot, Petr
    et al.
    Czech Technical University in Prague, Czech Republic.
    Kuklík, Petr
    CTU in Prague, Czech Republic.
    Ormarsson, Sigurdur
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Patlakas, Panagiotis
    Southampton Solent University, UK.
    Numerical simulations of timber element connections using angle brackets with a rib under the external load2016In: Proceedings of the 2016 World Conference on Timber Engineering (WCTE), Vienna University of Technology, Austria , 2016Conference paper (Refereed)
    Abstract [en]

    The paper presents experimental, numerical, and analytical methods for the prediction of the loadbearing capacity of timber connections with metal angle brackets, utilising annular ring nails as fasteners. Full-scale testing experiments were performed in order to obtain the stiffness of the connection. Numerical simulations are employed to predict the load-bearing capacity of the angle brackets, when the external force is in the direction of the opening of the angle bracket. The characteristic load-bearing capacity of the connection was calculated using both the results of the numerical simulation, and analytical formulas, utilising laboratory measurements of the timber density. The paper presents the results of the three approaches, allowing direct comparison of the veracity of the simulations.

  • 133.
    Sejkot, Petr
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Ormarsson, Sigurdur
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Vessby, Johan
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Numerical and experimental study of punched metal plate connection used for long-span pitched timber roof truss structure2018In: WCTE 2018 - World Conference on Timber Engineering, World Conference on Timber Engineering (WCTE) , 2018Conference paper (Refereed)
    Abstract [en]

    According to the harmonized European design code for timber structures, Eurocode 5, all pitched timber trusses used in load bearing roofs are designed as in-plane structures which means that a bracing system must be designed and put in place to prevent the out-of-plane instability. Results from numerical 3D stability analyses of the whole roof structure indicate that the out of plane stability is often the critical factor. Therefore, influence of stiffness properties of that system is studied in detail herein for long-span timber roofs. Focus is put on how the stiffness of the mechanical connections in the roof structure influences the load carrying capacity of the roof. The punched metal plate connections are modelled as non-coupled spring elements connecting the various beam elements in the timber truss respectively. The spring stiffness of the connections is derived from full-scale tests, which were made for all in- and out-of-plane degrees of freedom. To evaluate the experimental testing, a digital image correlation method was used. The results from the digital image correlation tests were compared with numerical simulations of the experimentally tested connections to check the potential of using the numerical simulations instead of the experimental testing to get the stiffness properties of various connections used in the whole roof stability analysis. Based on such analysis, punched metal plate fasteners showed to be an important contributor to the roof stability because of its relatively high stiffness in all six degrees of freedom.

  • 134.
    Sejkot, Petr
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Ormarsson, Sigurdur
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Vessby, Johan
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Numerical and experimental study of punched metal plate connections to obtain spring stiffness needed for 3D buckling analysis of long-span timber trusses2017In: Presented at CompWood 2017 – ECCOMAS Thematic Conference on Computational Methods in Wood Mechanics – from Material Properties to Timber, June 7-9, 2017, Vienna, Austria, 2017Conference paper (Refereed)
  • 135.
    Sjödin, Johan
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Steel-to-timber dowel joints: Influence of moisture induced stressesManuscript (Other academic)
  • 136.
    Stenberg, Rebecca
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Enkelt avhjälpta hinder: En jämförande tillgänglighetsstudie mellan två centrum2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Rapporten är en utredning av tillgängligheten (enkelt avhjälpta hinder) för fem olika delområden i Sollentuna C. i Stockholm som jämförs mot motsvarande delområden i shoppingcentrumet Grand Samarkand i Växjö.

    De utvalda delområdena jämförs i ett tillgänglighetsperspektiv för att utredas om de är tillgängliga eller inte. Jämförelsen visar olika hinder och olika åtgärdade hinder för motsvarande delområden i centrumen. På så sätt kan centrumen ta hjälp av varandra för att se olika alternativ till att åtgärda samma eller motsvarande hinder i samma delområde.

    I resultatet redovisas alla icke åtgärdade hinder för de olika delområdena i båda centrumen. Med hjälp av bifogade kartor kan läsaren lätt se var delområdena ligger i centrumen och var hindren finns som behöver åtgärdas.

  • 137.
    Swahn, Trixie
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Rashem, Adam
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Platsgjuten eller prefabricerad plattrambro: En jämförande livscykel- och livscykelkostnadsanalys2018Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Flat frame bridges are the most common type of bridge in Sweden and constitutes almost half of all bridges in Sweden. In this study, a comparison between two production methods of flat frame bridges from a lifecycle perspective has been conducted. The study is built on comparing production methods from cost and environmental viewpoints where suggestions for improvements are presented to facilitate the choice of production method. Focus on environmentally sustainable constructions is increasing and by comparing different production methods from a lifecycle perspective it is possible to decrease environmental impact and increase cost-efficiency.

    The results of this case-study show that prefabricated production method offers greater savings regarding environment as well as economy. The possibility of further material savings exists for both production methods, prefabricated and site-cast, if changes of the regulations regarding bridge construction are made, as current regulations on design inhibits possibilities of new and better solutions. The result of the study shows that by choosing the right production method it is possible to decrease emissions of carbon dioxide, reduce energy consumption and costs for the infrastructure. Further gains can be made if regulations are changed.

  • 138.
    Tettey, Uniben Yao Ayikoe
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Dodoo, Ambrose
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Gustavsson, Leif
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Carbon balances for a low energy apartment building with different structural frame materials2019In: Innovative Solutions for Energy Transitions: Proceedings of the 10th International Conference on Applied Energy (ICAE2018), Elsevier, 2019, Vol. 158, p. 4254-4261Conference paper (Refereed)
    Abstract [en]

    We analyse the life cycle carbon implications of a building, with structural frame of prefabricated concrete, prefabricated modular timber or cross laminated timber (CLT) elements, designed to meet the Swedish passive house criteria. The analysis covers non-biogenic carbon flows related to the building alternatives, over an assumed life time of 80 years. The building alternatives are all modelled to have the same housing service and operation energy demand. Substitution factors, showing the efficiency of CO2 emissions reductions when wood alternatives are used instead of non-wood alternatives, are calculated for the CLT and modular alternatives with reference to the concrete alternative. The results show that the CLT and modular buildings give less carbon emissions to the atmosphere during production and when the buildings are demolished at the end-of-life. Moreover, the wood residues from the production and end-of-life activities for the timber alternatives far exceed that for the concrete alternative. The substitution factors differ slightly between the CLT and the modular alternatives, and are significantly lower when fossil gas is substituted by wood residues instead of fossil coal. In summary, the life cycle carbon emissions are significantly lower for the timber alternatives.

  • 139.
    Tommerup, Henrik
    et al.
    Technical University of Denmark, Denmark.
    Vanhoutteghem, Lies
    Technical University of Denmark, Lyngby, Denmark.
    Svendsen, Svend
    Danish Technical University, Lyngby, Denmark.
    Mahapatra, Krushna
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Gustavsson, Leif
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Haavik, Trond
    Segel As, Norway.
    Aabrekk, Synnøve
    Segel As, Norway.
    Paiho, Satu
    VTT, Espoo, Finland.
    Ala-Juusela, Mia
    VTT, Espoo, Finland.
    Analysis of promising sustainable renovation concepts, Deliverable D1.2 of the project Successful Sustainable Renovation Business for Single-Family Houses - SuccessFamilies.2009Report (Other academic)
  • 140.
    Tommerup, Henrik
    et al.
    Technical University of Denmark, Denmark.
    Vanhoutteghem, Lies
    Technical University of Denmark, Denmark.
    Svendsen, Svend
    Technical University of Denmark, Denmark.
    Mahapatra, Krushna
    Mid Sweden University, Sweden.
    Gustavsson, Leif
    Mid Sweden University, Sweden.
    Haavik, Trond
    Segel AS, Norway.
    Aabrekk, Synnøve
    Segel AS, Norway.
    Paiho, Satu
    VTT Technical Research Centre of Finland, Finland.
    Ala-Juusela, Mia
    VTT Technical Research Centre of Finland, Finland.
    Existing sustainable renovation concepts, Deliverable D1.1: Successful Sustainable Renovation Business for Single-Family Houses - SuccessFamilies2010Report (Other academic)
    Abstract [en]

    The Nordic single-family house renovation market is dominated by a craftsman based approach with individual solutions, traditional warehouses ”do-it-yourself-shops” and some actors marketing single products. To speed up the implementation of sustainable renovation of single-family houses there is a great need for full-service packages including consulting, contract work, follow-up, financing and operation and maintenance. There are few Nordic examples of such service models for renovation of single-family houses which entered the market recently. The success of these concepts is yet to be evaluated.

    One successful full-service package described in the report is a campaign by an energy company in Sweden who convinced 78% of 456 owners of houses with resistance heaters to connect to its biomass based district heating network. The campaign was successful because of its package offer and information provision with emphasis on economic aspects and functional reliability.

    The existing technical renovation concepts, typically focussing on application of only a few of the available technical solutions, have not been successful in realizing large scale energy efficiency gains. Renovation of single-family houses might be carried out based on design solutions with good combinations of the possible range of technical solutions including e.g. “passive (insulation) measures” and “solar measures” in order to reach a low primary energy level. Key aspects of reaching a low primary energy level in connection with renovation are described in the form of typical energy renovation measures and technical principles of low energy renovation including recommended extent of measures.

    Full service and technical renovation concepts should make it easy, simple and secure for the consumer to invest in a low energy renovation of their house. The building sector needs easy to use knowledge and initiatives which ensures that they can offer solutions which fulfil the demand for quality, economy and a simple process. To speed up the implementation of sustainable renovation of single-family houses, society needs to stimulate the process including better incentives structures, e.g. increased tax on energy and/or subsidy programmes. Combined with an outlook for rising global energy prices, sustainable renovation of single-family houses then has the potential to become an important market area in the future.

  • 141.
    Trischler, Johann
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology. johann.trischler@lnu.se.
    Sandberg, Dick
    Luleå University of Technology.
    Anaerobic digestion of monocotyledons in particleboard production: a concept of process integration to increase substitution of wood raw material2015In: International Wood Products Journal, ISSN 2042-6445, E-ISSN 2042-6453, Vol. 6, no 4, p. 154-164Article in journal (Refereed)
    Abstract [en]

    The purpose of this conceptual study was to introduce a possibility of integrating a surface treatment of monocotyledons by enzymes into particleboard production to provide a substitute raw material to replace wood particles. Because of the greater competition for wood as a raw material for particleboard production, there is increasing interest in monocotyledons as a substitute for wood. Monocotyledons, such as grass or cereal straw, differ from wood mostly in that they have a surface layer of waxes and embedded silica. If particles of monocotyledons are to be used in combination with wood in particleboards they must be modified. Using the concept of anaerobic digestion, it is possible to modify the surface of monocotyledon particles, having methane as a side product and to achieve a process, which leads to greater product diversity. A SWOT analysis was used to evaluate the process.

  • 142.
    Trischler, Johann
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Sandberg, Dick
    Luleå University of Technology.
    Wheat protein as adhesive for wood products for interior use2015In: Pro Ligno, ISSN 1841-4737, E-ISSN 2069-7430, Vol. 11, no 4, p. 246-252Article in journal (Refereed)
    Abstract [en]

    Protein is one of the most researched and widely used natural adhesives. Before the break through of synthetic adhesives in the wood industry, proteins were commonly used in furniture production. Today, proteins in the form of industrial by-products e.g. soy protein, blood and wheat protein are on the market, and these proteins can in general be used as a base for wood-products adhesives. Proteins are in general denatured by a change in pH, heat or organic solvents before they can be used as adhesives. In this study, a cold-dissolution of wheat protein (gluten) was tested with regard to its usability for the production of particleboards and laminated veneer products. The bonding was evaluated by testing the internal bond strength, thickness swelling, tensile strength and tensile shear strength. The results showed that the strength of the bond-line was in some cases as high as the strength of the wood material, but also that there were in some cases problems with the penetration of the adhesive into the wood and this lowered the bond-line strength considerably. The main conclusion is that cold-dissolved gluten adhesives are a good alternative to commercial synthetic adhesives for interior use, but that there are still challenges with the poor moisture resistance of the adhesive. 

  • 143.
    Trischler, Johann
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Sandberg, Dick
    Luleå University of Technology.
    Nuszkowski, Kalle
    Linnaeus University, Faculty of Arts and Humanities, Department of Design.
    The use of gluten adhesive and removable surface finishes in rebyblable furniture panels2015In: Pro Ligno, ISSN 1841-4737, E-ISSN 2069-7430, Vol. 11, no 4, p. 613-618Article in journal (Refereed)
    Abstract [en]

    A general problem in the recycling of furniture is that different materials and components are included within a single piece of furniture. Not only is the furniture built of components such as wood, leather, textiles, foams, steel and others but the wood component is also very often a composite made of wood, adhesives and functional additives such as water repellents or chemical substances as surface treatments. Sometimes these additives make cost-effective recycling of the composite wood difficult because of problems related to the separation of the components. The purpose of this study was to present an alternative product design for wood-based panels i.e. particleboards, which reduces or avoids many of the problems in the recycling of wood-based panels used in furniture. The results show that it is possible to produce wood-based panels in a way that facilitates the recycling of these panels although there are still some challenges which have to be dealt with. The concept as such seems to be promising. 

  • 144.
    Truong, Nguyen Le
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Gustavsson, Leif
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Effects of energy efficiency measures in district-heated buildings on energy systems2016In: Proceedings of International Conference on Sustainable Built Environment - SBE 16.  March 8 - 11, 2016, Hamburg, Germany, International Sustainable Built Environment , 2016Conference paper (Refereed)
    Abstract [en]

    The primary energy savings depend on both the final energy savings and the energy efficiency of the supply system. In this study, we evaluate primary energy savings of different energy efficiency measures in a multistory district-heated building in Sweden. We consider various locations of the building with different district heat production systems (DHS) of different scales, technical charac-teristics and heat-load profiles. We show that the primary energy savings of the energy efficiency measures vary with the type of measure and with the type of energy supply systems. The energy efficiency measures give large final energy savings but their primary energy savings vary signifi-cantly. Of the energy efficiency measures, the measure that gives electricity savings but increase the use of district heat is the most primary energy efficient in relation to the final energy savings. Heat savings in buildings connected to small-scale DHS using heat-only boilers is more primary energy efficient than that in buildings connected to medium- and large- scale DHS using combined heat and power units. Evaluation of energy efficiency measures for district-heated buildings re-quires a systems perspective where the final energy savings in buildings are matched to the actu-al energy supply systems.

  • 145.
    Vanhoutteghem, Lies
    et al.
    Technical University of Denmark, Denmark.
    Tommerup, Henrik
    Technical University of Denmark, Denmark.
    Svendsen, Svend
    Danish Technical University, Denmark.
    Mahapatra, Krushna
    Mid Sweden University.
    Gustavsson, Leif
    Mid Sweden University.
    Haavik, Trond
    Segel As, Norway.
    Aabrekk, Synnøve
    Segel As, Norway.
    Paiho, Satu
    VTT, Finland.
    Ala-Juusela, Mia
    VTT, Finland.
    Sustainable renovation concepts for single-family houses, Deliverable D1.3 of the project Successful Sustainable Renovation Business for Single-Family Houses - SuccessFamilies.2009Report (Other academic)
    Abstract [en]

    Due to the introduction of low energy standards for new houses as minimum requirements, rising energy prices and generally more focus on energy performance, there is a need for farreaching energy efficiency improvements in connection with renovation if existing singlefamily houses in the Nordic countries are to have competitive power compared to new houses on the future housing market. If the market is able to explain this to the homeowners there is an open market with undreamt-of possibilities. Good technical solutions exist but need to be combined based on the full range of (standard) solutions in order to reach the low primary energy level of new houses. The typical single-family houses identified to have large primary energy saving potential almost descend from the same time period in each Nordic country. The first segment is houses built in large numbers in the 1960 and 1970 before tightening of the insulation standards in the building codes in the late 1970’s due to the oil crisis. The second segment is houses built before 1945 (except for Finland) where a large part of them has been renovated, but energy renovation of those houses today would still account for a large energy saving. The third segment is type houses from the post-war period in Finland. A complete energy efficient renovation of a typical house include post-insulation and sealing of the buildings envelope - roof/ceiling, façade, windows/doors and foundation and maybe slab on ground - installation of a mechanical ventilation system with high efficiency heat recovery and low electricity use and if not already there, an energy efficient heating system based on district heating, heat pump etc. This package of technical solutions can be carried out during an overall or step wise planned renovation dependent on the condition of the house, the financial possibilities of the homeowner etc. Calculation of packages of energy efficient renovation solutions targeted the three segments of houses show that primary energy use and heating bill can be reduced with up to about 75% or a factor 4 corresponding to the level of a new house or better. It seems that the passive house level can not quite be reached with standard solutions. They require that more ambitious measures are applied. The total investment needed to reduce the heating bill by a factor 4 including replacement of e.g. roof and windows is up to EUR 100,000. It is generally difficult to obtain an economy in balance in the sense that the annual payment on a cheap loan, e.g. mortgage refinancing, to finance the investment is not fully offset by the expected annual energy savings. Since, the cost of energy measures today may not correspond to the increased market value of the house, it is important to find mechanisms so that the total cost of the energy investments in the future is reflected as an increased value of the house. But with due regard to all the non-energy benefits, such as better and healthier indoor environment and comfort, and less dependence on expected future higher energy prices, energy efficient renovation will probably still be attractive for the average homeowner. One-stop-shops in the form of full-service providers of energy efficient renovation of singlefamily house are missing in the Nordic countries. This service is vital to open up the market. A one-stop-shop could be seen as a possibility to make it easy for the homeowner to comply with possible future requirements to realize far-reaching energy savings in connection with extensive renovations, provided that the building sector offers the solutions. Homeowners need someone to take care of all relevant steps necessary for the renovation of the house including quotation for the work, financing and management of the contract work. An ideal full-service concept in five phases is proposed, going from initial evaluation of the house, to extensive analyses, proposal for package solutions, coordinated execution and operation and finally management of the house after renovation.

  • 146.
    Wallin, Johan
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Karlsson Bäcklund, Filip
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Materialoptimering för kulvertelement i betong2017Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    I detta arbete undersöks prefabricerade kulvertelement som främst används i djurstall. Arbetet utgår från Abetongs befintliga kulvertelement och elementet kontrolleras enligt dagen dimensioneringsregler. Materialoptimering av elementet beräknas och materialbesparing tas fram. Resultatet visar att det befintliga elementet uppfyller alla kontrollera normkrav. Optimeringen visar att det finns stora möjligheter att minska materialåtgången och samtidigt följa dagens dimensioneringsregler.

  • 147.
    Wang, Xiaodong Alice
    et al.
    Luleå University of Technology.
    Hagman, Olle
    Luleå University of Technology.
    Sundqvist, Bror
    SP Technical Research Institute of Sweden.
    Ormarsson, Sigurdur
    Technical University of Denmark, Denmark.
    Wan, Hui
    Mississippi State University, USA.
    Niemz, Peter
    ETH Zurich, Switzerland.
    Wood construction under cold climate: Part one : Impact of cold temperatures on the shear strength of different adhesives glued wood joints of Norway spruce and Scots pine2014In: WCTE 2014 World Conference on Timber Engineering, Quebec City, Canada, August 10-14, 2014 / [ed] Alexander Salenikovich, 2014Conference paper (Refereed)
    Abstract [en]

    As wood constructions increasingly use engineered wood products worldwide, concerns arise about the integrity of the wood and adhesives system. The glueline stability is a crucial issue for engineered wood application, especially under cold climate. In this study, Norway spruce (Picea abies) and Scots pine (Pinus sylvestris) joints (150mm x 20mm x 10mm) were bonded with seven commercially available resins (PUR, PVAc, EPI, MF, MUF1, PRF and MUF2) and tested at six temperatures (20, -20, -30, -40, -50 and -60 °C), respectively. Generally, for both species, temperature changes significantly affected shear strength of wood joints. As temperature decreased, the shear strength decreased. PUR resin resulted in the strongest shear strength at all temperatures tested. MF resin responded to temperature changes in a similar ways as the PUR resin. The shear strength of wood joints with EPI resins was sensitive to temperature change. MUF, PRF and PVAc resins demonstrated different characters with Norway spruce and Scot pine. At room temperature, all types of adhesive showed relative stability, in terms of shear strength variation. While at low temperature, the shear strength varied considerably. More specimens need to be tested in further work to more completely present the issue. The EN 301 and EN 302 may need to be specified based on wood species.

  • 148.
    Wiesner, Felix
    et al.
    University of Edinburgh, UK.
    Klippel, Michael
    ETH Zürich, Switzerland.
    Dagenais, Christian
    FPInnovations, Canada.
    Dunn, Andrew
    Timber Development Association (NSW), Australia.
    Östman, Birgit
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Janssens, Marc
    Southwest Research Institute, USA.
    Kagiya, Koji
    Building Research Institute, Japan.
    Requirements for Engineered Wood Products and their Influence on the Structural Fire Performance2018In: WCTE2018, World Conference on Timber Engineering, 20-23 August, Seoul, Republic of Korea, World Conference on Timber Engineering (WCTE) , 2018Conference paper (Refereed)
    Abstract [en]

    Engineered wood products e.g. cross-laminated timber (CLT), glued-laminated timber (glulam) and laminated veneer lumber (LVL) are increasingly used as the material of choice for mid-rise to tall construction timber projects. However, the requirements to manufacture these timber elements are considerably different among countries and, consequently, do have an influence on their fire performance. Requirements for sizes of the boards, allowed knot sizes and structural adhesives, among others, are of particular interest. The present paper gives an overview of the production requirements for CLT, glulam and LVL in different countries and discusses how the requirements affect the fire performance of these products.

  • 149.
    Wu, Min
    et al.
    Technical University of Denmark, Denmark;COWI AS, Denmark.
    Fridh, Katja
    Lund University.
    Johannesson, Björn
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Geiker, Mette
    Norwegian University of Science and Technology, Norway.
    Impact of sample crushing on porosity characterization of hardened cement pastes by low temperature calorimetry: Comparison of powder and cylinder samples2018In: Thermochimica Acta, ISSN 0040-6031, E-ISSN 1872-762X, Vol. 665, p. 11-19Article in journal (Refereed)
    Abstract [en]

    Theimpact of sample crushing on the detected porosity of hardened cement pastes bylow temperature calorimetry (LTC) was studied using powder and cylindersamples. Two types of cements, CEM I and CEM III were used to prepare thepastes. A model porous material, MCM-41, was also used in order to investigatesome aspects of the measurement and the evaluation approach. The powder andcylinder samples of the cement pastes were compared in terms of the calculatedice content curves, total pore volumes and pore size distribution curves. For thetwo studied cement pastes, the calculated ice content curves of freezing of thepowder sample differed from that of the cylinder samples, especially for thepaste CEM III. The results indicate that sample crushing changed the poreconnectivity as compared to non-crushed samples. One important differencebetween the powder sample and the cylinder samples of the paste CEM III wasthat the determined maximum ice content in the powder sample was much higherthan that in the cylinder samples, the relatively difference being about 40–50%.However, this kind of marked difference was not found in the paste CEM I. Theobserved difference between the calculated pore volume of the powder and thecylinder samples of the paste CEM III is possibly due to some of the “isolated”pores which, presumably, cannot be fully filled with water in the preparationof the cylinder samples. However, sample crushing makes it possible to saturatethe pores to a greater extent if the crushing contributes to open up the“isolated” pores. Consequently, more pores are detected in the powder samples.The argument that the “isolated” pores have a tendency to be opened up by thecrushing process is supported by results using gravimetric measurements and“dynamic (water) vapor sorption” measurements on powder samples.

  • 150.
    Wu, Min
    et al.
    Technical University of Denmark, Denmark.
    Fridh, Katja
    Lund University.
    Johannesson, Björn
    Technical University of Denmark, Denmark.
    Geiker, Mette Rica
    Norwegian University of science and Technology, Norway.
    Influence of frost damage and sample preconditioning on the porosity characterization of cement based materials using low temperature calorimetry2015In: Thermochimica Acta, ISSN 0040-6031, E-ISSN 1872-762X, Vol. 607, p. 30-38Article in journal (Refereed)
    Abstract [en]

    Low temperature calorimetry (LTC) can be used to study the meso-porosity of cement based materials. The influence of frost damage on the meso-porosity determination by LTC was explored on a model material MCM-41 and two cement pastes by conducting repeated cycles of freezing and melting measurements. The results indicate that the pressure generated during freezing and melting measurements has little impact on the pore structure of the powder MCM-41 samples. As for the studied cylinder samples of cement pastes, frost damage probably took place and it changed the pore connectivity while it had limited effect on changing the interior size distribution of the meso-pores. The analysis of the freezing and melting behavior of the pore liquid of cement based materials is complicated by the presence of ions. The freezing and melting behavior of the pore solution of cement paste samples preconditioned in either a small amount or a big amount of saturated limewater was compared. The results suggest that either the preconditioning in a big amount of limewater does not change the ionic concentration of the pore solution very much or the possible leaching of ions from cement hydrates during the preconditioning has limited influence on the freezing and melting behavior of the pore solution in the studied cement paste samples.

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