| 1. |
- 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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| 2. |
- Ahn, Namhyuck, et al.
(författare)
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Envisioning mass timber buildings for circularity : life cycle assessment of a mass timber building with different end-of-life (EoL) and post-EoL options
- 2023
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Ingår i: WCTE 2023-World Conference on Timber Engineering. - : Curran Associates, Inc.. - 9781713873297 ; , s. 3581-3587
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Konferensbidrag (refereegranskat)abstract
- The foundation of the circular economy in the construction sector is based on implementing the deconstruction and reuse of buildings, providing the potential for a closed loop of building materials within the supply chain. Mass timber buildings using large, prefabricated elements and certain types of reversible mechanical connections are deemed to have great potential for post end-of-life (EoL) options, including recycling and reuse. To fully characterize the benefits of reusing post-use mass timber in new construction projects, it is crucial to conceptualize a ‘grave-to-gate’ approach, including the complete analysis of post-EoL activities and impacts on the material’s second life. In this study, a comparative life cycle assessment (LCA) including different EoL and post-EoL options for a virtual reference mid-rise mass timber building in the Pacific Northwest (PNW) of the United States was conducted. Among four different deconstruction and reuse scenarios examined in this study, a case of nearly complete reconstruction of a mass timber building for the second service life used as an idealized reference established an optimistic limit for reduction of global warming potential (GWP) by 13-41% compared to the ‘demolish and landfill’ decision, depending on the scenario. The demolition and landfill scenario had the lowest net impact since the GWMP calculations accounted for the carbon storage benefits in the landfill in addition to the carbon stored in the building.
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| 3. |
- Alen, Malagic, et al.
(författare)
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Reinforced notched cross-laminated timber plates : Load-bearing capacity and methodology for predicting the force in reinforcement
- 2023
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Ingår i: Proceedings from the 13th World Conference on Timber Engineering (2023). - 9781713873273 - 9781713873297 ; , s. 2442-2453
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Konferensbidrag (refereegranskat)abstract
- This paper deals with the estimation of the design force in self-tapping screws used as a reinforcement ofnotched cross laminated timber plates (CLT). With the reinforcement, apart from an increased load-carrying capacity, amore ductile behaviour of this detail can be achieved. An analytical model based on the Timoshenko Beam Theory wasdeveloped, enabling the estimation of the axial force in the reinforcement. A parametric numerical analysis was conductedto verify the model and to provide possible ways for the calibration. The results show a good matching of the model withthe numerical results. The load-bearing capacity is analysed using a simple fracture mechanics model taking intoconsideration the effect of the reinforcement to correctly depict the increase in performance. Theoretical and numericalresults are compared with experimental findings and show acceptable correlations encouraging a further development anda subsequent implementation in EN 1995-1-1.
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| 4. |
- Aquino, Caroline, et al.
(författare)
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Influence of Test Methods on the Parallel to Grain Embedment Strength and Foundation Modulus Characterization
- 2023
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Ingår i: Proceedings from the 13th World Conference on Timber Engineering 2023. - Oslo, Norway : World Conference on Timber Engineering (WCTE). - 9781713873297 - 9781713873273 ; , s. 3667-3674
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Konferensbidrag (refereegranskat)abstract
- 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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| 5. |
- Azinović, Boris, et al.
(författare)
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INNOCROSSLAM : Adding knowledge towards increased use of cross laminated timber (CLT)
- 2023
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Ingår i: Proceedings from the 13th World Conference on Timber Engineering (2023). - 9781713873297 - 9781713873273 ; , s. 2432-2441
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Konferensbidrag (refereegranskat)abstract
- The research project Innovative Solutions for Cross Laminated Timber Structures (InnoCrossLam) wasrecently finished. The project aimed at increasing the competitiveness of CLT as a versatile engineered product, byincreasing its predictability in demanding design situations not covered by the guidelines of today, or standards and codesforeseeable in the near future (e.g., second generation of European design standards). This paper summarises the mainproject findings in the context of innovative CLT structures, such as: i. contemporary design approaches ii. the use of(non)linear FE modelling iii. experimental investigation of complex details for CLT structures, iv. investigation ofmultifunctional CLT. In this paper, the motivation behind the research topics within the project InnoCrossLam isexplained and backed-up by exemplary results and discussion on future work.
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| 6. |
- Dagenais, Christian, et al.
(författare)
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Fire Safe Use of Wood in Buildings : Global Design Guide
- 2023
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Ingår i: World Conference on Timber Engineering. - : World Conference on Timber Engineering (WCTE). - 9781713873297 ; , s. 4627-4635
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Konferensbidrag (refereegranskat)abstract
- Building codes around the globe dictate the design and construction of buildings. For most buildings, designers will follow prescriptive code provisions to demonstrate code compliance. However, some buidling codes allow the use of performance-based design to demonstrate code compliance. Performance-based design is usually more complex but allows for greater flexibility in the use of materials and systems. Regardless of the code compliance methods, the combustibility of timber structures and wood products needs to be well understood and properly accounted for in building designs. This paper describes the develpment of a new international guidance document on fire safety in timber building within the Fire Safe Use of Wood (FSUW) network, written by 13 lead authors assisted by more than 20 experts in over a dozen different countries.
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| 7. |
- Gikonyo, Joan, et al.
(författare)
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Numerical Modelling of a Cross-Laminated Timber-to-Concrete Dowel-Type Connection Using the Beam-on-Foundation Model
- 2023
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Ingår i: Proceedings from the 13th World Conference on Timber Engineering 2023. - Oslo, Norway : World Conference on Timber Engineering (WCTE). - 9781713873297 - 9781713873273 ; , s. 3101-3110
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Konferensbidrag (refereegranskat)abstract
- The aim of the research presented herein is to investigate the mechanical behaviour of cross-laminated timber (CLT)-to-concrete dowel-type connections. For reliable timber-concrete-composite structures, mechanical connections between the two construction materials are of great importance. This paper investigates the nonlinear load-displacement behaviour, giving access to the stiffness and strength, as well as ductile connection failure modes, of a CLT-to-concrete composite connection using a Beam-on-Foundation (BoF) model. The latter is a numerical model that utilizes non-linear springs for the interaction between the fastener and the surrounding CLT and concrete materials. The influence of: (i) fastener diameter, (ii) initial slip, (iii) concrete embedment properties, and (iv) axial fastener resistance due to friction, on the connection shear capacity and slip modulus, was investigated in a parameter study. The nonlinear load-displacement response, connection stiffness and strength predicted by the BoF model were moreover compared to laboratory tests and the European Yield Model (EYM), which supported the validity of the BoF model. In addition, it was shown that the BoF model could enhance the prediction of the slip modulus compared to the current design regulations in Eurocode 5.
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| 8. |
- Huber, Johannes Albert Josef, 1989-, et al.
(författare)
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Evaluation of Models Of Fibre Orientation in Sawn Timber Using Synchronised Computed Tomography and Optical Scanning Data
- 2023
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Ingår i: World Conference on Timber Engineering (WCTE 2023). - : World Conference on Timber Engineering 2023 (WCTE 2023). ; , s. 421-427, s. 421-427
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Konferensbidrag (refereegranskat)abstract
- Optical scanning and X-ray computed tomography (CT) scanning of sawn timber provide a large number of data points, on which data-driven numerical models can be based for simulations. These models require information about the deviations of the fibre orientations in the vicinity of knots. Optical scanning can be used to measure the in-plane fibre orientation on wood surfaces. In CT scans of sawn timber, the fibre orientation around knots can be estimated using a new fibre reconstruction algorithm based on the density gradient. The goal of this paper is to compare and synchronise optical and CT scanning data of sawn timber and then use the combined data set to evaluate fibre orientations derived from both representations. The material comprised sawn timber of Norway spruce, in which alignment holes were drilled. The timber was scanned in an industrial CT scanner and subsequently in an industrial optical scanner where scanning was repeated after successive planing of the sawn timber surface. The results show that a projective mapping in combination with a spline interpolation are required for synchronisation, and that the in-plane fibre orientations calculated from the density gradients are qualitatively similar to the orientations derived from the optical data.
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| 9. |
- Kržan, Meta, et al.
(författare)
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Protocols and Results Analysis Methods for Cyclic Tests of Timber Joints : A Discussion
- 2023
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Ingår i: Proceedings from the 13th World Conference on Timber Engineering 2023. - Oslo, Norway : World Conference on Timber Engineering (WCTE). - 9781713873297 - 9781713873273 ; , s. 3685-3693
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Konferensbidrag (refereegranskat)abstract
- Current testing procedures for cyclic loading are quite flexible and the influence of fundamental testing parameters on the obtained load-deformation behaviour is often questioned (number and amplitude of the loading cycles, loading rate, number of specimens, etc.). On the other hand, different methods for data assessment have been used for the definition of stiffness, ductility, strength and stiffness degradation, as well as parameters for analytical and numerical models. However, reliable and well-established assessment methods are required, to support the safe and economic design of timber joints. Fundamental parameters for seismic design, such as ductility or strength degradation, cannot depend on the testing protocol and method for assessment of the data results. In this context, it is important to compare the most representative loading protocols, and assessment methods of the test results, through detailed analysis and discussion. Different types of timber connections, made of distinct materials and tested in different laboratories, must be evaluated. This work will be developed within the RILEM TC TPT, and this paper represents a first contribution to a needed discussion about the testing protocols to evaluate timber connections. In the end, it is expected to present proposals on how to characterize better the properties and behaviour of timber connections under cyclic loading and how to fully utilize their potential in design.
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| 10. |
- Larsson, Carl, et al.
(författare)
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A Survey of the design of timber-concrete hybrid buildings in Sweden
- 2023
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Ingår i: World Conference on Timber Engineering (WCTE 2023), 19-22 June, Oslo. - Oslo : World Conference on Timber Engineering (WCTE). - 9781713873297 ; , s. 4338-4344
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Konferensbidrag (refereegranskat)abstract
- There is a growing interest in timber buildings in Sweden and increased availability of Glulam (GLT) andparticularly Cross Laminated Timber (CLT) products. Timber buildings, though, often have difficulties in fulfilling theperformance requirements of a building project. The use of concrete elements in addition to timber elements in the load-bearing structure is a widespread solution, introducing timber-concrete hybrid buildings. The study presents responsesfrom interviews regarding ten different timber-concrete hybrid building projects in Sweden with a load-bearing structureabove the foundation level in both timber and concrete. Four main types of timber-concrete hybrids were found: a CLTstructure on top of a concrete structure, a post-beam system in GLT with CLT slabs and concrete walls, a post-beamsystem in GLT with concrete hollow core slabs, and a timber structure with some slabs in concrete. The results show thattimber-concrete hybrid buildings are flexible and suitable for various construction types. The reasons for using concretein timber construction were primarily to increase self-weight, obtain longer span lengths, and overcome shear wallcapacity issues. There is still a lack of competence in the design of structural timber projects, and at most, five differentstructural designers were involved in the load-bearing design of a single building. This highlights issues regarding projectmanagement of the design process within timber-concrete hybrid buildings
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