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6 records – page 1 of 1.

A study on beam-to-column moment-resisting timber connections under service load, comparing full-scale connection testing and mock-up frame assembly

https://research.thinkwood.com/en/permalink/catalogue3116
Year of Publication
2022
Topic
Connections
Application
Frames
Author
Vilguts, Aivars
Nesheim, Sveinung Ørjan
Stamatopoulos, Haris
Malo, Kjell Arne
Organization
Norwegian University of Science and Technology
Publisher
Springer
Year of Publication
2022
Format
Journal Article
Application
Frames
Topic
Connections
Keywords
Moment-resisting Connection
Semi-rigid Connection
Screwed-in Threaded Rods
Experimental Modal Analysis
Research Status
Complete
Series
European Journal of Wood and Wood Products
Summary
A new timber frame structural system consisting of continuous columns, prefabricated hollow box timber decks and beam-to-column moment-resisting connections is investigated. The hollow box timber decks allow long spans with competitive floor height and efficient material consumption. To achieve long spans, semi-rigid connections at the corners of deck elements are used to join the columns to the deck elements. In the present paper, experimental investigations of a semi-rigid moment-resisting connection and a mock-up frame assembly are presented. The semi-rigid connection consists of inclined screwed-in threaded rods and steel coupling parts, connected with friction bolts. Full-scale moment-resisting timber connections were tested under monotonic and cyclic loading to quantify rotational stiffness, energy dissipation and moment resistance. The mock-up frame assembly was tested under cyclic lateral loading and with experimental modal analysis. The lateral stiffness, energy dissipation, rotational stiffness of the connections and the eigen frequencies of the mock-up frame assembly were quantified based on the experimental tests in combination with a Finite Element model, i.e., the model was validated with experimental results from the rotational stiffness tests of the beam-to-column connections. Finally, the structural damping measured with experimental modal analysis was evaluated and compared with FE model using the material damping of timber parts and equivalent viscous damping of the moment-resisting connections.
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Moment-resisting beam-to-column timber connections with inclined threaded rods: Structural concept and analysis by use of the component method

https://research.thinkwood.com/en/permalink/catalogue3132
Year of Publication
2022
Topic
Connections
Author
Stamatopoulos, Haris
Malo, Kjell Arne
Vilguts, Aivars
Organization
Norwegian University of Science and Technology
Publisher
Elsevier
Year of Publication
2022
Format
Journal Article
Topic
Connections
Keywords
Moment-resisting Connection
Threaded Rod
Rotational Stiffness
Research Status
Complete
Series
Construction and Building Materials
Summary
The use of moment-resisting frames with semi-rigid connections as a lateral load-carrying system in timber buildings can reduce the need for bracing with diagonal members or walls and allow for more open and flexible architecture. The overall performance of moment-resisting frames depends largely on the properties of their connections. Screwed-in threaded rods with wood screw thread feature high axial stiffness and capacity and they may be used as fasteners in beam-to-column, moment-resisting timber connections. In the present paper, a structural concept for a beam–to-column, moment-resisting timber connection based on threaded rods is presented and explained. Analytical expressions for the estimation of the rotational stiffness and the forces in the rods were derived based on a component-method approach. The analytical predictions for stiffness were compared to experimental results from full scale tests and the agreement was good.
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Parametric analyses and feasibility study of moment-resisting timber frames under service load

https://research.thinkwood.com/en/permalink/catalogue3023
Year of Publication
2021
Topic
Mechanical Properties
Application
Frames
Author
Vilguts, Aivars
Stamatopoulos, Haris
Malo, Kjell Arne
Organization
Norwegian University of Science and Technology
Publisher
Elsevier
Year of Publication
2021
Format
Journal Article
Application
Frames
Topic
Mechanical Properties
Keywords
Moment-resisting Timber Frame
Serviceability
Acceleration
Lateral Displacement
Inter-Story Drift
Fundamental Eigen-frequency
Mode Shape
Research Status
Complete
Series
Engineering Structures
Summary
Over the last decades, the increasing urbanization and environmental challenges have created a demand for mid-rise and high-rise timber buildings in modern cities. The major challenge for mid-rise and high-rise timber buildings typically is the fulfillment of the serviceability requirements, especially limitation with respect to the wind-induced displacements and accelerations. The purpose of the present paper is to evaluate the feasibility and the limitations of moment-resisting timber frames under service load according to the present regulations. The parametric analyses investigate the effects of the rotational stiffness of beam-to-column and column-to-foundation connections, storey number and height, number and length of bays, column cross-section dimensions and spacing between frames on the overall serviceability performance of the frames. Elastic and modal analysis were carried out for a total of 17,800 planar moment-resisting timber frames with different parameters by use of Abaqus Finite Element (abbr. FE) software. Finally, the obtained results were used to derive simple expressions for the lateral displacement, maximum inter-story drift, fundamental eigen-frequency, mode shapes and acceleration.
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Effects of interconnections between timber floor elements: dynamic and static evaluations of structural scale tests

https://research.thinkwood.com/en/permalink/catalogue3113
Year of Publication
2021
Topic
Acoustics and Vibration
Material
Glulam (Glue-Laminated Timber)
Application
Floors
Author
Nesheim, Sveinung
Malo, Kjell Arne
Labonnote, Nathalie
Organization
Norwegian University of Science and Technology
Publisher
Springer
Year of Publication
2021
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Floors
Topic
Acoustics and Vibration
Keywords
Closed Hollow Section
Interconnection
Cyclic Loading Experiments
Point-load Deflection
Vibration Serviceability Performance
Research Status
Complete
Series
European Journal of Wood and Wood Products
Summary
Long-span timber floor elements increase the flexibility of a building and exhibit a significant market potential. Timber floor elements are endeavouring to fulfil this potential, but building projects employing long-span timber floors have encountered drawbacks. High costs and vibration performance are challenging, and the timber industry is under substantial pressure to find attractive solutions for building components with otherwise favourable environmental features. Only a few existing studies have investigated serviceability sensitivity in relation to timber floor connections. Interconnections are inexpensive to produce and install and may offer a resource-efficient approach to improving serviceability performance. In the present study, the effect of interconnections is investigated in a full-scale structural test. Floor elements positioned in different configurations have been tested for static and dynamic performance using different types of interconnections. The observed effects of interconnection types vary according to the configuration and direction of mode shapes, and are assessed in terms of shift in frequency, damping and resonant energy. These can all be utilised in combination with observed differences in the deflection parameter. The present work demonstrates that connections between timber elements have significant effects on timber floor serviceability and may offer interesting solutions to improve the vibration performance of long-span timber floors.
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Stress-laminated timber decks in bridges: Friction between lamellas, butt joints and pre-stressing system

https://research.thinkwood.com/en/permalink/catalogue2891
Year of Publication
2020
Application
Decking
Author
Massaro, Francesco Mirko
Malo, Kjell Arne
Organization
Norwegian University of Science and Technology
Publisher
Elsevier
Year of Publication
2020
Format
Journal Article
Application
Decking
Keywords
Stress Laminated
Timber Bridges
Butt-Joint
Stiffness
Friction
Pre-Stress
Research Status
Complete
Series
Engineering Structures
Summary
Stress-laminated timber (SLT) decks in bridges are popular structural systems in bridge engineering. SLT decks are made from parallel timber beams placed side by side and pre-stressed together by means of steel rods. SLT decks can be in any length by just using displaced butt joints. The paper presents results from friction experiments performed in both grain and transverse direction with different levels of pre-stress. Numerical simulations of these experiments in addition to comparisons to full-scale experiments of SLT decks presented in literature verified the numerical model approach. Furthermore, several alternative SLT deck configurations with different amounts of butt joints and pre-stressing rod locations were modelled to study their influence on the structural properties of SLT decks. Finally, some recommendations on design of SLT bridge decks are given.
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Withdrawal of Pairs of Threaded Rods with Small Edge Distances and Spacings

https://research.thinkwood.com/en/permalink/catalogue1395
Year of Publication
2017
Topic
Mechanical Properties
Connections
Material
Glulam (Glue-Laminated Timber)
Author
Stamatopoulos, Haris
Malo, Kjell Arne
Publisher
Springer Berlin Heidelberg
Year of Publication
2017
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Topic
Mechanical Properties
Connections
Keywords
Threaded Rods
Withdrawal Capacity
Stiffness
Research Status
Complete
Series
European Journal of Wood and Wood Products
Summary
An experimental investigation on withdrawal of pairs of screwed-in threaded rods embedded in glued-laminated timber elements is presented in this paper. Specimens with varying angles between the rod axis and the grain direction (a = 15°, 30°, 60°, 90°) and 2 different configurations with respect to edge distances and spacings were tested. The diameter and the embedment length of the rods were 20 and 450 mm, respectively. The threaded rods were embedded in a row perpendicular to the plain of the grain. The edge distances and spacings were smaller than the minimum requirements according to Eurocode 5. The withdrawal capacity of pairs of rods was compared to the withdrawal capacity of single rods and the effective number, n ef , was found to be in the range 1.72–1.94, despite the small edge distances and spacings. Based on the experimental results obtained, a simple approximating expression was derived for n ef . An analytical model based on Volkersen theory with an idealized bi-linear constitutive relationship was used to estimate the withdrawal capacity and stiffness. The analytical estimations were in good agreement with the experimental results. Finally, the withdrawal stiffness was estimated by use of finite element simulations. The numerical estimations for the withdrawal stiffness were also in good agreement with the experimental results.
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6 records – page 1 of 1.