Skip header and navigation

7 records – page 1 of 1.

Effect of Array on Tensile Load Carrying Capacity CLT Drift Pinned Joint

https://research.thinkwood.com/en/permalink/catalogue1532
Year of Publication
2016
Topic
Connections
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Nakashima, Shoichi
Kitamori, Akihisa
Araki, Yasuhiro
Isoda, Hiroshi
Year of Publication
2016
Country of Publication
Austria
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Topic
Connections
Mechanical Properties
Keywords
Reduction Coefficients
Dowel-Type Connections
Drift Pinned Joint
Tensile Tests
Stiffness
Proportional Limit Load
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 772-779
Summary
A reduction coefficient is applied in usual design of multiple dowels type connections. The numbers of stiffeners in row is one of important factor to decide this coefficient. CLT drift pinned joint showed small orthotropy against in plane tensile load. Tensile tests of multiple drift pins joints were performed to evaluate the effect of array. Numbers of drift pins n in each specimen were same (n=12), but the arrangements were different (2 x 6, 3 x 4, 4 x 3, 6 x 2). Also the grain directions were parameters (0, 90 degrees). The reduction of initial stiffness and proportional limit load showed good agreement between theoretical prediction and experimental results.
Online Access
Free
Resource Link
Less detail

Experimental Study on Innovative Connections for Large Span Timber Truss Structures

https://research.thinkwood.com/en/permalink/catalogue47
Year of Publication
2015
Topic
Connections
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
Yang, Huifeng
Crocetti, Roberto
Larsson, Gustaf
Gustafsson, Per-Johan
Publisher
International Association for Shell and Spatial Structures (IASS)
Year of Publication
2015
Country of Publication
Japan
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Connections
Mechanical Properties
Keywords
Reinforcement
Single Large Diameter Dowel Connection (SCDDC)
Full Scale
Tensile Tests
Quasi-Static
Steel Plates
Language
English
Conference
IASS WORKING GROUPS 12 + 18 International Colloquium 2015
Research Status
Complete
Notes
April 10-13, 2015, Tokyo, Japan
Summary
This paper summarizes an experimental investigation on several innovative reinforcing techniques for the “Single Large Diameter Dowel Connection”, SLDDC in timber truss structures. Besides lateral reinforcing or prestressing, also steel plates glued on two sides of the glulam specimens were used as reinforcing measure. To study the efficiency of these techniques, 15 full-scale quasi-static tensile tests on glulam members with a SLDDC on either ends of each member were performed. It was found that the reinforcement significantly enhanced the bearing capacity of the SLDDCs. All of the reinforcing techniques showed a satisfactory efficiency, preventing splitting of wood. Moreover, most of the specimens remains showed a remarkable post failure strength.
Online Access
Free
Resource Link
Less detail

Influence of Varying Material Properties on the Load-Bearing Capacity of Glued Laminated Timber

https://research.thinkwood.com/en/permalink/catalogue173
Year of Publication
2014
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
Fink, Gerhard
Organization
ETH Zurich
Year of Publication
2014
Country of Publication
Switzerland
Format
Thesis
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Mechanical Properties
Keywords
Knot Clusters
Non-Destructive
Tensile tests
Load Carrying Capacity
Joints
Model
Language
English
Research Status
Complete
Summary
Glued laminated timber (GLT) is a structural product composed of several layers of timber boards glued together. GLT components have many advantages, such as the larger range of available component dimensions to choose from, the environmental sustainability or the e- cient ratio between weight and load-bearing capacity. Because of that, GLT beams have been established as one of the most important products in timber engineering in the last decades. As a natural grown material, timber properties exhibit higher variability, compared with other building materials. The variability is pronounced not only between dierent structural elements but also within single elements, the latter being highly related to the occurrence of knot clusters. Due to the highly inhomogeneous structure of timber, the prediction of the material properties of GLT beams is aected by large uncertainties. In the presented thesis, the in uence of varying material properties on the load-bearing capacity of GLT beams was investigated. Thus the thesis contributes to develop the quality of GLT beams, in terms of reliability and eciency. Detailed, non-destructive investigations of altogether 400 timber boards were performed. Thereby, dierent strength and stiness related indicators, such as the position and characteristic of knots, or the eigenfrequency, were assessed. Furthermore, non-destructive tensile test were performed to estimate the stiness properties of knot clusters. Out of the investigated timber boards, GLT beams having a precisely-known beam setup were fabricated. As a result, the exact position of each particular timber board (and each particular knot cluster) within the GLT beams was known. Afterwards, bending tests were performed to estimate the load-bearing capacity of these GLT beams. Thereby, the in uence of knot clusters and nger joint connections on the deformation and failure behaviour was investigated. In addition to the experimental investigations, a probabilistic approach for modelling GLT beams (referred to as GLT model ) was developed. Thereby, at rst, timber boards are simulated according to their natural growth characteristics. Afterwards, out of the simulated timber boards, virtual GLT beams are fabricated. Finally, the load-bearing behaviour of these GLT beams is estimated by using a numerical model. To assure the quality of the numerical model, it was validated with the test results. Using the GLT model, the in uence of dierent parameters, such as the position and characteristics of knots, or the quality of nger joint connections, on the load-bearing capacity of GLT beams was investigated. One further goal of this thesis was the investigation of machine-grading indicators, that are measured during the grading process. Therefore, all the investigations presented in this thesis are conducted for indicators measured in laboratory and machine-grading indicators. The same applies for the GLT model, which was also developed for both types of indicators
Online Access
Free
Resource Link
Less detail

Mechanical Behaviour of Dovetail Connections for Cross Laminated Timber Wall Elements

https://research.thinkwood.com/en/permalink/catalogue501
Year of Publication
2014
Topic
Connections
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Walls
Author
Stecher, Georg
Kögl, Josef
Beikircher, Wilfried
Year of Publication
2014
Country of Publication
Canada
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Walls
Topic
Connections
Mechanical Properties
Keywords
Beech
Tensile tests
Shear Tests
Dovetails
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 10-14, 2014, Quebec City, Canada
Summary
The goal of this study is to determine the shear and tension resistance capacity of a tenon connector made out of beech plywood for the connection of cross laminated timber wall elements. To determine the tensile and shear capacity of the connector according to EN 26 891 [1], tensile and shear tests were performed on cross laminated timber elements with thicknesses of 100 mm, 150mm and 180 mm which were connected with the pin connector. The sample set consisted of 36 test specimens of which were 18 tensile specimens and 18 shear specimens. For each test series, three tensile and three shear tests with the top layer parallel and perpendicular to the load direction were performed. The test specimens were stored for four weeks in normal climate at 20 ° C and 65% relative humidity before they were tested. The shear and tension capacity shows a substantially linear behaviour by increasing the length of the connector. In the tensile tests a transverse tension failure happened in the transverse layer. In the shear tests a plastic failure of the beech plywood connector happened.
Online Access
Free
Resource Link
Less detail

Mechanical Behaviour of Finger Joints at Elevated Temperatures

https://research.thinkwood.com/en/permalink/catalogue612
Year of Publication
2012
Topic
Fire
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Author
Frangi, Andrea
Bertocchi, Marco
Clauß, Sebastian
Niemz, Peter
Publisher
Springer-Verlag
Year of Publication
2012
Country of Publication
Germany
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Topic
Fire
Mechanical Properties
Keywords
Fire Resistance
Tensile tests
Bending Tests
Finger Joints
Language
English
Research Status
Complete
Series
Wood Science and Technology
ISSN
1432-5225
Summary
Finger joints are commonly used to produce engineered wood products like glued laminated timber beams. Although comprehensive research has been conducted on the structural behaviour of finger joints at ambient temperature, there is very little information about the structural behaviour at elevated temperature. A comprehensive research project on the fire resistance of bonded timber elements is currently ongoing at the ETH Zurich. The aim of the research project is the development of simplified design models for the fire resistance of bonded structural timber elements taking into account the behaviour of the adhesive used at elevated temperature. The paper presents the results of a first series of tensile and bending tests on specimens with finger joints pre-heated in an oven. The tests were carried out with different adhesives that fulfil current approval criteria for the use in loadbearing timber components. The results showed substantial differences in temperature dependant strength reduction and failure between the different adhesives tested. Thus, the structural behaviour of finger joints at elevated temperature is strongly influenced by the behaviour of the adhesive used for bonding and may govern the fire design of engineered wood products like glued laminated timber beams.
Online Access
Free
Resource Link
Less detail

Non-Destructive Tests to Determine the Modulus of Elasticity of Wooden Boards

https://research.thinkwood.com/en/permalink/catalogue1140
Year of Publication
2012
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Author
Fink, Gerhard
Kohler, Jochen
Organization
ETH Zurich
Year of Publication
2012
Country of Publication
Switzerland
Format
Thesis
Material
Glulam (Glue-Laminated Timber)
Topic
Mechanical Properties
Keywords
Spruce
Non-Destructive Tests
Tensile tests
Young's Modulus
Knots
Language
German
Research Status
Complete
Summary
At the institute of structural engineering at the ETH Zurich multiple of investigations are conducted to analyse the material properties of Norway spruce timber boards. The investigations are part of the research project “Influence of varying material properties on the load bearing capacity of glued laminated timber (glulam)”. The majority of the investigations are non-destructively. The investigations are taking place on 400 timber boards. On all specimens the moisture content, the density, the Eigenfrequency and the longitudinal ultrasonic runtime was investigated. Further all knots with a diameter larger then 10mm are measured. Thereby the position and the size of all the knots are documented. Subsequently on 200 selected boards non-destructive tensile test are performed to analyse the local young modulus. Herewith it was particularly focused on the investigation of the stiffness of areas having knots or knot clusters and areas without knots. The strains are measured with an optical coordinatemeasurement device. In the last part of the experimental investigation the deformation and failure behaviour of significant knot clusters is analysed. The strains are measured with digital image correlation. Focus of the entire experimental analysis was the investigation of the young modulus and the quantifications of its variability within timber members and between timber members. Within this study a database was produced to evaluate existing test methods for the estimation of the young modulus. Further, the results can be used as a basis for further investigations on the variability of structural timber.
Online Access
Free
Resource Link
Less detail

Steel-to-Timber Joints of Beech-LVL with Very High Strength Steel Dowels

https://research.thinkwood.com/en/permalink/catalogue1502
Year of Publication
2016
Topic
Connections
Mechanical Properties
Material
LVL (Laminated Veneer Lumber)
Author
Misconel, Andrea
Ballerini, Marco
Van de Kuilen, Jan-Willem
Year of Publication
2016
Country of Publication
Austria
Format
Conference Paper
Material
LVL (Laminated Veneer Lumber)
Topic
Connections
Mechanical Properties
Keywords
Beech
Steel-to-Timber
Joints
Steel Plates
Steel Dowels
Very High Strength Steel
Tensile Tests
Full Scale
Load Carrying Capacity
Ductility
Stiffness
Eurocode 5
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 301-308
Summary
Double-shear steel-to-timber joints of beech laminated veneer lumber (LVL) with slotted-in steel plates using very high strength steel (VHSS) dowels have been investigated. Tensile tests on full-scale joints with one, two, three and six dowels have been carried out, using both VHSS and mild steel dowels. The goal of the research was to investigate the mechanical behaviour of joints of beech-LVL, with regard to load-carrying capacity (LCC), ductility, stiffness; and to find out whether the current design rules of Eurocode 5 are suitable for LVL and VHSS steels. Other examined aspects were the effect of multiple fasteners in a row and the influence of fastener steel grade. Tests showed higher values of joints with VHSS dowels, characterized generally by low scatter. The prediction ability of Eurocode 5 has been found to be inadequate and too conservative. A proposal for improvement is included.
Online Access
Free
Resource Link
Less detail

7 records – page 1 of 1.