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Build-up schemes of block glulam according to DIN 1052-10:2010 a), b) several glulam components of different depths and widths glued by block glue lines at the wide faces c), d) I-or box-shaped block glulam build-ups e) block glulam rib plate
Source publication
The paper reports on the assets of block glued glulam for heavy duty load bearing components to be used in bridges, long-span arches and members as a substitute for steel and reinforced concrete: The term "block glued glulam" defines beam-like timber elements with a cross-sectional build-up consisting of at least two glulam beams glued together. By...
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Citations
... The pioneering work on the path of ultrasonic waves propagating in a timber glulam structure by [123] developed a finite difference model in the time domain which incorporates the following parameters: the wood stiffnesses and their local variations, the damping of ultrasonic wave and the density of wood. Ultrasonic wave propagation in wood was studied and explained with a time-varying wavefront in unbounded timber with curved growth annual rings. ...
Acoustics is a field with significant application in wood science and technology for the classification and grading, through non-destructive tests, of a large variety of products from standing trees to building structural elements and musical instruments. In this review article the following aspects are treated: (1) The theoretical background related to acoustical characterization of wood as an orthotropic material. We refer to the wave propagation in anisotropic media, to the wood anatomic structure and propagation phenomena, to the velocity of ultrasonic waves and the elastic constants of an orthotropic solid. The acoustic methods for the determination of the elastic constants of wood range from the low frequency domain to the ultrasonic domain using direct contact techniques or ultrasonic spectroscopy. (2) The acoustic and ultrasonic methods for quality assessment of trees, logs, lumber and structural timber products. Scattering-based techniques and ultrasonic tomography are used for quality assessment of standing trees and green logs. The methods are based on scanning stress waves using dry-point-contact ultrasound or air-coupled ultrasound and are discussed for quality assessment of structural composite timber products and for delamination detection in wood-based composite boards. (3) The high-power ultrasound as a field with important potential for industrial applications such as wood drying and other applications. (4) The methods for the characterization of acoustical properties of the wood species used for musical instrument manufacturing, wood anisotropy, the quality of wood for musical instruments and the factors of influence related to the environmental conditions, the natural aging of wood and the effects of long-term loading by static or dynamic regimes on wood properties. Today, the acoustics of wood is a branch of wood science with huge applications in industry.
... Glue-laminated timber is being used as an alternative to steel and concrete construction, and is seeing an increase in formal and technical complexity due to advances in computer-controlled machining and advanced timber engineering (Müller 2000). New adhesives and lamination techniques have introduced new possibilities, such as hardwood glulams (Muraleedharan, Reiterer, and Bader 2016) -which allow the utilization of new hardwood timber stocks previously left untapped for large-volume construction; block gluing -the structural gluing of finished architecturally-scaled components, exemplified in bridge construction (Aicher and Stapf 2014); and reinforcement via fibres and other composite means (Romani and Blaß 2001). ...
Integrated material practice in free-form timber structures is a practice-led research project at CITA (Centre for IT and Architecture) that develops a digitally-augmented material practice around glue-laminated timber. The project is part of the InnoChain ETN and has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 642877. The advent of digital tools and computation has shifted the focus of many material practices from the shaping of material to the shaping of information. The ability to process large amounts of data quickly has made computation commonplace in the design and manufacture of buildings, especially in iterative digital design workflows. The simulation of material performance and the shift from models as representational tools to functional ones has opened up new methods of working between digital model and physical material. Wood has gained a new relevance in contemporary construction because it is sustainable, renewable, and stores carbon. In light of the climate crisis and concerns about overpopulation, and coupled with developments in adhesives and process technology, it is returning to the forefront of construction. However, as a grown and heterogeneous material, its properties and behaviours nevertheless present barriers to its utilization in architecturally demanding areas. Similarly, the integration of the properties, material behaviours, and production constraints of glue-laminated timber (glulam) assemblies into early-stage architectural design workflows remains a challenging specialist and inter-disciplinary affair. Drawing on a partnership with Dsearch – the digital research network at White Arkitekter in Sweden – and Blumer Lehmann AG – a leading Swiss timber contractor – this research examines the design and fabrication of glue-laminated timber structures and seeks a means to link industrial timber fabrication with early-stage architectural design through the application of computational modelling, design, and an interrogation of established timber production processes. A particular focus is placed on large-scale free-form glulam structures due to their high performance demands and the challenge of exploiting the bending properties of timber. By proposing a computationally-augmented material practice in which design intent is informed by material and fabrication constraints, the research aims to discover new potentials in timber architecture. The central figure in the research is the glulam blank - the glue-laminated near-net shape of large-scale timber components. The design space that the blank occupies - between sawn, graded lumber and the finished architectural component - holds the potential to yield new types of timber components and new structural morphologies. Engaging with this space therefore requires new interfaces for design modelling and production that take into account the affordances of timber and timber processing. The contribution of this research is a framework for a material practice that integrates processes of computational modelling, architectural design, and timber fabrication and acts as a broker between domains of architectural design and industrial timber production. The research identifies four different notions of feedback that allow this material practice to form.
... Related concepts, precedents to IGST, include structural finger-jointed timber [11], glulam and glued solid timber [12], block glulam [13], as well as commercial products such as Bilam and Trilam beams [14]. However, as the concept is new, it was deemed necessary to examine the performance of the core mechanisms behind IGST, namely the performance of the diagonal joint, both in isolation, and as part of a composite member. ...
This paper introduces a novel mass timber construction (MTC) system and presents the results of an initial exploration of its structural performance. This system is called Interlocking Glued Solid Timber (IGST) and employs standard-sized solid timber joists, glued together in overlapping patterns. Diagonal cuts are utilised in order to bond adjoining elements. For the purposes of the tests described in this paper, a total of 70 spruce joists were collected at a sawmill and categorised via dynamic modulus of elasticity measurements. Materials testing provided the compressive strength perpendicular to the grain and the shear strength parallel to the grain. Three different types of IGST prototypes were manufactured and tested to failure in a four-point bending test. An additional two series were tested, one of solid joists and one of a glued joist. Three-dimensional finite element models (FEM) were also developed to perform numerical analyses. The results demonstrated that the ultimate capacity of one type of IGST prototype was very similar to that of a solid joist of equal cross-section. As the IGST prototype is scalable, it allows for applications similar to other MTC systems. Finally, the FEMs were generally accurate in predicting the performance of the IGST assemblies, thus allowing them to be used to simulate performance.
Block-glued glulam is a structural material that can be used as a construction member of a large-section wooden building, which is produced by edgewise bonding of two or more glulam beam elements. The edgewise bonding performance of the block-glued glulam was examined through delamination test and block shear strength test. According to the test results, the block-glued glulam that was manufactured with 1.5 MPa of compressive pressure after applying 500 g/m² of Resorcinol adhesive showed the best edgewise bonding performance. The block-glued glulam produced in a good edgewise bonding condition was compared with a control glulam with the same section modulus for bending strength performance. The modulus of elasticity (MOE) in bending was similar to that of the control glulam. The modulus of rupture (MOR) of the block-glued glulam was higher by 27% than that of the control glulam. No interfacial failure or cohesive failure were observed in the edgewise bonding layer.
