| 1. |
- Abrahamsen, Rune, et al.
(författare)
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Dynamic Response of Tall Timber Buildings Under Service Load : The DynaTTB Research Program
- 2020
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Ingår i: EURODYN 2020, XI international conferece on structural dynamics. - : National Technical University of Athens. - 9786188507210 ; , s. 4900-4910
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Konferensbidrag (refereegranskat)abstract
- 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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| 2. |
- Abrahamsen, Rune, et al.
(författare)
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Dynamic response of tall timber buildings under service load : results from the dynattb research program
- 2023
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Ingår i: World Conference on Timber Engineering 2023 (WCTE 2023). - : Curran Associates, Inc.. - 9781713873297 ; , s. 2907-2914
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Konferensbidrag (refereegranskat)abstract
- 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.
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| 3. |
- Atashipour, Rasoul, 1983, et al.
(författare)
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Accuracy evaluation of gamma-method for deflection prediction of partial composite beams
- 2018
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Ingår i: WCTE 2018 - World Conference on Timber Engineering.
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Konferensbidrag (refereegranskat)abstract
- In this paper a precise model is established for deflection prediction of mechanically jointed beams with partial composite action. High accuracy of the proposed method is demonstrated through comparison with a comprehensive finite element (FE) modelling for a timber-concrete partial composite beam. Next, the obtained numerical results are compared with gamma-method, a well-known simplified solution for timber engineers according to the Eurocode 5. Validity and accuracy level of the gamma-method are investigated for various boundary conditions as well as different values of beam length-to-depth ratio, and discussed in details.
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| 4. |
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| 5. |
- Brandon, Daniel, et al.
(författare)
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High-Fire-Resistance Glulam Connections for Tall Timber Buildings
- 2019
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Tall timber buildings generally require fire resistance ratings of 90 minutes, 120 minutes or more. The vast majority of fire tested structural timber connections, however, did not reach a fire resistance that was relevant for these buildings. Commonly timber connections between glued laminated timber members comprise of exposed steel fasteners, such as bolts, screws, nails and dowels. However, it has previously been concluded that connections with exposed steel fasteners, generally do not achieve fire resistance ratings of 30 minutes and are, therefore, inadequate to be implemented in tall timber buildings without fire encapsulation. The research project presented in this report consists of four connection fire tests that are designed to achieve structural fire resistance ratings of 90 minutes, using different design strategies. This goal was achieved for all tested column-beam connections. A single test of a moment resisting connection did not lead to a fire resistance rating of 90 minutes, due to timber failure at the smallest cross-section after 86 minutes. The low temperature of the steel fasteners and the limited rotation of the connection, however, suggest that the connection would have been capable of achieving a 90 minutes fire resistance rating if larger beam cross-sections would be used.
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| 6. |
- Jockwer, Robert, 1984, et al.
(författare)
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FATIGUE RESISTANCE OF ADHESIVE BONDED CONNECTIONS WITH AND WITHOUT INTERNAL STEEL PLATES IN LARGE TIMBER STRUCTURES
- 2023
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Ingår i: World Conference on Timber Engineering (WCTE 2023). ; 4, s. 2118-2124
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Konferensbidrag (refereegranskat)abstract
- A modular wooden wind turbine tower has been developed by the Swedish company Modvion AB, where the prefabricated modular elements are connected by glued timber-timber edge joints and by hybrid timber joints with bonded-in perforated steel plates. The application of wood-based products in such a demanding application and highperformance structure is challenging and a variety of questions had to be solved to ensure a reliable performance. The fatigue performance of the adhesive bonded connections has been evaluated in a research project and is presented in this paper. Test specimens of the fatigue resistance of the adhesive and the bond line has been developed. Different stress ratios with alternating loads and high numbers of load cycles have been tested. The results of the tests are presented in this paper.
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| 7. |
- Johansson, Marie, 1973-, et al.
(författare)
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Tall timber buildings : a preliminary study of wind-induced vibrations of a 22-storey building
- 2016
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Ingår i: Proceedings of the World Conference on Timber Engineering (WCTE 2016). - Vienna : Vienna University of Technology. - 9783903039001
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- During the last years the interest in multi-storey timber buildings has increased and several medium-to-high-rise buildings with light-weight timber structures have been designed and built. Examples of such are the 8-storey building “Limnologen” in Växjö, Sweden, the 9-storey “Stadthouse” in London, UK and the 14-storey building “Treet” in Bergen, Norway. The structures are all light-weight and flexible timber structures which raise questions regarding wind induced vibrations. This paper will present a finite element-model of a 22 storey building with a glulam-CLT structure. The model will be used to study the effect of different structural properties such as damping, mass and stiffness on the peak acceleration and will be compared to the ISO 10137 vibration criteria for human comfort. The results show that it is crucial to take wind-induced vibrations into account in the design of tall timber buildings.
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| 8. |
- Johansson, Pernilla, et al.
(författare)
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Kvalitet hos byggnadsmaterial i cirkulära flöden
- 2017
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Denna rapport är en del av ett projekt med det övergripande målet att bygg- och rivningsavfall i högre utsträckning skall återvinnas eller återanvändas. Detta utan att kvaliteten på materialet, och därmed framtida byggnader, försämras.Syftet med projektet har varit att kartlägga och sammanställa de kunskaper och erfarenheter som finns kring de tekniska aspekterna vid cirkulära flöden av byggmaterial, med fokus på kvalitetsfrågor, att identifiera nya projekt som kan minska mängden bygg- och rivningsavfall som deponeras eller förbränns samt att skapa nya nätverk. Det finns spridd kunskap i byggbranschen om dessa frågor och dessutom finns en mängd forskningsresultat inom olika områden. I projektet har kunskaper och erfarenheter inom området samlats in genom litteraturstudier, workshops och seminarier, studiebesök och intervjuer.I första delen av rapporten diskuteras generella tekniska erfarenheter och utmaningar i olika delar av byggkedjan, medan utmaningar för specifika materialgrupper diskuteras i den andra delen av rapporten. Dessa materialgrupper är polymera material, planglas, stenull, glasull, gipsskivor, krossad betong samt trä och träbaserade material. I rapporten redovisas en enkätundersökning som genomförts av Optimera hos deras proffskunder, i syfte att samla in dessas erfarenheter och synpunkter kring hållbart byggande.Generellt kan vi konstatera att det finns stora utmaningar med att öka återvinningsgraden för rivnings- och ombyggnadsavfall. För installationsspill och byggavfall är de tekniska utmaningarna inte lika stora. Utmaningar och förutsättningar för ökad återvinning med bibehållen god kvalitet varierar mellan olika materialslag/produkter, typ av byggprojekt samt avsedd användning.I rapporten föreslås ett antal konkreta förslag på områden där arbetet kan drivas vidare. Dessa inkluderar bland annat förbättrad/utökad inventering inför rivning och ombyggnad, rutiner och metoder för provtagning, korrekt sortering, hantering och lagring för att få rätt och jämn kvalitet, ge möjlighet för separering av sammansatta material, logistikfrågor, produktionstekniska lösningar samt kvalitetssäkring. Resultaten visar också på vikten av utbildning, nätverk och mötesplatser samt att forskningsprojekt genomförs tvärvetenskapligt. Det finns goda möjligheter för ökad återvinning genom samarbete genom hela byggkedjan.
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| 9. |
- Källander, Björn, et al.
(författare)
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Effects of heat treatment of small clearwood samples on equilibrium moisture content and deformation
- 2007
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Ingår i: Quality Control for Wood and Wood Products. - : COST, European Cooperation in Science and Technology. ; , s. 63-68
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Konferensbidrag (refereegranskat)abstract
- High Temperature drying has by numerous studies been shown to affect strength properties as well as moisture properties of the wood treated. The present study aims at determining the effects of different heat treatments of small clearwood samples on material properties. Samples were treated in dry and moist air, saturated steam and water. Temperatures varied from 20 °C to 150 °C. Treatment periods varied from 6 h to 96 h. The results of the study indicate that the effects of treatment are dependent not only on the method of treatment and time, but also on the pre treatment of the samples such as ingoing moisture content.
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| 10. |
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