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Publications (10 of 18) Show all publications
Linderholt, A., Landel, P. & Johansson, M. (2024). Forced Response Measurements on a Seven-Story Timber Building. In: SEM 2023: Dynamics of Civil Structures. Paper presented at Society for Experimental Mechanics Annual Conference and Exposition (pp. 1-4). Springer
Open this publication in new window or tab >>Forced Response Measurements on a Seven-Story Timber Building
2024 (English)In: SEM 2023: Dynamics of Civil Structures, Springer , 2024, p. 1-4Conference paper, Published paper (Refereed)
Abstract [en]

Within the project Dyna-TTB, vibrational tests have been conducted on eight high-rise timber buildings, in Europe. A main objective of the project is to gain knowledge about damping in timber buildings to assist in predicting the accelerations, at the top of a building, due to wind-induced vibrations. One of the buildings is Eken (the oak) in Mariestad in Sweden. That building is seven stories tall, thus questionable as a tall timber building, yet an interesting test object. The building structure is made up of glue laminated timber beams and columns stabilized with glulam trusses. Forced vibration were conducted on Eken with the aim to estimate the building’s dynamic properties from test data. Estimates of the eigenfrequencies, mode shapes, and their scalings are useful both in the calculations of wind-induced vibrations and to calibrate numerical models. However, the most important outcome is estimates of the modal damping values. The damping impacts the acceleration and thus the serviceability of the building, and at the same time, it is very hard to model damping. So, during the design phase, one must rely on previous test data (of which very few exist for taller timber buildings) and rule of thumbs. It is therefore important to gain knowledge about the damping for timber buildings in order to enable good designs of future and taller timber buildings.

Place, publisher, year, edition, pages
Springer, 2024
Series
Conference Proceedings of the Society for Experimental Mechanics Series, ISSN 21915644
Keywords
Damping; Structural dynamics; Timber; Vibrations (mechanical); Wooden buildings; Dyna-TTB; Forced response; Forced vibration; Response measurement; Stepped sine excitation; Tall timber building; Test data; Timber buildings; Wind induced motions; Wind induced vibrations; Acceleration
National Category
Building Technologies
Identifiers
urn:nbn:se:ri:diva-68096 (URN)10.1007/978-3-031-36663-5_1 (DOI)2-s2.0-85175995864 (Scopus ID)9783031366628 (ISBN)
Conference
Society for Experimental Mechanics Annual Conference and Exposition
Note

The research leading to these results has received funding from the ForestValue Research Programme which is a transnational research, development and innovation programme jointly funded by national funding organizations within the framework of the ERA-NET Cofund “ForestValue – Innovating forest-based bioeconomy.” The authors also express gratitude to the building owner Mariehus for allowing us to perform the measurements.

Available from: 2023-12-07 Created: 2023-12-07 Last updated: 2024-04-10Bibliographically approved
Jockwer, R., Landel, P., Norbäck, V., Ziethén, R., Dölerud, E., Naveda, L. A. & Åkerström, C.-J. (2023). FATIGUE RESISTANCE OF ADHESIVE BONDED CONNECTIONS WITH AND WITHOUT INTERNAL STEEL PLATES IN LARGE TIMBER STRUCTURES. In: World Conference on Timber Engineering (WCTE 2023): . Paper presented at World Conference on Timber Engineering (WCTE 2023), Oslo, Norway (pp. 2118-2124).
Open this publication in new window or tab >>FATIGUE RESISTANCE OF ADHESIVE BONDED CONNECTIONS WITH AND WITHOUT INTERNAL STEEL PLATES IN LARGE TIMBER STRUCTURES
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2023 (English)In: World Conference on Timber Engineering (WCTE 2023), 2023, p. 2118-2124Conference paper, Published paper (Refereed)
Abstract [en]

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.

Keywords
Bonded-in steel plates, adhesive testing, butt-joints, fatigue strength
National Category
Building Technologies
Identifiers
urn:nbn:se:ri:diva-66209 (URN)10.52202/069179-0281 (DOI)
Conference
World Conference on Timber Engineering (WCTE 2023), Oslo, Norway
Note

The project “Strong Enough: Testing technology for environmentally friendly and cost-efficient wind turbine towers” with project number 2020-014383 described in this paper was funded by Energimyndigheten, the Swedish Energy Agency.

Available from: 2023-09-20 Created: 2023-09-20 Last updated: 2024-05-17Bibliographically approved
Linderholt, A., Landel, P. & Johansson, M. (2023). FORCED RESPONSE MEASUREMENTS ON A SEVEN STOREY TIMBER BUILDING IN SWEDEN. In: : . Paper presented at World Conference on Timber Engineering. 2023. Oslo, Norway..
Open this publication in new window or tab >>FORCED RESPONSE MEASUREMENTS ON A SEVEN STOREY TIMBER BUILDING IN SWEDEN
2023 (English)Conference paper, Published paper (Refereed)
Abstract [en]

Forced vibration tests have been conducted on the seven-storey timber building Eken in Mariestad in Sweden. The main objective is to estimate the building’s dynamic properties from test data. The eigenfrequencies, mode shapes and their scaling are useful to calibrate numerical models. However, the most important outcomes are the estimates of the modal damping values. The reason is that the damping impacts the acceleration, and thus the serviceability of the building, and at the same time, it is very hard to model damping. So, during the design phase, one must rely on previous test data (of which very few exist for taller timber buildings) or rule of thumbs. It is therefore important to gain knowledge about the damping for timber buildings in order to enable good designs of future and taller timber buildings. The test data shows that the modal damping is roughly equal to 2% of the critical viscous ones for the eigenmodes extracted. The test campaign on Eken is made as a part of the project Dyna-TTB in which vibrational tests have been performed on eight high-rise timber buildings, in Europe, of which Eken is one.

Keywords
Forced vibration, timber building, damping, eigenmodes, experimental modal analysis, Dyna-TTB
National Category
Building Technologies
Identifiers
urn:nbn:se:ri:diva-64166 (URN)
Conference
World Conference on Timber Engineering. 2023. Oslo, Norway.
Available from: 2023-03-06 Created: 2023-03-06 Last updated: 2023-06-26Bibliographically approved
Norbäck, V., Landel, P., Dölerud, E. & Wickström, A. (2023). ON-SITE GLUING AND WEATHER EFFECTS ON TALL WOODEN WINDTURBINE TOWERS. In: : . Paper presented at WCTE World Conference on Timber Engineering. 2023. Oslo, Norway..
Open this publication in new window or tab >>ON-SITE GLUING AND WEATHER EFFECTS ON TALL WOODEN WINDTURBINE TOWERS
2023 (English)Conference paper, Published paper (Refereed)
Abstract [en]

Modvion develops modular wind turbine towers made of wood. The application requires strong and stiff connections and to achieve the desired performance, a hybrid connection with perforated steel plates slotted into LVL modules is used. The parts will be glued together on site, using a polyurethane adhesive (PUR), providing high strength and stiffness to the connection. This paper presents a preliminary screening on how temperature and relative humidity of the surrounding air during assembly and curing will influence the strength of the bond glued on-site. Static tests were performed on the hybrid connections which were glued and cured in different climates. Tests were also performed at different hardening times to evaluate strength growth in the studied climates. The test results show that at cold temperatures of 9 °C to 12 °C there is a breakpoint where the rate of strength growth starts to decline. The experiments show also that the relative humidity may influence the final strength of the bond. However, the low number of tested specimens brings uncertainties to this observation. High temperatures up to 27 ºC and dry climates down to 20% RH did not impact the strength of the tested hybrid connections.

Keywords
Hybrid connection, Polyurethane adhesive, On-site gluing, LVL, Glued-in plates connection type
National Category
Construction Management
Identifiers
urn:nbn:se:ri:diva-65516 (URN)
Conference
WCTE World Conference on Timber Engineering. 2023. Oslo, Norway.
Note

This project is funded by Energimyndigheten (SwedishEnergy Agency) through SWPTC (Swedish Wind PowerTechnology Centre at Chalmers University). SWPTCaims to develop the Swedish wind turbine industry andpromote its expansion.

Available from: 2023-06-16 Created: 2023-06-16 Last updated: 2023-11-21Bibliographically approved
Linderholt, A., Johansson, M. & Landel, P. (2023). Tall Timber Buildings Subjected to Wind Loads - Full Scale Experimental Dynamics. In: Wood Building Nordic: . Paper presented at Wood Building Nordic.
Open this publication in new window or tab >>Tall Timber Buildings Subjected to Wind Loads - Full Scale Experimental Dynamics
2023 (English)In: Wood Building Nordic, 2023Conference paper, Published paper (Other academic)
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. a vibration serviceability problem. The DynaTTB project, funded by the ForestValue research program, mixed on-site measurements on timber buildings, for identification of the structural system, with numerical modelling of timber structures. The goal was 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 project.    The paper also presents measurements using forced vibration conducted on the seven-storey timber building Eken in Mariestad in Sweden. The main objective is to estimate the building’s dynamic properties from test data. The eigenfrequencies, mode shapes and their scalings are useful to calibrate numerical models. However, the most important outcomes are the estimates of the modal damping values. The test data shows that the modal damping is roughly equal to 2% of the critical viscous ones for the eigenmodes extracted.

Keywords
Dynamics, wind load, forced response, Dyna-TTB
National Category
Building Technologies
Identifiers
urn:nbn:se:ri:diva-67494 (URN)
Conference
Wood Building Nordic
Funder
Vinnova
Available from: 2023-10-04 Created: 2023-10-04 Last updated: 2023-10-05Bibliographically approved
Landel, P. & Linderholt, A. (2022). Reduced and test-data correlated FE-models of a large timber truss with dowel-type connections aimed for dynamic analyses at serviceability level. Engineering structures, 260, Article ID 114208.
Open this publication in new window or tab >>Reduced and test-data correlated FE-models of a large timber truss with dowel-type connections aimed for dynamic analyses at serviceability level
2022 (English)In: Engineering structures, ISSN 0141-0296, E-ISSN 1873-7323, Vol. 260, article id 114208Article in journal (Refereed) Published
Abstract [en]

The rise of wood buildings in the skylines of cities forces structural dynamic and timber experts to team up to solve one of the new civil-engineering challenges, namely comfort at the higher levels, in light weight buildings, with respect to wind-induced vibrations. Large laminated timber structures with mechanical joints are exposed to turbulent horizontal excitation with most of the wind energy blowing around the lowest resonance frequencies of 50 to 150 m tall buildings. Good knowledge of the spatial distribution of mass, stiffness and damping is needed to predict and mitigate the sway in lighter, flexible buildings. This paper presents vibration tests and reductions of a detailed FE-model of a truss with dowel-type connections leading to models that will be useful for structural engineers. The models also enable further investigations about the parameters of the slotted-in steel plates and dowels connections governing the dynamical response of timber trusses. © 2022 The Author(s)

Place, publisher, year, edition, pages
Elsevier Ltd, 2022
Keywords
Connection stiffness, Dowel-type fastener, Dynamic properties, FE-model reduction, Glulam truss, Mechanical connection, Modal testing, Serviceability, Tall timber structure, Wind-induced vibration, Finite element method, Stiffness, Structural dynamics, Tall buildings, Timber, Trusses, Vibration analysis, Wind power, Dynamics properties, FE model, Mechanical connections, Modal testings, Model reduction, Timber structures, Wind induced vibrations, Modal analysis
National Category
Building Technologies
Identifiers
urn:nbn:se:ri:diva-59220 (URN)10.1016/j.engstruct.2022.114208 (DOI)2-s2.0-85128704705 (Scopus ID)
Note

Funding details: VINNOVA; Funding details: Svenska Forskningsrådet Formas; Funding details: Energimyndigheten; Funding text 1: This research received funding from the ForestValue Research Program, which is a transnational research, development and innovation program jointly funded by national funding organizations within the framework of the ERA-NET Cofund ‘ForestValue – Innovating forest-based bioeconomy. The Swedish part of the Project Dyna-TTB is supported under grant No 2018-04976 by Swedish Governmental Agency for Innovation Systems (Vinnova), The Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning (FORMAS) and Swedish Energy Agency (SWEA). Moelven Töreboda AB is deeply thanked for the opportunity to do this research at their factory and for their kind assistance in handling the glulam truss.

Available from: 2022-06-10 Created: 2022-06-10 Last updated: 2023-06-07Bibliographically approved
Landel, P., Johansson, M. & Linderholt, A. (2021). Comparative study of wind-induced accelerations in tall timber buildings according to four methods. In: World Conference on Timber Engineering 2021, WCTE 2021: . Paper presented at World Conference on Timber Engineering 2021, WCTE 2021, 9 August 2021 through 12 August 2021. World Conference on Timber Engineering (WCTE)
Open this publication in new window or tab >>Comparative study of wind-induced accelerations in tall timber buildings according to four methods
2021 (English)In: World Conference on Timber Engineering 2021, WCTE 2021, World Conference on Timber Engineering (WCTE) , 2021Conference paper, Published paper (Refereed)
Abstract [en]

The height and the market share of multi-story timber buildings are both rising. During the last two decades, the Architectural and Engineering Construction industry has developed new reliable solutions to provide strength, structural integrity, fire safety and robustness for timber structures used in the mid- and high-rise sectors. According to long-time survey and lab experiments, motion sickness and sopite syndrome are the main adverse effects on the occupants of a wind sensitive building. For tall timber buildings, wind-induced vibrations seem to be a new critical design aspect at much lower heights than for traditional steel-concrete buildings. To guarantee good comfort, the horizontal accelerations at the top of tall timber buildings must be limited. Two methods in the Eurocode for wind actions (EN1991-1-4), procedure 1 in Annex B (EC-B) and procedure 2 in Annex C (EC-C), provide formulas to estimate the along-wind accelerations. The Swedish code advises to follow a method specified in the National Annex to the Eurocode (EKS) and the American ASCE 7-2016 recommend another method. This study gives an overview on the background of the different methods for the evaluation of along-wind accelerations for buildings. Estimated accelerations of several tall timber buildings evaluated according to the different methods are compared and discussed. The scatter of the accelerations estimated with different codes is big and increases the design uncertainty of wind induced response at the top of tall timber buildings

Place, publisher, year, edition, pages
World Conference on Timber Engineering (WCTE), 2021
Keywords
Along-wind peak acceleration, Building code, Comfort, Dynamical response, Serviceability, Tall timber buildings, Wind loads, Wind-induced vibrations, Accident prevention, Codes (standards), Competition, Construction industry, Housing, Timber, Uncertainty analysis, Vibrations (mechanical), Comparatives studies, Eurocodes, Peak acceleration, Wind induced vibrations, Wind load, Wind-induced acceleration, Acceleration
National Category
Building Technologies
Identifiers
urn:nbn:se:ri:diva-57965 (URN)2-s2.0-85120725506 (Scopus ID)
Conference
World Conference on Timber Engineering 2021, WCTE 2021, 9 August 2021 through 12 August 2021
Note

Funding text 1: The research leading to these results has received funding from the ForestValue Research Programme which is a transnational research, development and innovation programme jointly funded by national funding organisations within the framework of the ERA-NET Cofund ‘ForestValue – Innovating forest-based bioeconomy.

Available from: 2022-01-12 Created: 2022-01-12 Last updated: 2023-06-07Bibliographically approved
Abrahamsen, R., Bjertnaes, M. A., Bouillot, J., Brank, B., Cabaton, L., Crocetti, R., . . . Tulebekova, S. (2020). Dynamic Response of Tall Timber Buildings Under Service Load: The DynaTTB Research Program. In: : . Paper presented at EURODYN 2020, XI International Conference on Structural Dynamics, Athens, Greece, 22–24 June 2020.
Open this publication in new window or tab >>Dynamic Response of Tall Timber Buildings Under Service Load: The DynaTTB Research Program
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2020 (English)Conference paper, Published 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.

Keywords
timber building, wind load, discomfort, modelling, damping, full scale
National Category
Civil Engineering
Identifiers
urn:nbn:se:ri:diva-50886 (URN)
Conference
EURODYN 2020, XI International Conference on Structural Dynamics, Athens, Greece, 22–24 June 2020
Available from: 2020-11-30 Created: 2020-11-30 Last updated: 2023-06-07Bibliographically approved
Landel, P. & Linderholt, A. (2020). Validation of a structural model of a large timber truss with slotted-in steel plates and dowels. In: Proceedings of the International Conference on Structural Dynamic , EURODYN: . Paper presented at 11th International Conference on Structural Dynamics, EURODYN 2020, 23 November 2020 through 26 November 2020 (pp. 4349-4357). European Association for Structural Dynamics
Open this publication in new window or tab >>Validation of a structural model of a large timber truss with slotted-in steel plates and dowels
2020 (English)In: Proceedings of the International Conference on Structural Dynamic , EURODYN, European Association for Structural Dynamics , 2020, p. 4349-4357Conference paper, Published paper (Refereed)
Abstract [en]

The dynamic response to time varying loads, e.g. wind loads or earthquakes, is in many cases decisive when designing a tall timber building. The structural parameters governing the dynamic behaviour are the mass, the damping and the stiffness. The last two parameters are not well-known at serviceability levels for timber structures in general and for timber connections specifically. Results from forced vibration tests on single components and on a full-scale truss for an eight-storey residential building have been analyzed. In parallel, a detailed Finite Element (FE) model of a large Glulam truss with slotted-in steel plates and dowels connections has been developed and simulations have been made. The damping caused by the structural components, the embedment of fasteners and friction of mating surfaces of components in the selected connection types is quantified experimentally. The materials' stiffness values in the model were evaluated. The results from this study bring knowledge on the structural dynamic properties of large timber structures with mechanical connections and will facilitate the performance prediction of new tall timber buildings for better comfort at higher levels in environmentally friendly expansions of our cities. 

Place, publisher, year, edition, pages
European Association for Structural Dynamics, 2020
Keywords
Damping, Experimental and numerical modal analysis, Glued-Laminated-Timber (Glulam) truss, Induced vibrations in timber structure, Slotted-in steel plates and dowels connection, Stiffness, Dynamic response, Fasteners, Structural dynamics, Timber, Trusses, Vibration analysis, Wooden buildings, Forced vibration tests, Mechanical connections, Performance prediction, Residential building, Serviceability levels, Structural component, Structural dynamic properties, Structural parameter, Plates (structural components)
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-51906 (URN)10.47964/1120.9356.18990 (DOI)2-s2.0-85098691632 (Scopus ID)9786188507210 (ISBN)
Conference
11th International Conference on Structural Dynamics, EURODYN 2020, 23 November 2020 through 26 November 2020
Note

Funding details: 942-2015-115; Funding text 1: We would like to express our thanks to Moelven T?reboda AB for the opportunity and the help to measure in their factory while manufacturing had to run with a tight schedule for the building project. The authors gratefully acknowledge the funding for the project ?Tall Timber Buildings - concept studies? from Formas the Swedish Research Council for Environment, Agricultural Science and Spatial Planning [Dnr: 942-2015-115].

Available from: 2021-01-28 Created: 2021-01-28 Last updated: 2023-06-07Bibliographically approved
Brandon, D., Landel, P., Ziethén, R., Allbrektsson, J. & Just, A. (2019). High-Fire-Resistance Glulam Connections for Tall Timber Buildings.
Open this publication in new window or tab >>High-Fire-Resistance Glulam Connections for Tall Timber Buildings
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2019 (English)Report (Other academic)
Abstract [en]

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.

Series
RISE Rapport ; 2019:26
National Category
Building Technologies
Identifiers
urn:nbn:se:ri:diva-59183 (URN)978-91-88907-52-3 (ISBN)
Available from: 2022-05-09 Created: 2022-05-09 Last updated: 2024-05-17Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-8970-7114

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