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226 records – page 1 of 23.

Experimental study on bending properties of bamboo-wood composite beams with different tectonic patterns

https://research.thinkwood.com/en/permalink/catalogue3347
Year of Publication
2023
Topic
Mechanical Properties
Application
Beams
Author
Zhang, Zichen
Qiu, Zhenyu
Organization
Nanjing Forestry University
Publisher
Elsevier
Year of Publication
2023
Format
Journal Article
Application
Beams
Topic
Mechanical Properties
Keywords
Bamboo-wood Composite
Bending Properties
Tectonic Pattern
Research Status
Complete
Series
Polymer Testing
Summary
This study investigated the mechanical properties of bamboo-wood composite beams by conducting four-point bending static load tests on eight laminated beams. It was shown that a new bamboo-wood composite material was obtained by laminating denser laminated bamboo to the surface of timber panels employing hot pressing. Failure of the beams was mainly due to interlaminar shear damage and brittle fracture at the bottom. The test results showed that the polyurethane and epoxy binders ensured good interlaminar bonding properties. In the same adhesive specimen, the increase in the number of bamboo panels increased the ultimate load-carrying capacity of the bamboo-wood composite beams. The predicted load capacity using the equivalent section calculation method agreed well with the experimental results and was effective for assessing the mechanical properties of bamboo-wood composite laminated beams.
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Structural Behaviour of Aluminium–Timber Composite Beams with Partial Shear Connections

https://research.thinkwood.com/en/permalink/catalogue3388
Year of Publication
2023
Topic
Mechanical Properties
Material
LVL (Laminated Veneer Lumber)
Application
Beams
Author
Chybinski, Marcin
Polus, Lukasz
Organization
Poznan University of Technology
Publisher
MDPI
Year of Publication
2023
Format
Journal Article
Material
LVL (Laminated Veneer Lumber)
Application
Beams
Topic
Mechanical Properties
Keywords
Aluminium-Timber Composite Beams
Partial Shear Connection
Screws
Bending Test
Finite Element Method
Research Status
Complete
Series
Applied Sciences
Summary
In this paper, the short-term behaviour of innovative aluminium–timber composite beams was investigated. Laminated veneer lumber panels were attached to aluminium beams with screws. Recently conducted theoretical, experimental, and numerical investigations have focused on aluminium–timber composite beams with almost full shear connections. However, no experiments on aluminium–timber composite beams with partial shear connections have yet been conducted. For this reason, composite action in composite beams with different screw spacing was studied in this paper. Four-point bending tests were performed on aluminium–timber composite beams with different screw spacing to study their structural behaviour (ultimate load, mode of failure, load versus deflection response, load versus slip response, and short-term stiffness). The method used for steel–concrete composite beams with partial shear connection was adopted to estimate the load bearing capacity of the investigated aluminium–timber composite beams. The resistance to sagging bending of the aluminium–timber composite beams with partial shear connections from the theoretical analyses differed by 6–16% from the resistance in the laboratory tests. In addition, four 2D numerical models of the composite beams were developed. One model reflected the behaviour of the composite beam with full shear connection. The remaining models represented the composite beams with partial shear connections and were verified against the laboratory test results. Laminated veneer lumber was modelled as an orthotropic material and its failure was captured using the Hashin damage model. The resistance to sagging bending of the aluminium–timber composite beams with partial shear connections from the numerical analyses were only 3–6% lower than the one from the experiments.
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Experimental and theoretical investigation on shear performances of glued-in perforated steel plate connections for prefabricated timber–concrete composite beams

https://research.thinkwood.com/en/permalink/catalogue3373
Year of Publication
2023
Topic
Mechanical Properties
Material
Timber-Concrete Composite
Application
Beams
Floors
Author
Yang, Huifeng
Lu, Yan
Ling, Xiu
Tao, Haotian
Shi, Benkai
Organization
Nanjing Tech University
Southeast University
Publisher
Elsevier
Year of Publication
2023
Format
Journal Article
Material
Timber-Concrete Composite
Application
Beams
Floors
Topic
Mechanical Properties
Keywords
Glued-in Perforated Steel Plate
Prefabricated Concrete Slab
Slip Modulus
Experimental Study
Research Status
Complete
Series
Case Studies in Construction Materials
Summary
Glued-in perforated steel plate (GIPSP) connections demonstrate significant shear strength and high slip modulus. Consequently, they indicate substantial potential for application in timber–concrete composite (TCC) structures according to the emerging tendencies in high-storey and large-span buildings. However, the application pattern in prefabricated TCC structures and the theoretical analysis of the shear performances of GIPSP connections are highly deficient. This hinders the application of this type of shear connection. In this study, the shear performances of GIPSP connections were evaluated using push-out tests. Ten groups of push-out specimens with different steel plate numbers, steel plate lengths, and concrete slab types were tested. The concrete slab types investigated in the experiments included a prefabricated concrete slab and cast-in-situ concrete slab. The experimental results were discussed in terms of the failure mode, load-carrying capacity, and slip modulus. The theoretical models for the load-carrying capacity related to the associate failure mode were discussed based on an analysis of the failure mechanisms. In addition, design proposals with regard to the load-carrying capacity and slip modulus of the GIPSP connection were presented. The research results can provide design guidance for TCC beams using GIPSP connections and prefabricated concrete slabs.
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Modeling approach to estimate the bending strength and failure mechanisms of glued laminated timber beams

https://research.thinkwood.com/en/permalink/catalogue2939
Year of Publication
2022
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
Vida, Christoffer
Lukacevic, Markus
Eberhardsteiner, Josef
Füssl, Josef
Organization
TU Wien
Publisher
Elsevier
Year of Publication
2022
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Mechanical Properties
Keywords
Extended Finite Element Method
Bending Strength
Size Effect
Laminating Effect
Failure Mechanism
Research Status
Complete
Series
Engineering Structures
Summary
The numerical simulation of four-point bending tests on glued laminated timber (GLT) beams requires an adequate description of the material behavior and of relevant failure mechanisms. The wooden lamellas, building up the GLT element, include knots, as a result of the natural tree growth process, which significantly affect the mechanical behavior. The variability of the morphology and arrangement of these knots lead to a large fluctuation, especially of strength properties, along the wooden lamellas. This leads to complex and, in general, quite brittle structural failure mechanisms of the GLT element. Such failure mechanisms can numerically be described with discrete cracks, using the framework of the extended finite element method (XFEM) for cracks without predefined positions or cohesive surfaces for cracks with predefined positions. In this work, a modeling approach to reliably estimate the bending strength and failure mechanisms of GLT beams subjected to four-point bending tests is proposed. Herein, the approach is validated by simulating replications of experimentally tested GLT beams of two beam sizes and strength classes, where each knot group is considered as a section with reduced individual stiffness and strength in exactly the same position as in the real beam. The results show that the application of quasi-brittle material failure may still result in a brittle global failure of GLT beams. The present study exemplarily shows how valuable insight into progressive failure processes can be gained by allowing the formation of continuous crack patterns. Moreover, a refined consideration of the knot geometries with such sophisticated realizations of discrete cracks may be able to simulate the actual failure mechanisms even more precisely.
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Finite Element Modeling on Shear Performance of Grouted Stud Connectors for Steel–Timber Composite Beams

https://research.thinkwood.com/en/permalink/catalogue2944
Year of Publication
2022
Topic
Mechanical Properties
Material
Steel-Timber Composite
Application
Beams
Author
Zhang, Henan
Ling, Zhibin
Organization
Suzhou University of Science and Technology
Editor
Lopes, Sérgio
Publisher
MDPI
Year of Publication
2022
Format
Journal Article
Material
Steel-Timber Composite
Application
Beams
Topic
Mechanical Properties
Keywords
Shear Connection
Finite Element Modeling
Grouted Stud Connections
Research Status
Complete
Series
Materials
Summary
Steel–timber composite (STC) systems are considered as an environmentally friendly alternative to steel–concrete composite (SCC) structures due to its advantages including high strength-to-weight ratio, lower carbon footprint, and fully dry construction. Bolts and screws are the most commonly used connectors in STC system; however, they probably make great demands on the accuracy of construction because of the predrilling in both the timber slabs and steel girder fangles. To address this issue, the STC connections with grouted stud connectors (GSC) were proposed in this paper. In addition, stud connectors can also provide outstanding stiffness and load-bearing capacity. The mechanical characteristic of the GSC connections was exploratorily investigated by finite element (FE) modeling. The designed parameters for the FE models include stud diameter, stud strength, angle of outer layer of cross-laminated timber (CLT) panel, tapered groove configurations, and thickness of CLT panel. The numerical results indicated that the shear capacity and stiffness of the GSC connections were mainly influenced by stud diameter, stud strength, angle of outer layer of CLT panel, and the angle of the tapered grooves. Moreover, the FE simulated shear capacity of the GSC connections were compared with the results predicted by the available calculation formulas in design codes and literatures. Finally, the group effect of the GSC connections with multiple rows of studs was discussed based on the numerical results and parametric analyses. An effective row number of studs was proposed to characterize the group effect of the GSC connections.
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Study on the strength of glued laminated timber beams with round holes: proposal of the design formula for the splitting strength

https://research.thinkwood.com/en/permalink/catalogue2946
Year of Publication
2022
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
Okamoto, Shigefumi
Akiyama, Nobuhiko
Araki, Yasuhiro
Aoki, Kenji
Inayama, Masahiro
Organization
Osaka City University
Publisher
Springer
Year of Publication
2022
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Mechanical Properties
Keywords
Round Hole
Splitting
Finite Element Method (FEM)
Design Formula
Research Status
Complete
Series
Journal of Wood Science
Summary
When a glued laminated timber (GLT) beam with a round hole is subjected to a shear force and bending moment, the hole will crack and fail due to a large tensile stress perpendicular to the grain and shear stresses. If the stresses acting on the hole are known, it is possible to estimate the fracture load. However, it is necessary to obtain the stresses acting on the hole by finite element analysis, which is very time consuming. In this study, to easily estimate the fracture load, we proposed a formula to estimate the bearing capacity at the time of a hole fracture by obtaining the stress acting on the hole through fnite element analysis and an approximate formula. The validity of the proposed formula was verifed using the existing experimental data of a GLT beam. As a result, it was confrmed that the proposed equation can estimate the fracture load of GLT beams in Japan and that the proposed equation can estimate the fracture load of GLT beams in countries other than Japan with some accuracy.
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An Experimental and Analytical Study on the Bending Performance of CFRP-Reinforced Glulam Beams

https://research.thinkwood.com/en/permalink/catalogue2972
Year of Publication
2022
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
He, Minjuan
Wang, Yuxuan
Li, Zheng
Zhou, Lina
Tong, Yichang
Sun, Xiaofeng
Organization
Tongji University
University of Victoria
Editor
Tam, Lik-ho
Publisher
Frontiers
Year of Publication
2022
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Mechanical Properties
Keywords
CFRP Sheet
Four-point Bending Test
Numerical Model
Theoretical Analysis
Research Status
Complete
Series
Frontiers in Materials
Summary
The fiber-reinforced polymer is one kind of composite material made of synthetic fiber and resin, which has attracted research interests for the reinforcement of timber elements. In this study, 18 glued-laminated (glulam) beams, unreinforced or reinforced with internally embedded carbon fiber–reinforced polymer (CFRP) sheets, were tested under four-point bending loads. For the reinforced glulam beams, the influences of the strengthening ratio, the modulus of elasticity of the CFRP, and the CFRP arrangement on their bending performance were experimentally investigated. Subsequently, a finite element model developed was verified with the experimental results; furthermore, a general theoretical model considering the typical tensile failure mode was employed to predict the bending–resisting capacities of the reinforced glulam beams. It is found that the reinforced glulam beams are featured with relatively ductile bending failure, compared to the brittle tensile failure of the unreinforced ones. Besides, the compressive properties of the uppermost grain of the glulam can be fully utilized in the CFRP-reinforced beams. For the beams with a 0.040% strengthening ratio, the bending–resisting capacity and the maximum deflection can be enhanced approximately by 6.51 and 12.02%, respectively. The difference between the experimental results and the numerical results and that between the experimental results and analytical results are within 20 and 10%, respectively.
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The Possibility to Use Pine Timber Pieces with Small Size in the Production of Glulam Beams

https://research.thinkwood.com/en/permalink/catalogue3042
Year of Publication
2022
Topic
Market and Adoption
Application
Beams
Author
Dziurka, Dorota
Kawalerczyk, Jakub
Walkiewicz, Joanna
Derkowski, Adam
Mirski, Radoslaw
Organization
Poznan University of Life Sciences
Editor
Sadowski, Tomasz
Publisher
MDPI
Year of Publication
2022
Format
Journal Article
Application
Beams
Topic
Market and Adoption
Keywords
Engineered Wood Products
Low-quality Timber
Pine
Structural Elements
Research Status
Complete
Series
Materials
Summary
Engineered wood products, such as glulam beams, attract much attention from the building industry in recent years. Therefore, there is a constant necessity to seek new models of structural beams, which assume the use of outsized sawn wood pieces as an alternative for the standard construction timber. Three variants of glulam beams, composed of the main yield and side boards arranged in various structures, were proposed. Moreover, the usefulness of wedge-jointed, small-sized timber pieces was also investigated. The manufactured beams were tested, in terms of their mechanical properties, such as bending strength, elastic energy, modulus of elasticity, and resilience. The outcomes have shown that the beams manufactured using wedge-bonded timber of lower grade do not deviate considerably from beams produced from homogeneous lamellas. Furthermore, the results of modulus of elasticity, in the case of the three-layered beams composed of both small-sized non-homogenous main yield and side boards, exceeded the requirements from EN 14080. It allowed us to classify the obtained materials as GL 32c, which is the highest grade specified within the standard.
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GL Beams Reinforced with Plywood in the Outer Layer

https://research.thinkwood.com/en/permalink/catalogue3101
Year of Publication
2022
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
Dziurka, Dorota
Derkowski, Adam
Wieruszewski, Marek
Kulinski, Marcin
Mirski, Radoslaw
Organization
Poznan University of Life Sciences
Editor
Sadowski, Tomasz
Publisher
MDPI
Year of Publication
2022
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Mechanical Properties
Keywords
Glued Elements
Solid Wood
Plywood
Research Status
Complete
Series
Materials
Summary
Glulam beams are increasingly used in the construction industry because of their high strength and the possibility of using round timber with smaller cross-sections. The load-bearing capacity of beams is strongly related to the quality of the outer layers and, in the case of wood, especially the tension zones. For these reasons, this study decided to replace the outer lamella with tensile plywood. The produced beams were subjected to static bending strength and modulus of elasticity evaluation. It was shown that the best static bending strength values were obtained for beams containing plywood in the tension layer. However, the change in structure in the tension zone of beams made of glued laminated timber results not only in an increase in the load capacity of elements produced in this way but also in a decrease in the range/range of the obtained results of bending strength. This way of modifying the construction of glued laminated beams allows a more rational use of available pine timber.
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The Effect of Periodic Loading of Glued Laminated Beams on Their Static Bending Strength

https://research.thinkwood.com/en/permalink/catalogue3102
Year of Publication
2022
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
Dziurka, Dorota
Derkowski, Adam
Dukarska, Dorota
Kawalerczyk, Jakub
Mirski, Radoslaw
Organization
Poznan University of Life Sciences
Publisher
MDPI
Year of Publication
2022
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Mechanical Properties
Keywords
Periodic Loading
Static Bending Strength
Research Status
Complete
Series
Materials
Summary
Engineered wood products (EWP) such as glulam beams are gaining more and more popularity due to several advantages resulting from the wood itself, as well as the constant search for structural materials of natural origin. However, building materials face some requirements regarding their strength. Thus, the study aimed to assess the static bending strength of structural beams produced with the use of pine wood, after the periodic loading of approximately 80 kN for a year. The manufactured beams differed in the type of facing layers, i.e., pine timber with a high modulus of elasticity and plywood. The produced beams, regardless of their structure, are characterized by a similar static bending strength. Moreover, it has been shown that the loading of beams in the range of about 45% of their immediate capacity does not significantly affect their static bending strength and linear modulus of elasticity.
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226 records – page 1 of 23.