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12 records – page 1 of 2.

Predicting the Average Compression Strength of CLT by Using the Average Density or Compressive Strength of Lamina

https://research.thinkwood.com/en/permalink/catalogue3020
Year of Publication
2022
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Tian, Zhaopeng
Gong, Yingchun
Xu, Junhua
Li, Mingyue
Wang, Zhaohui
Ren, Haiqing
Organization
Chinese Academy of Forestry
Editor
Elustondo, Diego
Publisher
MDPI
Year of Publication
2022
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Compressive Strength
Density
Linear Regression Analysis
Monte Carlo Simulation
Plated Larch
Prediction Model
Research Status
Complete
Series
Forests
Summary
The compressive strength in the major direction of cross-laminated timber CLT is the key to supporting the building load when CLT is used as load-bearing walls in high-rise wood structures. This study mainly aims to present a model for predicting the average compressive strength of CLT and promoting the utilization of CLT made out of planted larch. The densities and compressive strengths of lamina specimens and CLT samples with widths of 89 and 178 mm were evaluated, and their relationship was analyzed to build a prediction model by using Monte Carlo simulation. The results reveal that the average density of the lamina and CLT were about equal, whereas the average compressive strength of the CLT was just about 72% of that of the lamina. Width exerted no significant effect on the average compressive strength of the CLT, but homogenization caused the wider CLT to have a smaller variation than that of the lamina. The average compressive strength of the lamina could be calculated by using the average density of lamina multiply by 103.10, and the average compressive strength of the CLT could be calculated according to the compression strength of lamina in major and minor direction, therefore, a new prediction model is determined to predict the average compression strength of CLT by using the average density of lamina or CLT, the average compression strength of CLT made in this study is about 74.23 times of the average density of the lamina. The results presented in this study can be used to predict the average compressive strength of CLT by using the average density of lamina and provide a fundamental basis for supporting the utilization of CLT as load-bearing walls.
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Structural Reliability Analysis of Cross Laminated Timber Plates Subjected to Bending

https://research.thinkwood.com/en/permalink/catalogue2713
Year of Publication
2020
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Vilela, Ramon
Mascia, Nilson
Santos, Luciano
Year of Publication
2020
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Bending
Structural Reliability
Monte Carlo Simulation
Failure Mode
Probability of Failure
Load Capacity
Four Point Bending Test
Conference
Society of Wood Science and Technology International Convention
Research Status
Complete
Summary
Failure modes of Cross Laminated Timber (CLT) plates reach by an excess of tensile stress on finger joints, shear stress on transverse layer due to rolling shear effect and by natural vibration. The Probability of Failure (POF) of CLT plates can be estimated from the probability distribution of their ruptures and stiffnesses, as well as their correlation coefficients. In this context, the aim of this paper is to estimate the load capacity of Cross Laminated Timber plates from a specific probability of failure and the experimental results of mechanical and physical properties. For this purpose, CLT plates were manufactured with wood species of Pinus taeda L., from Brazilian reforestation plantations. Four-point bending tests were conducted to investigate the failure behavior of the CLT plates. Density and moisture content were obtained from small specimens extracted from these plates. Monte Carlo simulation was carried out to predict the probabilistic loads that produce the failure of CLT plates, considering the failure occasioned by natural vibration as well. Experimental and numerical results of the failure modes were compared and the maximum loads to an acceptable probability of failure of the several CLT lengths were estimated too.
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Torque Loading Tests on the Rolling Shear Strength of Cross-Laminated Timber

https://research.thinkwood.com/en/permalink/catalogue1416
Year of Publication
2016
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Lam, Frank
Li, Yuan
Li, Minghao
Publisher
Springer Japan
Year of Publication
2016
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Rolling Shear Strength
Polyurethane
Mountain Pine Beetle
Torque Loading Tests
Failure Modes
Monte Carlo
Finite Element Model
Brittle Failure
Research Status
Complete
Series
Journal of Wood Science
Summary
In this study , torque loading tests on small shear blocks were performed to evaluate the rolling shear strength of cross-laminated timber (CLT). The CLT plates in the tests were manufactured with Mountain Pine Beetle-afflicted lumber boards and glued with polyurethane adhesive; two types of layups (five-layer and three-layer) with a clamping pressure 0.4 MPa were studied. The small block specimens were sampled from full-size CLT plates and the cross layers were processed to have an annular cross section. These specimens were tested under torque loading until brittle shear failure occurred in the middle cross layers. Based on the test results, the brittle shear failure in the specimens was evaluated by detailed finite element models to confirm the observed failure mode was rolling shear. Furthermore, a Monte Carlo simulation procedure was performed to investigate the occurrence probability of different shear failure modes in the tests considering the randomness of the rolling shear strength and longitudinal shear strength properties in the wood material. The result also suggested the probability of rolling shear failure is very high, which gives more confident proof that the specimens failed dominantly in rolling shear. It was also found that the torque loading test method yielded different rolling shear strength values compared to the previous research from short-span beam bending tests; such a difference may mainly be due to the different stressed volumes of material under different testing methods, which can be further investigated using the size effect theory in the future.
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Design of Timber Members Subjected to Axial Compression or Combined Axial Compression and Bending Based on 2nd Order Theory

https://research.thinkwood.com/en/permalink/catalogue115
Year of Publication
2015
Topic
Design and Systems
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Columns
Author
Frangi, Andrea
Steiger, René
Theiler, Matthias
Organization
International Network on Timber Engineering Research (INTER)
Year of Publication
2015
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
Application
Columns
Topic
Design and Systems
Mechanical Properties
Keywords
Bending
Buckling
Codes
Compression
Deformation
Monte Carlo
Simulation
Structural
Testing
Conference
INTER 2015
Research Status
Complete
Notes
August 24-27, 2015, Sibenik, Croatia
Summary
The paper examines the behaviour of structural timber members subjected to axial compression or combined axial compression and bending. Based on experimental and numerical investigations, the accuracy of the existing approach in Eurocode 5 for the design of timber members subjected to axial compression or combined axial compression and bending is assessed and modifications are suggested. By means of extensive experimental investigations, a data base was created for the validation of calculation models and for the assessment of design concepts. In order to assess the behaviour of timber members subjected to axial compression or combined axial compression and bending, strain-based calculation models were developed. The investigations indicate that the existing approach of Eurocode 5 based on 2nd order analysis can lead to an overestimation of the load-bearing capacity. Hence, a modified design approach was developed which agrees with the results of the Monte Carlo simulations very well and thus ensures a safe and economical design of timber members subjected to compression or combined compression and bending.
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Prediction of Compressive Strength of Cross-Laminated Timber Panel

https://research.thinkwood.com/en/permalink/catalogue517
Year of Publication
2015
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Walls
Author
Oh, Jung-Kwon
Lee, Jun-Jae
Hong, Jung-Pyo
Publisher
Springer Japan
Year of Publication
2015
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Walls
Topic
Mechanical Properties
Keywords
Lamina
Monte Carlo
Compressive Strength
Research Status
Complete
Series
Journal of Wood Science
Summary
Compressive strength of cross-laminated timber (CLT) is one of the important mechanical properties which should be considered especially in design of mid-rise CLT building because it works to resist a vertical bearing load from the upper storeys. The CLT panel can be manufactured in various combinations of the grade and dimension of lamina. This leads to the fact that an experimental approach to evaluate the strength of CLT would be expensive and time-demanding. In this paper, lamina property-based models for predicting the compressive strength of CLT panel was studied. A Monte Carlo simulation was applied for the model prediction. A set of experimental compression tests on CLT panel (short column) was conducted to validate the model and it shows good results. Using this model, the influence of the lamina’s width on the CLT compressive strength was investigated. It reveals that the CLT compressive strength increases with the increase in the number of lamina. It was thought that repetitive member effect (or dispersion effect) is applicable for the CLT panel, which was explained by the decrease of the variation in strength. This dependency of the number of lamina needs further study in development of reference design values, CLT wall design and CLT manufacturing.
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Bending Strength of Cross Laminated Timber Beams Loaded In Plane

https://research.thinkwood.com/en/permalink/catalogue28
Year of Publication
2014
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Beams
Author
Blaß, Hans Joachim
Flaig, Marcus
Year of Publication
2014
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Beams
Topic
Mechanical Properties
Keywords
Bending Strength
Monte Carlo Model
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 10-14, 2014, Quebec City, Canada
Summary
A computer aided numerical model for the simulation of the in-plane bending strength of CLT beams is presented. The model uses the Monte-Carlo-Method to generate mechanical characteristics of board lamellae and is suitable for the investigation of statistical effects such as homogenisation and size effects. Six different types of CLT beams, varying in size and in layup, were tested to validate the model and except for beams with only one lamella in direction of the beam height good agreement was found between the experimental results and the model’s simulations.
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Reassessment of the Integrity of a Partially Failed Glulam Structure

https://research.thinkwood.com/en/permalink/catalogue128
Year of Publication
2014
Topic
Design and Systems
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Roofs

Compressive Strength of Cross-Laminated Timber Panel

https://research.thinkwood.com/en/permalink/catalogue280
Year of Publication
2014
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Walls
Author
Oh, Jung-Kwon
Hong, Jung-Pyo
Lee, Junjae
Year of Publication
2014
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Walls
Topic
Mechanical Properties
Keywords
Compression Strength
Mid-Rise
Vertical Bearing Load
Monte Carlo
Conference
International Convention of Society of Wood Science and Technology
Research Status
Complete
Notes
June 23-27, 2014, Zvolen, Slovakia, p.761-768
Summary
Compressive strength of cross-laminated timber (CLT) is one of the important mechanical properties which should be considered in the design of mid-rise CLT building because it work to resist a heavy vertical bearing load from the upper level. The CLT panel can be manufactured in various combinations of the grade and dimension of lamina. Therefore, an experimental approach to evaluating the strength of CLT would be expensive and time-demanding. In this paper, lamina-property based models for predicting the compressive strength of CLT panel was studied. Monte Carlo simulation was applied for the model prediction. A set of experimental compression test on CLT panel (short column) was conducted to validate this model. Using this model, the influence of the panel’s width on the global CLT compressive strength was investigated. It reveals that the CLT compressive strength increases with the increase in width of the panel (or increase of number of lamina). It can be thought that there is repetitive member effect for the CLT panel wall, which was explained by the decrease of the variation in strength in case of the model simulation. This dependency of the number of lamina needs to be considered when reference design value was determined and very narrow CLT column (Wall) will be designed.
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Structural Behaviour of Glued Laminated Timber Beams with Unreinforced and Reinforced Notches

https://research.thinkwood.com/en/permalink/catalogue311
Year of Publication
2014
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
Jockwer, Robert
Organization
ETH Zurich
Year of Publication
2014
Format
Thesis
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Mechanical Properties
Keywords
Finite Element Model
Load Carrying Capacity
notch
Monte Carlo
Failure Behavior
Research Status
Complete
Summary
In this thesis the reliability of the design of unreinforced notched beams is evaluated and recommendations for the design of reinforced notched beams are given. The review of design approaches for reinforced notched beams shows, that so far the reinforcement is designed only with regard to the perpendicular to grain force acting in the notch corner. The evaluation of test results from literature shows that a stiff reinforcement has the best reinforcing effect but initial cracking cannot be prevented. The failure behaviour of the reinforced notch is studied in more detail by means of experiments and a FE model. Initial cracking of the reinforced notch comes along with crack opening, whereas ultimate failure with excessive crack growth is accompanied by shearing of the crack. An analytical model is presented for the description of the structural behaviour of reinforced notched beams. The parallel and perpendicular to the grain stiffness of the reinforcement is accounted for in the model. A high stiffness of the reinforcement parallel to the grain is required in order to reduce the mode 1 loading of the notch corner and to prevent initial cracking. The mode 2 loading of the crack increases with increasing crack length. In order to achieve higher load-carrying capacities for notched beams with longer cracks, reinforcement with high stiffness parallel to the grain is required. Recommendations are given for the required reinforcement of notched beams in order to restore the shear capacity of the reduced cross-section.
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Estimation of Bending Stiffness, Moment Carrying Capacity and Internal Shear Force of Sugi CLT Panel

https://research.thinkwood.com/en/permalink/catalogue622
Year of Publication
2014
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Floors
Author
Okabe, Minoru
Yasumura, Motoi
Kobayashi, Kenji
Year of Publication
2014
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Floors
Topic
Mechanical Properties
Keywords
Internal Shear Strength
Bending Strength
Moment Carrying Capacity
Monte Carlo
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 10-14, 2014, Quebec City, Canada
Summary
CLT panels consist of several layers of lumber stacked crosswise and glued together on their faces. Prototype Sugi CLT floor panels were manufactured and bending and internal shear tests were carried out under the different parameters of lumber MOE, number of layers, thickness of lumber and thickness of CLT panels. On the basis of above tests, internal shear strength, bending stiffness and moment carrying capacity were estimated based on the lumber properties by Monte Carlo method. Bending stiffness EI of CLT panels could be estimated by adopting parallel layer theory and equivalent section area. Experimental moment carrying capacity showed 12% higher value than the calculated moment carrying capacity by average lumber failure method, and also showed 45% higher value than the calculated moment carrying capacity by minimum lumber failure method due to the reinforcement of the outer layer by the neighboring cross layer. Experimental internal shear force of CLT panel showed 30% higher value than the calculated one.
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12 records – page 1 of 2.