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Experimental Investigation on the Long-Term Behaviour of Prefabricated Timber-Concrete Composite Beams with Steel Plate Connections

https://research.thinkwood.com/en/permalink/catalogue2741
Year of Publication
2021
Topic
Connections
Serviceability
Material
Timber-Concrete Composite
Application
Beams
Author
Shi, Benkai
Liu, Weiqing
Yang, Huifeng
Publisher
ScienceDirect
Year of Publication
2021
Format
Journal Article
Material
Timber-Concrete Composite
Application
Beams
Topic
Connections
Serviceability
Keywords
TCC
Prefabrication
Steel Plate
Long-term Behaviour
Interface Slip
Loading
Shear Connections
Deflection
Temperature
Humidity
Language
English
Research Status
Complete
Series
Construction and Building Materials
Summary
This paper presents the results of long-term experiments performed on three timber-concrete composite (TCC) beams. An innovative fabricated steel plate connection system, which consists of screws and steel plates embedded in concrete slabs, was adopted in the TCC beam specimens. The adopted shear connection can provide dry-type connection for TCC beams. Steel plates were embedded in concrete slabs while the concrete slab was constructed in factories. The timber beam and concrete slab can be assembled together using screws at the construction site. In this experimental programme, the beam specimens were subjected to constant loading for 613 days in indoor uncontrolled environments. The influence of long-term loading levels and the number of shear connections on the long-term performance of TCC beams was investigated and discussed. The mid-span deflection, timber strain, and interface relative slip at the positions of both connections and beam-ends were recorded throughout the long-term tests. It was found the long-term deflection of the TCC beam increased by approximately 60% while the long-term loads were doubled. Under the influence of the variable temperature and humidity, the TCC specimens with 8 shear connections showed slighter fluctuations compared with the TCC beam with 6 shear connections. In the 613-day observation period, the maximum deflection increment recorded was 6.56 mm for the specimen with eight shear connections and 20% loading level. A rheological model consisting of two Kelvin bodies was employed to fit the curves of creep coefficients. The final deflections predicted of all specimens at the end of 50-year service life were 2.1~2.7 times the initial deflections caused by the applied loads. All beam specimens showed relative small increments in mid-span deflection, strain and relative slip over time without any degradations, demonstrating the excellent long-term performance of TCC beams using the innovative steel plate connection system, which is also easily fabricated.
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Cyclic Response of Insulated Steel Angle Brackets Used for Cross-Laminated Timber Connections

https://research.thinkwood.com/en/permalink/catalogue2765
Year of Publication
2021
Topic
Seismic
Acoustics and Vibration
Connections
Material
CLT (Cross-Laminated Timber)
Application
Walls
Floors
Author
Kržan, Meta
Azinovic, Boris
Publisher
Springer
Year of Publication
2021
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Walls
Floors
Topic
Seismic
Acoustics and Vibration
Connections
Keywords
Angle Bracket
Sound Insulation
Insulation
Monotonic Test
Cyclic Tests
Wall-to-Floor
Stiffness
Load Bearing Capacity
Shear
Tensile
Language
English
Research Status
Complete
Series
European Journal of Wood and Wood Products
Summary
In cross-laminated timber (CLT) buildings, in order to reduce the disturbing transmission of sound over the flanking parts, special insulation layers are used between the CLT walls and slabs, together with insulated angle-bracket connections. However, the influence of such CLT connections and insulation layers on the seismic resistance of CLT structures has not yet been studied. In this paper, experimental investigation on CLT panels installed on insulation bedding and fastened to the CLT floor using an innovative, insulated, steel angle bracket, are presented. The novelty of the investigated angle-bracket connection is, in addition to the sound insulation, its resistance to both shear as well as uplift forces as it is intended to be used instead of traditional angle brackets and hold-down connections to simplify the construction. Therefore, monotonic and cyclic tests on the CLT wall-to-floor connections were performed in shear and tensile/compressive load direction. Specimens with and without insulation under the angle bracket and between the CLT panels were studied and compared. Tests of insulated specimens have proved that the insulation has a marginal influence on the load-bearing capacity; however, it significantly influences the stiffness characteristics. In general, the experiments have shown that the connection could also be used for seismic resistant CLT structures, although some minor improvements should be made.
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Deconstructable Timber-Concrete Composite Connectors

https://research.thinkwood.com/en/permalink/catalogue2740
Year of Publication
2020
Topic
Connections
Material
Timber-Concrete Composite
Glulam (Glue-Laminated Timber)
Application
Floors
Author
Derikvand, Mohammad
Fink, Gerhard
Publisher
Society of Wood Science & Technology
Year of Publication
2020
Format
Conference Paper
Material
Timber-Concrete Composite
Glulam (Glue-Laminated Timber)
Application
Floors
Topic
Connections
Keywords
Deconstructable Connections
Deconstructable Connector
TCC
Push-Out Tests
Shear Strength
Slip Modulus
Failure Mode
Self-Tapping Screws
Language
English
Conference
Society of Wood Science and Technology International Convention
Research Status
Complete
Summary
The application of deconstructable connectors in timber-concrete composite (TCC) floors enables the possibility of disassembly and reuse of timber materials at the end of building’s life. This paper introduces the initial concept of a deconstructable TCC connector comprised of a self-tapping screw embedded in a plug made of rigid polyvinyl chloride and a level adjuster made of silicone rubber. This connection system is versatile and can be applied for prefabrication and in-situ concrete casting of TCC floors in both wet-dry and dry-dry systems. The paper presents the results of preliminary tests on the shear performance of four different configurations of the connector system in T-section glulam-concrete composites. The shear performance is compared to that of a permanent connector made with the same type of self-tapping screw. The failure modes observed are also analyzed to provide technical information for further optimization of the connector in the future.
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Static and Dynamic Performance of Direct Hybrid Connections of Cross-Laminated Timber with Steel, Concrete and Laminated Strand Lumber Composites

https://research.thinkwood.com/en/permalink/catalogue2697
Year of Publication
2020
Topic
Connections
Material
CLT (Cross-Laminated Timber)
LSL (Laminated Strand Lumber)
Application
Hybrid Building Systems
Author
Carrero, Tulio
Montaño, Jairo
Santa-María, Hernán
Guindos, Pablo
Publisher
SciELO
Year of Publication
2020
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
LSL (Laminated Strand Lumber)
Application
Hybrid Building Systems
Topic
Connections
Keywords
Hybrid Connection
Structural Connection
Composite Connection
Steel
Concrete
Monotonic
Cyclic
Language
English
Research Status
Complete
Series
Latin American Journal of Solids and Structures
Summary
Hybrid multistory buildings are every day more common in the construction industry. However, there is little understanding of the performance of the hybrid connections. In this research, the static and dynamic response of cross-laminated timber (CLT) composites combined with reinforced concrete (RC), hollow steel profiles and laminated strand lumber (LSL) has been investigated. In addition, the effects of posttensioning stresses as well as distinct types of connectors such as nails, self-tapping screws and self-tapping dowels has been accounted for. After experimental work, numerical modelling for simulating the static and dynamic behavior for these hybrid connections was also investigated. Results indicate that such massive timber composite connections behave reasonably similar to conventional timber connections, except in that inelastic deformations may increase up to 200%. In addition, it has been found that existing hysteretic models like the modified Stewart hysteretic model (MSTEW) fit for modelling purposes except that very asymmetric hysteretic behavior can be found for timber-concrete hybrid connections.
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Connection Details Between Composite Beam and Cross-Laminated Timber Slab

https://research.thinkwood.com/en/permalink/catalogue2720
Year of Publication
2020
Topic
Connections
Material
CLT (Cross-Laminated Timber)
Application
Floors
Author
Zhukov, Pavel
Publisher
Hämeenlinna University Center
Year of Publication
2020
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Application
Floors
Topic
Connections
Keywords
Composite Beam
Timber Slab
Connection Details
Connectors
Language
English
Research Status
Complete
Summary
The aim of the Bachelor’s thesis was to describe and evaluate the most common connection details between steel-concrete composite (SCC) beam DELTABEAM® and Cross-Laminated Timber (CLT) slab in two variations: with and without concrete topping. The purpose of the thesis was to provide a basis for future studies that are to expand the CLT range of appliance in Finland. The thesis was based on a theoretical description of the four different connectors that utilize the same working principles as the connections used for joining concrete floor slabs and the beam using the German standard details. The calculations were done according to the Eurocode 1995 and German timber design code DIN1052. The result of the thesis was the connection details library. The result of the study allows to conclude that by using described connection details, the CLT slabs and DELTABEAM® form a reliable flooring system.
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Edge Connection Technology for Cross Laminated Timber (CLT) Floor Slabs Promoting Two-Way Action

https://research.thinkwood.com/en/permalink/catalogue2718
Year of Publication
2020
Topic
Connections
Material
CLT (Cross-Laminated Timber)
Application
Floors
Author
Asselstine, Julian
Publisher
University of British Columbia
Year of Publication
2020
Country of Publication
Canada
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Application
Floors
Topic
Connections
Keywords
Bending
Two-Way
Self-Tapping Screws
Stiffness
Modulus of Elasticity
Language
English
Research Status
Complete
Summary
Cross-laminated timber (CLT) is a class of engineered wood product with the ability to act as a flat plate floor system transferring loads in two-directions due to the orthogonally crossed layers. Currently, dimensional limitations from manufacturing and transportation limit the minor span to about 3.0 m. This results in under utilization of the bending properties of the cross-layers or the choice of a different product because of the common use of one-way bending support conditions such as drop beams simply supporting the ends of the longer span. This study investigates the performance of a newly developed edge connection system to maintain continuity in the minor direction span of CLT and promote two-way bending action. Three connections utilizing a tension splice fastened to the underside of the panel edges with self-tapping screws are investigated, with experimental results showing promise to maintain a high level of stiffness. This connection system was placed in the maximum moment location of the minor span - attaining a connected span modulus of elasticity up to 1.17 times the intact span modulus of elasticity, indicating a reinforcing effect created by the connection. Further, the minor direction span is additionally stiffened through the use of parallel-strand lumber rim beams fixed to the edges of the CLT in the minor direction span and hidden within the cross-section of the CLT. ANSYS finite element modelling calibrated and validated from the experimental results show the potential of this flat-plate system using 5-layer CLT to reach column spacing of 6.0 m by 6.0 m limited by deflection under a serviceability limit state uniformly distributed load of 3.25 kPa. This claim maintains a high degree of conservatism, as the boundary stress obtained from the minimum observed failure load is greater than 6 times the maximum stress at an ultimate limit state load of 4.67 kPa. This system has the ability to expand the flexibility for designers to utilize CLT more efficiently and create large open floor spaces uninhibited by drop-beams.
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Analysis of Rotational Stiffness of the Timber Frame Connection

https://research.thinkwood.com/en/permalink/catalogue2763
Year of Publication
2020
Topic
Connections
Material
Glulam (Glue-Laminated Timber)
Application
Frames
Author
Johanides, Marek
Kubíncová, Lenka
Mikolášek, David
Lokaj, Antonín
Sucharda, Oldrich
Mynarcík, Petr
Publisher
MDPI
Year of Publication
2020
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Frames
Topic
Connections
Keywords
Rotational Stiffness
Frame Connection
Screw
Numerical Model
FEM
Finite Element Model
Mechanical Fasteners
Language
English
Research Status
Complete
Series
Sustainability
Summary
Initially, timber was considered only as an easily accessible and processable material in nature; however, its excellent properties have since become better understood. During the discovery of new building materials and thanks to new technological development processes, industrial processing technologies and gradually drastically decreasing forest areas, wood has become an increasingly neglected material. Load-bearing structures are made mostly of reinforced concrete or steel elements. However, ecological changes, the obvious problems associated with environmental pollution and climate change, are drawing increasing attention to the importance of environmental awareness. These factors are attracting increased attention to wood as a building material. The increased demand for timber as a building material offers the possibility of improving its mechanical and physical properties, and so new wood-based composite materials or new joints of timber structures are being developed to ensure a better load capacity and stiffness of the structure. Therefore, this article deals with the improvement of the frame connection of the timber frame column and a diaphragm beam using mechanical fasteners. In common practice, bolts or a combination of bolts and pins are used for this type of connection. The subject of the research and its motivation was to replace these commonly used fasteners with more modern ones to shorten and simplify the assembly time and to improve the load capacity and rigidity of this type of frame connection.
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A Method to Characterize Biological Degradation of Mass Timber Connections

https://research.thinkwood.com/en/permalink/catalogue2724
Year of Publication
2020
Topic
Connections
Serviceability
Material
CLT (Cross-Laminated Timber)
Author
Sinha, Arijit
Udele, Kenneth
Cappellazzi, Jed
Morrell, Jeff
Year of Publication
2020
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Connections
Serviceability
Keywords
Biological Durability
Fungal Degradation
Fungus
Connection Strength
Language
English
Research Status
Complete
Series
Wood and Fiber Science
Summary
Biological durability issues in cross-laminated timber (CLT) have been majorly ignored in North America because of the European origin of the material and careful construction practices in Europe. However, the risks of fungal and insect attacks are increased by the North American climatic conditions and lack of job-site measures to keep the material dry. The methods to evaluate durability in solid timber are inadequate for use in mass timber (MT) for a number of reasons, such as moisture variation and size being critical issues. This study therefore proposes a method, which is suitable to evaluate the strength of MT assemblies that are exposed to fungal degradation. The objective of the study was to explore a controlled method for assessing the effects of wetting and subsequent fungal attack on the behavior of CLT connections. Two different methods were used to create fungal attack on CLT assemblies. Although they were both successful, one was cumbersome, left room for many errors, and was not as efficient as the other. In addition, a standardized method to evaluate and characterize key performance metric for the connections is presented.
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Cross Laminated Timber Shear Wall Connections for Seismic Applications

https://research.thinkwood.com/en/permalink/catalogue2405
Year of Publication
2020
Topic
Connections
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Walls
Author
Falk, Michael
Publisher
Kansas State University
Year of Publication
2020
Country of Publication
United States
Format
Report
Material
CLT (Cross-Laminated Timber)
Application
Walls
Topic
Connections
Seismic
Keywords
Panels
Earthquake
Rocking Walls
Shear Walls
Language
English
Research Status
Complete
Online Access
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Cross Laminated Timber Shear Wall Connections for Seismic Applications

https://research.thinkwood.com/en/permalink/catalogue2406
Year of Publication
2020
Topic
Connections
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Walls
Author
Falk, Michael
Publisher
Kansas State University
Year of Publication
2020
Country of Publication
United States
Format
Report
Material
CLT (Cross-Laminated Timber)
Application
Walls
Topic
Connections
Seismic
Keywords
Panels
Earthquake
Rocking Walls
Shear Walls
Language
English
Research Status
Complete
Online Access
Free
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High Performance Connections to Mitigate Seismic Damage in Cross Laminated Timber (CLT) Structures

https://research.thinkwood.com/en/permalink/catalogue2707
Year of Publication
2020
Topic
Connections
Seismic
Material
CLT (Cross-Laminated Timber)
Application
Floors
Walls
Author
Smiroldo, Francesco
Gaspari, Andrea
Viel, Davide
Piazza, Maurizio
Year of Publication
2020
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Floors
Walls
Topic
Connections
Seismic
Keywords
Finite Element Modelling
Non-linear Analysis
Seismic Engineering
Earthquake
Connection Systems
Language
English
Conference
World Conference on Earthquake Engineering
Research Status
Complete
Summary
The present study proposes a new connection system for Cross Laminated Timber (CLT) structures in earthquake prone areas. The system is suitable for creating wall-floor-wall and wall-foundation connections, where each connection device can transfer both shear and tension forces, thus replacing the role of traditional “hold downs” and “angle brackets”, and eliminating possible uncertainty on the load paths and on the force-transfer mechanism. For design earthquakes intensity, the proposed system is designed to remain elastic without accessing the inelastic resources, avoiding in this way permanent deformations in both structural and non-structural elements. However, in case of unforeseen events of exceptional intensity, the system exhibits a pseudo-ductile behaviour, with significant deformation capacity. Furthermore, in the proposed system the vertical forces are directly transferred through the contact between wall panels, avoiding compressions orthogonal to the grain of the floor panels. In this research, the connection system was analysed via finite element modelling based on numerical strategies with different levels of refinements. Nonlinear analyses were performed in order to investigate the response of the connection to shear, tension and a combination of such forces. The numerical responses were compared with those of full-scale experimental tests performed on the proposed connection subjected to different kind of loading configuration. The results appear as promising, suggesting that the proposed connection system could represent a viable solution to build medium-rise seismic-resistant CLT structures, that minimise damage to structural and non-structural elements and the cost of repair.
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Effects of Moisture Intrusion on the Performance of a Cross-Laminated Timber (CLT) Angle Bracket Connection

https://research.thinkwood.com/en/permalink/catalogue2703
Year of Publication
2020
Topic
Connections
Moisture
Material
CLT (Cross-Laminated Timber)
Author
Bora, Shrenik
Publisher
Oregon State University
Year of Publication
2020
Country of Publication
United States
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Topic
Connections
Moisture
Keywords
Shear Walls
Wall-to-Diaphragm L-Bracket Connection
High Moisture Exposure Conditions
Moisture Cycling
Language
English
Research Status
Complete
Summary
Cross-laminated timber (CLT) is revolutionizing the use of wood in the construction sector of North America as a solution for walls and diaphragms in mid-rise or even high-rise timber structures on account of its environmental advantages, high strength-to- weight ratio, fire-safety performance, and propensity for prefabrication. However, considering the hygroscopic nature of wood, moisture intrusion can affect material properties and, moreover, moisture increases the possibility of biological degradation, which can directly affect the durability of CLT structural members and their connections. The favorable seismic performance of connections in the CLT structural systems has been well researched in numerous studies. In addition, even though several research efforts have been conducted to understand the hygrothermal performance of CLT panels, knowledge of the CLT connections when subjected to moisture cycling is minimal. In this study, a CLT shear wall-to-diaphragm L-bracket connection is exposed to two high moisture exposure conditions - flood and simulated rain with increased humidity as well as different exposure durations to investigate the connection performance under the effects of moisture intrusion. Currently, there are four major species that are used for CLT, namely, Douglas-fir, Southern yellow pine, Norway spruce, and Spruce Pine Fir. All four species were incorporated into the study. A total of 264 cyclic tests were performed on wall-to-diaphragm L-bracket connection specimens to evaluate the connection performance in terms of strength, stiffness, and energy dissipation along with the development of two force-displacement engineering models. Results from both exposure studies suggest no significant degradation in connection performance after a moisture cycle of wetting and drying apart from a significant decrease in energy dissipation in flood exposure. However, the effects of multiple moisture cycling merit further study.
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Verification of Seismic Resistant Performance of Developed Original Cross-Laminated Timber Core Structure Method by Shaking Table Experiment

https://research.thinkwood.com/en/permalink/catalogue2699
Year of Publication
2020
Topic
Seismic
Connections
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Gunawan, Indra
Moritani, K
Isoda, Hiroshi
Mori, Takuro
Shinohara, M
Noda, T
Hosomi, R
Kurumada, Shinsuke
Makita, T
Publisher
IOP Publishing Ltd
Year of Publication
2020
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Seismic
Connections
Keywords
Core Structure
Shaking Table
Joint
Wall-to-Foundation
Wall-to-Wall
Earthquake
Shear Force
Research Status
Complete
Series
IOP Conference Series: Materials Science and Engineering
Summary
In recent years, development of wood engineering is gradually increasing. Instead of using many wood columns, cross laminated timber is expected for constructing spacious open space building. Since cross-laminated timber has high rigidity and strength, cross-laminated timber is expected to be used as earthquake resistant wall or floor diaphragm that makes the span of building can be increased and the position of the wall can be adjusted openly. In order to optimize the performance of cross-laminated timber for open space building, original cross laminated timber core structure method was developed. In this paper, the development concept of original cross laminated timber core structure method will be explained. In this method, the joint connection for each element such as joint connection for wall-concrete foundation, wall-beam, and wall to hanging wall was also developed. The experiment to verify the strength and rigidity of each connection has been conducted and the result will be described. The shaking table experiment of 3-story open space building constructed by original cross laminated timber structure using varies earthquake waves was conducted. In this experiment natural period, shear force for each floor, story drift, and building response data is taken. The result shows the structure designed by original CLT core structure method is satisfy the requirement based on Japan cross-laminated panel structure regulation.
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Experimental Investigation on the Fire Resistance of Glued-In Rod Timber Joints with Heat Resistant Modified Epoxy Resin

https://research.thinkwood.com/en/permalink/catalogue2665
Year of Publication
2020
Topic
Fire
Connections
Material
Glulam (Glue-Laminated Timber)
Author
Luo, Liquan
Shi, Benkai
Liu, Weiqing
Yang, Huifeng
Ling, Zhibin
Publisher
MDPI
Year of Publication
2020
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Topic
Fire
Connections
Keywords
Fire Resistance
Glued-In Rod Joint
Glued-In Rod Timber Joint
Pull-Out Test
Heat Resistant
Modified Epoxy Resin
Adhesive
Language
English
Research Status
Complete
Series
Materials
Summary
This paper presents an experimental evaluation of the fire resistance of glued-in rod timber joints using epoxy resin, with and without modification. A heat-resistant modified resin was designed by adding inorganic additives into the epoxy resin, aiming to improve the heat resistance. Joints that were made using the modified epoxy resin at room temperature showed a bearing capacity comparable to those with commercial epoxy resin. Twenty-one joint specimens with the modified epoxy resin and six with a commercial epoxy resin were tested in a fire furnace to evaluate the fire resistance. The main failure mode was the pull-out of the rod, which is typical in fire tests of this type of joints. As to the effects of the test parameters, this study considered the effects of adhesive types, sectional sizes, stress levels, and fireproof coatings. The test results showed that the fire resistance period of a joint can be evidently improved by modifying the resin and using the fireproof coating, as the improvements reached 73% and 35%, respectively, compared with the joint specimens with commercial epoxy resin. It was also found that, for all specimens, the fire resistance period decreased with an increase in the stress level and increased with an increase in the sectional sizes.
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Mechanical Experimental Study on Tensile Bolted Connections of Crosslaminated Timber

https://research.thinkwood.com/en/permalink/catalogue2450
Year of Publication
2020
Topic
Connections
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Walls
Floors
Author
Su, Chenxiao
Xiong, Haibei
Publisher
Tech Science Press
Year of Publication
2020
Country of Publication
United States
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Walls
Floors
Topic
Connections
Mechanical Properties
Keywords
Monotonic Loading
Cyclic Loading
Deformation
Failure Modes
Wall-to-Wall
Wall-to-Floor
Bolted Connection
Load-Slip
Bearing Capacity
Yielding Point
Stiffness
Ductility
Language
English
Research Status
Complete
Series
Structural Durability & Health Monitoring
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Investigation and Optimization of Connections in Timber Assemblies Subjected to Blast Loading

https://research.thinkwood.com/en/permalink/catalogue2509
Year of Publication
2020
Topic
Design and Systems
Connections
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Application
Wood Building Systems

Development of Novel Standardized Structural Timber Elements Using Wood-Wood Connections

https://research.thinkwood.com/en/permalink/catalogue2747
Year of Publication
2020
Topic
Design and Systems
Connections
Material
CLT (Cross-Laminated Timber)
Author
Gamerro, Julien
Publisher
Lausanne, EPFL
Year of Publication
2020
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Topic
Design and Systems
Connections
Keywords
Timber Construction
Connections
Digital Fabrication
Design for Manufacturing and Assembly
Structural Design
Structural Frameworks
Semi-Rigid Connection
Experimental
Shear Strength
Compression Strength
Wood-Wood Connections
Bending Test
Bending Stiffness
Numerical Model
Load Carrying Capacity
Slip Modulus
Language
English
Research Status
Complete
Summary
Traditional wood-wood connections, widely used in the past, have been progressively replaced by steel fasteners and bonding processes in modern timber constructions. However, the emergence of digital fabrication and innovative engineered timber products have offered new design possibilities for wood-wood connections. The design-to-production workflow has evolved considerably over the last few decades, such that a large number of connections with various geometries can now be easily produced. These connections have become a cost-competitive alternative for the edgewise connection of thin timber panels. Several challenges remain in order to broaden the use of this specific joining technique into common timber construction practice: (1) prove the applicability at the building scale, (2) propose a standardized construction system, (3) develop a convenient calculation model for practice, and (4) investigate the mechanical behavior of wood-wood connections. The first building implementation of digitally produced through-tenon connections for a folded-plate structure is presented in this work. Specific computational tools for the design and manufacture of more than 300 different plates were efficiently applied in a multi-stakeholder project environment. Cross-laminated timber panels were investigated for the first time, and the potential of such connections was demonstrated for different engineered timber products. Moreover, this work demonstrated the feasibility of this construction system at the building scale. For a more resilient and locally distributed construction process, a standardized system using through-tenon connections and commonly available small panels was developed to reconstitute basic housing components. Based on a case-study with industry partners, the fabrication and assembly processes were validated with prototypes made of oriented strand board. Their structural performance was investigated by means of a numerical model and a comparison with glued and nailed assemblies. The results showed that through-tenon connections are a viable alternative to commonly used mechanical fasteners. So far, the structural analysis of such construction systems has been mainly achieved with complex finite element models, not in line with the simplicity of basic housing elements. A convenient calculation model for practice, which can capture the semi-rigid behavior of the connections and predict the effective bending stiffness, was thus introduced and subjected to large-scale bending tests. The proposed model was in good agreement with the experimental results, highlighting the importance of the connection behavior. The in-plane behavior of through-tenon connections for several timber panel materials was characterized through an experimental campaign to determine the load-carrying capacity and slip modulus required for calculation models. Based on the test results, existing guidelines were evaluated to safely apply these connections in structural elements while a finite element model was developed to approximate their performance. This work constitutes a firm basis for the optimization of design guidelines and the creation of an extensive database on digitally produced wood-wood connections. Finally, this thesis provides a convenient design framework for the newly developed standardized timber construction system and a solid foundation for research into digitally produced wood-wood connections.
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Cyclic Testing of Pre-engineered Beam-Hanger Connections & Reinforcement of Holes in Glulam Beams Using Self-tapping Screws

https://research.thinkwood.com/en/permalink/catalogue2518
Year of Publication
2020
Topic
Connections
Mechanical Properties
Application
Beams

Performance of Notched Connectors for CLT-Concrete Composite Floors

https://research.thinkwood.com/en/permalink/catalogue2656
Year of Publication
2020
Topic
Mechanical Properties
Connections
Material
CLT (Cross-Laminated Timber)
Timber-Concrete Composite
Application
Floors
Author
Van Thai, Minh
Ménard, Sylvain
Elachachi, Sidi Mohammed
Galimard, Philippe
Publisher
MDPI
Year of Publication
2020
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Timber-Concrete Composite
Application
Floors
Topic
Mechanical Properties
Connections
Keywords
Notched Connections
Finite Element Model
Connectors
Deconstructable Connections
Screw
Language
English
Research Status
Complete
Series
Buildings
Summary
CLT-concrete composite floor systems are a solution for timber buildings with a long-span floor. It yields a reduction of carbon footprint and even eco-friendly structure at the end of its service life. This study will evaluate the structural performance of notched connectors in the CLT-concrete composite floor, comprised of the serviceability stiffness, maximum load, and behavior at failure. The parameters of the test plan are the loaded edge length, the notch depth, the concrete thickness, and the screw length. Other secondary variables are also assessed, such as different loading sequences, speed of test, and timber moisture content. Experimental results prove that the performance of the connector depends significantly but not linearly on the notch depth and the length of the loaded edge. The connector with a deeper notch and a shorter heel will be stiffer and more robust, but it also tends to have a brittle rupture. The test results also help validate a solution for deconstructable connector systems. A nonlinear finite element model of the connector is built and validated versus the experimental results. It yields reasonably good predictions in terms of resistance and can capture the load-slip relationship.
Online Access
Free
Resource Link
Less detail

Geopolymer-Bonded Laminated Veneer Lumber as Environmentally Friendly and Formaldehyde-Free Product: Effect of Various Additives on Geopolymer Binder Features

https://research.thinkwood.com/en/permalink/catalogue2484
Year of Publication
2020
Topic
Connections
Mechanical Properties
Material
LVL (Laminated Veneer Lumber)
Author
Shalbafan, Ali
Thoemen, Heiko
Publisher
MDPI
Year of Publication
2020
Country of Publication
Switzerland
Format
Journal Article
Material
LVL (Laminated Veneer Lumber)
Topic
Connections
Mechanical Properties
Keywords
Bonding Quality
Geopolymer
Shear
Bending
Compression
Language
English
Research Status
Complete
Series
Applied Sciences
Online Access
Free
Resource Link
Less detail

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