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48 records – page 2 of 5.

Disproportionate Collapse Analysis of Mid-rise Cross-laminated Timber Buildings

https://research.thinkwood.com/en/permalink/catalogue2181
Year of Publication
2018
Topic
Design and Systems
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Walls
Author
Tannert, Thomas
Mpidi Bita, Hercend
Currie, Neil
Organization
University of British Columbia
University of Salford
Year of Publication
2018
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Walls
Topic
Design and Systems
Keywords
Progressive Collapse
Robustness
Structural Integrity
Redundancy
Reliability Analysis
Mid-Rise
Engineered Wood Product (EWP)
Research Status
Complete
Series
Structure and Infrastructure Engineering
Notes
DOI link: http://dx.doi.org/10.1080/15732479.2018.1456553
Summary
This paper investigates the structural behaviour of a twelve-storey Cross-Laminated Timber (CLT) building subjected to sudden removal of internal and external ground floor load-bearing walls, and computes the probability of disproportionate collapse. Analyses are carried out at three different structural idealisations, accounting for feasibility and complexity of finite elements models to understand their performance at: i) the global, ii) the component, and iii) the connection level. Focus is devoted on force and deformation-demands obtained from nonlinear dynamic analyses of the building. The demands are compared against the supply from common CLT panel sizes and the rotational stiffness (k) of the joints, detailed with off-the-shelf angle brackets and self-tapping screws. The study demonstrates that the applied forces and deformations required to develop resistance mechanisms are too large to be supplied by the proposed element and connection designs, if an internal ground floor wall is removed. The considered building has a probability of failure as high as 32% if designed without considerations of the complexities associated with disproportionate collapse. Consequently, to resist the effects of internal wall removal, the floors need to be redesigned and improved structural detailing with sufficient strength, stiffness, and ductility is necessary to trigger collapse resistance mechanisms.
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Effective Out-of-Plane Stiffness and Strength of Rotated Cross Laminated Timber Panels

https://research.thinkwood.com/en/permalink/catalogue1622
Year of Publication
2016
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Cheng, Alexandra
Schneider, Johannes
Tannert, Thomas
Year of Publication
2016
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Strength
Stiffness
Analytical Model
Finite Element Model
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 2557-2564
Summary
This research considers the effect of in-plane rotation angles on the structural performance of Cross Laminated Timber (CLT) panels. In the interest of expanding the application of CLT to folded or freeform structures, rectangular CLT panels are likely to be divided into irregular geometries, in which case the loading will be applied at an intermediate orientation between the longitudinal and transverse panel axes. Such a loading condition is not accounted for in the existing analytical methods for dimensioning and designing with CLT. An analytical method is proposed which hybridizes the Shear Analogy method with Hankinson’s equation, allowing a designer to determine the effective stiffness of a CLT panel with any layup and at any in-plane rotation angle. An analytical study, followed by implementation with 3D parametric Finite Element Modelling and an experimental investigation, is used to evaluate this method. Results show that cross-grain/in-plane rotation has considerable effect on strength and stiffness of CLT panels with fewer than 5 laminations.
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Effects of Ground Motion Duration on the Seismic Performance of a Two-Storey Balloon-Type CLT Building

https://research.thinkwood.com/en/permalink/catalogue3154
Year of Publication
2022
Topic
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Jafari, Maral
Pan, Yuxin
Shahnewaz, Md
Tannert, Thomas
Organization
University of Northern British Columbia
Fast + Epp
Editor
Bento, Rita
Publisher
MDPI
Year of Publication
2022
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Seismic
Keywords
Ground Motion
Collapse Capacity
Dynamic Analysis
Research Status
Complete
Series
Buildings
Summary
The effects of long duration ground motions on the seismic performance of a newly constructed two-storey balloon-type cross-laminated timber (CLT) building located in Vancouver, Canada, was studied. A three-dimensional numerical model of the building was developed in OpenSees. The connection and shear wall models were validated with test data. Twenty-four pairs of long and short duration records with approximately the same amplitude, frequency content, and rate of energy build-up were used for nonlinear dynamic analyses. Fragility curves were developed based on the results of incremental dynamic analysis to assess the building’s collapse capacity. At design intensity level, ground motion duration was shown not to be a critical factor as the difference in inter-storey drift ratio between the two sets of records was negligible. However, due to the larger number of inelastic cycles, the long duration motions increased the median probability of collapse by 9% when compared with the short duration motions. Further research is required to evaluate the duration effects on taller and platform-type CLT buildings.
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Experimental and Numerical Investigation of Novel Steel-Timber-Hybrid System

https://research.thinkwood.com/en/permalink/catalogue81
Year of Publication
2014
Topic
Design and Systems
Seismic
Connections
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Bhat, Pooja
Azim, Riasat
Popovski, Marjan
Tannert, Thomas
Year of Publication
2014
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Design and Systems
Seismic
Connections
Keywords
Tall Wood
Timber-Steel Hybrid
FFTT
Quasi-Static
Monotonic Testing
Cyclic Testing
Strong-column Weak-beam Failure
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 10-14, 2014, Quebec City, Canada
Summary
This paper summarises the experimental and numerical investigation conducted on the main connection of a novel steel-timber hybrid system called FFTT. The component behaviour of the hybrid system was investigated using quasi-static monotonic and reversed cyclic tests. Different steel profiles (wide flange I-sections and hollow rectangular sections) and embedment approaches for the steel profiles (partial and full embedment) were tested. The results demonstrated that when using an appropriate connection layout, the desired strong-column weak-beam failure mechanism was initiated and excessive wood crushing was avoided. A numerical model was developed that reasonably reflected the real component behaviour and can subsequently be used for numerical sensitivity studies and parameter optimization. The research presented herein serves as a precursor for providing design guidance for the FFTT system as an option for tall wood-hybrid buildings in seismic regions.
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Experimental and Numerical Investigations of Fire Resistance of Novel Timber-Concrete-Composite Decks

https://research.thinkwood.com/en/permalink/catalogue891
Year of Publication
2013
Topic
Fire
Material
Timber-Concrete Composite
Application
Floors
Author
Meena, Rahul
Schollmayer, Martin
Tannert, Thomas
Publisher
American Society of Civil Engineers
Year of Publication
2013
Format
Journal Article
Material
Timber-Concrete Composite
Application
Floors
Topic
Fire
Keywords
Fire Resistance
Temperature
Research Status
Complete
Series
Journal of Performance of Constructed Facilities
Summary
A wood-concrete composite deck is presented, where wooden beams are placed in the compression side and the concrete layer is in the tension side. The main motive for this unusual setup is the better fire resistance of the system. The composite system was investigated under fire conditions. Experimental investigations were conducted on a small section of the structure in order to analyze the behaviour of the system. The specimen was subjected to the ISO-834 standard temperature-time curve with the concrete slab exposed to fire. Subsequently, the experiment was modeled using a commercial software package, and a transient thermal analysis was performed with temperature dependent material properties. The temperature profiles for all the materials are adequately comparable from both the investigations, i.e. experimental and numerical. The validated numerical model allows modifying geometrical parameters and determining fire-resistance ratings of different system configurations.
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Experimental Investigations of Full-Scale Cross-Laminated Timber Concrete Composite Floors

https://research.thinkwood.com/en/permalink/catalogue3351
Year of Publication
2021
Topic
Mechanical Properties
Material
Timber-Concrete Composite
Application
Floors
Author
Shahnewaz, Md
Jackson, Robert
Tannert, Thomas
Organization
Fast + Epp
University of Northern British Columbia
Publisher
Springer
Year of Publication
2021
Format
Conference Paper
Material
Timber-Concrete Composite
Application
Floors
Topic
Mechanical Properties
Keywords
Self-tapping screw
Steel Kerf Plates
Glued-in Holz-Beton-Verbund (HBV) Plates
Conference
Proceedings of the Canadian Society of Civil Engineering Annual Conference 2021
Research Status
Complete
Notes
Page 401
Summary
Experimental investigations on full-scale Timber Concrete Composite (TCC) floor systems with various composite connectors are presented in this paper. The stiffness, strength, and failure modes of were evaluated. The 9.2 m long and 2.4 m wide TCC floor segments were comprised of 245 mm thick, 7-ply Cross-laminated Timber (CLT) panels with 150 mm concrete topping connected with three types of shear connectors: (i) self-tapping screws, (ii) steel kerf plates, and (iii) glued-in Holz-Beton-Verbund (HBV) plates. Six TCC floor segments were tested to failure under symmetric four-point bending and three TCC floor segments were tested under torsional bending by applying eccentric loading near the edge. The floor deformations at nine locations and connector slips at CLT-concrete interfaces at eight locations along the length of the floor were measured. The full-scale tests showed that the steel kerf plates—for the selected connector configurations- exhibited the highest capacity and stiffness.
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Feasibility of Cross-Laminated Timber Cores for the UBC Tall Wood Building

https://research.thinkwood.com/en/permalink/catalogue1905
Year of Publication
2018
Topic
Design and Systems
Material
CLT (Cross-Laminated Timber)
Application
Shafts and Chases
Author
Connolly, Thomas
Moudgil, Manu
Loss, Christiano
Iqbal, Asif
Tannert, Thomas
Year of Publication
2018
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Shafts and Chases
Topic
Design and Systems
Keywords
Brock Commons
Hybrid
Environmental Footprint
Seismic Performance
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 20-23,2018. Seoul, Republic of Korea
Summary
The innovation in tall mass-timber buildings is illustrated by the Brock Commons student residence at the University of British Columbia also known as the UBC Tall Wood Building. It is amongst the world’s tallest timber hybrid building with 18 stories and 53 meters’ height. The building has 17 stories of mass-timber superstructure resting on a concrete podium with two concrete cores that act as a lateral force resisting system for earthquake and wind forces. Construction of the mass-timber superstructure took ten weeks whereas the concrete cores were built in fourteen weeks. There could have been a substantial reduction in the project timeline leading to cost savings, as well as a further reduction of environmental footprint if mass-timber had been used for the cores. The objective of this work was to evaluate the possibility to design the UBC Tall Wood Building using mass-timber cores. A validated numerical model was used to study the feasibility of replacing the concrete cores by cores made of Cross Laminated Timber (CLT). The results presented herein show that, with adjustments in the configuration, the structure can meet the seismic performance criteria as per the Canadian code with CLT cores.
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Feasibility Study of Mass-Timber Cores for the UBC Tall Wood Building

https://research.thinkwood.com/en/permalink/catalogue1895
Year of Publication
2018
Topic
Design and Systems
Environmental Impact
Seismic
Wind
Material
LVL (Laminated Veneer Lumber)
Application
Shafts and Chases
Author
Connolly, Thomas
Loss, Cristiano
Iqbal, Asif
Tannert, Thomas
Publisher
MDPI
Year of Publication
2018
Format
Journal Article
Material
LVL (Laminated Veneer Lumber)
Application
Shafts and Chases
Topic
Design and Systems
Environmental Impact
Seismic
Wind
Keywords
Student Residence
Inter-Storey Drift
Environmental Footprint
Building Codes
Research Status
Complete
Series
Buildings
Summary
The UBC Brock Commons building in Vancouver, which comprises of 18 stories and stands 53 m in height, was at the time of completion in 2016 the world’s tallest hybrid wood-based building. The building’s 17 stories of mass-timber superstructure, carrying all gravity loads, rest on a concrete podium with two concrete cores that act as both the wind and seismic lateral load-resisting systems. Whereas the construction of the concrete cores took fourteen weeks in time, the mass-timber superstructure took only ten weeks from initiation to completion. A substantial reduction in the project timeline could have been achieved if mass-timber had been used for the cores, leading to a further reduction of the building’s environmental footprint and potential cost savings. The objective of this research was to evaluate the possibility of designing the UBC Brock Commons building using mass-timber cores. The results from a validated numerical structural model indicate that applying a series of structural adjustments, that is, configuration and thickness of cores, solutions with mass-timber cores can meet the seismic and wind performance criteria as per the current National Building Code of Canada. Specifically, the findings suggest the adoption of laminated-veneer lumber cores with supplementary ‘C-shaped’ walls to reduce torsion and optimize section’s mechanical properties. Furthermore, a life cycle analysis showed the environmental benefit of these all-wood solutions.
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Finite element analysis of alternative load paths to prevent disproportionate collapse in platform-type CLT floor systems

https://research.thinkwood.com/en/permalink/catalogue2901
Year of Publication
2021
Topic
Design and Systems
Material
CLT (Cross-Laminated Timber)
Application
Floors
Author
Huber, Johannes
Bita, Hercend
Tannert, Thomas
Berg, Sven
Organization
Luleå University of Technology
University of Northern British Columbia
Publisher
Elsevier
Year of Publication
2021
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Floors
Topic
Design and Systems
Keywords
Mass Timber
Structural Robustness
High Fidelity Model
Progressive Collapse
Structural Integrity
Component Model
Research Status
Complete
Series
Engineering Structures
Summary
Multi-storey buildings require mitigation of consequences of unexpected or accidental events, to prevent disproportionate collapse after an initial damage. Cross-laminated timber (CLT) in platform-type construction is increasingly used for multi-storey buildings, however, the collapse behaviour and alternative load paths (ALPs) are not fully understood. A 3D non-linear component-based finite element model was developed for a platform-type CLT floor system to study the ALPs after an internal wall loss, in a pushdown analysis. The model, which accounted for connection failure, timber crushing and large displacements, was calibrated to experimental results and then adapted for boundary conditions corresponding to typical residential and office buildings. Subsequently, five parameters (floor span, connection type, vertical location of the floor, tying level, horizontal wall stiffness) were varied, to study their effects on the ALPs in 80 models. The results showed that three ALPs occurred, of which catenary action was the most dominant. Collapse resistance was mainly affected by the floor span, followed by the axial strength, stiffness and ductility of the floor-to-floor connection, the weight of the level above and the floor panel thickness. This study provides an approach to model ALPs in a platform-type CLT floor system to design disproportionate collapse resistant multi-storey CLT buildings.
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Group Effect for Self-Tapping-Screws in CLT Subjected to Shear and Axial Loads

https://research.thinkwood.com/en/permalink/catalogue1975
Year of Publication
2018
Topic
Design and Systems
Connections
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Walls
Wood Building Systems
Author
Hossain, Afrin
Tannert, Thomas
Popovski, Marjan
Year of Publication
2018
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Walls
Wood Building Systems
Topic
Design and Systems
Connections
Mechanical Properties
Keywords
Self-Tapping Screws
Shear Connections
Group Effect
Load Carrying Capacity
Fasteners
Panels
Conference
World Conference on Timber Engineering
Research Status
Complete
Summary
Cross-laminated-timber (CLT) panels, when used as shear walls or diaphragms are commonly connected with multiple fasteners in a row. For such connections, it is frequently observed that the load carrying capacity of multiple-fasteners is less than the sum of the individual fastener capacities. This phenomenon is referred to as “group-effect” which is accounted for differently in contemporary timber design standards for several types of fasteners. The research presented in this paper investigated the group-effect factor for self-tapping-screw (STS) shear connections between CLT panels. Different joint types (surface splines with STS in shear, and half-lap and butt joints with STS in either shear or withdrawal) were evaluated with a total of 122 quasi-static tests. The number of STS in one row was varied (1, 2, 8, 16, and 32) with their installation satisfying minimum spacing requirements. The results demonstrated that the effect of number of screws on joint capacity can be described using the expression neff = 0.9*n. For the reduction in stiffness, neff = n0.8 can be used.
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48 records – page 2 of 5.