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An Analytical Model for Design of Reinforcement around Holes in Laminated Veneer Lumber (LVL) Beams

https://research.thinkwood.com/en/permalink/catalogue135
Year of Publication
2013
Topic
Design and Systems
Mechanical Properties
Material
LVL (Laminated Veneer Lumber)
Application
Beams
Author
Ardalany, Manoochehr
Fragiacomo, Massimo
Moss, Peter
Deam, Bruce
Publisher
Springer Netherlands
Year of Publication
2013
Format
Journal Article
Material
LVL (Laminated Veneer Lumber)
Application
Beams
Topic
Design and Systems
Mechanical Properties
Keywords
Failure
Glued-In Rods
Model
Reinforcement
Screws
Tensile
Research Status
Complete
Series
Materials and Structures
Summary
Openings are usually required to allow services like plumbing, sewage pipes and electrical wiring to run through beams. This prevents an extra depth of the floor/ceiling, while preserving architectural considerations. The introduction of large opening causes additional tension perpendicular to grain in timber beams. The low tensile strength perpendicular to grain of wood allows crack formation. Crack propagation around the hole considerably decreases the load-carrying capacity of the beam. However, in most cases, crack formation and propagation around the hole can be prevented by the use of an appropriate reinforcement. Screw, glued-in rods, and plywood are alternative options for the reinforcement. Design of the reinforcement requires that the working mechanism of the reinforcement is fully understood and properly addressed. In addition, reinforcement should be designed for actions produced in the section of the beam weakened by the hole. The current paper uses a simple truss model around the opening to calculate the tensile force in the reinforcement. Two simple formulations for design of the reinforcement are derived and compared with numerical and experimental results, showing an overall good correspondence. The proposed truss model can be considered for incorporation in future codes of practice.
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Assessment of the Pull Out Strength of Glued In Rods with Different Test Methods

https://research.thinkwood.com/en/permalink/catalogue1667
Year of Publication
2016
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Author
Rajcic, Vlatka
Stepinac, Mislav
Košcak, Janko
Damjanovic, Domagoj
Year of Publication
2016
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Topic
Mechanical Properties
Keywords
Glued-In Rods
Pull-Out Strength
Pull-Pull Tests
Pull-Compression Tests
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 3795-3802
Summary
Glued-in rods (GiR) are an effective way to connect timber elements from both load bearing capacity/stiffness and aesthetic point of view. This method is also widely accepted as a method for reinforcement of the new and existing timber structures. Although GiR are widely used in timber structures, there is still no unified European test standards, product standards or design equations for such connections. At present, there are several test methods and procedures applied in research and development. In this paper two different methods for obtaining pull-out strength are presented. Furthermore, experimental investigation was conducted and results obtained from both methods are mutually compared. Pull – compression test procedure is the most common setup for experimental investigation, however this setup is sometimes not representative and it is often characterized as unreliable because it does not quite good correspond to practical applications. The second examined test procedure was pull-pull. Within the experimental investigation, total number of 36 specimens were tested and results obtained from both methods are shown, discussed and compared in this paper.
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Bond Behavior of Glued-In Timber Joint with Deformed Bar Epoxied in Glulam

https://research.thinkwood.com/en/permalink/catalogue537
Year of Publication
2014
Topic
Connections
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Author
Ling, Zhibin
Liu, Weiqing
Yang, Huifeng
Lu, Weidong
Year of Publication
2014
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
Topic
Connections
Mechanical Properties
Keywords
Glued-in Rods
Bond behavior
Withdrawal Strength
Pull-Pull tests
Failure Modes
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 10-14, 2014, Quebec City, Canada
Summary
This paper describes the test program of glued-in deformed bar timber joint conducted in pull-pull configuration, which aims to investigate the bond behavior of glued-in deformed bar systems in glulam. The varying parameter are bar slenderness ratio and glue-line thickness. In order to obtain the bond stress distribution along the anchorage length, special deformed bar with strain gauges attached internally were designed. Test results show that both the bar slenderness ratio and glue-line thickness have obvious influence on withdrawal strength and bond behavior of glued-in deformed bar joint. Failure modes of specimens are also analyzed in this paper. Ductile failure modes of glued-in rod timber joint could be realized with reasonable design.
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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)
Author
Vallée, Till
Kaufmann, Marvin
Alter, Benjamin
Tannert, Thomas
Year of Publication
2018
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
Topic
Connections
Keywords
Glued-In Rods
GFRP
Numerical Models
Capacity
Conference
World Conference on Timber Engineering
Research Status
Complete
Summary
Glued-in-rods (GiR) represent a class of joints being used in timber engineering that are mostly used to transfer axial loads in structural members with Glass Fibre Reinforced Polymers (G-FRP) increasingly being considered as rod material. The primary objective of the research presented herein was to apply a probabilistic capacity prediction method to timber joints with G-FRP GiR. The experimental campaign was specific in two ways: firstly, G-FRP rods were bonded into both ends of the timber block with both ends being tested to failure; and secondly, as opposed to most previous studies exhibiting stiff adhesives, a ductile Polyurethane with markedly non-linear behaviour was used. All material characterisation was performed with methods that can be reproduced by any standard laboratory equipment, to provide parameters for the subsequent numerical analyses. Based thereupon, a probabilistic method was used and provided reasonably accurate predictions of the joint capacities of 25 different geometrical GiR configurations. The probabilistic method was extended for realistic estimations of the experimental capacity scattering in form of upper and lower quantiles.
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A Composite System Using Ultra High-Performance Fibre-Reinforced Concrete and Cross-Laminated Timber

https://research.thinkwood.com/en/permalink/catalogue1420
Year of Publication
2016
Topic
Mechanical Properties
Acoustics and Vibration
Connections
Material
CLT (Cross-Laminated Timber)
Timber-Concrete Composite
Application
Floors
Author
Chen, Mengyuan
Organization
University of Toronto
Year of Publication
2016
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Timber-Concrete Composite
Application
Floors
Topic
Mechanical Properties
Acoustics and Vibration
Connections
Keywords
Ultra-High-Performance Fibre-Reinforced Concrete
Push-Out Tests
Glued-In Rods
Bending Tests
Vibration Tests
Span Limits
Research Status
Complete
Summary
The application of cross-laminated timber (CLT) as floor panels is limited by excessive deflection and vibration. A composite system combining CLT and ultra high-performance fibre-reinforced concrete (UHPFRC) was developed to extend span limits. Push-off tests were conducted on different connectors, and a glued-in rod connector was chosen and further refined for the proposed system. Static bending tests and free vibration tests were conducted on bare CLT panels and two composite specimens. By comparing the results, it is concluded that the proposed system considerably extend the span limits of CLT panels.
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Cyclic Load Behaviour of Beam-to-Column Glulam Joints Combining Glued-in Rods with Steel Brackets

https://research.thinkwood.com/en/permalink/catalogue2028
Year of Publication
2018
Topic
Connections
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Author
Ling, Zhibin
Liu, Weiqing
Yang, Huifeng
Xiang, Zhe
Year of Publication
2018
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
Topic
Connections
Mechanical Properties
Keywords
Beam-to-Column
Joints
Glued-In Rods
Steel Brackets
Cyclic Loading
Monotonic Loading
Failure Modes
Stiffness
Ductility
Energy Dissipation
Hysteresis Loop
Douglas-Fir
Conference
World Conference on Timber Engineering
Research Status
Complete
Summary
This paper presents an experimental campaign conducted on the beam-to-column glulam joints combing glued-in rods and steel brackets (BCGS glulam joints) aiming to investigate the mechanical behaviour of these glulam joints under low cyclic loading. Three types of steel brackets were designed for connecting the beam and column combing with glued-in rods and to work as energy dissipaters. In each group of specimens (except for group MJ4), two specimens were tested under monotonic loading and the others were subjected to low cyclic loading. The test results were summarized comprehensively in terms of failure modes, joint stiffness, hysteresis loops, ductility and energy dissipation ability. Generally, the difference of load capacity between BCGS glulam joints and the beam-to-column glulam joints only with glued-in rods (BCG glulam joints) was not significant. The joint stiffness of BCG glulam joints was higher than that of the BCGS glulam joints, while the stiffness degradation of the later is slower than the former. The hysteresis loops of the BCGS glulam joints exhibited less pinching effect obviously compared with the BCG glulam joints, which indicated that the energy dissipation ability of the glulam joints with glued-in rods could be improved significantly by using the steel brackets as energy dissipaters. Moreover, it should be noted that the hysteresis loops of groups CJ1 showed slipping effect obviously during testing. This might due to the insufficient shear resistance of these two groups, so that further investigations on BCG glulam joints with shear-resisting components are urgently needed.
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Design of Connections in Timber Structures

https://research.thinkwood.com/en/permalink/catalogue1937
Year of Publication
2018
Topic
Connections
Design and Systems
Material
CLT (Cross-Laminated Timber)
Author
Bader, Thomas
Blaß, Hans Joachim
Bocquet, Jean-François
Branco, Jorge
Brandner, Reinhard
Manuel Cabrero, José
de Proft, Kurt
Descamps, Thierry
Dietsch, Philipp
Franke, Bettina
Franke, Steffen
Görlacher, Rainer
Jockwer, Robert
Jorissen, André
Kleiber, Marion
Lemaître, Romain
Munch-Andersen, Jørgen
Pazlar, Tomaž
Ranasinghe, Keerthi
Ringhofer, Andreas
Sandhaas, Carmen
Schweigler, Michael
Stepinac, Mislav
Tuhkanen, Eero
Verbist, Maxime
Yurrita, Miguel
Editor
Sandhaas, Carmen
Munch-Andersen, Jørgen
Dietsch, Philipp
Publisher
COST (European Cooperation in Science and Technology)
Year of Publication
2018
Format
Book/Guide
Material
CLT (Cross-Laminated Timber)
Topic
Connections
Design and Systems
Keywords
Eurocode 5
Fasteners
Screws
Dowel Type Fastener
Glued-In Rods
Numerical Modeling
Europe
Load Distribution
Research Status
Complete
Summary
This state-of-the-art report has been prepared within COST Action FP1402 Basis of structural timber design from research to standards, Working Group 3 Connections. The Action was established to create an expert network that is able to develop and establish the specific information needed for standardization committee decisions. Its main objective is to overcome the gap between broadly available scientific results and the specific information needed by standardization committees. This necessitates an expert network that links practice with research, i.e. technological developments with scientific background. COST presents the ideal basis to foster this type of joint effort. Chapter 8 Connections presents an integral part of Eurocode 5 and is in need of revision. This state-of-the-art report shall provide code writers with background information necessary for the development of the so-called Second Generation of the Eurocodes, now aimed to be produced in 2022.
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The Effect of Depth and Diameter of Glued-In Rods on Pull-Out Connection Strength of Bamboo Glulam

https://research.thinkwood.com/en/permalink/catalogue1451
Year of Publication
2016
Topic
Connections
Mechanical Properties
Material
Other Materials
Author
Yan, Yan
Liu, Huanrong
Zhang, Xiubiao
Wu, Heng
Huang, Yun
Publisher
Springer Japan
Year of Publication
2016
Format
Journal Article
Material
Other Materials
Topic
Connections
Mechanical Properties
Keywords
Bamboo
Steel Connections
Pullout Tests
Glued-In Rods
Threaded Rods
Pull-Out Strength
Adhesives
Failure Modes
Research Status
Complete
Series
Journal of Wood Science
Summary
In order to explore bamboo glulam utilization in structure construction, the adhesive bonded steel connection of bamboo glulam was investigated in this study. By carrying out both-end pullout tests on glued-in threaded rods in bamboo glulam, the effects of depth and diameter of embedded rods in bamboo glulam on the pullout strength and the failure modes were discussed. Results showed that threaded rods fracture and adhesive interface failure were the two main different failure modes in the tests. The pullout peak load of both-end glued-in rods in bamboo glulam increased with the diameter and the embedded length of the threaded rods. To satisfy tensile load of the glued threaded rods (quality 4.8) used in the connections between engineering structural materials, the slenderness ratio ( , the ratio of depth and diameter of glued-in threaded rods) equal to 10 or over was necessary.
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Effect of Glue-line Thickness on Pull-Out Behavior of Glued-in GFRP Rods in LVL: Finite Element Analysis

https://research.thinkwood.com/en/permalink/catalogue1331
Year of Publication
2017
Topic
Mechanical Properties
Material
LVL (Laminated Veneer Lumber)
Author
Madhoushi, Mehrab
Ansell, Martin
Publisher
ScienceDirect
Year of Publication
2017
Format
Journal Article
Material
LVL (Laminated Veneer Lumber)
Topic
Mechanical Properties
Keywords
Finite Element Analysis
Glue-line Thickness
Pull-Out Behavior
Modulus of Elasticity
Glued-In Rods
Research Status
Complete
Series
Polymer Testing
Summary
This paper uses finite element analysis (FEA) to verify the results of previous experimental works conducted on the effect of glue-line thickness and rate of loading on pull-out behavior of glued-in GFRP rods in LVL. For this purpose, the materials were considered as orthotropic for the timber and the GFRP rod, and isotropic for epoxy resin. To determine the effects of thickness on pull-out, four glue-lines namely 0.5, 1, 2 and 4 mm were modelled. To examine the effects of rate of loading, three glue-lines 0.5, 2 and 4 mm were modelled with different values of modulus of elasticity selected for the resin to simulate higher and lower rates of loading. Results showed that with an increasing thickness of glue-line, the concentration of Z-direction stresses declines across the glue-line thickness from the rod-adhesive interface towards the adhesive-timber interface and the magnitude of shear stresses, tXZ, increases to a maximum within the glue-line in a zone about 20e30% into the resin layer and this is seen for all glueline thicknesses. Also, by changing values of elastic modulus for the resin in the FE model to simulate rate of loading, it was shown that thicker glue-lines are more sensitive to loading rate
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Experimental and Numerical Analysis of Flexible Polymer Connections for CLT Buildings

https://research.thinkwood.com/en/permalink/catalogue2057
Year of Publication
2018
Topic
Connections
Mechanical Properties
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Azinovic, Boris
Kramar, Miha
Pazlar, Tomaž
Gams, Matija
Kwiecien, Arkadiusz
Weckendorf, Jan
Sustersic, Iztok
Organization
Cracow University of Technology
Year of Publication
2018
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Connections
Mechanical Properties
Seismic
Keywords
Pull-Pull Tests
Cyclic Loading
Energy Dissipation
Glued-In Rods
Conference
World Conference on Timber Engineering
Research Status
Complete
Summary
This paper explores the possibility of using flexible adhesives to dissipate energy in CLT buildings during earthquakes. In the first series of tests, a rod glued in a CLT panel with flexible adhesive was investigated. The connection was tested in pull-pull configuration using cyclic, tension-only loading. Different rod diameters and different thicknesses of the glue layer were tested. The tests have shown that the adhesive can resist large deformations and exhibits fairly large energy dissipation capacity. Based on the test results the numerical analyses were performed to test the behaviour of the connection when applied in CLT buildings. Existing constitutive models available in OpenSees software were used to simulate the specific hysteretic behaviour of the connection. The results have shown that the CLT wall anchored with "flexible" glued-in rods would have a significant energy dissipation capacity if a sufficient number of them were used as the hold-down devices. Such system could be used to dissipate energy in seismic areas.
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20 records – page 1 of 2.