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Application of Particle Tracking in Large Scale Timber Connection Testing

https://research.thinkwood.com/en/permalink/catalogue1943
Year of Publication
2018
Topic
Connections
Material
CLT (Cross-Laminated Timber)
Author
Ottenhaus, Lisa-Mareike
Li, Minghao
Nokes, Roger
Year of Publication
2018
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Topic
Connections
Keywords
Particle Tracking Velocimetry
Digital Image Correlation
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 20-23, 2018, Seoul, Republic of Korea
Summary
Particle Tracking Velocimetry (PTV) is a quantitative field measuring technique originally designed to track individual particles in fluid flows. In this study, PTV was applied for the first time in the context of large scale timber connection testing. The suitability of PTV in structural applications was assessed by tracking the attachment points of string potentiometers and comparing the PTV displacements to those obtained by the potentiometers. Furthermore, it was found that PTV was able to capture crack growth and compute the resulting displacement field in the connection area.
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Direct Displacement-based Seismic Design of Glulam Frames with Buckling Restrained Braces

https://research.thinkwood.com/en/permalink/catalogue3265
Year of Publication
2022
Topic
Seismic
Material
Glulam (Glue-Laminated Timber)
Application
Frames
Author
Dong, Wenchen
Li, Minghao
Sullivan, Timothy
MacRae, Gregory
Lee, Chin-Long
Chang, Theodore
Organization
University of Canterbury
University College London
Publisher
Taylor&Francis Online
Year of Publication
2022
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Frames
Topic
Seismic
Keywords
Glulam Frame
Buckling Restrained Braces
Direct Displacement-Based Design
BRB-Timber Connections
Nonlinear Time-history Analyses
Research Status
Complete
Series
Journal of Earthquake Engineering
Summary
This paper presents a direct displacement-based design (DDBD) approach for the buckling restrained braces (BRBs) braced glue-laminated timber (glulam) frame (BRBGF) structures. First, the critical design parameters of the DDBD approach were derived for BRBGFs. Then, using experimentally verified numerical models, pushover analyses and nonlinear time-history analyses (NLTHAs) were conducted on a series of one-storey BRBGFs to calibrate the stiffness adjustment factor for BRB-timber connections and the spectral displacement reduction factor . Finally, the DDBD approach was verified as a prospective approach for the seismic design of multi-storey BRBGF buildings by NLTHAs of the case study buildings.
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Ductility and Overstrength of Dowelled LVL and CLT Connections Under Cyclic Loading

https://research.thinkwood.com/en/permalink/catalogue1504
Year of Publication
2016
Topic
Connections
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
LVL (Laminated Veneer Lumber)
Author
Ottenhaus, Lisa-Mareike
Li, Minghao
Smith, Tobias
Quenneville, Pierre
Year of Publication
2016
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
LVL (Laminated Veneer Lumber)
Topic
Connections
Mechanical Properties
Keywords
Ductility
Overstrength
Cyclic Loading
Monotonic Loading
Dowels
Ductile Failure
Brittle Failure
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 325-333
Summary
This paper presents an experimental study on ductility and overstrength of dowelled connections. Connection ductility and overstrength derived from monotonic testing are often used in timber connection design in the context of seismic loading, based on the assumption that these properties are similar under monotonic and cyclic loading. This assumption could possibly lead to non-conservative connection design. Therefore, it is necessary to quantify ductility and overstrength for cyclic loading and contrast them with their monotonic performance. For this purpose, monotonic and quasi-static cyclic experimental tests were performed on dowelled LVL and CLT connections. The experimental results were also compared with strength predictions from state-of-the-art analytical models in literature that were verified for ductile and brittle failure under monotonic loading. This work also allowed investigation into a generally applicable overstrength factor for push-pull loaded dowelled connections.
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Ductility of Dowelled New Zealand Douglas-Fir CLT Connections Under Monotonic and Cyclic Loading

https://research.thinkwood.com/en/permalink/catalogue2114
Year of Publication
2019
Topic
Connections
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Author
Ottenhaus, Lisa-Mareike
Li, Minghao
Brown, J.
Ravn, C.
Scott, B.
Organization
University of Canterbury
Year of Publication
2019
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Topic
Connections
Keywords
Multi-Story
Douglas-Fir
Dowel-Type Connections
Dowels
Conference
Pacific Conference on Earthquake Engineering
Research Status
Complete
Summary
Cross-laminated Timber (CLT) is gaining popularity in Australasia as a building material for multi-storey structures. For multi-storey timber buildings located in seismic areas, designing strong but ductile hold-downs for CLT shear walls can be challenging and requires careful structural connection design. In this study, dowelled connections in New Zealand Douglas-Fir (D.Fir) CLT with inserted steel plates were experimentally investigated as a solution for hold-downs in multi-storey timber buildings. The dowel group spacing was varied for CLT3 (3-ply, 135 mm thick), CLT5 (5-ply, 175 mm thick) and CLT7 (7-ply, 275 mm thick) D.Fir CLT to investigate the spacing impact on ductility of the hold-down connections under both monotonic and quasi-static cyclic loading. These results were also compared with past similar testing of dowelled connections in 5-ply (150 mm) Radiata Pine CLT. A total of 12 monotonic and 36 quasi-static cyclic tests were carried out and it was observed that increased dowel spacing increases ductility with similar strength when compared to past more dense dowel spacing tests. Furthermore, to deter the onset of tension perpendicular to grain brittle failure, fully threaded screws and nuts were added to the dowelled connection and the impact of this is discussed.
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Ductility of Large-scale Dowelled CLT Connections under Monotonic and Cyclic Loading

https://research.thinkwood.com/en/permalink/catalogue2254
Year of Publication
2017
Topic
Connections
Material
CLT (Cross-Laminated Timber)
LVL (Laminated Veneer Lumber)
Application
Shear Walls

Evaluating Rolling Shear Strength Properties of Cross-Laminated Timber by Short-Span Bending Tests and Modified Planar Shear Tests

https://research.thinkwood.com/en/permalink/catalogue1403
Year of Publication
2017
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Li, Minghao
Publisher
Springer Japan
Year of Publication
2017
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Rolling Shear Strength
Non-Edge-Glued
Pine
Thickness
Three Point Bending Test
Planar Shear Tests
Europe
Canada
Research Status
Complete
Series
Journal of Wood Science
Summary
This paper presents an experimental study on rolling shear (RS) strength properties of non-edge-glued cross-laminated timber (CLT) made out of New Zealand Radiata pine (Pinus radiata) structural timber. CLT specimens with 35 and 20 mm thick laminations were studied to evaluate the influence of lamination thickness on the RS strength of CLT. Short-span three-point bending tests were used to introduce high RS stresses in cross layers of CLT specimens and facilitate the RS failure mechanism. Modified planar shear tests from the conventional two-plate planar shear tests were also used to evaluate the RS strength properties. It was found that two test methods yielded comparable RS strength properties and the lamination thickness significantly affected RS strength of the CLT specimens. The test results also indicated that the recommended characteristic RS strength values of CLT products in Europe and Canada might be over conservative. Also, it might be more efficient to specify different RS strength values for CLT with different lamination thickness given the minimum width-to-depth ratio of laminations is satisfied.
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Evaluating Rolling Shear Strength Properties of Cross Laminated Timber by Torsional Shear Tests and Bending Test

https://research.thinkwood.com/en/permalink/catalogue307
Year of Publication
2014
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Li, Minghao
Lam, Frank
Li, Yuan
Year of Publication
2014
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
SPF
Polyurethane
Rolling Shear Strength
Torsional Shear Test
Bending Test
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 10-14, 2014, Quebec City, Canada
Summary
This paper presents a study on evaluating rolling shear (RS) strength properties of cross laminated timber (CLT) using torsional shear tests and bending tests. The CLT plates were manufactured with Spruce-Pine-Fir boards and glued with polyurethane adhesive. Two types of layups (3-layer and 5-layer) and two clamping pressures (0.1 MPa and 0.4 MPa) were studied. For the torsional shear tests, small shear block specimens were sampled from the CLT plates and the cross layers were processed to have an annular cross section. Strip specimens were simply sampled from the CLT plates for the bending tests. Based on the failure loads, RS strength properties were evaluated by torsional shear formula, composite beam formulae as well as detailed finite element models, respectively. It was found that the two different test methods yielded different average RS strength value for the same type of CLT specimens. The test results showed that the CLT specimens pressed with the higher clamping pressure had slightly higher average RS strength. The specimens with thinner cross layers also had higher RS strength than the specimens with thicker cross layers.
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Experimental testing and analytical modelling of glulam moment connections with self-drilling dowels

https://research.thinkwood.com/en/permalink/catalogue3011
Year of Publication
2021
Topic
Connections
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Author
Dong, Wenchen
Li, Minghao
He, Minjuan
Li, Zhen
Organization
University of Canterbury
Tongji University
Publisher
ASCE
Year of Publication
2021
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Topic
Connections
Mechanical Properties
Keywords
Beam-column Connections
Moment Capacity
Self-drilling Dowels
Experimental Testing
Analytical Model
Research Status
Complete
Series
Journal of Structural Engineering
Notes
Accepted Version
Summary
An experimental and analytical study on rotational behaviour of glulam beam-column moment connections with self-drilling dowels (SDD) was conducted. Connection properties including strength, stiffness, ductility and energy dissipation were experimentally evaluated by testing seven full-scale connection specimens with and without self-tapping screw (STS) reinforcement along timber perpendicular to grain. All the connections showed high initial stiffness and high moment capacity when compared with the test results of bolted connections reported in literature. The unreinforced connections had relatively low ductility due to timber splitting despite the increased fastener edge distance. The STS reinforcement effectively reduced timber splitting tendency and encouraged the yielding of more SDD, leading to slightly increased moment capacity, but significantly improved ductility. A modified analytical model (MAM) was then proposed to predict strength and rotation of the SDD moment connections based on force and moment equilibrium of the glulam members. Improved prediction accuracy was achieved for the SDD moment connections when compared with the past analytical methods.
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Influence of Lamination Aspect Ratios and Test Methods on Rolling Shear Strength Evaluation of Cross Laminated Timber

https://research.thinkwood.com/en/permalink/catalogue2367
Year of Publication
2019
Topic
Design and Systems
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Li, Minghao
Dong, Wenchen
Lim, Hyungsuk
Year of Publication
2019
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Design and Systems
Mechanical Properties
Keywords
Rolling Shear Strength
Lamination Aspect Ratio
Short-Span Bending
Numerical Modelling
Douglas-Fir
Radiata Pine
Research Status
Complete
Series
Journal of Materials in Civil Engineering
Summary
Rolling shear (RS) strength may govern load carrying capacity of cross laminated timber (CLT) subjected to high out-of-plane loading because high RS stresses may be induced in cross layers and wood typically has low RS strength. This study investigates RS strength properties of none-edge-glued CLT via experimental testing (short-span bending tests and modified planar shear tests) and numerical modelling. CLT specimens with different manufacturing parameters including two timber species (New Zealand grown Douglas-fir and Radiata pine), three lamination thickness (20 mm, 35 mm, and 45 mm) and various lamination aspect ratios (4.1~9.8) were studied. The lamination aspect ratio was found to have a substantial impact on RS strength of CLT. Higher aspect ratios led to a significant increase of RS strength and an approximately linear relationship could be established. With similar lamination aspect ratios, the Radiata pine CLT had higher RS strength than the Douglas-fir CLT. The two different test methods, however, yielded comparable RS strength assessments. Numerical models were further developed to study the influence of the test configurations and gaps in the cross layers on stress distributions in the cross layers. It was also found the compressive stresses perpendicular to grain in cross layers had negligible influence on the RS strength evaluations.
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Lateral Behaviour of Cross Laminated Timber Shear Walls under Reversed Cyclic Loads

https://research.thinkwood.com/en/permalink/catalogue198
Year of Publication
2015
Topic
Seismic
Connections
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Author
Li, Minghao
Lam, Frank
Year of Publication
2015
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Topic
Seismic
Connections
Keywords
Finite Element Model
Conference
Pacific Conference on Earthquake Engineering
Research Status
Complete
Notes
November 6-8, 2015, Sydney, Australia
Summary
Cross laminated timber (CLT) shear walls typically consist of solid engineered timber panels connected by metal hardware such as hold-downs, angle-brackets and others. Under seismic loads, the panel elements deform mainly in a rocking mode coupled with a sliding mode and small amount of in-plane bending/shear deformations. The connection system normally governs the lateral behaviour of CLT shear walls. This paper presents a finite element wall model CLTWALL2D to study CLT shear wall behaviour. The model consists of elastic orthotropic plate elements for the panels and nonlinear spring elements for the connections. Contact elements are also used for the panel-to-panel interactions. The nonlinear spring properties are represented by a subroutine called HYST that is able to model the strength and stiffness degradation and the pinching effect commonly observed in timber connections. The HYST parameters are calibrated by experimental data of CLT connections and embedded to the CLTWALL2D model. The wall model is validated against experimental data of a CLT shear wall test database. Parametric studies are then carried out to study the influence of gravity loads and vertical connection densities on the wall behaviour in terms of strength, stiffness, ductility, and energy dissipation.
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16 records – page 1 of 2.