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7 records – page 1 of 1.

Advanced Wood-Based Solutions for Mid-Rise and High-Rise Construction: In-Situ Testing of the Brock Commons 18-Storey Building for Vibration and Acoustic performances

https://research.thinkwood.com/en/permalink/catalogue1180
Year of Publication
2018
Topic
Acoustics and Vibration
Material
CLT (Cross-Laminated Timber)
Application
Hybrid Building Systems
Author
Hu, Lin
Cuerrier-Auclair, Samuel
Organization
FPInnovations
Year of Publication
2018
Format
Report
Material
CLT (Cross-Laminated Timber)
Application
Hybrid Building Systems
Topic
Acoustics and Vibration
Keywords
Non-Destructive Testing
Vibration Performance
Natural Frequencies
Damping Ratios
Sound Insulation
Ambient Vibration Testing
Apparent Sound Transmission Class
Research Status
Complete
Summary
This report addresses serviceability issues of tall wood buildings focusing on their vibration and sound insulation performance. The sound insulation and vibration performance may not affect the building’s safety, but affects the occupants’ comfort and the proper operation of the buildings and the function of sensitive equipment, consequently the acceptance of the midrise and tall wood buildings in market place. Lack of data, knowledge and experience of sound and vibration performance of tall wood buildings is one of the issues related to design and construction of tall wood buildings. The measured and estimated values should also be correlated with actual experiences of the occupants in the building if such information is obtained, for example, through a survey.
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Free
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Air-Coupled Ultrasound Propagation and Novel Non-Destructive Bonding Quality Assessment of Timber Composites

https://research.thinkwood.com/en/permalink/catalogue13
Year of Publication
2012
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Author
Martín, Sergio
Organization
ETH Zurich
Year of Publication
2012
Format
Thesis
Material
Glulam (Glue-Laminated Timber)
Topic
Mechanical Properties
Keywords
Adhesives
Bonding
Delamination
Failure
Non-Destructive Testing
Air-coupled Ultrasound (ACU)
Finite-Difference Time-Domain (FDTD) model
Research Status
Complete
Summary
Glued laminated timber (glulam) is manufactured by gluing and stacking timber lamellas, which are sawn and finger-jointed parallel to the wood grain direction. This results in a sustainable and competitive construction material in terms of dimensional versatility and load-carrying capacity. With the proliferation of glued timber constructions, there is an increasing concern about safety problems related to adhesive bonding. Delaminations are caused by manufacturing errors and in service climate variations simultaneously combined with long-sustained loads (snow, wind and gravel filling on flat roofs). Several recent building collapses were related to bonding failure, which should be prevented in the future with a timely defect detection. As an outlook, the feasibility of air-coupled ultrasound tomography was demonstrated with numerical tests and preliminary experiments on glulam. The FDTD wave propagation model was excited by the difference of the time-reversed sound fields transmitted through a test and a reference (defect-free) glulam cross-section. Both datasets were obtained with the same SLT setup. Wave convergences then provided a map of bonding defects along the height and width of the inspected glulam cross-sections. Further research is envisaged in this direction
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Free
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Cross Laminated Timber (CLT) manufactured with European oak recovered from demolition: Structural properties and non-destructive evaluation

https://research.thinkwood.com/en/permalink/catalogue3008
Year of Publication
2022
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Llana, Daniel
González-Alegre, Violeta
Portela, María
Íñiguez-González, Guillermo
Organization
Universidad Politécnica de Madrid
Universidad de Santiago de Compostela
Publisher
Elsevier
Year of Publication
2022
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Cascading
Circular Economy
Non-Destructive Testing
Reclaimed
Recycling
Reuse
Salvaged
Secondary Timber
Research Status
Complete
Series
Construction and Building Materials
Summary
The demolition sector generates a large amount of timber waste that could be directly reused or recycled in other products for structural purposes. Timber should be graded before it is used for structural purposes, and visual strength grading standards designed for new timber do not properly grade recovered timber. Cross Laminated Timber (CLT) is now one of the most common wood products used in construction. CLT would therefore be a good option for recycling timber due to the high quantity of material used in CLT manufacturing. This paper investigates the possibilities of using recovered timber from demolition to manufacture CLT. Twelve CLT panels from recovered and new timber were manufactured and tested. The static modulus of elasticity was found to be the same between recovered and new timber, while the bending strength of CLT from recovered timber was lower than it was for CLT from new timber. Non-destructive testing for the estimation of mechanical properties of boards and CLT panels was successfully developed.
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Free
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Experimental and Numerical Analysis of Mixed I-214 Poplar/Pinus Sylvestris Laminated Timber Subjected to Bending Loadings

https://research.thinkwood.com/en/permalink/catalogue2592
Year of Publication
2020
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Author
Rescalvo, Francisco
Timbolmas, Cristian
Bravo, Rafael
Gallego, Antolino
Publisher
MDPI
Year of Publication
2020
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Topic
Mechanical Properties
Keywords
Poplar
Pine
Bending
Numerical Modelling
Non-Destructive Testing
Research Status
Complete
Series
Materials
Summary
The structural use of timber coming from fast growing and low-grade species such as poplar is one of the current challenges in the wood value chains, through the development of engineering products. In this work, a qualitative comparison of the behavior of mixed glued laminated timber made of pine in their outer layers and of poplar in their inner layers is shown and discussed. Single-species poplar and pine laminated timber have been used as control layouts. The investigation includes destructive four-point bending tests and three non-destructive methodologies: finite elements numerical model; semi-analytical model based on the Parallel Axes theorem and acoustic resonance testing. An excellent agreement between experimental and numerical results is obtained. Although few number of samples have been tested, the results indicate that the use of poplar as a low-grade species in the inner layers of the laminated timber can be a promising technology to decrease the weight of the timber maintaining the good mechanical properties of pine. Likewise, the need for the use of the shear modulus in both experimental measurements and numerical analysis is suggested, as well as the need to reformulate the vibration methodology for non-destructive grading in the case of mixed timber.
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Non-Destructive Testing of Wood–Correlation of Ultrasonic and Stress Wave Test Results in Glued Laminated Timber Members

https://research.thinkwood.com/en/permalink/catalogue1122
Year of Publication
2015
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Author
Nowak, Tomasz
Hamrol-Bielecka, Katarzyna
Jasienko, Jerzy
Organization
Wroclaw University of Technology
Year of Publication
2015
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Topic
Mechanical Properties
Keywords
Non-Destructive Testing
Ultrasonic Waves
Stress Waves
Physical Properties
Spruce
Wave Propagation
Research Status
Complete
Series
Annals of Warsaw University of Life Sciences - SGGW
Summary
Non-destructive testing of wood – correlation of ultrasonic and stress wave test results in glued laminated timber members. The paper presents application of selected non-destructive testing techniques – ultrasonic and stress wave methods - for assessment of the physical and mechanical properties of wood. Nondestructive testing is a scientific field related to: identification of mechanical properties and physical parameters of materials and structural members, detecting material defects and discontinuities, measurement of geometrical dimensions without affecting the functional properties of the elements under investigation. The paper provides a short description of selected methods used for non-destructive and quasi non-destructive testing of wood. It also reports on research on the correlation between glued laminated spruce wood properties and parameters of ultrasonic and stress wave propagation The research was carried out with a Sylvatest Trio device, which uses ultrasonic technology and a Fakopp Microsecond Timer device, which uses the stress wave technique.
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A Vibration-Based Approach for the Estimation of the Loss of Composite Action in Timber Composite Systems

https://research.thinkwood.com/en/permalink/catalogue218
Year of Publication
2013
Topic
Mechanical Properties
Material
LVL (Laminated Veneer Lumber)
Application
Beams
Author
Dackermann, Ulrike
Li, Jianchun
Rijal, Rajendra
Samali, Bijan
Publisher
Scientific.net
Year of Publication
2013
Format
Journal Article
Material
LVL (Laminated Veneer Lumber)
Application
Beams
Topic
Mechanical Properties
Keywords
Non-Destructive Testing
Static Loading Test
Damage Index (DI) Method
Loss of Composite Action Index (LCAI)
Research Status
Complete
Series
Advanced Materials Research
Summary
This paper presents a novel approach for the determination of the loss of composite action for timber composite systems using only measurements from non-destructive vibration testing. Traditionally, the composite action of a system is evaluated from static load testing using deflection measurements. However, static load testing is expensive, time consuming and inappropriate for existing flooring systems. The method proposed in this paper is based on the Damage Index (DI) method, which uses changes in modal strain energies, to detect locations and severities of damage. In the proposed method, a new Loss of Composite Action Index (LCAI), which is derived from direct mode shape measurements obtained from dynamic testing, is introduced to evaluate the loss of composite action. The proposed method is tested and validated on numerical and experimental models of a timber composite beam structure, which consists of two timber components that are connected with different numbers of screws to simulate various degrees of partial composite states. The results obtained from the new method are very encouraging and show a clear trend of the proposed dynamic-based LCAI in indicating the loss of composite action in the investigated timber composite structure.
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Free
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Water in Mass Timber

https://research.thinkwood.com/en/permalink/catalogue2318
Topic
Moisture
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Application
Wood Building Systems
Organization
TallWood Design Institute
Oregon State University
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Application
Wood Building Systems
Topic
Moisture
Keywords
Vibration Testing
Non-Destructive Testing
Biodegradation
Structural Performance
Aesthetic Properties
Cracks
Delamination
Funghi
Insects
CAT-Scan Imaging
Research Status
In Progress
Notes
Project contact is Arijit Sinha at Oregon State University
Summary
This project will undertake a comprehensive analysis of the effects of water exposure, in various forms, on mass timber building elements. Water intrusion is mostly commonly seen during construction, but can also occur during failure of roofs or external facades or as a result of internal plumbing failures. The research team will employ CAT-scan imaging, vibrational testing, non-destructive and small-scale physical tests to assess the effects of moisture intrusion and any subsequent biodegradation on the structural performance and aesthetic characteristics of the building elements and connections. This analysis will include investigating the effects of cracking and delamination that may occur as a result of wetting and drying. The project will facilitate development of guidelines on moisture control during construction, help identify suitable methods for protecting mass timber products where required and highlight design features that can be used to mitigate the risk of fungal and insect attack.
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7 records – page 1 of 1.