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  • 1.
    Abdeljaber, Osama
    et al.
    Qatar University, Qatar.
    Hussein, Mohammed
    Qatar University, Qatar.
    Avci, Onur
    Qatar University, Qatar.
    Davis, Brad
    University of Kentucky, USA.
    Reynolds, Paul
    University of Exeter, UK.
    A novel video-vibration monitoring system for walking pattern identification on floors2020In: Advances in Engineering Software, ISSN 0965-9978, E-ISSN 1873-5339, Vol. 139, article id 102710Article in journal (Refereed)
    Abstract [en]

    Walking-induced loads on office floors can generate unwanted vibrations. The current multi-person loading models are limited since they do not take into account nondeterministic factors such as pacing rates, walking paths, obstacles in walking paths, busyness of floors, stride lengths, and interactions among the occupants. This study proposes a novel video-vibration monitoring system to investigate the complex human walking patterns on floors. The system is capable of capturing occupant movements on the floor with cameras, and extracting walking trajectories using image processing techniques. To demonstrate its capabilities, the system was installed on a real office floor and resulting trajectories were statistically analyzed to identify the actual walking patterns, paths, pacing rates, and busyness of the floor with respect to time. The correlation between the vibration levels measured by the wireless sensors and the trajectories extracted from the video recordings were also investigated. The results showed that the proposed video-vibration monitoring system has strong potential to be used in training data-driven crowd models, which can be used in future studies to generate realistic multi-person loading scenarios.

  • 2.
    Abdula, Sham
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Oksman, Dan
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Attefallshus som komplementbostadshus: Drömhus eller mardröm?2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Den 2 juli 2014 blev det enligt lag tillåtet för en- och tvåbostadshusägare att uppföra en bygglovsbefriad komplementbyggnad på max 25 kvadratmeter på den egna fastigheten. Rapporten undersöker vilket genomslag lagändringen har haft i Stor-Stockholm, Stor-Göteborg och Stor-Malmö. Undersökningen visar att lagändringen ännu inte har haft något stort genomslag. I rapporten undersöks även en utvald del av marknadsaktörers utbud av attefallshus avsett som komplementbostadshus. 

    Ett attefallshus utformas med miljövänligt hållbara material och inspireras av Vitruvius tre principer för god arkitektur. Huset konstrueras med avsikt att uppfylla kraven som ställs i PBL, PBF, BBR och EKS. Målet med de framtagna bygghandlingarna är att få startbesked från byggnadsnämnden i Växjö. 

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  • 3.
    Abdulhadi, Ahmed
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Brånemo, Oskar
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Jämförelse av betongkonstruktioner som dimensionerats under olika svenska byggnormer2023Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In the construction sector today, there is a lot of discussion about material reuse tominimize the negative environmental impact. By reuse of precast concreteelements, significant amounts of CO2 emissions can be prevented. In order toreuse a concrete element for structural purposes in a building, the element need tobe assessed to ensure it can withstand the required loads.

    This report is based on a comparison of different building codes, it describes andcompares three selected building codes and their associated concrete standardsfrom different eras. The purpose of the report is to compare the results obtainedwhen designing predetermined concrete elements and components. The findingswill indicate whether it is possible to reuse concrete elements that were designedaccording to previous standards. The calculations will demonstrate bothsimilarities and, more importantly, differences in the design approaches of thebuilding codes and how they have evolved.

    An investigation concludes that by employing a chain of checks, it is possible todetermine if an existing component is reusable considering its load capacity.

    The differences in reinforcement content vary within approximately 0-25% infavor of the previous code, i.e. the older code requires more reinforcement.

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  • 4.
    Abrahamsen, Rune
    et al.
    Moelven Limtre, Norway.
    Bjertnaes, Magne A.
    Sweco, Norway.
    Bouillot, Jacques
    Eiffage, France.
    Brank, Bostjan
    University of Ljubljana, Slovenia.
    Cabaton, Lionel
    Arbonis, France.
    Crocetti, Roberto
    Moelven, Sweden.
    Flamand, Olivier
    CSTB, France.
    Garains, Fabien
    Eiffage, France.
    Gavric, Igor
    InnoRenew, Slovenia.
    Germain, Olivier
    Galeo, France.
    Hahusseau, Ludwig
    Eiffage, France.
    Hameury, Stephane
    CSTB, France.
    Johansson, Marie
    RISE, Sweden.
    Johansson, Thomas
    Moelven, Sweden.
    Ao, Wai Kei
    University of Exeter, UK.
    Kurent, Blaz
    University of Ljubljana, Slovenia.
    Landel, Pierre
    RISE, Sweden.
    Linderholt, Andreas
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering. Linnaeus University, Linnaeus Knowledge Environments, Advanced Materials.
    Malo, Kjell
    NTNU Norwegian University of Science and Technology, Norway.
    Manthey, Manuel
    CSTB, France.
    Nåvik, Petter
    Sweco, Norway.
    Pavic, Alex
    University of Exeter, UK.
    Perez, Fernando
    Smith and Wallwork, UK.
    Rönnquist, Anders
    NTNU Norwegian University of Science and Technology, Norway.
    Stamatopoulos, Haris
    NTNU Norwegian University of Science and Technology, Norway.
    Sustersic, Iztok
    InnoRenew, Slovenia.
    Tulebekova, Salue
    NTNU Norwegian University of Science and Technology, Norway.
    Dynamic Response of Tall Timber Buildings Under Service Load: The DynaTTB Research Program2020In: EURODYN 2020, XI international conferece on structural dynamics: Proceedings, Volym II / [ed] M. Papadrakakis, M. Fragiadakis, C. Papadimitriou, National Technical University of Athens , 2020, p. 4900-4910Conference paper (Refereed)
    Abstract [en]

    Wind-induced dynamic excitation is becoming a governing design action determin-ing size and shape of modern Tall Timber Buildings (TTBs). The wind actions generate dynamic loading, causing discomfort or annoyance for occupants due to the perceived horizontal sway – i.e. vibration serviceability failure. Although some TTBs have been instrumented and meas-ured to estimate their key dynamic properties (natural frequencies and damping), no systematic evaluation of dynamic performance pertinent to wind loading has been performed for the new and evolving construction technology used in TTBs. The DynaTTB project, funded by the Forest Value research program, mixes on site measurements on existing buildings excited by heavy shakers, for identification of the structural system, with laboratory identification of building elements mechanical features coupled with numerical modelling of timber structures. The goal is to identify and quantify the causes of vibration energy dissipation in modern TTBs and pro-vide key elements to FE modelers.

    The first building, from a list of 8, was modelled and tested at full scale in December 2019. Some results are presented in this paper. Four other buildings will be modelled and tested in spring 2020.

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  • 5.
    Abrahamsen, Rune
    et al.
    Moelven Limtre, Norway.
    Bjertnæs, Magne A.
    Sweco, Norway.
    Bouillot, Jacques
    Eiffage, France.
    Brank, Boštjan
    University of Ljubljana, Slovenia.
    Crocetti, Roberto
    Moelven SE, Sweden.
    Flamand, Olivier
    CSTB, France.
    Garains, Fabien
    Arbonis, France.
    Gavrić, Igor
    InnoRenew, Slovenia.
    Hahusseau, Ludwig
    Eiffage, France.
    Jalil, Alan
    CSTB, France.
    Johansson, Marie
    RISE, Sweden.
    Johansson, Thomas
    Moelven, Sweden.
    Ao, Wai Kei
    Uni Exeter, UK.
    Kurent, Blaž
    University of Ljubljana, Slovenia.
    Landel, Pierre
    Linnaeus University, Faculty of Technology, Department of Building Technology. Rise, Sweden.
    Linderholt, Andreas
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Malo, Kjell
    NTNU, Norway.
    Manthey, Manuel
    CSTB, France.
    Nåvik, Petter
    Sweco, Norway.
    Pavic, Alex
    Uni Exeter, UK.
    Perez, Fernando
    Smith&Wallwork, Switzerland.
    Rönnquist, Anders
    NTNU, Norway.
    Šušteršič, Iztok
    InnoRenew, Slovenia.
    Tulebekova, Saule
    NTNU, Norway.
    Dynamic response of tall timber buildings under service load: results from the dynattb research program2023In: World Conference on Timber Engineering 2023 (WCTE 2023): Timber for a Livable Future, 19-22 june, 2023,Oslo, Norway / [ed] Nyrud, A. Q. and Malo, K. A. et al., Curran Associates, Inc., 2023, p. 2907-2914Conference paper (Refereed)
    Abstract [en]

    Wind-induced dynamic excitation is a governing design action determining size and shape of modern Tall Timber Buildings (TTBs). The wind actions generate dynamic loading, causing discomfort or annoyance for occupants due to the perceived horizontal sway, i.e. vibration serviceability problem. Although some TTBs have been instrumented and measured to estimate their key dynamic properties (eigenfrequencies, mode shapes and damping), no systematic evaluation of dynamic performance pertinent to wind loading had been performed for the new and evolving construction technologies used in TTBs. The DynaTTB project, funded by the ForestValue research program, mixed on site measurements on existing buildings excited by mass inertia shakers (forced vibration) and/or the wind loads (ambient vibration), for identification of the structural system, with laboratory identification of building elements mechanical features, coupled with numerical modelling of timber structures. The goal is to identify and quantify the causes of vibration energy dissipation in modern TTBs and provide key elements to finite element models. This paper presents an overview of the results of the project and the proposed Guidelines for design of TTBs in relation to their dynamic properties.

  • 6.
    Abrahamsson, Jenny
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    la Fleur, Filip
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    The impact of connection stiffness on the global structural behavior in a CLT building: A combined experimental-numerical study2021Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Cross Laminated Timber (CLT) has in recent years become a more important building material. This means that the demand for accurate calculation methods in building standards such as Eurocode 5 has increased. There is limited knowledge about the connections in CLT buildings which is an important part of a CLT structure. This thesis was therefore focused on investigating a wall-floor-wall type connection commonly found in platform type buildings. 

    An experimental and numerical study on typical wall-floor-wall connections was carried out in this thesis. In the experimental part 60 tests with 8 different configurations were conducted to investigate the influence of different parameters on the connection, moment capacity and rotational stiffness. During the tests the deformation of the specimens under four load levels were investigated. Compression tests were also performed on the specimens to determine the compressive strength and stiffness of the elements. In the numerical part two different models for the connection were created. One simplified model with rotational springs and one more complex model with compression springs. With these models the influence from the number of stories, span and thickness of the wall on the global behavior of a structure was investigated. 

    The result from this thesis shows that there is both moment capacity and rotational stiffness in the wall-floor-wall type connection that can be utilized in the design phase of a structure. This was proven by both the experimental and the numerical study. The parameters that influence the behavior of the connection most were the load level applied on the wall and the wall thickness. The model created in the numerical study showed great potential regarding the replication of the connection behavior observed in the experimental study.  

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  • 7.
    Ahaki Lakeh, Amir
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Tahmasbi, Milad
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Life cycle assessment and structural analysis of renovation of Ulriksberg school building in Växjö2022Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Massive volumes of hazardous emissions have been produced by the construction sector for which some adequate steps are implemented, but the rising trend of emissions can still be seen. In this thesis, the goal is to identify and analyze renovation measures from primary energy use and environmental impacts perspective, according to Boverket’s mandatory provisions and general recommendations (BBR 2018), for an old school building. Also, as a part of the study goal, the building structure is analyzed under the updated Eurocode SS-EN 90-91-96 in order to see if the building meets structural stability requirements. Life cycle assessment of the building is limited to production and construction stages, and it is used as a tool to evaluate the environmental impacts according to standard SS-EN 15978:2011. Most of the relevant data are provided by VÖFAB, in cooperation with Växjö municipality, as well as the company WSP group.

    The object of the thesis is an old three-story school building constructed in 1950 in Växjö, Sweden. The gross area of the building is 1,300 m2 and for renovation scenarios, building envelope components are investigated by adding new insulation materials considering two life cycle stages. In the production phase, the lowest primary energy use was 137 kWh/m2 for the scenario of using cellulose insulation material plus windows and exterior doors with a U-value of 1.1 [W/m2 K]. The lowest environmental impacts were also obtained for this scenario, with 14 kg CO2-eq/m2 global warming potential (GWP), 0.06 kg SO2-eq/m2 acidification potential (AP), and 0.06 kg NO3-eq/m2 eutrophication potential (EP). The results indicate that the share of the installation step in the primary energy use and environmental impacts during the construction phase is negligible, but the transportation role in this stage is significant. The highest global warming potential is for the scenario using cellulose insulation material plus windows and exterior doors with a U-value of 0.7 [W/m2 K] with 4.4 kg CO2-eq/m2 in the construction stage. Ultimately, the material production stage accounts for the most share of primary energy use and environmental impacts. 

    This research provides several renovation measures investigated by life cycle assessment resulting in performing climate declarations. Regarding the sensitivity analysis, the electricity source has a considerable effect on reducing total primary energy consumption and environmental impacts during the production phase. It is also found that the scenario utilizing cellulose insulation material with windows with a U-value of 1.1 [W/m2 K] shows the lowest total primary energy use and environmental impacts. Through analyzing the building structure, all Eurocode criteria within the serviceability limit state (SLS) and ultimate limit state (ULS) are fulfilled, and the structure is still stable when new materials are added through renovation.

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  • 8.
    Ahn, Namhyuck
    et al.
    College of Forestry, USA.
    Dodoo, Ambrose
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Riggio, Mariapaola
    College of Forestry, USA.
    Muszynski, Lech
    College of Forestry, USA.
    Schimleck, Laurence
    College of Forestry, USA.
    Puettmann, Maureen
    WoodLife Environmental Consultants, USA.
    Circular economy in mass timber construction: State-of-the-art, gaps and pressing research needs2022In: Journal of Building Engineering, E-ISSN 2352-7102, Vol. 53, article id 104562Article in journal (Refereed)
    Abstract [en]

    The building and construction sector is a major contributor to human environmental impact on the planet. It follows that the sector's contribution is also crucial for transition towards a low carbon society and circular economy (CE). Mass timber products, are one of the sustainable alternatives to traditional building materials and have led to the recent revolution in timber construction. While environmental benefits of mas timber manufacturing and construction is well documented the end-of-life (EOL) and the post-EOL options for mass timber buildings, their environmental benefits and CE potential are discussed much less. Short history of construction technology involving prefabricated mass timber panels compared to traditional building types results in virtually no documented cases of panelized mass timber structures reaching the EOL stage and no practical examples of incorporating CE concepts in such projects. In this study, a two-step systematic literature review was used, to define and classify 23 CE-based governing principles from six categories in the construction industry, and to use those principles to analyze the state-of-the-art circular approach in mass timber research. The study covered a total of 90 papers, of which 68 focused on the general construction industry and 22 specifically on the mass timber construction. Results of this review suggest substantial gaps in knowledge and pressing research needs for the development of holistic approaches to prepare the mass timber construction for circular economy.

  • 9.
    Akter, Shaheda T.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Experimental characterization and numerical modeling of compression perpendicular to the grain in wood and cross-laminated timber2022Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Compression perpendicular to the grain (CPG) of wood is a typical loading situation in timber structures. It has been an extensively studied research topic for decades, due to the highly ductile behavior of wood under such loading, the large variations in mechanical properties, and the relevance of these properties in structural design. Among others, the main influencing factors for CPG properties are stressed volume, load and support configurations, and annual ring orientations to the loading direction. After the innovation of the massive, engineered wood based product, cross-laminated timber (CLT) and its application in high rise buildings, CPG of wood has gained further importance. The development of a non-homogeneous, undesired and combined stress state under CPG in solid wood, due to the material anisotropy in the radial-tangential plane, can build up a complex multi-axial stress state in CLT. As a comparatively new product, the study of the influencing factors for CPG properties of CLT, and an understanding of the local material behavior under such loading, is essential for product characterization and for the development of design guidelines to ensure safe and efficient design.

    The main aim of the doctoral thesis is to establish a relationship betweenthe anisotropic behavior of clear wood in the transverse plane and the structural response of CLT under CPG loading. Both experimental and numerical studies were adopted herein, to enhance the understanding of the basic material behavior and the product and structural behavior. On the clear wood scale, the focus was on developing a test setup for uniaxial and biaxial loading in the radial-tangential(RT) plane. The potential of the developed test setup for the biaxial testing in the transverse plane was exploited for the investigation of the moisture and time dependent behavior of clear wood under radial compression and rolling shear loading. For data acquisition, in addition to the force and displacement data measured by the internal actuators of the testing machine and an external load cell,a contact-free digital image correlation (DIC) system was used in the experimental investigations. A numerical model was developed, which can describe the elasto-plastic behavior of wood under compression in the transverse plane and predict the structural behavior of solid wood and CLT. For that purpose, a novel Quadratic multi-surface (QMS) failure criterion and a simplified Hoffman failure criterion were implemented in a user-subroutine in the finite element software Abaqus®, and their suitability was compared with the Abaqus implemented Hill’s criterion.The validation of the material models was based on the experimental investigations of failure behavior of clear wood under stress perpendicular to the grain with rolling shear interaction. The material models were further utilized to predict the structural response of solid wood and CLT wall-to-floor connections under CPG loading. The predicted response of CLT connections under CPG by using the above-mentioned material models was compared with experiments, which investigated the influences of different connection types, wall and floor thicknesses, positions of walls, and outer deck layer orientations. The models were then applied to investigate the influence of the pith location in the boards, the number of layers and the thickness of walls and the floor on the stiffness and strength of CLT connections. Moreover, the CLT connection’s rotational rigidity as a consequence of compressive force from the upper floor in a multi-story building was studied by means of finite element calculations.

    The DIC measured strain fields from the experiments on clear wood confirmed the dependence of strain field on the curvature of the annual rings. As regards the material models, Hill’s model resulted in significantly higher force carrying capacity than experiments on clear wood, whereas Hoffman’s and QMS models predicted reasonably well the force-displacement relationships as found in experiments. The Hoffman’s and QMS models predicted stiffness was about 5–10% higher than corresponding experimental results on clear wood, and about 25% higher for CLT connections. The higher difference in the latter case is due to the difference in material properties of clear wood and structural timber, and the contact behavior between the structural members. The results from CLT wall-to-floor connections revealed a strong influence of loading and supporting configurations, wall thickness and pith locations on their stiffness and strength. A compressive loading on the CLT wall showed a positive effect on the rotational stiffness of CLT wall-to-floor connections, which considerably reduces the CLT floor mid-span deflection in comparison to a simply-supported floor.The thesis work contributes to an enhanced understanding of the anisotropic material behavior of wood in the RT-plane and of its effects on structural timber and CLT under CPG loading. The outcomes of the thesis are beneficial to the product design and standardization of CLT and can be applied in further product development and in optimized structural design.

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  • 10.
    Akter, Shaheda T.
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Bader, Thomas K.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Enquist, Bertil
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Failure envelope for interaction of stresses perpendicular to the grain with rolling shear stress in wood2018In: 6th European Conference on Computational Mechanics (ECCM 6), 7th European Conference on Computational Fluid Dynamics (ECFD 7), 11 – 15 June 2018, Glasgow, UK, 2018Conference paper (Refereed)
    Abstract [en]

    The orthotropic material property in combination with ductility in compression, brittleness in shear and tension, very low shear modulus in radial-tangential (RT) plane etc. requires anisotropic stress failure criteria, as well as their evolution with increasing strains. Three- dimensional failure criteria have been proposed for this purpose, but their validation in the RT plane with interaction of rolling shear stresses has attracted less attention. Corresponding stress interactions are however important for modelling of engineered wood-based products under compression perpendicular to the grain when taking into account influence of the annual ring structure.

    The work aims at defining failure envelopes for stresses perpendicular to the grain with rolling shear stress interaction based on experimental investigations performed on Norway spruce. The experimental set-up was realized in a biaxial testing frame and consisted of stiff steel plates to transfer load from the testing machine to wood specimen. Mechanical grips prevented rotation and uplifting of the specimen in case of pure shear and tensile loading, respectively. In addition to conventional linear variable differential transformers, a digital image correlation system was used to measure strain fields on the surface of wood specimens and steel plates. Measurements of dog-bone shaped specimens were carried out along different stress interaction paths by displacement controlled loading.

    The experimental dataset was then compared with commonly used phenomenological failure criteria, namely Tsai-Hill, Tsai-Wu [1], Norris [2] and Hoffman, as well as with regression equations from previous works [3].Experiments revealed that the stress-strain relationship under compression, shear, and biaxial loading differs in radial and tangential directions. None of the three-dimensional stress failure criteria provided good prediction of experiments under compression and rolling shear, but experimental data was closer to the regression equation proposed in [3].

  • 11.
    Akter, Shaheda T.
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Bader, Thomas K.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Serrano, Erik
    Lund University, Sweden.
    Modeling of wood under combination of normal stresses with rolling shear stress2019In: Presented at CompWood 2019 - International Conference on Computational Methods in Wood Mechanics - from material properties to Timber Structures, Växjö, Sweden, June 17-19, 2019, Växjö, Sweden, 2019Conference paper (Refereed)
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  • 12.
    Akter, Shaheda T.
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Bader, Thomas K.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Serrano, Erik
    Lund University, Sweden.
    Modelling of wood under compression perpendicular to the grain with rolling shear in cross-laminated timber2019In: Presented at COMPLAS 2019 - XV International Conference on Computational Plasticity: Fundamentals and Applications, Barcelona, Spain, September 3-5, 2019, Barcelona, Spain: European Community on Computional Methods in Applied Sciences (ECCOMAS), 2019Conference paper (Refereed)
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  • 13.
    Akter, Shaheda T.
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Bader, Thomas K.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Serrano, Erik
    Lund University, Sweden.
    Stiffness of cross-laminated timber (CLT) wall-to-floor-to-wall connections in platform-type structures2021In: World Conference on Timber Engineering 2021, WCTE 2021, Santiago, Chile: World Conference on Timber Engineering, WCTE , 2021, article id WPC0232Conference paper (Refereed)
    Abstract [en]

    Wall-to-floor-to-wall connections are important for the performance of multi-storey, platform-type cross-laminated timber (CLT) structures. Their stiffness properties are studied by means of a numerical model, which was previously validated with experimental data from material testing and CLT connections loaded perpendicular to the grain. In this work, the stiffness of CLT wall-to-floor-to-wall connections is derived and its dependence on the compressive loading in the CLT walls and on wall and floor thicknesses were investigated. The compatibility of the local model with the connection size in structural design models, was investigated by studying the effect of the floor length and the wall height in the numerical model. The results showed that both rotational elastic stiffness and moment capacity of the floor connection increase with increasing compressive force on the CLT wall. However, a moderate decrease in stiffness, but a stronger rotation hardening was found for higher wall pressures, while lower wall pressures yielded an ideal plastic behaviour. The wall thickness showed a higher influence on the connection stiffness and moment capacity than the floor thickness. The influence of the support condition on the deflection of a CLT floor was exemplified. This study includes novel stiffness data for the design of CLT floors in platform type constructions.

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  • 14.
    Akter, Shaheda T.
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Binder, Eva
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Bader, Thomas K.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Moisture and short-term time-dependent behavior of Norway spruce clear wood under compression perpendicular to the grain and rolling shear2023In: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 18, no 2, p. 580-593Article in journal (Refereed)
    Abstract [en]

    Material properties of wood under compression perpendicular to the grain and rolling shear are important for the engineering design of timber structures. This regards the short-term stiffness and strength, their dependence on the moisture content of wood, as well as the time-dependent behavior. Norway spruce clear wood properties in the transverse plane of wood were studied inan experimental campaign exploiting an earlier developed biaxial test setup. The moisture dependence of the stiffness and strength and the short-term time-dependent creep deformations under compression in the radial direction and under rolling shear were characterized. Loading and unloading stiffness, as well as the strength, were determined in quasi-static tests at five different moisture contents from 4% to 29%. The elastic and viscous stiffnesses were identified in creep tests at three compressive stress levels of 0.50, 0.75, and 1.00 N/mm2, and at two rolling shear stress levels of 0.33 and 0.50 N/mm2. The test data complements the existing experimental database, especially with novel data regarding the moisture dependence of the rolling shear strength, which showed less moisture dependence than the compressive strength perpendicular to the grain. The results of the creep tests revealed different material properties for the different loading and material directions of wood.

  • 15.
    Akter, Shaheda T.
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Schweigler, Michael
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Serrano, Erik
    Lund University, Sweden.
    Bader, Thomas K.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    A Numerical Study of the Stiffness and Strength of Cross-Laminated Timber Wall-to-Floor Connections under Compression Perpendicular to the Grain2021In: Buildings, E-ISSN 2075-5309, Vol. 11, no 10, article id 442Article in journal (Refereed)
    Abstract [en]

    The use of cross-laminated timber (CLT) in multi-story buildings is increasing due to the potential of wood to reduce green house gas emissions and the high load-bearing capacity of CLT. Compression perpendicular to the grain (CPG) in CLT is an important design aspect, especially in multi-storied platform-type CLT buildings, where CPG stress develops in CLT floors due to loads from the roof or from upper floors. Here, CPG of CLT wall-to-floor connections are studied by means of finite element modeling with elasto-plastic material behavior based on a previously validated Quadratic multi-surface (QMS) failure criterion. Model predictions were first compared with experiments on CLT connections, before the model was used in a parameter study, to investigate the influence of wall and floor thicknesses, the annual ring pattern of the boards and the number of layers in the CLT elements. The finite element model agreed well with experimental findings. Connection stiffness was over estimated, while the strength was only slightly under estimated. The parameter study revealed that the wall thickness effect on the stiffness and strength of the connection was strongest for the practically most relevant wall thicknesses between 80 and about 160 mm. It also showed that an increasing floor thickness leads to higher stiffness and strength, due to the load dispersion effect. The increase was found to be stronger for smaller wall thicknesses. The influence of the annual ring orientation, or the pith location, was assessed as well and showed that boards cut closer to the pith yielded lower stiffness and strength. The findings of the parameter study were fitted with regression equations. Finally, a dimensionless ratio of the wall-to-floor thickness was used for deriving regression equations for stiffness and strength, as well as for load and stiffness increase factors, which could be used for the engineering design of CLT connections.

  • 16.
    Al Jaafar, Jaafar
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Projektering av platsbyggd villa2008Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Abstract (in English)

    "This thesis work is a design project of an on-site construcktions. The issue addressed by the project was how to

    devise and design an detached house

    I have examined which architecture-drawings, construcktion-drawings and static calculations are needed to

    produce an on-site construcktions detached house.

    The result is presented in the finished drawings for the construction documents, which show a one-storey

    detached house with an attractive/accessible construction plan. It uses the combination of a strong style of

    architecture and a clear influence of functional design. This is clarified by the bench ceilings, and the facade,

    which is partly laying panel, partly white trimmed.

    Size: 153 square meters

    Number of rooms: 6, where of 3 are bedrooms."

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  • 17.
    Al Jaafar, Jaafar
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Projektering av platsbyggd villa2008Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Abstract (in English)

    "This thesis work is a design project of an on-site construcktions. The issue addressed by the project was how to

    devise and design an detached house

    I have examined which architecture-drawings, construcktion-drawings and static calculations are needed to

    produce an on-site construcktions detached house.

    The result is presented in the finished drawings for the construction documents, which show a one-storey

    detached house with an attractive/accessible construction plan. It uses the combination of a strong style of

    architecture and a clear influence of functional design. This is clarified by the bench ceilings, and the facade,

    which is partly laying panel, partly white trimmed.

    Size: 153 square meters

    Number of rooms: 6, where of 3 are bedrooms."

    Download full text (pdf)
    FULLTEXT01
  • 18.
    Al-Ansari, Nabil
    et al.
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Te Seng, Meng
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Studentbostäder i trä med Prefab-teknik2009Independent thesis Basic level (degree of Bachelor), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    The Results of this thesis was the creation of two designed house variants with a module to

    all the apartments. In addition till the first module there are three other modules of

    apartments that can be put in the houses if it so needs. The house are volume prefabricated

    and are placed on site in a way that it create an enclosure of the area which faces against the

    nature and car parks also lies hidden behind these houses.

    For the actual structure, a cross beam was created to carry the floor above and it is support

    by all four walls. The structure between the first and the second floor has no "syll" but

    instead there are two differently alternative to linking the floors in order so that it will not

    move. The reason with this solution was that there will not be any subsidence when the

    forces from above are pressed down ward. The forces are instead directly down to the next

    timber frame system. This can happen when the real estate's owner might want to build

    more floors on the house than the present two floors house when there is no land to build

    and spaces are needed in the future.

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  • 19.
    Alashker, Basel
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Lindström, Erik
    Karimi, Aziz
    Backaryds kyrka- Bevarande av golvbjälklag2021Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This study was carried out in Backaryd’s church following a proposal from Ankdammen konsult. Backaryd’s church was built more than 200 years ago in Ronneby municipality in Blekinge County. Due to changes in heating methods and energy requirements since the church was built, the church today does not meet the energy and comfort requirements of today’s buildings. The study of the Backaryd’s church aims to investigate the floor construction in the church and to find out what factors may be at risk of moisture damage. The study will analyse the church and mainly the condition of the crawl space. In addition, some improvement measures will be proposed to get a comfortable heating inside the church with an appropriate energy use. Both law and society place high requirements on the preservation of valuable and cultural-historical buildings for future generations. In addition, any changes to churches that have been built before 1939 must be approved by the county administrative board.Results from the study show that relative humidity does not reach critical levels either in the crawl space or the church room. There are also no injuries such as mold and rot attacks on the structure. The inventory is of good quality and lacks damage such as cracks and rots.The writers have come up with the following improvement measures:● An annual entertainment of water management systems in crawl space. ● Cover the stone walls with plastic wrap on the inside and make them as dense as possible. ● Place the base of the panty bottom from below up against the floor beam. ● Insulate the floor structure with mineral wool. ● Place a plastic wrap all over the ground in the crawl space. ● install a dehumidifier. 

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    Backaryds kyrka- Bevarande av golvbjälklag
  • 20.
    Albertsen, Henrik
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Lindberg, Amanda
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Lokalt omhändertagande av dagvatten på bostadsfastigheter2016Independent thesis Basic level (professional degree), 180 HE creditsStudent thesis
    Abstract [sv]

    Ett behov finns av att fördröja dagvatten innan det släpps på det kommunala ledningsnätet för att minska flödestopparna och undvika överbelastning. Studien avser att ta fram en förenklad metod för val och utformning av LOD-metod som är anpassad för privata fastighetsägare.

    Ett flertal LOD-anläggningar samt förutsättningar kring dessa har undersökts. Studien har gett en grundläggande information och en beräkningsgång som har förenklats, är lätt att följa och som kan anpassas efter befintliga förutsättningar och önskemål. 

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    fulltext
  • 21.
    Algabroun, Hatem
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    On the development of a maintenance approach for factory of the future implementing Industry 4.02017Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The objective of this thesis is to develop a maintenance approach that fulfills the requirements of Industry 4.0. It explores the role and importance of maintenance activities in today’s industry. Then, it develops the features and tasks required to be performed by maintenance to fulfill the demands of Industry 4.0. Finally, it develops a reference model to be used in designing maintenance system for Industry 4.0. To perform these studies, real data were collected and applied as well as a typical scenario was implemented.

    The results achieved in the papers of this thesis are 1) a mathematical representation and application of a model that identifies, analyses and prioritizes economic weakness in working areas related to production, 2) a model that analyses, identifies and prioritizes failures that impact the competitive advantages and profitability of companies, 3) characterization of a suitable maintenance technique for Industry 4.0 and 4) a reference model i.e. a framework, that could be utilized to develop a maintenance approach for Industry 4.0.

    The conclusion of this thesis confirms that maintenance has a significant impact on companies’ competitive advantages, other working areas and profitability. To achieve a suitable maintenance technique for Industry 4.0, this technique must be able to monitor, diagnose, prognosis, schedule, assist in execution and present the relevant information. In order to perform these tasks several features must be acquired, the most important features are to be: digitized, automated, intelligent, able to communicate with other systems for data gathering and monitoring, openness, detect deviation in the condition at an early stage, cost- effective, flexible for adding new CM techniques, provide accurate decisions and scalable. The developed framework could be used as a base to design a maintenance system for Industry 4.0. This study contributes to our understanding of the maintenance importance in today’s industry and how to develop a maintenance approach for Industry 4.0.

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    Licentiate Thesis (Comprehensive Summary)
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    Front Page
  • 22.
    Alhameedi, Ali
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Hybrid testing procedure development: An experimental study a hybrid simulation of a steel truss element2019Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Hybrid simulation is a numerical and experimental structural testing technique in which the critical structural members are tested experimentally, while the rest of the structure is modeled numerically. During hybrid testing, the numerical model is updated continuously based on the output of the experimental test. In this study, a quasi-static hybrid simulation was conducted on a steel truss structure. A single truss member was considered as the physical substructure, while the remaining members were modeled using Abaqus finite element software. The communication between the physical and numerical models was established using OpenFresco as a middleware. Using this setup, the structure was loaded until the physical substructure failed due to buckling. Finally, the results of the hybrid simulation were verified numerically and experimentally.

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  • 23.
    Alijagic, Denis
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Att uppnå god energiprestanda: En jämförelse av teoretiska energiberäkningar och verklig energianvänding i småhus2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    En studie som utfördes på uppdrag av Norrköpings kommun med syfte att undersöka varför energideklarationer visar en annan specifik energianvändning gentemot energiberäkningar. Ett stickprov togs där tio småhus energiberäkningar och energideklarationer analyserades. Dessutom genomfördes intervjuer med tre medelstora kommuner (Norrköpings-, Linköpings- och Jönköpings kommun) samt Boverket för att lokalisera möjliga fel och förbättringar gällande Boverkets Bygg Regler, BBR. Boverkets föreskrifter och allmänna råd om fastställande av byggnadens energianvändning vid normalt brukande och ett normalår, BEN, togs även i beaktande att lokalisera felkällor i upprättade energiberäkningar för hus 1-10.

    Download (pdf)
    bilaga
  • 24.
    Al-Jadirji, Abdullah
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Utredning om lönsamhet av solceller för privata hushåll2024Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In 2015, the United Nations outlined 17 global goals for sustainable development, with Target 7.2 falling under the seventh goal, focusing on sustainable energy for all. This target emphasizes the necessity of increasing the global share of renewable energy to mitigate the impacts of fossil fuel consumption. Renewable energy sources are deemed essential for the future, with individuals playing a crucial role in this transition. Private property owners investing in solar cells face various challenges in gathering and comprehending information on the subject. While the environmental benefits of solar cell investments are evident, there are additional reasons for investors to consider this solution, particularly from a financial standpoint. By reducing reliance on public grid electricity and selling excess self-produced electricity, investors can both save money and contribute to sustainable practices.The thesis sets three objectives: 1. to delineate the available types of solar panels in the market, 2. to assess how factors such as roof direction, slope, and solar radiation impact annual electricity production, and 3. to explore the influence of electricity prices in southern and northern Sweden on annual savings, surplus electricity sale, and the payback period/profitability. Calculations have been conducted to estimate the annual electricity production potential of solar cells for a specific property.Considering the time constraints, certain limitations were imposed, mainly due to the vastness of solar cell technology. These limitations encompassed specific investment costs such as profile rails, screws for securing solar panels, and labour costs for installers.The study relied on calculations, site visits, and interviews with a private property owner, incorporating various assumptions and statistical averages related to potential profit and efficient electricity production in different geographical areas and from different solar cell manufacturers.Two scenarios were explored: the first, based on a relatively low electricity consumption of 4,500 kWh/year, and the second, assuming a higher consumption of 20,000 kWh/year. Beyond solar radiation and electricity prices, these scenarios were investigated to compare different consumption levels and analyse their impact on potential savings and profits through excess electricity sales.Fluctuations in electricity prices and solar radiation at the property's location significantly influence the final results. A strategic choice of solar panels and inverters from the outset can effectively impact the payback period and overall profitability of the investment.

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    Utredning om lönsamhet av solceller för privata hushåll
  • 25.
    Almeida, Roma
    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.
    Analytical review of methodological approaches for measuring circularity in building renovation2023In: Proceedings of the International Conference “Sustainable Built Environment and Urban Transition”: 12-13 October, Växjö, Växjö: Linnaeus University Press, 2023Conference paper (Refereed)
    Abstract [en]

    Circularity in construction industry requires understanding of the complex system dynamics, which are affected by various building layers and societal systems. While the existing building stock offers opportunities to enable re-looping of construction and demolition waste, the assessment of building circularity performance is not straightforward, due to lack of standard database, methods, and tools. This may lead to subjective interpretations by practitioners who rely on lifecycle assessment (LCA) approach complemented with circularity indicators (C-indicators) to know the level of circularity (LOC) of building materials, components, and elements. Thus, these C-indicators requires careful evaluation of the current methodological approaches. The aim of this paper is to map and evaluate the nexus between assessment methodologies highlighting their strengths, limitations, and areas of improvement. In this study, a complementary approach of systematic literature review and design research concept was used to classify seven primary aspects covering 18 key performance indicators, that impact the system thinking approach of the renovation project. The critical analysis of ten distinguished C-indicators show conditional, beneficial and trade-off relationships between various indicators. At the same time, the dynamic aspect of re-looping the resources is missing in these indicators and sustainability is accounted by complementing lifecycle impacts rather than coupling them. Results of this review highlight substantial gaps in C-indicators applicability for renovation projects with emphasis to formulate a practical guidance to assess recirculation of materials throughout the value chain. 

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    ANALYTICAL REVIEW OF METHODOLOGICAL APPROACHES FOR MEASURING CIRCULARITY IN BUILDING RENOVATION
  • 26.
    Almutairi, Mohammad
    et al.
    Leeds University, UK.
    Nikitas, Nikolaos
    Leeds University, UK.
    Abdeljaber, Osama
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Avci, Onur
    Iowa State University, USA.
    Bocian, Mateusz
    Wrocław University of Science and Technology, Poland.
    A methodological approach towards evaluating structural damage severity using 1D CNNs2021In: Structures, E-ISSN 2352-0124, Vol. 34, p. 4435-4446Article in journal (Refereed)
    Abstract [en]

    Evaluating the severity of structural damage is a critical component of Structural Health Monitoring (SHM). Convolutional Neural Networks (CNNs) have been used before to detect structural damage and evaluate its severity by utilising only raw vibration data. However, these vibration-based CNN applications were limited to discrete user-defined levels of damage. To provide a more accurate representation of structural damage, this paper aims to design and validate a framework for evaluating structural damage severity within a continuous range of damage levels, using 1D CNNs and distributed raw acceleration data. To this purpose, a simple Finite Element (FE) cantilever model with non-rigid rotational spring support was adopted. Damage was simulated at the support as reduction of the rotational spring stiffness. The performance of the proposed framework was assessed under different excitation scenarios and data pre-processing techniques. The results demonstrate the ability of 1D CNNs to evaluate damage severity with high accuracy. By estimating the reduced value of the rotational spring stiffness, the proposed framework can also be used towards FE model updating in parallel with damage severity evaluation.

  • 27.
    Al-Najjar, Ahmad
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Full life cycle assessment of a cross laminated timber modular building in Sweden2021Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Building industry contributes to massive amounts of harmful emissions. This trend will continue to rise unless appropriate measures are taken. This master thesis aims to calculate the environmental impact during the whole life time of a prefabricated cross-laminated timber (CLT) modular building. The environmental impacts from the end-of-life stage and the benefit of the most of the building material beyond the system boundary is also included. Life cycle assessment (LCA) is used as a tool to assess the environmental impacts following the standard SS-EN 15978:2011. Since there is a lack of environmental data about CLT in general and about prefabricated CLT volumetric modules buildings in particular the results from this work will enhance the understanding of the environmental performance of this kind of building system. This work is done with Size AB, a company that only produces CLT modular multi-storeys buildings. 

    The studied object is three storeys building located in Nykvarn in Sweden. The total emissions during the building life cycle are at least 377 kg CO2-eq/m2 of the gross floor area (GFA), 0,296 kg PO43--eq/m2 of GFA and 1,1 kg SO2-eq/m2 of GFA for global warming potential (GWP), eutrophication potential (EP) and acidification potential (AP) respectively. The result shows that the share of the AP and EP during the end-of-life stage is only 1% for each, whereas CO2-eq emission is accounted for 14% during this stage. The material production stage accounts for more than 50% for all environmental indicators. 

    This study provides fundamental data to perform LCAs in this area and to carry out climate declarations. Through sensitivity analysis it was discovered inter alia that high production intensity in the modules fabrication factory plays a significant role in reducing the environmental impacts during the construction stage. It was also found that modification of the LCA’s system boundary is recommended to present a transparent LCA of modular buildings. 

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  • 28.
    Alriksson, Tobias
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Visualisering av byggprojekt i Revit2014Independent thesis Basic level (degree of Bachelor), 180 HE creditsStudent thesis
    Abstract [sv]

    Rapporten avhandlar visualiseringen i marknadsföringsstadiet av ett byggnadsprojekt med tillämpning på Trivselhus bostäder. För att få en grund till vad som ska ändras gällande företagets nuvarande visualisering har intervjuer genomförts med samtliga berörda parter. Dessa är säljare, kunder och husdesigners. Efter detta har två förslag till förändringar av nuvarande visualiseringar arbetats fram i Revit med intervjuerna som underlag.

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  • 29.
    Amaddeo, Carmen
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Dorn, Michael
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Ambient Vibration Tests and Modal Analysis of a Six-Story Lightweight Timber Frame Building2023In: World Conference on Timber Engineering (WCTE 2023): 19-22 June, Oslo, World Conference on Timber Engineering (WCTE) , 2023, p. 2898-2906Conference paper (Refereed)
    Abstract [en]

     This paper describes the in-situ ambient vibration tests of a lightweight timber frame building, performed in order to obtain its modal properties. Our case study is a six-story lightweight timber frame building in Varberg, Sweden. Five battery-driven wireless data acquisition units with a total of 14 uni-axial accelerometers were used to perform the in-situ measurements. Accelerations along the two horizontal directions were recorded with a duration of approximately 40 minutes. Two different only-output frequency and time domain Operational Modal Analysis (OMA) methods were used to evaluate the dynamic properties of the building. The modal parameters obtained from the in-situ measurements, such as natural frequencies and mode shapes, were compared with the parameters obtained from the Finite Element (FE) model of the structure. To perform a detailed numerical analysis of the light-frame timber building, all lateral-load resisting system components were modelled. The FE model was calibrated in function of the results obtained from the OMA of the building. Based on the obtained results from the calibrated FE model, it was possible to conclude that the non-structural elements have an influence on the global dynamic response of the building.

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  • 30.
    Amaddeo, Carmen
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Dorn, Michael
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Dynamic characterization of a six-story light-weight timber-frame building2022In: Proceedings of the SHATIS 2022: 6th International Conference on Structural Health Assessment of Timber Structures, 7-9 September 2022, Prague, 2022 / [ed] Jiřı Kunecky & Hana Hasnıkova, Institute of Theoretical and Applied Mechanics , 2022, p. 173-179Conference paper (Refereed)
    Abstract [en]

    Multi-story residential and commercial timber buildings are an efficient solution for sustainable cities. Numerous projects have been and are expected to be realized in Sweden. In-situ wind-induced ambient vibrations tests have been conducted on a six-story light-weight timber-frame building in Varberg (Sweden). The load-bearing structure is composed of outer walls and some interior walls. For horizontal stabilization, the walls are supported by a bracings system realized with steel rods. To perform the in-situ measurements, multiple battery-driven data acquisition units, with uni-axial accelerometers have been used. Repeated measurements at different positions have been performed to be able to collect data at each floor and along both directions (longitudinal and transversal). Two different Operational Modal Analysis (OMA) methods have been used to evaluate the modal parameters: frequency, damping and mode shapes. The in-situ dynamics properties have been compared with the dynamic properties obtained from the Finite Element (FE) model of the structure.

  • 31.
    Andersen, Mattias
    et al.
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Claeson, Martin
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Utvärdering av ett nyutvecklat samverkansbjälklag och dess utvecklingspotential2008Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    I dagens byggnader ställs allt högre krav på stora rum och öppna ytor vilket ger efterfrågan på ökad spännvidd hos bjälklagen. Detta är svårt att klara av med traditionella träbjälklag. För att ändå få ett lätt bjälklag undersöks möjligheten att kunna fördela ut bjälklagets belastning i två riktningar. Bjälklaget ska alltså vara fyrsidigt upplagt. För att lösa detta har en idé uppkommit som går ut på ett samverkansbjälklag mellan trä och plåt. Detta bjälklag ska i bärriktning 1 bära genom fackverkan medan det i bärriktning 2 ska bära genom balkverkan. För att ett fyrsidigt upplagt bjälklag ska fungera krävs att sambandet mellan kraft och deformation är likvärdigt i båda riktningarna.

    Examensarbetets uppgift har varit att tillverka provkroppar för att undersöka sambandet mellan kraft och deformation i både bärriktning 1 och bärriktning 2. Provning utförs för att se om bjälklaget har förutsättningar att kunna användas i praktiken.

    Efter provning av bjälklagsprovkropparna konstaterades att det finns möjligheter att gå vidare med produkten och fortsätta utvecklingsarbetet. För de provkroppar som provades i bärriktning 1 och 2 var sambandet mellan kraft och deformation nära identisk upp till 7,5 kN då mittnedböjningen var ca 10 mm.

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  • 32.
    Andersson, Alexander
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Bergman, Carl
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Underlag för fördelaktig upphängning av kylvattenledningar i en äldre byggnad2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Arbetet redovisar möjligheterna att hänga upp tyngre vattenledningar i en äldre industrilokal där en äldre byggnadsstandard användes vid uppförandet.

    Ett flertal alternativ har tagits fram och där de mest lämpade har arbetats vidare genom att jämföra fördelar och nackdelar.

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  • 33.
    Andersson, Bernt-Ove
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Malmstedt, Anthon
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Innovativa boendeformer för unga vuxna: En möjlig väg in på den svenska bostadsmarknaden2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This work concerns the examination of the interest and awareness of three innovative forms of housing that target young adults between the ages of 18 and 35 in the Swedish housing market. It also describes the existing stock of housing and highlights the most serious obstacles for the target group to obtain an accommodation. The work takes it’s starting point in the current housing shortage in Sweden where many groups for various reasons are hindered from the housing market for various reasons. The market is in need for public actors and various housing developers to find new ways to remedy the problem of obtaining an accommodation for these vulnerable groups. The study is based on previous research, surveys with young adults and interviews with intermediaries from different parts of the industry as a methodology. The results show an interest for, but low knowledge about the three types of housing: rent purchases, youth sets and cooperative rental apartments adapted for young adults. These are all adapted to reduce the problem for some persons within the target group to enter the housing market.

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  • 34.
    Andersson, Carl
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Pettersson, John
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Behovet av ökad kontroll i stålbyggnadskonstruktioner2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In the work the need of increased inspections of steel structures with respect to errors of execution was examined. On 1 June 1994, the Swedish parliament decided to change the Planning and Building Act (PBL) and the changes came into force in 1995, where the entire responsibility for the construction and control of a building was placed on the developer. After the winters of 2009/10 and 2010/11, when several roofs collapsed by the snow weight, a number of design and execution faults were discovered. During the thesis work it was investigated what happens to the safety of building structures in steel that undergo changes during its lifetime and a comparison with current regulations was made.

    A field study and several interviews were conducted where the focus was on execution errors and how changes in regulations led to today's self-control systems that affect the number of execution errors. The results of the work show that there may be a need to review the current control system and that the number of serious execution errors in the case study object increased after 1995.

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  • 35.
    Andersson, Emma
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Olsson, Emelie
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Utveckling av ödehus: Gestaltningsförslag som bidrar till landsbygdsutveckling och social hållbarhet2022Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Sweden's population is constantly growing and so are the larger cities. Meanwhile thousands of buildings in the countryside are unused and forgotten. Recent world events have resulted in more opportunities for remote work, enabling more freedom in choosing where to live.The aim of this study is to exemplify how the change of an abandoned building can contribute to social sustainability and development of rural areas. The suggestions presented in the report should be applicable in accordance with current regulations, such as Plan- och bygglagen. Therefore a presentation of relevant laws is included in the study.The exemplification in this study is presented in the form of a design for a repurposed school-building in a small society near Älmhult. The design allows the space to be used for public activities and greenery. This is in accordance with theories and answers from interviews, which were conducted with a selection of people relevant to the subject, regarding how to make rural areas more attractive.

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  • 36.
    Andersson, Josefine
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Svensson, Simon
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Mätning av fuktkvot i sammansatta KL-träelement2018Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Moisture related damage is an occurring problem in wood-based buildings if the material is exposed to rainfall during construction. Measurement of moisture content can be done with various instruments and methods. The purpose of the thesis is to study change in moisture content in cross-laminated-timber, with prolonged exposure to water in laboratory environment. To advance the field, the Linnaeus University has been developing a measurement instrument of their own in collaboration with the company Saab. The instrument measures electrical resistance in wood where the obtained values will be compared to similar measurements from a product named Gigamodule. The self-developed sensor card is still a product under development. In addition to the lab setting measurements the instrument was also installed in a local building in Växjö.

    To verify the result from the previously mentioned resistance measurers additional instruments and methods have been utilized. Two separate models have been used to represent the detail of the connection between the wall element and the joist. Both models have been submerged under water for an equal amount of time. The experimental setting took place between the 19th of April to the 18th of May 2018. The measurements and calculations have been resulting in values that can be the subject of internal evaluation. Difference in result based on the direction of the grain have been observed in several measurement methods. The CLT-elements demonstrated good drying properties despite periodically high moisture content and the wood indicate a return towards initial levels of moisture.

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    Mätning av fuktkvot i sammansatta KL-träelement
  • 37.
    Andersson, Magnus
    et al.
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Cederholm, Anders
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Alternativa byggsystem för att minska transmissionsförlusterna på miljonprogrammets byggnader2009Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose with this project is to explore and verify three renovating systems for Miljonprogrammet (common expression for

    buildings constructed during the years 1965-1975 when over a million houses where built in Sweden) to take measure to the

    largely transmission losses of these buildings. Many of the buildings from this period have similar constructions and therefore

    the same techniques can be used to renovate several of them. This project only considers the climate scale, although there

    are many more factors to concern for to efficient the buildings of Miljonprogrammet.

    This thesis presents examples of renovations carried out using two of the three renovation systems.

    The essay presents a reference house of choice on which we apply the three systems and calculate the new U-values,

    consumption of energy and the investment costs. The new U-values the building is given is matched to the values of

    recommendation for passive houses. Our reference house is a two story apartment building, located in the village of

    Lammhult, with brick facades at the ends and plaster at the long sides. One of the long sides contains balconies. The three

    systems are additional insulation, prefabricated additional insulation and replacement of the facade. We consider which

    renovation systems are best in different conditions, also considering the treatment of the tenants.

    The result of the study shows that with additional insulation and prefabricated additional insulation the buildings transmission

    losses will be major lowered. The investment cost and payoff time for the prefabricated version is much lower. If the standard

    of passive house is wanted the replacement of facade technique should be used. This method requires that the tenants move

    out during the renovation work. The investment cost for this method is significantly higher but the payoff time is equal with the

    additional insulation methods payoff time

     

     

    .

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  • 38.
    Andersson, Mikael
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Energieffektivisering av kulturhistoriska byggnader: Energi och klimat i Lekaryd kyrka2007Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Detta examensarbete syftar till att utreda inneklimat- och energisituationen i Lekaryd kyrka. För att göra detta har klimatmätning genomförts, samt simuleringar med datorsimuleringsprogrammet IDA – Klimat och energi. Kyrkan har höga energikostnader och för att få kännedom om energiförlusternas storlek och fördelning, har en kartläggning av kyrkans energiflöden genomförts i syfte att fastställa dess energibalans. Målet är att resultaten från klimatmätningen och datorsimuleringarna ska kunna användas som underlag vid utarbetande av åtgärdsförslag för en lönsammare och ur bevarandesynpunkt skonsammare drift av Lekaryd kyrka. Kyrkan värms intermittent vilket är skonsammare för kyrkan då långvariga variationer i den relativa fuktigheten undviks. Analysen av inneklimatet i kyrkan visar att den relativa fuktigheten ligger inom ett intervall där risk för uttorkningsskador och mögeltillväxt inte bör vara överhängande. De datorsimuleringar som har genomförts, innefattar simulering av kyrkans inomhusklimat och kyrkans energibalans. Vid datorsimulering av en tung stenkyrka är det viktigt att programmet tar hänsyn till väggarnas värmetekniska egenskaper för att ett bra resultat ska erhållas. Byggnadens värmelagrande förmåga tar programmet hänsyn till, men komplikationer uppstår när noggranna värden i relativa fuktigheten önskas. Resultatet från energisimuleringen pekar på att kyrkan dras med stora energiförluster i form av transmission genom byggnadsskalet, samtidigt som det visat sig att det passiva värmetillskottet från sol och intern transmission har en betydande inverkan på kyrkans aktiva uppvärmning.

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  • 39.
    Andersson, Sören
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Risker med karbamidskumplast- och cellplastisolering i kulturhistoriskt värdefulla byggnader2008Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Examensarbetet har genomförts på uppdrag av Länsstyrelsen i Blekinge och Ronneby Kommun och syftar på att utreda om tidigare tilläggsisolering med karbamidskumplast och polystyrencellplastkulor, på tre stycken byggnadsminnesförklarade byggnader på Ronneby Brunn i Blekinge, har medfört eventuella fuktskador. Undersökningarna av byggnaderna har utförts med ett antal valda undersökningsmetoder som var, okulär besiktning, termografering, klimatmätning, materialtest, fuktkvotsmätning elektrisk, fuktkvotsmätning med metoden vägning-torkning-vägning, samt simulerade fuktdiffusionsberäkningar. Efter att ha sammanvägt de olika undersökningsmetodernas resultat för respektive byggnad antas det att isoleringen inte utgör något hot för väggkonstruktionerna så länge de har en hög ånggenomsläpplighet och har tätt ytskikt på utsidan. Den förhöjda relativa fuktigheten som har noterats vid beräkningar av väggkonstruktionerna antas torka ut snabbt då konstruktionen har lågt ånggenomgångsmotstånd. De skador som upptäckts vid undersökningarna beror inte på byggnadernas isolering. Ett materialtest på karbamidskumplasten visar att fuktupptagningsförmågan är högre för material ifrån byggnaderna än från ett nyare material. Det innebär att om byggnaderna utsätts för inträngande vatten kan detta sugas upp kapillärt. Därför är det av vikt att den yttre tätningen som endast består av träpanel och färg har ett tätt skikt. Polystyrencellplasten antas däremot inte ha någon större kapillaritet alls. Då konstruktionerna har ett mycket begränsat värmemotstånd och vetskapen om att ogenomtänkta åtgärder kan skapa problem, bör det företas en kartläggning av byggnadernas möjlighet till att bli mer fuktsäkra och inte minst mer energieffektiva.

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  • 40.
    Anuar Bahari, Shahril
    et al.
    Universiti Teknologi MARA (UiTM), Malaysia.
    Nazarudin Zakaria, Mohd
    Universiti Teknologi MARA (UiTM), Malaysia.
    Osman, Syaiful
    Universiti Teknologi MARA (UiTM), Malaysia.
    Abu, Falah
    Universiti Teknologi MARA (UiTM), Malaysia.
    Jani Saad, Mohamad
    Malaysian Agricultural Research and Development Institute (MARDI), Malaysia.
    Hosseinpourpia, Reza
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology. Linnaeus University, Linnaeus Knowledge Environments, Advanced Materials. Linnaeus University, Linnaeus Knowledge Environments, Green Sustainable Development.
    Strength Performance and Microstructure Characteristic of Naturally-Bonded Fiberboard Composite from Malaysian Bamboo (Bambusa vulgaris)2022In: Journal of Renewable Materials, ISSN 2164-6325, E-ISSN 2164-6341, Vol. 10, no 10, p. 2581-2591Article in journal (Refereed)
    Abstract [en]

    This study investigated the mechanical properties and microstructural characteristics of fiberboard composite produced by naturally-bonded Malaysian bamboo fiber (Bambusa vulgaris). The components that obtained through soda pulping of bamboo culms such as fiber and black liquor, were used for the preparation of high-density fibreboard composite at two target densities of 850 and 950 kg/m3. The bamboo fiberboard composite (BFC) were then produced at 200°C and two pressing parameters of 125 and 175 s/mm. The mechanical properties, e.g., flexural strength and internal bonding (IB) of BFC samples were evaluated according to BS EN 310: 1993 and BS EN 319: 1993, respectively. It was found that the mechanical performance of the composite with 850 kg/m3 density was significantly higher than 950 kg/m3 ones, especially for the samples with 125 s/mm pressing parameter. Microstructure characteristic of the BFC samples illustrated that the fiber linkages were cracked in the composites with higher density, e.g., the composite with the density of 950 kg/m3 and also black liquor were slightly degraded at longer pressing time, which led to the reduction in mechanical properties, especially in IB strength.

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  • 41.
    Appelkvist, Rasmus
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Persson, Patrik
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Utvärdering av ett nyutvecklat bjälklagsupplag för inhängda bjälklag2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In an effort to streamline processes and create a better standard, industrial construction has become increasingly common in the Swedish construction industry. Therefore, this thesis focuses on a unique proposal on floors for balloon systems, where the aim has been to investigate the possibility of a new type of bracket for balloon systems. The work will focus on the bearing capacity of the landfill and the establishment of a spring constant for this heap. This will be achieved through practical tests and simple calculations. The practical work relates to load the two prototypes of a new type of flooring warehouse to breach and then analyze the weaknesses in the structures. This degree will only consider the design and construction of a mounting profile designed to facilitate the slab types with varying span. The two prototypes have been stressed to breach, and the force and deflection have been measured to develop a spring constant. The laboratory results indicate that it is possible to use this heap profile in construction of light beams.

    Keywords: prefabricated construction, light beams, balloon systems, bracket for balloon systems and building systems for lightweight construction.

  • 42.
    Aquino, Caroline
    et al.
    University of Minho, Portugal.
    Rodrigues, Leonardo
    University of Nottingham, UK.
    Kržan, Meta
    Slovenian National Building and Civil Engineering Institute, Slovenia.
    Schweigler, Michael
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Li, Zheng
    Tongji University, China.
    Branco, Jorge
    University of Minho, Portugal.
    Influence of Test Methods on the Parallel to Grain Embedment Strength and Foundation Modulus Characterization2023In: Proceedings from the 13th World Conference on Timber Engineering 2023: 19-22 June, 2023, Oslo / [ed] Anders Q. Nyrud, Kjell Arne Malo, Kristine Nore, Oslo, Norway: World Conference on Timber Engineering (WCTE) , 2023, p. 3667-3674Conference paper (Refereed)
    Abstract [en]

    Different test setups have been reported in the literature for the determination of the embedment strengthin timber elements. These variances hinder a straightforward comparison between available test data. It is difficult todetermine if the source of variability lies in intrinsic timber properties or is related to the test protocol used. This paperaims to provide a better insight into the influence of embedment strength test methods, comparing experimental resultsfrom different test setups within the guidelines of EN 383 and ASTM D 5764-97a for Scots pine wood (Pinus sylvestris)and Spruce (Picea Abies). A robust statistical analysis was performed to identify statistically significant differencesbetween the groups evaluated. The analysis of the parallel to grain embedment strength showed that the results differedbetween standards, pointing out the potential bias inserted in the embedment properties given their evaluation method.Moreover, the thickness of the specimen tests also proved to influence the yield and ultimate embedment strength for thewood species tested.

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  • 43.
    Aronsson, Alexander
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Gustavsson, Markus
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Minimering av köldbryggor vid balkonger hos miljonprogramshus2015Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    I studien görs en klimatsimulering av en byggnad från miljonprogrammet och jämförs sedan med en klimatsimulering där en ombyggnation av byggnadens indragna balkonger har gjorts.

    Studien ger konstruktionslösningar på hur en ombyggnation skulle kunna se ut.

    Resultatet visar att det går att minska energibehovet om balkongväggarna rivs och nya väggar konstrueras i liv med fasaden.

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  • 44.
    Aronsson, Anton
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Andersson, Jesper
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Sjöberg, Mikael
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Förskola i kombination med andra verksamheter: Vilka konsekvenser medför detta?2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Växjö kommun har ont om ledig mark vilket har medfört att en undersökning harpåbörjats, där förskolor kombineras med andra verksamheter i en och sammabyggnad. Syftet har varit att undersöka möjligheten med dessa kombinationer för attse vilka konsekvenser som uppstår.

    Undersökningen behandlar två tomter i Växjö som har olika förutsättningar gällandedess detaljplaner. Resultatet visar att en kombination mellan de olika verksamheternaär möjligt men att dagens regler och standardiseringar inte alltid går att ta hänsyn tillvid dessa kombinationer.

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    Förskola i kombination med andra verksamheter
  • 45.
    Assarsson, Jakob
    et al.
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Eskilsson, Mattias
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Arbetsberedningar och Egenkontroller i produktionen: Work preparations and quality controls in production2009Independent thesis Basic level (degree of Bachelor), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [sv]

    I byggproduktionen behövs noggranna förberedelser för att undvika störningar och kvalitetsfel. En form av styrnings- och planeringsverktyg är arbetsberedningar och egenkontroller som vi i detta examensarbete har undersökt. Syftet har varit att se hur de fungerar och att finna förbättringsmöjligheter för dem. I arbetet gjordes en intervjustudie som visade att anställda på Peab tycker att arbetsberedningarna är ett mycket bra hjälpmedel i produktionen och att användandet fungerar ganska bra i nuläget. Enligt medarbetarna finns det dock mycket som kan utvecklas och förbättras. På företaget tycker personalen även att egenkontrollerna är något bra men själva användandet fungerar inte särskilt bra ute i produktionen.

     

    För att förbättra och utöka användandet av arbetsberedningarna krävs att tjänstemännen får en ökad förståelse och vilja att använda dem. När det gäller egenkontrollerna är det däremot hantverkarnas inställning som är bekymret, de ser inte kontrollen som något viktigt utan mer som ett moment som ödslar deras tid. Studien visar att egenkontrollen, om den används på rätt sätt, kan öka hantverkarnas engagemang och få dem att ta större ansvar för det de utför.

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  • 46.
    Augustino, Daudi Salezi
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Adjei Antwi-Afari, Bernard
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Parameterized Modelling of Global Structural Behaviour of Modular Based Two Storey Timber Structure2018Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The global stiffness behaviour of modular-based two storey timber structures was studied under prescribed horizontal displacements at the upper corners of the volume modules. To be able to study this behaviour, a numerical finite element model was created in Abaqus. A parametric study was performed in which the geometry and spring stiffness of joints were varied until the enough stiff module was attained for safe transfer of shear forces through the module structure. The FE-model was parameterized to have possibility to vary positions of door and window openings in the volume modules. These openings had influence on the global structural behaviour of the two storey module structure since the side wall with two openings showed less reaction forces at its top corner point A compared to the other wall point B. In addition, the module#3 was assigned with small spring stiffness in x-direction representing friction in the joint between the volume modules. This was done without uplift plates and angle brackets. The findings showed that there was significant slipdeformation between the volume modules and small reaction forces at points A and B. The spring stiffness value in x-direction was varied until large value was obtained which resulted in overall shear deformations of the walls in both volume modules. When the angle bracket and the uplift plates were introduced between the modules when small spring stiffness along the joint between the volume modules was used, the results showed that most of the shear forces were transferred through the angle brackets instead of the fastener joints between the modules. Moreover, the results showed that the reaction forces at the points A and B increased when the angle brackets were assigned in the module. Furthermore, the results also showed that uplift plates used in the model worked well for simulations with low vertical spring stiffness between the modules.

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    Maters thesis-2018
  • 47.
    Augustsson, Tina
    et al.
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Söderberg, Emma
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Sandgärdsgatan, Växjö: - En attraktivare gågata2006Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In the outskirts of Växjö many shoppingmalls are vastly expanding which in time could pose a threat to the city centre. Växjö city is, in shoppingaspects dominated by one main street, Storgatan. To achieve a more competitive central part of the city and complex street network, a widening of the center would be preferred. Closest at hand for a widening of the city centre is the paralell pedestrian street Sandgärdsgatan, which today is thought of as a backstreet. Our project is to propose examples on how to turn Sandgärdsgatan into a more attractive pedestrian street. Research have been carried out in the form of literaturestudies, interviews and polls aswell as fieldtrips to various urban environments. The proposals we have created include everything from remodelling and general restorations to street markets and placarding. The main proposals aside from being presented in text are also visualised in drawings whilst smaller changes are only mentioned in text.

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  • 48.
    Avci, Onur
    et al.
    Iowa State University, USA.
    Abdeljaber, Osama
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Kiranyaz, Serkan
    Qatar University, Qatar.
    Hussein, Mohammed
    Qatar University, Qatar.
    Gabbouj, Moncef
    Tampere University of Technology, Finland.
    Inman, Daniel J.
    University of Michigan, USA.
    A review of vibration-based damage detection in civil structures: from traditional methods to Machine Learning and Deep Learning applications2021In: Mechanical systems and signal processing, ISSN 0888-3270, E-ISSN 1096-1216, Vol. 147, article id 107077Article in journal (Refereed)
    Abstract [en]

    Monitoring structural damage is extremely important for sustaining and preserving the service life of civil structures. While successful monitoring provides resolute and staunch information on the health, serviceability, integrity and safety of structures; maintaining continuous performance of a structure depends highly on monitoring the occurrence, formation and propagation of damage. Damage may accumulate on structures due to different environmental and human-induced factors. Numerous monitoring and detection approaches have been developed to provide practical means for early warning against structural damage or any type of anomaly. Considerable effort has been put into vibration-based methods, which utilize the vibration response of the monitored structure to assess its condition and identify structural damage. Meanwhile, with emerging computing power and sensing technology in the last decade, Machine Learning (ML) and especially Deep Learning (DL) algorithms have become more feasible and extensively used in vibration-based structural damage detection with elegant performance and often with rigorous accuracy. While there have been multiple review studies published on vibration-based structural damage detection, there has not been a study where the transition from traditional methods to ML and DL methods are described and discussed. This paper aims to fulfill this gap by presenting the highlights of the traditional methods and provide a comprehensive review of the most recent applications of ML and DL algorithms utilized for vibration-based structural damage detection in civil structures.

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    fulltext
  • 49.
    Avci, Onur
    et al.
    Iowa State University, USA.
    Alkhamis, Khalid
    Public Works Authority, Qatar.
    Abdeljaber, Osama
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Alsharo, Anas
    Qatar University, Qatar.
    Hussein, Mohammed
    Qatar University, Qatar.
    Operational modal analysis and finite element model updating of a 230 m tall tower2022In: Structure, E-ISSN 2352-0124, Vol. 37, p. 154-167Article in journal (Refereed)
    Abstract [en]

    Dynamic response levels are critical for tall and slender civil structures. Studying the dynamic behavior of large civil structures with finite element modeling techniques requires detailed and accurate modeling of structural geometry, material properties, member fixities, connection types, and accompanying assumptions. Still, the finite element model results are approximations that could be away from representing the actual structural behavior. Structures are dynamically tested at their operational conditions to validate the finite element model results. This paper presents Operational Modal Analysis (OMA) and finite element model updating of a tall structure located in the West Bay area of Doha (Qatar). The structure is a reinforced concrete building with shear wall cores situated towards the center of the building plan, which was constructed between 2012 and 2016. With 53 stories above the ground and two stories below ground, the 230 m (755 ft) tall building is being used for residential and hotel purposes. For the finite element model updating and calibration tasks presented in this paper, the authors intentionally introduced drastic model changes for the first two model updates so that the results from the first two attempts guide how to proceed with a more reasonable update for the third calibration of the finite element model. While this is a non-standard technique that represents a specific condition where the initial attempts on the finite element model are very crude approximations, it is a systematized demonstration of how to operate when the structural parameters are sparse or uncertain for modeling purposes. While in theory, the finite element model updates can always be fine-tuned in a way to further decrease the error between the measured and predicted OMA results, in this paper, the authors predominantly focused on the presentation of three finite element model updates to demonstrate the way they have improved the modal assurance criteria plots and lowered the average absolute errors by visiting two drastic and then one moderate finite element model updates. The material presented here in this paper is arguably the first published work on large-scale dynamic testing of a civil structure in the State of Qatar. © 2021 Institution of Structural Engineers

  • 50.
    Avci, Onur
    et al.
    Iowa State University, USA.
    Alkhamis, Khalid
    Qatar University, Qatar.
    Abdeljaber, Osama
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Hussein, Mohammed
    Qatar University, Qatar.
    Operational Modal Analysis and Finite Element Model Updating of a 53-Story Building2022In: Dynamics of Civil Structures, Volume 2 / [ed] Grimmelsman, K., Springer, 2022, Vol. 2, p. 83-91Conference paper (Refereed)
    Abstract [en]

    This paper presents Operational Modal Analysis (OMA) and Finite Element (FE) model updating of a tall structure. Located in the West Bay area of Doha (Qatar), the structure was constructed between 2012 and 2016. It is a reinforced concrete building with shear wall cores located towards the center of the building plan. With 53 stories above the ground and 2 stories below ground, the 230 m (755 ft) tall building is being used for residential and hotel purposes. The material presented here is arguably the first published work on large-scale dynamic testing of a civil structure in Qatar. The wireless sensors used for testing are state-of-the-art equipment that can capture very low frequencies, something that cannot be accomplished with most of the conventional accelerometers available in the market. © 2022, The Society for Experimental Mechanics, Inc.

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