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11 records – page 1 of 2.

An Analytical, Numerical and Experimental Study of Non-Metallic Mechanical Joints for Engineered Timber Constructions

https://research.thinkwood.com/en/permalink/catalogue1606
Year of Publication
2016
Topic
Connections
Mechanical Properties
Material
LVL (Laminated Veneer Lumber)
Author
Bazu, Gheorghe
Mahjourian Namari, Siavash
Wehsener, Jörg
Hartig, Jens
Haller, Peer
Year of Publication
2016
Country of Publication
Austria
Format
Conference Paper
Material
LVL (Laminated Veneer Lumber)
Topic
Connections
Mechanical Properties
Keywords
GFRP
Densified Veneer Wood
Plates
Dowels
Load Bearing Behaviour
Analytical Model
Numerical Model
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 2059-2068
Summary
Timber structures are strongly depending on the design of connections, which are mostly constructed from steel components. However, these joints have a number of limitations such as the tendency to be heavy, proneness to corrosion and often poor aesthetic appearances. Therefore, this study aims to replace metallic joints by non-metallic materials. An experimental testing program was performed to investigate the use of glass fiber reinforced plastics (GFRP), densified veneer wood (DVW) and laminated veneer lumber (LVL) in the form of plates and dowels in different test configurations. Analytical and numerical models were developed to better understand the load-bearing behaviour and to perform static verifications. The models were validated based on the experimental results. The results demonstrate that the use of GFRP dowels in combination with GFRP plates can provide a robust connection system for contemporary applications.
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Behaviour of FRP Retrofitted Glued-Laminated (Glulam) Beams Subjected to Simulated Blast Loads

https://research.thinkwood.com/en/permalink/catalogue1550
Year of Publication
2016
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
Lacroix, Daniel
Doudak, Ghasan
Year of Publication
2016
Country of Publication
Austria
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Mechanical Properties
Keywords
Retrofitted
Static Loads
Dynamic Loads
GFRP
Damage
Predictive Model
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 1207-1214
Summary
Preliminary results from an experimental program investigating the behaviour of retrofitted glulam beams subjected to static and dynamic loads are presented in this paper. The effect of glass fibre-reinforced-polymer (GFRP) laminates applied on the tension side was investigated under both static and dynamic loading as a potential retrofit on undamaged specimens. Furthermore, previously damaged beams were restored by applying GFRP confinement to the damaged region. The experimental results showed that the capacity of the retrofitted beams was improved significantly and the restored beams attained a significant level of their original dynamic capacity. Future work involves the development of a material predictive model that can account for the high-strain rate effects as well as investigating more retrofit options.
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Bond Behavior between Glulam and GFRP’s by Pullout Tests

https://research.thinkwood.com/en/permalink/catalogue560
Year of Publication
2011
Topic
Connections
Design and Systems
Material
Glulam (Glue-Laminated Timber)
Author
Sena-Cruz, José
Branco, Jorge
Jorge, Marco
Barros, Joaquim
Silva, Catarina
Cunha, Vitor
Publisher
ScienceDirect
Year of Publication
2011
Country of Publication
Netherlands
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Topic
Connections
Design and Systems
Keywords
GFRP
Bond behavior
Pull-Out Tests
Stress-Slip
Language
English
Research Status
Complete
Series
Composites Part B: Engineering
Summary
To evaluate the bond behavior between glulam and GFRP rods, applied according to the nearsurface mounted strengthening technique, an experimental program composed of beam and direct pullout tests was carried. In this experimental program three main variables were analyzed: the GFRP type, the GFRP location into the groove, and the bond length. From the monitoring system it was registered the loaded and free end slips, and the pullout force. Based on these experimental results, and applying an analytical-numerical strategy, the local bond stress-slip relationship was calculated. In this work the tests are described, the obtained results are presented and discussed, and the applicability of the inverse analysis to obtain the local bond law is demonstrated.
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Capacity Prediction for Glued-In FRP Joints

https://research.thinkwood.com/en/permalink/catalogue2022
Year of Publication
2018
Topic
Connections
Material
Glulam (Glue-Laminated Timber)

Experimental Investigation of Cracked End-notched Glulam Beams Repaired with GFRP Bars

https://research.thinkwood.com/en/permalink/catalogue2444
Year of Publication
2019
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Beams

Fire and Structural Performance of Non-Metallic Timber Connections

https://research.thinkwood.com/en/permalink/catalogue152
Year of Publication
2015
Topic
Connections
Fire
Material
LVL (Laminated Veneer Lumber)
Author
Brandon, Daniel
Organization
University of Bath
Year of Publication
2015
Country of Publication
United Kingdom
Format
Thesis
Material
LVL (Laminated Veneer Lumber)
Topic
Connections
Fire
Keywords
Creep
Deflection
Dowels
Fiber Reinforced Polymer
Glass Fiber Reinforced Polymer
Model
Densified Veneer Wood
Language
English
Research Status
Complete
Summary
Recent studies showed the need for timber connections with high fire performance. Connections of members in timber structures commonly comprise steel connectors, such as dowels, screws, nails and toothed plates. However, multiple studies have shown that the presence of exposed metal in timber connections leads to a poor performance under fire conditions. Replacing metallic fasteners with non-metallic fasteners potentially enhances the fire performance of timber connections. Previous studies showed that Glass Fibre Reinforced Polymer (GFRP) dowels can be a viable replacement for steel dowels and that Densified Veneer Wood functions well as a flitch plate material. However, as the resin matrix of GFRP dowels is viscoelastic, connection creep, which is not studied before, can be of concern. Also no research has been carried out on the fire performance of these connections. Therefore, a study of the creep behaviour and the fire performance of non-metallic timber connections comprising GFRP dowels and a Densified Veneer Wood flitch plate was performed, as is discussed in this thesis. Predictive models were proposed to determine the connection slip and load bearing capacity at ambient and elevated temperatures and in a fire. The material properties and heat transfer properties required for these models were determined experimentally and predictions of these models were experimentally validated. Furthermore, an adjustment of the predictive model of connection slip at ambient temperature allowed approximating the creep of the connection. The material properties, required for the creep model, were determined experimentally and predictions of the model were compared to results of longterm connection tests. The study confirmed that timber members jointed with non-metallic connectors have a significantly improved fire performance to timber joints using metallic connections. Models developed and proposed to predict fire performance gave accurate predictions of time to failure. It was concluded that non-metallic connections showed more creep per load per connector, than metallic connections. However, the ratio between initial deflection and creep (relative creep) and the ratio between load level and creep were shown to be similar for metallic and non-metallic connections.
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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
Country of Publication
United Kingdom
Format
Journal Article
Material
LVL (Laminated Veneer Lumber)
Application
Wood Building Systems
Topic
Connections
Fire
Keywords
Glass Fiber Reinforced Polymer
Thermal Behaviour
Mechanical Behaviour
Language
English
Research Status
Complete
Series
Proceedings of the Institution of Civil Engineers - Construction Materials
ISSN
1747-6518
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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Fully Reversible Reinforcement of Softwood Beams with Unbonded Composite Plates

https://research.thinkwood.com/en/permalink/catalogue210
Year of Publication
2016
Topic
Design and Systems
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
Borri, Antonio
Speranzini, Emanuela
Castori, Giulio
Corradi, Marco
Publisher
ScienceDirect
Year of Publication
2016
Country of Publication
Netherlands
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Design and Systems
Mechanical Properties
Keywords
Failure
Flexural Tests
Glass Fiber Reinforced Polymer
Modulus of Rupture
Reinforcement
Softwood
finite element method
Numerical model
Language
English
Research Status
Complete
Series
Composite Structures
Summary
In this paper, results of flexure tests aimed at improving the structural behavior of softwood beams reinforced with unglued composite plates and at developing an effective alternative to the use of organic resins are presented. The addition of modest ratios of GFRP (Glass Fiber Reinforced Polymer) composite strengthening can prevent tension failure in timber beams. However the application of organic matrices presents problems of reversibility, compatibility and durability with timber and poor performance at high temperatures. The increment in capacity and stiffness and the analysis of the failure modes is the central focus of this paper. The experimental campaign is dealing with a significant number of un-reinforced and reinforced beams strengthened with unbonded GFRP plates. A 3-dimensional finite element model is also presented for simulating the non-linear behavior of GFRP-reinforced softwood beams. The ability of the numerical model to reproduce experimental results for the load–deflection curves is validated.
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Glued-In Rods in Hardwood and Hardwood Laminated Veneer Lumber - Report on a Large Experimental Campaign

https://research.thinkwood.com/en/permalink/catalogue1528
Year of Publication
2016
Topic
Connections
Mechanical Properties
Material
LVL (Laminated Veneer Lumber)
Author
Vallée, Till
Bletz-Mühldorfer, Oliver
Myslicki, Sebastian
Grunwald, Cordula
Walther, Frank
Bathon, Leander
Year of Publication
2016
Country of Publication
Austria
Format
Conference Paper
Material
LVL (Laminated Veneer Lumber)
Topic
Connections
Mechanical Properties
Keywords
Glued-In Rods
Hardwood
GFRP
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 675-683
Summary
Glued-in rods are to be considered a main research field within timber engineering. While there are still many open questions, significant progress has been achieved with regard to steel bars embedded in softwoods. This paper ambition is extending the knowledge about glued-in rods towards hardwood and hardwood laminated veneer lumber, respectively, towards the use of G-FRP bars therein. For that purpose, an extensive experimental campaign was documented, starting from the extensive characterization of the timber, adhesive, small scale specimens to identify suitable adhesive, and concluded by full-scale specimen tests. The study will allow, by providing a coherent set of material parameters, for hardwood, a much better comparison of existing joint capacity methods of previously developed for softwood.
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Laminated Strand Lumber (LSL) Reinforced by GFRP; Mechanical and Physical Properties

https://research.thinkwood.com/en/permalink/catalogue1311
Year of Publication
2018
Topic
Mechanical Properties
Design and Systems
Material
LSL (Laminated Strand Lumber)
Author
Moradpour, Payam
Pirayesh, Hamidreza
Gerami, Masood
Jouybari, Iman
Publisher
ScienceDirect
Year of Publication
2018
Country of Publication
Netherlands
Format
Journal Article
Material
LSL (Laminated Strand Lumber)
Topic
Mechanical Properties
Design and Systems
Keywords
GFRP
Poplar
Modulus of Rupture
Modulus of Elasticity
Shear Strength
Compression Strength
Impact Strength
Water Absorption
Thickness Swelling
Language
English
Research Status
Complete
Series
Construction and Building Materials
Summary
The effect of glass fiber reinforced polymer (GFRP) on the technical properties of LSL made from poplar (Populus deltoids L.) employing pMDI and UF as binders was investigated. Technical properties such as modulus of rupture (MOR), Modulus of elasticity (MOE), shear strength (SS), compression strength parallel to the grains (CS //), impact strength (IS), water absorption (WA) and thickness swelling (TS) were determined. Results confirmed that resin type and GFRP have significant effects on the LSL properties. It was revealed that the most beneficial effect of GFRP is on MOR, MOE, IS, SS and CS respectively. The Highest properties were obtained by using pMDI as the resin and GFRP as the reinforcement, where properties such as MOR, MOE, IS, SS and CS were improved by 123, 114, 100, 94, and 90%, respectively, compared to control samples. Furthermore, GFRP incorporation led to alteration of fracture place from tension side to compression side. Depending on the treatment type, the WA and TS values of the LVLs improved between 23% to 68% and 19.5% to 78%, respectively.
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11 records – page 1 of 2.