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Elastic Properties of Thermo-Hydro-Mechanically Modified Bamboo (Guadua Angustifolia Kunth) Measured in Tension

https://research.thinkwood.com/en/permalink/catalogue164
Year of Publication
2014
Topic
Mechanical Properties
Moisture
Material
Other Materials
Author
Archila-Santos, Hector
Ansell, Martin
Walker, Pete
Publisher
Scientific.net
Year of Publication
2014
Format
Journal Article
Material
Other Materials
Topic
Mechanical Properties
Moisture
Keywords
Bamboo
Modulus of Elasticity
Thermo-hydro-mechanical (THM) treatments
Poissons Ratio
Dimensional Stability
Research Status
Complete
Series
Key Engineering Materials
Notes
DOI:10.4028/www.scientific.net/KEM.600.111
Summary
Guadua angustifolia Kunth (Guadua) was subjected to thermo-hydro-mechanical (THM) treatments that modified its microstructure and mechanical properties. THM treatment was applied to Guadua with the aim of tackling the difficulties in the fabrication of standardised construction materials and to gain a uniform fibre density profile that facilitates prediction of mechanical properties for structural design. Dry and water saturated Guadua samples were subjected to THM treatment. A densified homogenous flat sheet material was obtained. Mechanical properties of small clear specimens of THM modified Guadua were evaluated by testing in tension and compared to the results of the same test on a control specimen. Samples were tested in the elastic range to determine values for Modulus of Elasticity (MOE) and Poisson’s ratio. There was a significant increase in the tensile MOE values (parallel to the direction of the fibres) for densified samples. MOE values measured were 16.21 GPa, 22.80 GPa and 31.04 GPa for control, densified dry and densified water saturated samples respectively. Oven dry densities for these samples were 0.54 g/cm3, 0.81 g/cm3 and 0.83 g/cm3. Despite a 50 % reduction in the radial Poisson’s ratio for the water saturated sample, no further variation in the Poisson’s ratio as a result of densification was observed for control and densified dry samples. This paper presents the results of the first phase of a study focussed on the manufacturing of flat Guadua sheet (FGS) by THM treatment and the characterization of its mechanical properties. The achievement of a dimensionally stable FGS by THM modification, with a uniform density and achieved with reduced labour effort during manufacture, will be of key importance for the development of structural applications, and could have a significant impact in the bamboo industry. The final aim of the research at the University of Bath is the development of Cross Laminated Guadua (CLG) panels using THM modified and laminated FGS glued with a high performance resin.
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Elastic Response of Cross Laminated Engineered Bamboo Panels Subjected to In-Plane Loading

https://research.thinkwood.com/en/permalink/catalogue1805
Year of Publication
2017
Topic
Mechanical Properties
Material
Other Materials
Author
Archila-Santos, Hector
Walker, Pete
Ansell, Martin
Rhead, Andrew
Lizarazo-Marriaga, Juan
Publisher
ICE Publishing
Year of Publication
2017
Format
Journal Article
Material
Other Materials
Topic
Mechanical Properties
Keywords
Compression
Deformation
Elastic Moduli
Bamboo
Panels
G-XLam
Research Status
Complete
Series
Proceedings of the Institution of Civil Engineers - Construction Materials
Summary
Novel cross-laminated bamboo panels comprising three and five layers (G-XLam3 and G-XLam5) were tested in compression along the main (0°) and the transverse (90°) directions. Linear variable differential transformer (LVDT) and non-contact three-dimensional digital image correlation (DIC) measuring techniques were used separately to measure deformation in the elastic region, and the elastic moduli, Ep C,0 and Ep C,90, were derived. Mean elastic modulus values obtained using LVDTs exhibited a good match with analytically predicted values. In contrast, the elastic values obtained by the DIC method were considerably higher and presented a considerable scatter of results. For instance, the Ep C,0 for G-XLam3 and G-XLam5 panels were 17·22 and 15·67 GPa, and 14·86 and 12·48 GPa, using the DIC and LVDT methods, respectively. In general, G-XLam panels with a fifth of the cross-sectional thickness and twice the density of analogous cross-laminated timber exhibited an approximately two-fold increase in Ep C,0 and Ep C,90. Overall, this research provides guidelines for the assessment and standardisation of the testing procedures for similar engineered bamboo products using contact and non-contact methods and highlights the potential of using G-XLam panels in stiffness-driven applications and in combination with wood for structural purposes.
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Evaluation of the Mechanical Properties of Cross Laminated Bamboo Panels by Digital Image Correlation and Finite Element Modelling

https://research.thinkwood.com/en/permalink/catalogue533
Year of Publication
2014
Topic
Mechanical Properties
Material
Other Materials
Author
Archila-Santos, Hector
Brandon, Daniel
Ansell, Martin
Walker, Pete
Ormondroyd, Graham
Year of Publication
2014
Format
Conference Paper
Material
Other Materials
Topic
Mechanical Properties
Keywords
Bamboo
Finite Element Model
Compression
Shear
Digital Image Correlation
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 10-14, 2014, Quebec City, Canada
Summary
Guadua angustifolia Kunth (Guadua) is a bamboo species native to South and Central America that has been widely used for structural applications in small and large scale buildings, bridges and temporary structures. Guadua remains a material for vernacular construction associated with high levels of manual labour and structural unpredictability. The aim of this work is to develop standardised industrial structural products from Guadua and to measure and predict their mechanical behaviour. Cross laminated Guadua (CLG) panels comprised of three and five layers were manufactured and their mechanical properties evaluated by testing small and large specimens in compression and shear. The digital image correlation (DIC) method was used to measure strain variations in the X, Y and Z axes on the surface of small CLG panels with strain gauge measurements on the reverse face. The deformation of large CLG panels was measured using DIC on the front face and transducers on the reverse face. The results from mechanical tests and DIC were compared and a finite element (FE) model developed that predicts the response of the material. Overall, this study provides guidelines for structural design with engineered bamboo products which are of key importance for their mainstream use.
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Fire Performance of Metal-Free Timber Connections

https://research.thinkwood.com/en/permalink/catalogue2186
Year of Publication
2015
Topic
Fire
Connections
Material
LVL (Laminated Veneer Lumber)
CLT (Cross-Laminated Timber)
Other Materials
Application
Wood Building Systems
Beams
Columns
Trusses

Fire Performance of Metal-Free Timber Connections

https://research.thinkwood.com/en/permalink/catalogue82
Year of Publication
2015
Topic
Connections
Fire
Material
LVL (Laminated Veneer Lumber)
Application
Wood Building Systems
Author
Brandon, Daniel
Maluk, Cristian
Ansell, Martin
Harris, Richard
Walker, Pete
Bisby, Luke
Bregulla, Julie
Publisher
ICE Publishing
Year of Publication
2015
Format
Journal Article
Material
LVL (Laminated Veneer Lumber)
Application
Wood Building Systems
Topic
Connections
Fire
Keywords
Glass Fiber Reinforced Polymer
Thermal Behaviour
Mechanical Behaviour
Research Status
Complete
Series
Proceedings of the Institution of Civil Engineers - Construction Materials
Summary
The fire performance of heavy timber frame structures is often limited by the poor fire performance of its connections. Conventional timber connections, dowelled or toothed plate connections typically use steel as a connector material. In a fire, the steel parts rapidly conduct heat into the timber, leading to reduced fire performance. Replacing metallic connectors with alternative non-metallic, low thermal conductivity connector materials can, therefore, lead to improved connection performance in fire. This paper presents an experimental study into the fire performance of metal-free timber connections comprising a hot-pressed plywood flitch plate and glass-fibre-reinforced polymer dowels. The thermal behaviour of the connections at elevated temperatures is studied using a standard cone calorimeter apparatus and a novel heat transfer rate inducing system. The latter is a fire testing system developed at the University of Edinburgh. The mechanical behaviour of the connection during severe heating was also studied using an environmental chamber at temperatures up to 610°C. The results demonstrate that heat transfer in the non-metallic connections is governed by the thermal properties of the timber, resulting in significant enhancements in connection fire performance.
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