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12 records – page 1 of 2.

Bending, Shear, and Compressive Properties of Three- and Five-Layer Cross-Laminated Timber Fabricated with Black Spruce

https://research.thinkwood.com/en/permalink/catalogue2589
Year of Publication
2020
Topic
Design and Systems
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
He, Minjuan
Sun, Xiaofeng
Li, Zheng
Feng, Wei
Publisher
SpringerOpen
Year of Publication
2020
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Design and Systems
Mechanical Properties
Keywords
Black Spruce
Panels
Bending
Thickness
Language
English
Research Status
Complete
Series
Journal of Wood Science
Summary
Cross-laminated timber (CLT) is an innovative engineering wood product made by gluing layers of solid-sawn lumber at perpendicular angles. The commonly used wood species for CLT manufacturing include spruce-pine-fir (SPF), douglas fir-larch, and southern pine lumber. With the hope of broadening the wood species for CLT manufacturing, the purposes of this study include evaluating the mechanical properties of black spruce CLT and analyzing the influence of CLT thickness on its bending or shear properties. In this paper, bending, shear, and compressive tests were conducted respectively on 3-layer CLT panels with a thickness of 105 mm and on 5-layer CLT panels with a thickness of 155 mm, both of which were fabricated with No. 2-grade Canadian black spruce. Their bending or shear resisting properties as well as the failure modes were analyzed. Furthermore, comparison of mechanical properties was conducted between the black spruce CLT panels and the CLT panels fabricated with some other common wood species. Finally, for both the CLT bending panels and the CLT shear panels, their numerical models were developed and calibrated with the experimental results. For the CLT bending panels, results show that increasing the CLT thickness whilst maintaining identical span-to-thickness ratios can even slightly reduce the characteristic bending strength of the black spruce CLT. For the CLT shear panels, results show that increasing the CLT thickness whilst maintaining identical span-to-thickness ratios has little enhancement on their characteristic shear strength. For the CLT bending panels, their effective bending stiffness based on the Shear Analogy theory can be used as a more accurate prediction on their experiment-based global bending stiffness. The model of the CLT bending specimens is capable of predicting their bending properties; whereas, the model of the CLT shear specimens would underestimate their ultimate shear resisting capacity due to the absence of the rolling shear mechanism in the model, although the elastic stiffness can be predicted accurately. Overall, it is attested that the black spruce CLT can provide ideal bending or shear properties, which can be comparable to those of the CLT fabricated with other commonly used wood species. Besides, further efforts should focus on developing a numerical model that can consider the influence of the rolling shear mechanism.
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Comparison of Glulam Post-To-Beam Connections Reinforced by two Different Dowel-Type Fasteners

https://research.thinkwood.com/en/permalink/catalogue55
Year of Publication
2015
Topic
Connections
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
He, Minjuan
Liu, Hui-Fen
Publisher
ScienceDirect
Year of Publication
2015
Country of Publication
Netherlands
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Connections
Mechanical Properties
Keywords
Reinforcement
Rods
Seismic
Self-Tapping Screws
Moment Resistance
Language
English
Research Status
Complete
Series
Construction and Building Materials
Summary
In this paper, the performance improvement of glulam post-to-beam connections reinforced by plain round rods (PRRs) and self-tapping screws (STSs) were compared. Five non-reinforced post-to-beam bolted connections, five PRR-reinforcing connections and five STS-reinforcing connections were experimentally investigated under monotonic and low frequency cyclic loading. Their stiffness, ductility, moment resistance capacity, failure modes and seismic behavior were analyzed. The findings indicated that both of these two reinforcements could mitigate wood splitting, and change the failure mode from brittle failure to ductile failure. The maximum moment and failure rotation of PRR-reinforcing connection were increased by 29% and 6% respectively, compared with those of non-reinforced connection. In addition, those of STS-reinforcing connection increased by 86% and 145% respectively. Furthermore, the comparison of PRR-reinforcing and STS-reinforcing connections indicated that the connection ductility reinforced by self-tapping screws enhanced more significantly; 106% higher than that of PRR-reinforcing connection. Moreover, under the low frequency cyclic loading, PRR-reinforcing and STS-reinforcing connections dissipated more energy (336% and 641% respectively) with a lower stiffness degeneration rate and a higher equivalent viscous damping ratio than those of non-reinforced connection. Besides, the dissipation energy and equivalent viscous damping ratio of STS-reinforcing connection were larger than those of PRR-reinforcing connection.
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Comparison of the Seismic Performance of Different Hybrid Timber-Steel Frame Configurations

https://research.thinkwood.com/en/permalink/catalogue1775
Year of Publication
2016
Topic
Seismic
Design and Systems
Application
Hybrid Building Systems
Shear Walls
Author
Marin, Jose Alberto
He, Minjuan
Year of Publication
2016
Country of Publication
Austria
Format
Conference Paper
Application
Hybrid Building Systems
Shear Walls
Topic
Seismic
Design and Systems
Keywords
Finite Element Model
Timber-Steel Hybrid
Deformation
Lateral Loading
Abaqus
Displacement
Inter-Story Drift
Diaphragm
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 5401-5408
Summary
This paper presents a finite element modeling case study of three different designs of hybrid timber-steel 6-story buildings. One of the buildings is composed by steel frames and timber diaphragms while the other two cases consist of the initial design with timber shear walls added in different dispositions, one with outer walls and the other...
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Compressive Behavior of Glulam Columns with Initial Cracks Under Eccentric Loads

https://research.thinkwood.com/en/permalink/catalogue1463
Year of Publication
2018
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Columns
Author
Zhang, Jing
He, Minjuan
Li, Zheng
Publisher
Springer Berlin Heidelberg
Year of Publication
2018
Country of Publication
Germany
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Columns
Topic
Mechanical Properties
Keywords
Cracks
Compression Loads
Failure Modes
Load Bearing Capacity
Numerical Model
Language
English
Research Status
Complete
Series
International Journal of Advanced Structural Engineering
ISSN
2008-6695
Summary
This paper investigates the mechanical performance of longitudinally cracked glulam columns under eccentric compression loads. Experimental investigation was conducted to explore the influence of initial cracks on the failure modes and load bearing capacity of glulam columns. Two different crack patterns named DC and IC, and two column lengths (i.e. 600 and 1100 mm) were considered in the experiments. It was indicated that these two crack patterns reduced the capacity of slender glulam columns and the difference of failure modes was observed between glulam columns with and without initial cracks. Further, a numerical model was developed and validated by the test results. With the application of cohesive zone material model, the propagation of initial cracks could be considered in the numerical modeling. A parametric study was carried out by the verified model and the influence of crack lengths and crack locations was further investigated. From the numerical analysis, it was found that through cracks reduced the capacity of glulam columns significantly. Also, crack location impacts the capacity of glulam columns and the extent of impact relates to the slenderness ratio of the columns, while cracks with different lengths have similar influence on the capacity of columns.
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Investigation into the Hysteretic Performance of Self-Centering Timber Beam-to-Column Joints

https://research.thinkwood.com/en/permalink/catalogue1562
Year of Publication
2016
Material
Glulam (Glue-Laminated Timber)
Author
Wang, Kangli
Li, Zheng
He, Minjuan
Year of Publication
2016
Country of Publication
Austria
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
Keywords
China
Post-Tensioned
Self-Centering
Energy Dissipation
Joint
Cyclic Loading Tests
Hysteretic Behaviour
Moment-Resisting Capacity
Failure Mechanism
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 1540-1547
Summary
The seismic performance of a post-tensioned (PT) energy dissipating beam-to-column joint for glulam heavy timber structure is investigated in this paper. Such connection incorporates post-tensioned high-strength strand to provide self-centering capacity along with energy dissipating produced by a special steel cap, which is attached with the timber beam and also to prevent the end bearing failure of wood. The moment-rotation behaviour of the proposed posttensioned timber joint was investigated through a series of cyclic loading tests. The timber joint was loaded at the end of the beams to produce a moment at the joint, and the tests were conducted with three different post-tension forces in the steel strand. The hysteretic behaviour and self-centering capacity of the joint are evaluated based on the results from cyclic loading tests. The failure mechanism of the joint was illustrated through test observations, and the momentresisting capacity and energy dissipation of the joint were analysed with regard to various drift level. This research aims to provide possible solutions to minimize the residual deformation of heavy timber structure made of glulam in China.
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Numerical Analysis on Tensile Performance of Bolted Glulam Joints with Initial Local Cracks

https://research.thinkwood.com/en/permalink/catalogue1380
Year of Publication
2018
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Author
Zhang, Jing
He, Minjuan
Li, Zheng
Publisher
Springer Japan
Year of Publication
2018
Country of Publication
Japan
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Topic
Mechanical Properties
Keywords
Bolted Joints
Cracks
Finite Element Model
Failure Modes
Tension Load
Language
English
Research Status
Complete
Series
Journal of Wood Science
ISSN
1611-4663
Summary
Under varying climate conditions, cracks are commonly observed in bolted joints, owing to the shrinkage of wood and confinement from slotted-in steel plates and bolts. A three-dimensional finite element model was developed to investigate the mechanical behavior of bolted glulam joints with initial cracks. Wood foundation was prescribed in the model to simulate the local crushing behavior of wood surrounding the bolts. The behavior of wood in compression and the foundation were defined as transversely isotropic plastic in the software package ANSYS. Cohesive zone model was applied in the numerical analysis to consider the propagation of initial cracks and brittle failure of wood in the bolted joints under tension load. The numerical model was validated by the experiments conducted on full-scale specimens and it is indicated that the numerical model has good ability in predicting the failure modes and capacity of tension joints with local cracks. To further investigate the influence of crack number, length and locations, a parametric study was conducted with the verified model. Moreover, to study the effects of cracks on the behavior of bolted joints with different failure modes, another bolted joint including bolts with different strength grades and diameters was designed and analyzed in the parametric study, which was expected to have bolt yielding failure mode. It was found that the initial cracks can decrease the capacity and initial stiffness of tension joints by up to 16.5 and 34.8%, respectively.
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Performance Evaluation of Multi-Storey Cross-Laminated Timber Structures Under Different Earthquake Hazard Levels

https://research.thinkwood.com/en/permalink/catalogue1384
Year of Publication
2018
Topic
Design and Systems
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Shear Walls
Author
Sun, Xiaofeng
He, Minjuan
Li, Zheng
Shu, Zhan
Publisher
Springer Japan
Year of Publication
2018
Country of Publication
Japan
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Shear Walls
Topic
Design and Systems
Keywords
Equivalent Static Force Procedure
Multi-Storey
Seismic Performance
Lateral Load Resisting System
Inter-Story Drift
Pinching4 Model
Numerical Model
Probability of Non-Exceedance
Empirical Cumulative Distribution Functions
Language
English
Research Status
Complete
Series
Journal of Wood Science
ISSN
1611-4663
Summary
The inter-storey drift limitations are meaningful reference values for structural seismic performance evaluation. This paper presents an analytical investigation into the seismic performance of multi-storey cross-laminated timber (CLT) structures to obtain the drift limitations under different earthquake hazard levels reasonably. The Pinching4 model was used to simulate the nonlinear mechanical behavior of three types of connections used in CLT structures, and a numerical model was further developed to capture the lateral load-resisting properties of CLT shear walls. Moreover, three benchmark multi-storey CLT apartment buildings were designed using the Equivalent Static Force Procedure according to National Building Code of Canada (NBCC), and simplified structural models were developed for these buildings. Depending on the results from numerous time-history dynamic analyses, the empirical cumulative distribution functions (CDFs) of the maximum inter-storey drifts were constructed for the three benchmark buildings. The probability of non-exceedance (PNE) of inter-storey drift thresholds under different earthquake hazard levels was proposed and validated. It is recommended that for low-rise CLT buildings within three stories, values of 0.30%, 0.75%, and 1.40% can be considered as the drift limitations for frequent, medium, and rare seismic hazard levels, respectively. For mid-rise or high-rise buildings without three stories, 0.25%, 0.70%, and 1.30% can be considered as drift limitations.
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Seismic Performance Assessment of Steel Frame Infilled with Prefabricated Wood Shear Walls

https://research.thinkwood.com/en/permalink/catalogue1313
Year of Publication
2018
Topic
Seismic
Material
Light Frame (Lumber+Panels)
Application
Shear Walls
Hybrid Building Systems
Author
Li, Zheng
He, Minjuan
Wang, Xijun
Li, Minghao
Publisher
ScienceDirect
Year of Publication
2018
Country of Publication
Netherlands
Format
Journal Article
Material
Light Frame (Lumber+Panels)
Application
Shear Walls
Hybrid Building Systems
Topic
Seismic
Keywords
Timber-Steel Hybrid
Seismic Performance
Multi-Story
Numerical Model
Damage
Stiffness
Nonlinear Time History Analysis
Language
English
Research Status
Complete
Series
Journal of Constructional Steel Research
Summary
Steel-timber hybrid structural systems offer a modern solution for building multi-story structures with more environmentally-friendly features. This paper presents a comprehensive seismic performance assessment for a kind of multi-story steel-timber hybrid structure. In such a hybrid structure, steel moment resisting frames are infilled with prefabricated light wood frame shear walls to serve as the lateral load resisting system (LLRS). In this paper, drift-based performance objectives under various seismic hazard levels were proposed based on experimental observations. Then, a numerical model of the hybrid structure considering damage accumulation and stiffness degradation was developed and verified by experimental results, and nonlinear time-history analyses were conducted to establish a database of seismic responses. The numerical results further serve as a technical basis for estimating the structure's fundamental period and evaluating post-yielding behavior and failure probabilities of the hybrid structure under various seismic hazard levels. A load sharing parameter was defined to describe the wall-frame lateral force distribution, and a formula was proposed and calibrated by the time-history analytical results to estimate the load sharing parameter. Moreover, earthquake-induced non-structural damage and residual deformation were also evaluated, showing that if designed properly, desirable seismic performance with acceptable repair effort can be obtained for the proposed steel-timber hybrid structural system.
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Seismic Reliability Assessment of Mid- and High-rise Post-tensioned CLT Shear Wall Structures

https://research.thinkwood.com/en/permalink/catalogue2508
Year of Publication
2020
Topic
Seismic
Design and Systems
Material
CLT (Cross-Laminated Timber)
Application
Walls
Author
Sun, Xiaofeng
Li, Zheng
He, Minjuan
Publisher
KoreaScience
Year of Publication
2020
Country of Publication
Korea
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Walls
Topic
Seismic
Design and Systems
Keywords
Post-Tensioned Timber
Seismic Reliability
Fragility Analysis
Response Surface Method
Multi-Storey
Tall Timber
Language
English
Research Status
Complete
Series
International Journal of High-Rise Buildings
Online Access
Free
Resource Link
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12 records – page 1 of 2.