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Evaluation of Timber-Concrete Floor Performance under Occupant-Induced Vibrations using Continuous Monitoring

https://research.thinkwood.com/en/permalink/catalogue131
Year of Publication
2013
Topic
Acoustics and Vibration
Serviceability
Material
LVL (Laminated Veneer Lumber)
Timber-Concrete Composite
Application
Floors
Author
Omenzetter, Piotr
Kohli, Varun
Desgeorges, Yohann
Publisher
Scientific.net
Year of Publication
2013
Country of Publication
Switzerland
Format
Journal Article
Material
LVL (Laminated Veneer Lumber)
Timber-Concrete Composite
Application
Floors
Topic
Acoustics and Vibration
Serviceability
Keywords
Damping
Frequencies
Lightweight
Long Span
Office Buildings
Language
English
Research Status
Complete
Series
Key Engineering Materials
Summary
This paper describes the design of a system to monitor floor vibrations in an office building and an analysis of several months worth of collected data. Floors of modern office buildings are prone to occupant-induced vibrations. The contributing factors include long spans, slender and flexible designs, use of lightweight materials and low damping. As a result, resonant frequencies often fall in the range easily excited by normal footfall loading, creating potential serviceability problems due to undesirable levels of vibrations. This study investigates in-situ performance of a non-composite timber-concrete floor located in a recently constructed innovative multi-storey office building. The floor monitoring system consists of several displacement transducers to measure long-term deformations due to timber and concrete creep and three accelerometers to measure responses to walking forces, the latter being the focus of this paper. Floor response is typically complex and multimodal and the optimal accelerometer locations were decided with the help of the effective independence-driving point residue (EfI-DPR) technique. A novel approach to the EfI-DPR method proposed here uses a combinatorial search algorithm that increases the chances of obtaining the globally optimal solution. Several months worth of data collected by the monitoring system were analyzed using available industry guidelines, including ISO2631-1:1997(E), ISO10137:2007(E) and SCI Publication P354. This enabled the evaluation of the floor performance under real operating conditions.
Online Access
Free
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Experimental Evaluations of Material Damping in Timber Beams of Structural Dimensions

https://research.thinkwood.com/en/permalink/catalogue574
Year of Publication
2013
Topic
Acoustics and Vibration
Material
Glulam (Glue-Laminated Timber)
Application
Floors
Author
Labonnote, Nathalie
Rønnquist, Anders
Arne Malo, Kjell
Publisher
Springer Berlin Heidelberg
Year of Publication
2013
Country of Publication
Germany
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Floors
Topic
Acoustics and Vibration
Keywords
Damping
Flexural Vibrations
Language
English
Research Status
Complete
Series
Wood Science and Technology
Summary
Understanding the inherent damping mechanisms of floor vibrations has become a matter of increasing importance following the development of new composite floor layouts and increased span. The present study focuses on the evaluation of material damping in timber beam specimens with dimensions that are typical of common timber floor structures. Using the impact test method, 11 solid wood beams and 11 glulam beams made out of Norway Spruce (Picea abies) were subjected to flexural vibrations. The tests involved different spans and orientations. A total of 420 material damping evaluations were performed, and the results are presented as mean values for each configuration along with important statistical indicators to quantify their reliability. The consistency of the experimental method was validated with respect to repeatability and reproducibility. General trends found an increasing damping ratio for higher modes, shorter spans, and edgewise orientations. It is concluded from the results that material damping of timber beams of structural dimensions is governed by shear deformation, which can be expressed more conveniently with respect to the specific mode shape and its derivatives.
Online Access
Free
Resource Link
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Seismic Design of Timber Buildings with a Direct Displacement-Based Design Method

https://research.thinkwood.com/en/permalink/catalogue1904
Year of Publication
2013
Topic
Seismic
Design and Systems
Material
Light Frame (Lumber+Panels)
Application
Frames
Wood Building Systems
Author
Loss, Cristiano
Piazza, Maurizio
Zonta, Daniele
Editor
Cruz, Paulo J.S.
Publisher
CRC Press
Year of Publication
2013
Country of Publication
United States
Format
Book/Guide
Material
Light Frame (Lumber+Panels)
Application
Frames
Wood Building Systems
Topic
Seismic
Design and Systems
Keywords
Performance-Based Seismic Design
Direct Displacement-Based Design
Displacement
Damping
Language
English
Research Status
Complete
Series
Structures and Architecture: Concepts, Applications and Challenges
ISBN
978-1-4822-2461-0
Summary
Modern seismic design procedures are widely represented by the concept of Performance-Based Seismic Design (PBSD). Direct Displacement-Based Design (DDBD) procedure for PBSD of buildings is considered a very promising method which uses displacement as an input design parameter. The DDBD procedure first codified by Priestley requires an a priori estimate of the design displacement and the associated equivalent viscous damping of the structure, at design performance levels. In this paper, design parameters for the ultimate limit state have been developed for a common construction system for timber buildings. Such parameters are defined as a function of mechanical and geometrical connection configurations.
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Free
Resource Link
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