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Behaviour of Multi-Storey Cross-Laminated Timber Buildings Under Lateral Loading

https://research.thinkwood.com/en/permalink/catalogue2715
Year of Publication
2020
Topic
Connections
Design and Systems
Material
CLT (Cross-Laminated Timber)
Application
Walls
Author
Hughes, Claire
Publisher
Queen's University Belfast
Year of Publication
2020
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Application
Walls
Topic
Connections
Design and Systems
Keywords
Lateral Loading
Tall Wood
Tall Timber Buildings
Connections
Monotonic Loading Tests
Constant Vertical Load
Wall Systems
Experimental Tests
Analytical Approach
Multi-Storey
Language
English
Research Status
Complete
Summary
In response to the global drive towards sustainable construction, CLT has emerged as a competitive alternative to other construction materials. CLT buildings taller than 10-storeys and CLT buildings in regions of moderate to high seismicity would be subject to higher lateral loads due to wind and earthquakes than CLT buildings which have already been completed. The lack of structural design codes and limited literature regarding the performance of CLT buildings under lateral loading are barriers to the adoption of CLT for buildings which could experience high lateral loading. Previous research into the behaviour of CLT buildings under lateral loading has involved testing of building components. These studies have generally been limited to testing wall systems and connections which replicate configurations at ground floor storeys in buildings no taller than three storeys. Consequently, to develop the understanding of the performance of multi-storey CLT buildings under lateral loading, the performance of wall systems and connections which replicate conditions of those in above ground floor storeys in buildings taller than three storeys were experimentally investigated. The testing of typical CLT connections involved testing eighteen configurations under cyclic loading in shear and tension. The results of this experimental investigation highlighted the need for capacity-based design of CLT connections to prevent brittle failure. It was found that both hold down and angle bracket connections have strength and stiffness in shear and tension and by considering the strength of the connections in both directions, more economical design of CLT buildings could be achieved. The testing of CLT wall systems involved testing three CLT wall systems with identical configurations under monotonic lateral load and constant vertical load, with vertical loads replicating gravity loads at storeys within a 10-storey CLT building. The results show that vertical load has a significant influence on wall system behaviour; varying the vertical load was found to vary the contribution of deformation mechanisms to global behaviour within the elastic region, reinforcing the need to consider connection design at each individual storey. As there are still no structural design codes for CLT buildings, the accuracy of analytical methods presented within the literature for predicting the behaviour of CLT connections and wall systems under lateral loading was assessed. It was found that the analytical methods for both connections and wall systems are highly inaccurate and do not reflect experimentally observed behaviour.
Online Access
Free
Resource Link
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Composite CLT-Glulam Double-T Panels

https://research.thinkwood.com/en/permalink/catalogue2645
Topic
Mechanical Properties
Connections
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Application
Floors
Roofs
Organization
Fast + Epp
University of Northern British Columbia
Country of Publication
Canada
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Application
Floors
Roofs
Topic
Mechanical Properties
Connections
Keywords
Vibration
Stiffness Properties
Strength
Screw
Vibration Test
Monotonic Loading Tests
GCWood
Research Status
In Progress
Summary
To support the associated Sir Matthew Begbie Elementary School and Bayview Elementary School projects in pushing the boundaries forward for long-span floor and roof construction, this testing project aims to compare different connection approaches for composite connections between glulam and cross-laminated timber (CLT) – for vibration, stiffness, and strength. Working with the University of Northern British Columbia (UNBC), Fast + Epp aimed to complete a series of vibration and monotonic load tests on 30’ long full-scale double-T ribbed panels. The tests consisted of screws in withdrawal, screws in shear, and nominal screws clamping with glue. Both the strength and stiffness are of interest, including slip stiffness of each connection type. This physical testing was completed in January and February 2020, where the full composite strength of each system was reached. Initial data analysis has provided information for comparison with existing models for shear connection stiffness. Publications will follow in 2021.
Resource Link
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Fire Performance of Timber Beam-to-Column Connections

https://research.thinkwood.com/en/permalink/catalogue2788
Topic
Connections
Fire
Application
Wood Building Systems
Organization
TallWood Design Institute
Oregon State University
Country of Publication
United States
Application
Wood Building Systems
Topic
Connections
Fire
Keywords
Moment Frame Connection
Moment Resisting Joints
Post-earthquake Fire
Fire Loads
Monotonic Loading Tests
Cyclic Loading Tests
Displacement
Research Status
In Progress
Summary
The goals of this research are to gain a better understanding of the mechanics of timber moment-frame connections during two different fire scenarios: fire and post-earthquake fire. This research will develop the testing methodologies and benchmark data required to develop designs for the fire and post-earthquake performance of timber moment-resisting frame connections. The project wIll test two moment resisting frame connections under fire and post-earthquake fire loading scenarios. Full scale monotonic and cyclic loading tests on sub-assemblies for both connection types at the Emmerson lab. Fire testing of structurally tested and un-tested specimens at the National Research Council (NRC) of Canada. These tests will occur under service loading conditions and will measure temperature gradients through the cross section of the connection, as well as displacements between the beam and column and residual cross section dimensions. Data will be used to benchmark numerical models in order to perfom a parametric study that allows for varying of geometric parameters such as connection geometry and fastener configurations.
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Numerical Analysis of Self-Centring Cross-Laminated Timber Walls

https://research.thinkwood.com/en/permalink/catalogue2714
Year of Publication
2020
Topic
Design and Systems
Mechanical Properties
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Walls
Author
Slotboom, Christian
Publisher
University of British Columbia
Year of Publication
2020
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Application
Walls
Topic
Design and Systems
Mechanical Properties
Seismic
Keywords
Self-Centring
Model
Finite Element Model
Lumped Plasticity Elements
Fibre-Based Elements
Monotonic Loading Tests
Cyclic Loading Tests
Language
English
Research Status
Complete
Summary
Self-centring Cross-Laminated Timber (CLT) walls are a low damage seismic force resisting system, which can be used to construct tall wood buildings. This study examines two approaches to model self-centring CLT walls, one that uses lumped plasticity elements, and another that uses fibre-based elements. Finite element models of self-centring CLT walls are developed using the Python interpreter of Opensees, OpenSeesPy, and tested under monotonic and reverse cyclic loading conditions. Outputs from the analysis are compared with data from two existing experimental programs. Both models accurately predict the force displacement relationship of the wall in monotonic loading. For reverse cyclic loading, the lumped plasticity model could not capture cyclic deterioration due to crushing of CLT. Both models slightly overpredict the post-tension force. Sensitivity analyses were run on the fibre model, which show the wall studied is not sensitive to the shear stiffness of CLT. OpenSeesPy models are also created of a two-story structure, which is tested dynamically under a suite of ground motions. The structure is based on a building tested as part of the NHERI TallWood initiative. During testing the foundation of the building was found to be inadvertently flexible. To determine the appropriate model parameters for this foundation, calibrations were performed by running a sequence of OpenSeesPy analyses with an optimization algorithm. Outputs from the lumped plasticity and fibre models were compared to experimental results, which showed that both could capture the global behaviour of the system with reasonable accuracy. Both models overpredict peak post-tension forces. The suite of analyses is then run again on the building to predict the performance with a rigid foundation. Cyclic deterioration is more significant for the building with a rigid foundation, and as a result the fibre mode is more accurate.
Online Access
Free
Resource Link
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Seismic Design Approach for MTP Balloon Construction - Connection Properties

https://research.thinkwood.com/en/permalink/catalogue2648
Topic
Mechanical Properties
Connections
Author
Niederwestberg, Jan
Organization
University of Alberta
Country of Publication
Canada
Topic
Mechanical Properties
Connections
Keywords
Strength
Stiffness
Ductility
Energy Dissipation
Failure Mode
Steel Plates
Monotonic Loading Tests
Cyclic Loading Tests
Research Status
In Progress
Summary
The objective of this research is to characterize of load-deformation responses of tested connections(stiffness, strength, ductility, energy dissipation, failure modes) by testing large STS connections with steel side plates under monotonic and cyclic loads.
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