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22 records – page 1 of 3.

Analytical Model to Evaluate the Equivalent Viscous Damping of Timber Structures with Dowel-Type Fastener Connections

https://research.thinkwood.com/en/permalink/catalogue1893
Year of Publication
2012
Topic
Connections
Application
Frames
Author
Loss, Cristiano
Piazza, Maurizio
Zonta, Daniele
Year of Publication
2012
Format
Conference Paper
Application
Frames
Topic
Connections
Keywords
Equivalent Viscous Damping
Moment Resisting Joints
Dowel-Type Connections
Non-linear Dynamic Analysis
Metal Fasteners
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
July 16-19, 2012, Auckland, New Zealand
Summary
The Equivalent Viscous Damping (EVD) parameter is used to simplify the dynamic problem, passing from a non-linear solution of the system to a simple linear-elastic one. In the case of Direct Displacement-Based seismic Design (DDBD) methods, the EVD value allows direct design of structures, without an iterative computational process. This paper proposes a rational analytical formula to evaluate the EVD value of timber structures with dowel-type metal fastener connections. The EVD model is developed at the ultimate limit state, as a solution of the equilibrium problem related to an inelastic configuration. For a specific joint configuration, the EVD predicted via an analytical model was compared to experimental results. The proposed EVD model was validated using non-linear dynamic analysis on a portal frame, built with dowel-type fasteners arranged in two concentric crowns.
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CLT Buildings Laterally Braced with Core and Perimeter Walls

https://research.thinkwood.com/en/permalink/catalogue1663
Year of Publication
2016
Topic
Connections
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Author
Polastri, Andrea
Loss, Cristiano
Pozza, Luca
Smith, Ian
Year of Publication
2016
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Topic
Connections
Seismic
Keywords
Multi-Storey
Numerical Models
X-RAD
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 3706-3715
Summary
In this work the behaviour of hybrid multi-storey buildings braced with Cross-Laminated-Timber (CLT) cores and shear-walls is studied based on numerical analyses. Two procedures for calibrating numerical models are adopted and compared to test data and application of provisions in current design codes. The paper presents calibration of parameters characterising connections used to interconnect adjacent CLT panels and building cores, and attach shear-walls to foundations or floors that act as eleveted diaphragms. Different case studies are analysed comparing the structural responses of buildings assembled with „standard" fastening systems (e.g. hold-downs and angle-brackets), or using a special X-RAD connection system. The aim is to characterize behaviours of connections in ways that reflect how they perform as parts of completed multi-storey superstructure systems, rather than when isolated from such systems or their substructures. Results from various analyses are presented in terms of principal elastic periods, base shear forces, and uplift forces in buildings. Discussion addresses key issues associated with engineering analysis and design of buildings having around five or more storeys.
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Contemporary and Novel Hold-Down Solutions for Mass Timber Shear Walls

https://research.thinkwood.com/en/permalink/catalogue2941
Year of Publication
2022
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Author
Tannert, Thomas
Loss, Cristiano
Organization
University of Northern British Columbia
University of British Columbia
Editor
Tullini, Nerio
Publisher
MDPI
Year of Publication
2022
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Topic
Mechanical Properties
Keywords
Self-Tapping Screws
Internal-Perforated Steel Plates
Hyperelastic Bearing Pads
Proprietary Connections
Research Status
Complete
Series
Buildings
Summary
‘Mass timber’ engineered wood products in general, and cross-laminated timber in particular, are gaining popularity in residential, non-residential, as well as mid- and high-rise structural applications. These applications include lateral force-resisting systems, such as shear walls. The prospect of building larger and taller timber buildings creates structural design challenges; one of them being that lateral forces from wind and earthquakes are larger and create higher demands on the ‘hold-downs’ in shear wall buildings. These demands are multiple: strength to resist loads, lateral stiffness to minimize deflections and damage, as well as deformation compatibility to accommodate the desired system rocking behaviour during an earthquake. In this paper, contemporary and novel hold-down solutions for mass timber shear walls are presented and discussed, including recent research on internal-perforated steel plates fastened with self-drilling dowels, hyperelastic rubber pads with steel rods, and high-strength hold-downs with self-tapping screws.
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Deconstructable Hybrid Connections for the Next Generation of Prefabricated Mass Timber Buildings

https://research.thinkwood.com/en/permalink/catalogue2809
Year of Publication
2021
Topic
Connections
Material
CLT (Cross-Laminated Timber)
Application
Floors
Hybrid Building Systems
Shear Walls
Author
Shulman, Samuel
Loss, Cristiano
Organization
University of British Columbia
Year of Publication
2021
Format
Report
Material
CLT (Cross-Laminated Timber)
Application
Floors
Hybrid Building Systems
Shear Walls
Topic
Connections
Keywords
Steel Rods
Epoxy
Push-Out-Shear Tests
Prefabrication
Disassembly
Reuse
Research Status
Complete
Summary
Timber has been used for building construction for centuries, until the industrial revolution, when it was often replaced by steel and concrete or confined to low-rise housings. In the last thirty years however, thanks to the development of mass timber products and new global interest in sustainability, timber has begun to make a resurgence in the building industry. As building codes and public perception continues to change, the demand for taller and higher-performance timber buildings will only grow. Thus, a need exists for new construction technology appropriate for taller mass timber construction, as well as for fabrication and deconstruction practices that respect wood’s inherent sustainable nature. With this in mind, this research program aims to develop a new hybrid shear connection for mass timber buildings that allows for easy construction, deconstruction, and reuse of the structural elements. This report includes results of Phase 1, which focused on connections consisting of partially threaded 20M and 24M steel rods bonded into pockets formed in CLT and surrounded by thick crowns of high-strength three-component epoxy-based grout. A total of 168 specimens were designed and fabricated, and push-out shear tests carried out with a displacement-controlled monotonic loading protocol. Strength and stiffness values were assessed and effective failure modes in specimens identified. These latter, along with the recorded load-deformation curves, indicate that it is possible to develop mechanics-based design models and design formulas akin to those already used for typical dowel-type fastener timber connections. Additionally, the specimens were easily fabricated in the lab and quickly fastened to the test jig by means of nuts and washers, suggested such connections have a strong potential for prefabrication, disassembly, and reuse.
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Design of a "Mass-Timber" Building with Different Seismic Bracing Technologies

https://research.thinkwood.com/en/permalink/catalogue1900
Year of Publication
2017
Topic
Seismic
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Application
Wood Building Systems
Frames
Author
Fini, Giulio
Pozza, Luca
Loss, Cristiano
Tannert, Thomas
Publisher
ANIDIS Earthquake Engineering in Italy
Year of Publication
2017
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Application
Wood Building Systems
Frames
Topic
Seismic
Keywords
Timber Frames
Prefabrication
Seismic Performance
Conference
17th ANIDIS Conference
Research Status
Complete
Notes
September 17-21, 2017, Pistoia, Italy
Summary
The construction of mid- and high-rise wooden buildings has attracted more attention in the last decade, particularly due to the utilization of engineered materials and related construction methods. The wood industry offers a wide range of engineered wood products, such as glue-laminated timber (GLT), cross-laminated timber (CLT) or timber concrete composites (TCC), which have improved mechanical qualities and the freedom to select shapes and sizes. As a consequence, attention has shifted to solve structural design issues to meet specific building requirements, such as their seismic, fire and serviceability performance. The objective of this work is to explore some of the technologies currently available for wooden mid-rise buildings using a 5-storeys case study building under gravity and earthquake loads. An innovative construction method, obtained by combining TCC floors, CLT shear-walls and GLT columns to ensure a fast erection on site is presented and the building response analyzed by means of static and dynamic seismic analyses. Specifically, the gravity load resisting system was designed to meet ultimate and serviceability limit state requirements according to Eurocode. Different seismic bracing technologies are compared: CLT cores (i) and hybridized cores with (ii) post-tensioned tendons and (iii) steel link-beams.
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Diaphragmatic Behaviour of Hybrid Cross-Laminated Timber Steel Floors

https://research.thinkwood.com/en/permalink/catalogue1909
Year of Publication
2018
Topic
Seismic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Steel-Timber Composite
Application
Floors
Author
Loss, Cristiano
Gobbi, Filippo
Tannert, Thomas
Year of Publication
2018
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Steel-Timber Composite
Application
Floors
Topic
Seismic
Mechanical Properties
Keywords
Hybrid
Prefabrication
Modular
Load Distribution
Numerical Analysis
Sensitivity Analysis
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 20-23, 2018, Seoul, Republic of Korea
Summary
The diaphragmatic behaviour of floors represents one important requirement for earthquake resistant buildings since diaphragms connect the lateral load resisting systems at each floor level and transfer the seismic forces to them as a function of their in-plane stiffness. This paper presents an innovative hybrid timber-steel solution for floor diaphragms developed by coupling cross-laminated timber panels with cold-formed custom-shaped steel beams. The floor consists of prefabricated repeatable units which are fastened on-site using pre-loaded bolts and self-tapping screws, thus ensuring a fast and efficient installation. An experimentally validated numerical model is used to evaluate the influence of the; i) in-plane floor stiffness; ii) aspect ratio and shape of the building plan; and iii) relative stiffness and disposition of the shear walls, on the load distribution to the shear walls. The load transfer into walls and lateral deformation of the construction system primarily depend on the adopted layouts of shear walls, and for most cases an in-plane stiffness of floors two times larger than that of walls is recommended.
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Diaphragmatic Behaviour of Hybrid Cross-Laminated Timber Steel Floors

https://research.thinkwood.com/en/permalink/catalogue2039
Year of Publication
2018
Topic
Design and Systems
Mechanical Properties
Seismic
Material
CLT (Cross-Laminated Timber)
Steel-Timber Composite
Application
Floors
Author
Loss, Cristiano
Gobbi, Filippo
Tannert, Thomas
Organization
University of Northern British Columbia
University of Trento
Year of Publication
2018
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Steel-Timber Composite
Application
Floors
Topic
Design and Systems
Mechanical Properties
Seismic
Keywords
Numerical Model
In-Plane Stiffness
Aspect Ratio
Load Distribution
Conference
World Conference on Timber Engineering
Research Status
Complete
Summary
The diaphragmatic behaviour of floors represents one important requirement for earthquake resistant buildings since diaphragms connect the lateral load resisting systems at each floor level and transfer the seismic forces to them as a function of their in-plane stiffness. This paper presents an innovative hybrid timber-steel solution for floor diaphragms developed by coupling cross-laminated timber panels with cold-formed custom-shaped steel beams. The floor consists of prefabricated repeatable units which are fastened on-site using pre-loaded bolts and self-tapping screws, thus ensuring a fast and efficient installation. An experimentally validated numerical model is used to evaluate the influence of the; i) in-plane floor stiffness; ii) aspect ratio and shape of the building plan; and iii) relative stiffness and disposition of the shear walls, on the load distribution to the shear walls. The load transfer into walls and lateral deformation of the construction system primarily depend on the adopted layouts of shear walls, and for most cases an in-plane stiffness of floors two times larger than that of walls is recommended.
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Direct Displacement-Based Seismic Design of Timber Structures with Dowel-Type Fastener Connections

https://research.thinkwood.com/en/permalink/catalogue1899
Year of Publication
2012
Topic
Seismic
Connections
Application
Frames
Walls
Wood Building Systems
Author
Loss, Cristiano
Piazza, Maurizio
Zonta, Daniele
Publisher
Sociedade Portuguesa de Engenharia Sismica (SPES)
Year of Publication
2012
Format
Conference Paper
Application
Frames
Walls
Wood Building Systems
Topic
Seismic
Connections
Keywords
Direct Displacement-Based Design
Equivalent Viscous Damping
Dowel Type Fastener
Conference
15WCEE
Research Status
Complete
Notes
September 24-28, 2012, Lisbon, Portugal
Summary
The applicability of the Direct Displacement-Based Design (DBD) procedure is strictly related to a priori evaluation of the design displacement and the matching Equivalent Viscous Damping (EVD) of the structure. In this paper we propose analytical models of these design parameters, at the ultimate limit state, for wooden structures built with engineered joints. Experimental results show that the plastic resources and dissipative capabilities of timber structures under earthquake conditions are ensured by the connections between the members. Therefore, the formulation of the design DBD parameters is based on the mechanical model of the single connector and assumes the inelastic deformation of the structure to be concentrated at the joints. The expected non-linear response of the connections can be either ductile or brittle. However, through an appropriate choice of the geometry and strength characteristics of the materials, in the design process we can control the expected ductile behavior of joints.
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Displacement-Based Seismic Design of Timber Structures

https://research.thinkwood.com/en/permalink/catalogue1891
Year of Publication
2011
Topic
Design and Systems
Seismic
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
LVL (Laminated Veneer Lumber)
Other Materials
Application
Wood Building Systems
Walls
Floors
Beams
Columns
Frames
Author
Loss, Cristiano
Publisher
University of Trento
Year of Publication
2011
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
LVL (Laminated Veneer Lumber)
Other Materials
Application
Wood Building Systems
Walls
Floors
Beams
Columns
Frames
Topic
Design and Systems
Seismic
Keywords
Direct Displacement-Based Design
Direct-DBD
Full-Scale
Single Family Houses
Multi-Storey
Connections
Research Status
Complete
Notes
Doctoral Thesis (PhD)
Summary
The research is aimed at developing seismic methods for the design and evaluation of the seismic vulnerability of wooden structures, using a displacement-based approach. After a brief introduction on the seismic behaviour of timber structures, the general Direct Displacement-Based Design (Direct-DBD) procedure and the state-of-the-art are presented, with clear reference to the application of the Direct-DBD method to wooden buildings. The strength of the Direct-DBD method is its ability to design structures in a manner consistent with the level of damage expected, by directly relating the response and the expected performance of the structure. The research begins with a description of the procedural aspects of the Direct-DBD method and the parameters required for its application. The research presented focuses on the formulation of a displacement-based seismic design procedure, applicable to one-storey wooden structures made with a portal system. This typology is very common in Europe and particularly in Italy. A series of analytical expressions have been developed to calculate design parameters. The required analytical Direct-DBD parameters are implemented based on the mechanical behaviour of the connections, made with metal dowel-type fasteners. The calibration and subsequent validation of design parameters use a Monte Carlo numerical simulation and outcomes obtained by tests in full-scale. After the description of the Displacement-Based method for one-storey wooden structures, a series of guidelines to extend the Direct-DBD methodology to other types and categories of timber systems are proposed. The thesis presents the case of a multi-storey wood frame construction, which is a simple extension of the glulam portal frame system. Part of this work has been done within the RELUIS Project, (REte dei Laboratori Universitari di Ingegneria Sismica), Research Line IV, which in the years between 2005 and 2008 involved several Italian universities and Italian institutes of research in the development of new seismic design methods. The Project produced the first draft of model code for the seismic design of structures based on displacement (Direct-DBD). This thesis is the background to the section of the model code developed for timber structures.
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Experimental and numerical study on the bending response of a prefabricated composite CLT-steel floor module

https://research.thinkwood.com/en/permalink/catalogue3047
Year of Publication
2022
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Steel-Timber Composite
Application
Floors
Author
Owolabi, David
Loss, Cristiano
Organization
University of British Columbia
Publisher
Elsevier
Year of Publication
2022
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Steel-Timber Composite
Application
Floors
Topic
Mechanical Properties
Keywords
Composite Floors
Hybrid Construction
Mass Timber
Cross-laminated Timber
Prefabricated Construction
Low-Carbon Structures
Bending Stiffness
Research Status
Complete
Series
Engineering Structures
Summary
Cross-laminated timber (CLT) is one of the most widely utilized mass timber products for floor construction given its sustainability, widespread availability, ease of fabrication and installation. Composite CLT-based assemblies are emerging alternatives to provide flooring systems with efficient design and optimal structural performance. In this paper, a novel prefabricated CLT-steel composite floor module is investigated. Its structural response to out-of-plane static loads is assessed via 6-point bending tests and 3D finite-element computational analysis. For simply supported conditions, the results of the investigation demonstrate that the floor attains a high level of composite efficiency (98%), and its bending stiffness is about 2.5 times those of its components combined. Within the design load range, the strain diagrams are linear and not affected by the discontinuous arrangement and variable spacing of the shear connectors. The composite floor module can reach large deflection without premature failure in the elements or shear connectors, with plasticity developed in the cold-formed steel beams and a maximum attained load 3.8 times its ultimate limit state design load. The gravity design of the composite module is shown to be governed by its serviceability deflection requirements. However, knowledge gaps still exist on the vibration, fire, and long-term behaviour of this composite CLT-steel floor system.
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22 records – page 1 of 3.