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9 records – page 1 of 1.

Behavior of Cross-Laminated Timber Diaphragm Connections with Self-Tapping Screws

https://research.thinkwood.com/en/permalink/catalogue1288
Year of Publication
2018
Topic
Connections
Mechanical Properties
Seismic
Material
CLT (Cross-Laminated Timber)
Author
Sullivan, Kyle
Miller, Thomas
Gupta, Rakesh
Publisher
ScienceDirect
Year of Publication
2018
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Connections
Mechanical Properties
Seismic
Keywords
Seismic Force Resisting System
Monotonic Tests
Cyclic Tests
Strength
Stiffness
Shear Connections
Self-Tapping Screws
Research Status
Complete
Series
Engineering Structures
Summary
Monotonic and cyclic tests were carried out to determine strength and stiffness characteristics of 2.44 m (8 ft) long shear connections with 8 mm and 10 mm diameter self-tapping screws. The goal of this research is tocompare test values of cross-laminated timber (CLT) diaphragm connections in seismic force-resisting systems tothe design values calculated from formulas in the National Design Specification for Wood Construction (USA)and the Eurocode. Understanding and quantifying the behavior of these shear connections will provide structural engineers with increased confidence in designing these components, especially with regard to the seismic forceresisting systems. Ratios of the experimental yield strength (from the yield point on the load-deflection curve) to factored design strength were in the range of 2.1–6.1. In the ASCE 41-13 acceptance criteria analysis, the mfactors for the Life Safety performance level in cyclic tests ranged from 1.6 to 1.8 for surface spline connections and from 0.9 to 1.7 for cyclic half-lap connections. The half-lap connections with a unique combination of angled and vertical screws performed exceptionally well with both high, linear elastic initial stiffness and ductile, postpeak behavior.
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Bending Tests on Glulam-CLT Beams connected with Double-Sided Punched Metal Plate Fasteners and Inclined Screws

https://research.thinkwood.com/en/permalink/catalogue320
Year of Publication
2015
Topic
Connections
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Application
Beams
Floors
Author
Jacquier, Nicolas
Organization
Luleå University of Technology
Year of Publication
2015
Format
Report
Material
CLT (Cross-Laminated Timber)
Glulam (Glue-Laminated Timber)
Application
Beams
Floors
Topic
Connections
Mechanical Properties
Keywords
Bending Test
Shear Connections
Double-sided Punched Metal Plate
Inclined Screws
Research Status
Complete
Summary
This report presents bending tests performed on composite beams made from glulam beams and cross laminated timber (CLT) panels. The composite beam, with a T-cross section, represents a section of a floor element in a multi-storey CLT construction system. The shear connections used were made either of doublesided punched metal plate fasteners, either of inclined screws, or of a combination of both fastener types. The screws are used to secure the shear connection with double-sided nail plates with respect to possible separation forces between the glulam and the CLT. An additional test with a screw glued connection was made for comparison as the upper bound case in terms of composite action. The results show the beams with double-sided nail plates (with or without screws) achieved a very high level of composite action and an overall satisfactory behaviour. Almost full composite action was achieved for the screw-glued composite beam. A detailed design example of the beam element according to the Eurocode 5 and Finnish National Annex is presented.
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Coupled Timber–Concrete Ceiling Using Bonded Shear Connectors

https://research.thinkwood.com/en/permalink/catalogue886
Year of Publication
2013
Topic
Connections
Design and Systems
Material
Timber-Concrete Composite
Application
Ceilings
Author
Cajka, Radim
Burkovic, Kamil
Publisher
Scientific.net
Year of Publication
2013
Format
Journal Article
Material
Timber-Concrete Composite
Application
Ceilings
Topic
Connections
Design and Systems
Keywords
Shear Connector
Research Status
Complete
Series
Advanced Materials Research
Summary
This paper deals with the possibilities of using coupled timber-concrete structures by means a glued coupling bar. The described process of static reinforcement is particularly suitable for reconstruction of historic timber ceilings and places where it is necessary to prevent damage to non-supporting structures (e.g. ceiling, plaster, stucco decorations, etc.). The method is also employed in those cases where it is necessary to allow traffic-flow in the rooms below the reconstructed ceiling. The article describes the specific technological process that has been examined in the reconstruction of the ceiling structure of a house on Sokolska Street in Ostrava. Following experimental testing in laboratories at the Faculty of Civil Engineering VSB - TU Ostrava the technology of bonded shear bars under static reinforcement of timber ceilings was first applied and successfully tested in construction practice.
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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
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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Experimental Study on Timber-Lightweight Concrete Composite Beams with Ductile Bolt Connectors

https://research.thinkwood.com/en/permalink/catalogue3063
Year of Publication
2021
Topic
Mechanical Properties
Material
Timber-Concrete Composite
Application
Beams
Floors
Author
Hu, Yafeng
Wei, Yang
Chen, Si
Yan, Yadong
Zhang, Weiyao
Organization
Nanjing Forestry University
Editor
Corradi, Marco
Publisher
MDPI
Year of Publication
2021
Format
Journal Article
Material
Timber-Concrete Composite
Application
Beams
Floors
Topic
Mechanical Properties
Keywords
Composite Beam
Lightweight Concrete
Bending Performance
Shear Connections
Research Status
Complete
Series
Materials
Summary
A timber–lightweight-concrete (TLC) composite beam connected with a ductile connector in which the ductile connector is made of a stainless-steel bolt anchored with nuts at both ends was proposed. The push-out results and bending performance of the TLC composite specimens were investigated by experimental testing. The push-out results of the shear specimens show that shear–slip curves exhibit good ductility and that their failure can be attributed to bolt buckling accompanied by lightweight concrete cracking. Through the bending tests of ten TLC composite beams and two contrast (pure timber) beams, the effects of different bolt diameters on the strengthening effect of the TLC composite beams were studied. The results show that the TLC composite beams and contrast timber beams break on the timber fiber at the lowest edge of the TLC composite beam, and the failure mode is attributed to bending failure, whereas the bolt connectors and lightweight concrete have no obvious breakage; moreover, the ductile bolt connectors show a good connection performance until the TLC composite beams fail. The ultimate bearing capacities of the TLC composite beams increase 2.03–3.5 times compared to those of the contrast beams, while the mid-span maximum deformation decrease nearly doubled.
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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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Hybrid Steel-Timber Construction Systems for Social Housing Buildings

https://research.thinkwood.com/en/permalink/catalogue1903
Year of Publication
2014
Topic
Design and Systems
Connections
Material
CLT (Cross-Laminated Timber)
Steel-Timber Composite
Application
Wood Building Systems
Author
Loss, Cristiano
Piazza, Maurizio
Zandonini, Riccardo
Year of Publication
2014
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Steel-Timber Composite
Application
Wood Building Systems
Topic
Design and Systems
Connections
Keywords
Hybrid Structures
Shear Connections
Composite Structures
Multi-Story
Conference
International Conference on Hybrid Systems
Research Status
Complete
Notes
June 22-24, 2014, Freiburg, Switzerland
Summary
Hybrid construction systems proved to be valid structural solutions for the implementation of multi-storey buildings, especially if they require only the assembly of prefabricated and modular building elements. The structures here considered are designed to make different materials - firstly steel and timber - structurally collaborate, in order to develop a construction system with marked performance and architectonic flexibility features. Such systems can make the most of the heavily industrialized construction technology typical of steel systems, as well as of the advantages offered by CLT panels -lightness and structural stability- in which the timber element is recognized as an eco-friendly and eco-compatible material. Furthermore, in a sustainable urban development prospective, the use of cross-laminated timber panels, in short CLT, is recommended because wood is one of the fewest materials which has the capacity to isolate and store CO2 for a long period of time.
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Timber-concrete composite structural flooring system

https://research.thinkwood.com/en/permalink/catalogue3065
Year of Publication
2022
Topic
Mechanical Properties
Design and Systems
Material
Timber-Concrete Composite
Application
Floors
Author
Estévez-Cimadevila, J.
Martín-Gutiérrez, E.
Suárez-Riestra, F.
Otero-Chans, D.
Vázquez-Rodríguez, J. A.
Organization
Universidade da Coruña
Publisher
Elsevier
Year of Publication
2022
Format
Journal Article
Material
Timber-Concrete Composite
Application
Floors
Topic
Mechanical Properties
Design and Systems
Keywords
Timber Flooring System
Mixed Beams
Shear Connector
Research Status
Complete
Series
Journal of Building Engineering
Summary
An integrated solution is presented for the execution of building structures using timber-concrete composite (TCC) sections that make efficient use of the mechanical properties of both materials. The system integrates flooring and shaped prefabricated beams composed of a lower flange of glued laminated timber (GLT) glued to one or more plywood or laminated veneer lumber (LVL) ribs and linked to an upper concrete slab poured in situ. The parts may be prefabricated in T shape (only one rib), in p shape (two ribs), or with multiple ribs to create wider pieces, thereby reducing installation operations. The basis of the system is the timber-concrete shear connection in the form of holes through the ribs, which are filled by the in situ-poured concrete. The connection is complemented with the arrangement of reinforcement bars through the holes. Three test campaigns were undertaken. Shear tests of the timber-concrete connection in 12 test pieces. Shear test along the wood-wood glue line (72 planes tested) and wood -plywood (24 planes tested). Delamination test of the glued planes (24 wood-wood planes and 8 wood-plywood planes). The results indicate a high strength joint, with ductile failure and high composite effect. Likewise, the shear test results along the glue line and the delamination tests show section integrity under demanding hygrothermal conditions. Preliminary sizing curves were developed considering the Gamma Method to evaluate the performance of the system. The results show the possibilities of the system, as pouring the upper slab concrete in situ makes it possible to create continuous semi-rigid joints between the elements. This gives rise to slender flooring structures, light and with high stiffness plane against horizontal forces.
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Two-Way Spanning CLT-Concrete-Composite-Slab

https://research.thinkwood.com/en/permalink/catalogue1750
Year of Publication
2016
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Timber-Concrete Composite
Author
Loebus, Stefan
Winter, Stefan
Year of Publication
2016
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Timber-Concrete Composite
Topic
Mechanical Properties
Keywords
Two-Way
Fully Threaded Screws
Load Bearing
Notches
Push-Out Tests
Natural Frequency
Shear Connections
Bending Stiffness
Torsional Bending Stiffness
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 4982-4988
Summary
This paper examines the load-bearing behaviour of cross-laminated-timber-concrete-composite slabs. The inhomogeneous distributed orientation of the trajectories of principal stress within the slab effected the design of the shear connection between the cross-laminated-timber (CLT) and concrete layer. Two well-known shear connection types, fully threaded screws in an angle of 45° and rectangular milled in notches, were examined in bi-axially loaded push out tests. Natural frequency tests and medium-scale test including the two shear connection types and different CLT-layer configurations determined the effective bending stiffness of the slab and the effective torsional bending stiffness of the slab respectively. The results facilitate the description of the bi-axial load-bearing behaviour, and establish a basis for a structural design model in two-way spanning CLT-concrete-composite-slab engineering. The paper eventually suggests first calculation models, a simplified FEM-model and a grid model. In this regard, a force-fitting element joint was developed and tested for practical reasons.
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9 records – page 1 of 1.