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Wang, Y., Wang, T., Debertolis, M., Crocetti, R. & Wålinder, M. (2024). Design of birch plywood as gusset plates in timber-timber uniaxial tension connections: Influence of fastener pattern, face grain orientation, and discussions based on the Whitmore effective width theory. Journal of Building Engineering, 86, Article ID 108796.
Open this publication in new window or tab >>Design of birch plywood as gusset plates in timber-timber uniaxial tension connections: Influence of fastener pattern, face grain orientation, and discussions based on the Whitmore effective width theory
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2024 (English)In: Journal of Building Engineering, E-ISSN 2352-7102, Vol. 86, article id 108796Article in journal (Refereed) Published
Abstract [en]

This study reveals timber-timber composite joints consisting of glulam pieces and birch plywood plates with three different load-to-face grain angles. Utilizing a similar number of fasteners and arranging the fastener array from narrow to wide, uniaxial tension specimens were manufactured with four different fastener patterns. The thickness of birch plywood was intentionally under-designed so that the failure modes for all connections were net tension failure of birch plywood plates. Thereafter, the influence of the fastener pattern and face grain orientation on the load-bearing capacity and stiffness of the investigated composite joints was studied. The load capacity and nominal strength generally increased when the nail patterns varied from narrow to wide. This observation was associated with the Whitmore effective width theory (load spread angle) in steel gusset plate design. Moreover, to derive valid analytical methods to predict the net-tension capacity of birch plywood plates, the classic spread angle model that assumes rectangular stress blocks and the modified spread angle model that considers the summation of stresses from each fastener row were discussed. Both models were adopted to predict the net tension capacity of investigated specimens at 0°. In addition, the stiffness of joints was measured and compared with slip modulus formulas in Eurocode 5. The measured local stiffness values were found to be independent of the fastener pattern and load-face grain angles. The analytical slip modulus assuming the case without predrilling exhibited a satisfactory prediction, while formulas assuming the case with predrilling tend to give overestimations.

Place, publisher, year, edition, pages
Elsevier BV, 2024
Keywords
Birch plywood, Engineered wood products, Mechanical fasteners, Timber-timber composite joints
National Category
Materials Engineering Civil Engineering
Identifiers
urn:nbn:se:kth:diva-344006 (URN)10.1016/j.jobe.2024.108796 (DOI)2-s2.0-85185285877 (Scopus ID)
Note

QC 20240229

Available from: 2024-02-28 Created: 2024-02-28 Last updated: 2024-02-29Bibliographically approved
Wang, T., Wang, Y., Ringaby, J., Crocetti, R., Wålinder, M. & Blomqvist, L. (2024). Glulam beams adhesively bonded by birch plywood plates in moment-resisting beam-to-beam connections. Engineering structures, 302, 117471, Article ID 117471.
Open this publication in new window or tab >>Glulam beams adhesively bonded by birch plywood plates in moment-resisting beam-to-beam connections
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2024 (English)In: Engineering structures, ISSN 0141-0296, E-ISSN 1873-7323, Vol. 302, p. 117471-, article id 117471Article in journal (Refereed) Published
Abstract [en]

The design of timber connections is of vital importance in timber structures. Bonded connections exhibit the advantages of lower cost, higher load-bearing capacity, and higher stiffness compared to conventional mechanical connections. However, the potential of the bonded connections has yet to be fully exploited, not only due to their sensitivity to the adhesive types and process-related parameters but also due to the lack of studies regarding the structural performance of the bonded connection in various loading conditions. In this paper, birch plywood plates were utilized to adhesively connect two glulam beam halves to create a longer span. Plywood made of birch was chosen because birch is highly resourced on the Eurasian continent, with its mechanical properties better than most softwoods. Specifically, glulam beams were connected by birch plywood plates at mid-span and then loaded in four-point bending. Four test series with two different bonding areas and birch plywood face grain orientations were carried out. The bonded region was designed as the weakest part to investigate the failure modes, moment capacity, bending stiffness, and moment-rotation angle relationships. Furthermore, numerical models were developed to predict the structural behaviors in the linear elastic stage, while analytical models were proposed and subsequently modified to predict the moment-carrying capacities. Both numerical and analytical models displayed satisfactory agreement with the test results.

Place, publisher, year, edition, pages
Elsevier BV, 2024
Keywords
Bonded joints, Birch plywood, Moment capacity, Bending stiffness, Timber connections, Wood failure, Bond shear strength
National Category
Civil Engineering
Identifiers
urn:nbn:se:kth:diva-343874 (URN)10.1016/j.engstruct.2024.117471 (DOI)001155080400001 ()2-s2.0-85182021874 (Scopus ID)
Note

QC 20240227

Available from: 2024-02-27 Created: 2024-02-27 Last updated: 2024-03-12Bibliographically approved
Wang, T., Wang, Y., Crocetti, R., Wålinder, M., Bredesen, R. & Blomqvist, L. (2023). Adhesively bonded joints between spruce glulam and birch plywood for structural applications: experimental studies by using different adhesives and pressing methods. Wood Material Science & Engineering, 18(3), 1141-1150
Open this publication in new window or tab >>Adhesively bonded joints between spruce glulam and birch plywood for structural applications: experimental studies by using different adhesives and pressing methods
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2023 (English)In: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 18, no 3, p. 1141-1150Article in journal (Refereed) Published
Abstract [en]

Due to the increasing interest in reducing the usage of metals in the construction sector, birch plywood has shown good potential in structural engineering and timber connections as a substitute for the more conventional slotted-in metal plate solutions. However, a proper way of bonding birch plywood with other timber parts that results in adequate connection strength has not been fully investigated. In this paper, experimental studies were carried out to investigate the proper workflow when manufacturing bonded connections made of birch plywood and spruce glulam beams. Tensile shear mechanical tests were then conducted on produced bonded joints to evaluate the bond strength. Three adhesives, i.e. melamine-urea-formaldehyde (MUF), phenol–resorcinol–formaldehyde (PRF), and two-component polyurethane (2C PUR) were evaluated in dry and moist conditions. The influence of three pressing methods, i.e. (a) screw-gluing, (b) clamping by means of clamps, and (c) clamping by application of weight loads, on the bonding strength was investigated. The bonding strength was thereafter compared with the shear strength of spruce glulam and the wood failure percentage was also examined in this study.

Place, publisher, year, edition, pages
Informa UK Limited, 2023
Keywords
Birch plywood, bonding strength, tensile shear tests, wood failure percentage
National Category
Building Technologies
Identifiers
urn:nbn:se:kth:diva-338463 (URN)10.1080/17480272.2023.2201577 (DOI)000982422900001 ()2-s2.0-85153583741 (Scopus ID)
Note

QC 20231116

Available from: 2023-11-16 Created: 2023-11-16 Last updated: 2024-03-12Bibliographically approved
Wang, Y., Wang, T., Persson, P., Hedlund, P., Crocetti, R. & Wålinder, M. (2023). Birch plywood as gusset plates in glulam frame via mechanical connectors: A combined experimental and numerical study. Journal of Building Engineering, 65, 105744, Article ID 105744.
Open this publication in new window or tab >>Birch plywood as gusset plates in glulam frame via mechanical connectors: A combined experimental and numerical study
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2023 (English)In: Journal of Building Engineering, E-ISSN 2352-7102, Vol. 65, p. 105744-, article id 105744Article in journal (Refereed) Published
Abstract [en]

Birch is a short-lived hardwood species widespread in the Northern Hemisphere. Plywood made from birch has superior mechanical properties compared with that made from most softwoods, which makes it suitable for structural application. In this study, the feasibility of using birch plywood as gusset plates in timber-timber connections is presented. Test frames consisting of birch plywood gussets and glulam beams connected by nails were built and tested. A 2D analytical model based on truss theory and a 3D finite element model were proposed and constructed. Both models showed satisfactory agreements with the test results in terms of stiffness and strength. Tensile failure on the birch plywood gussets along the outermost row of nail holes was observed in the experiment. The observed failure modes and the stress distributions in the 3D numerical model suggest that the spreading angle (Whitmore effective width) theory should be considered in the design phase of birch plywood gusset plates. Besides, a modified spreading angle theory is proposed to both approximate the stress distribution and predict the load-bearing capacity.

Place, publisher, year, edition, pages
Elsevier BV, 2023
Keywords
Birch plywood, Finite element method, Gusset plate connection, Timber engineering
National Category
Building Technologies
Identifiers
urn:nbn:se:kth:diva-328719 (URN)10.1016/j.jobe.2022.105744 (DOI)000997865300001 ()2-s2.0-85144034849 (Scopus ID)
Note

QC 20230620

Available from: 2023-06-10 Created: 2023-06-10 Last updated: 2023-12-07Bibliographically approved
Wang, Y., Wang, T., Crocetti, R., Schweigler, M. & Wålinder, M. (2023). Embedment behavior of dowel-type fasteners in birch plywood: Influence of load-to-face grain angle, test set-up, fastener diameter, and acetylation. Construction and Building Materials, 384, Article ID 131440.
Open this publication in new window or tab >>Embedment behavior of dowel-type fasteners in birch plywood: Influence of load-to-face grain angle, test set-up, fastener diameter, and acetylation
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2023 (English)In: Construction and Building Materials, ISSN 0950-0618, E-ISSN 1879-0526, Vol. 384, article id 131440Article in journal (Refereed) Published
Abstract [en]

Birch plywood has superior mechanical properties compared with plywood made from most softwood species, which makes it suitable for structural application. Plywood is also more environmentally friendly, cost-efficient, and less prefabrication demanding than steel plates. For a proper design of birch plywood as joint plates in timber-timber connections, the embedment behavior of mechanical connectors into plywood needs to be properly investigated. In this study, the authors performed embedment tests of dowel connectors into birch plywood specimens under five different angles from parallel to perpendicular to the face grain with a step size of 22.5°. Dowel connectors with three different diameters were utilized to study the influence of dowel diameter on embedment strength and stiffness. Besides, test series using self-drilling screws and acetylated birch plywood specimens were conducted to study the effect of both fastener type and acetylation. Moreover, full-hole and half-hole test results were compared. The embedment strengths were calculated analytically according to different term definitions. The test results were then compared with the analytical results based on formulas reported in the literature, e.g., Eurocode 5 and other design standards.

Place, publisher, year, edition, pages
Elsevier BV, 2023
Keywords
Acetylation, Angle dependence, Birch plywood, Embedment behavior, Engineered wood products
National Category
Building Technologies
Identifiers
urn:nbn:se:kth:diva-330906 (URN)10.1016/j.conbuildmat.2023.131440 (DOI)000987203900001 ()2-s2.0-85153072871 (Scopus ID)
Note

QC 20230705

Available from: 2023-07-05 Created: 2023-07-05 Last updated: 2023-12-07Bibliographically approved
Wang, T., Wang, Y., Crocetti, R., Wålinder, M., Persson, P. & Hedlund, P. (2023). Glulam Frames Adhesively Bonded by Means of Birch Plywood Plates: Preliminary Investigations. In: 13th World Conference on Timber Engineering, WCTE 2023: . Paper presented at 13th World Conference on Timber Engineering: Timber for a Livable Future, WCTE 2023, Oslo, Norway, Jun 22 2023 - Jun 19 2023 (pp. 1453-1461). World Conference on Timber Engineering (WCTE), 3
Open this publication in new window or tab >>Glulam Frames Adhesively Bonded by Means of Birch Plywood Plates: Preliminary Investigations
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2023 (English)In: 13th World Conference on Timber Engineering, WCTE 2023, World Conference on Timber Engineering (WCTE) , 2023, Vol. 3, p. 1453-1461Conference paper, Published paper (Refereed)
Abstract [en]

The design of timber connections is of great importance since their performance is decisive for timber structures. The widely adopted technique utilizing the slotted-in steel plates could possibly be replaced by using timber-based gusset plates due to the significant advantages in terms of the environmental impact, economy, ease of prefabrication, and fire resistance of the latter one. Among the timber-based panels, plywood made of birch was chosen in the study due to the combined benefits of the cross laminated configuration of plywood and the superior mechanical properties of birch compared to most softwoods. In this paper, a preliminary experimental investigation was carried out to study the structural performance of the glulam trusses connected by means of bonded birch plywood gusset plates. Tests were performed on ad-hoc designed frame-like specimens. The plywood gusset plates were under-designed to be the weakest link in the structure, so as to study their load-bearing capacity. The knowledge obtained in this study is the first step towards the establishment of a model for the design of truss nodes with bonded plywood gusset plates. In the study, the face grain orientation of birch plywood was varied (0°, 5°, and 15° to the horizontal axis) in three test series. Test results show that the influence of the face grain angle from 0 to 15 degrees on the global stiffness of the frame structure is insignificant and it can be well predicted by a simplified planar 2D numerical models. Two analytical models, namely, the classic so-called 'Whitmore model' along with a more accurate analytical model, were utilized to illustrate the failure mechanism of birch plywood gusset plates with the concept of the effective width and the spreading angle.

Place, publisher, year, edition, pages
World Conference on Timber Engineering (WCTE), 2023
Keywords
Birch plywood, Effective width, Face grain angle, Glue connection, Glulam frame, Spreading angle
National Category
Architectural Engineering Building Technologies
Identifiers
urn:nbn:se:kth:diva-338039 (URN)2-s2.0-85172664000 (Scopus ID)
Conference
13th World Conference on Timber Engineering: Timber for a Livable Future, WCTE 2023, Oslo, Norway, Jun 22 2023 - Jun 19 2023
Note

Part of ISBN 9781713873297

QC 20231013

Available from: 2023-10-13 Created: 2023-10-13 Last updated: 2023-12-07Bibliographically approved
Debertolis, M., Wang, Y., Wang, T., Crocetti, R. & Wålinder, M. (2023). Investigation on mechanical connections with birch plywood gusset plates. In: Erik Larnøy (Ed.), 19th Annual Meeting of the Northern European Network for Wood Science and Engineering: . Paper presented at 19th Meetng of the Northern European Network for Wood Science and Engineering (WSE) (pp. 96-98). Ås, Norway: The Nordic Forest Research Cooperation Commitee
Open this publication in new window or tab >>Investigation on mechanical connections with birch plywood gusset plates
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2023 (English)In: 19th Annual Meeting of the Northern European Network for Wood Science and Engineering / [ed] Erik Larnøy, Ås, Norway: The Nordic Forest Research Cooperation Commitee , 2023, p. 96-98Conference paper, Oral presentation with published abstract (Refereed)
Abstract [en]

The construction industry is increasingly driven by sustainability concerns, prompting a search for alternative materials with a low environmental footprint, such as engineered wood products. Nowadays, connections of timber elements are still performed by the use of steel plates. However, steel plates can be replaced by plywood made of birch since it has superior mechanical properties compared to plywood made from softwood (Wang et al. 2021, 2022; Crocetti et al. 2021; Werner Åström, 2019). Besides, the capacity calculation for this connection according to the standards is conservative, meaning that the efficiency is low and the actual capacity could be much higher than the design value (Rossi et al. 2016). This research aims to enhance the knowledge and the design process of timber-to-timber connections with birch plywood (BP) plates.

Place, publisher, year, edition, pages
Ås, Norway: The Nordic Forest Research Cooperation Commitee, 2023
Keywords
birch plywood, mechanical connection, rope effect.
National Category
Civil Engineering
Research subject
Civil and Architectural Engineering
Identifiers
urn:nbn:se:kth:diva-338365 (URN)
Conference
19th Meetng of the Northern European Network for Wood Science and Engineering (WSE)
Note

QC 20231023

Available from: 2023-10-20 Created: 2023-10-20 Last updated: 2023-12-07Bibliographically approved
Wang, Y., Wang, T., Debertolis, M., Crocetti, R. & Wålinder, M. (2023). Preliminary experimental investigations on frame corner joints built of glulam beams, birch plywood via mechanical connectors. In: Erik Larnøy (Ed.), 19th Annual Meeting of the Northern European Network for Wood Science and Engineering: . Paper presented at Proceedings of the 19th Meeting of the Northern European Network for Wood Science and Engineering (WSE). Ås, Norway: The Nordic Forest Research Cooperation Commitee
Open this publication in new window or tab >>Preliminary experimental investigations on frame corner joints built of glulam beams, birch plywood via mechanical connectors
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2023 (English)In: 19th Annual Meeting of the Northern European Network for Wood Science and Engineering / [ed] Erik Larnøy, Ås, Norway: The Nordic Forest Research Cooperation Commitee , 2023Conference paper, Oral presentation with published abstract (Refereed)
Abstract [en]

Compared to steel plates, plywood plates are competitive in structural connections due to their low carbon footprint, high tolerance during assembly, relatively low cost, and less prefabrication demand (Kromoser et al. 2021). During the last few decades, plywood depicts its imprint as connections in timber structures such as truss connections, beam-to-column connections, and portal frames (Turnbull and Lefkovitch 1986; Furuheim et al. 2021; Kromoser et al. 2021). Analytical calculation models are essential for better design of birch plywood in portal frame corner joints (Wang et al. 2023a, b). However, the robustness and validity of such analytical models are yet to be examined. 

Place, publisher, year, edition, pages
Ås, Norway: The Nordic Forest Research Cooperation Commitee, 2023
Keywords
birch plywood, glued-laminated timber, frame corner joints, timber engineering.
National Category
Civil Engineering
Research subject
Civil and Architectural Engineering
Identifiers
urn:nbn:se:kth:diva-338081 (URN)
Conference
Proceedings of the 19th Meeting of the Northern European Network for Wood Science and Engineering (WSE)
Note

QC 20231016

Available from: 2023-10-13 Created: 2023-10-13 Last updated: 2023-12-07Bibliographically approved
Yin, H., Ringman, R., Moghaddam, M. S., Tuominen, M., Dédinaité, A., Wålinder, M., . . . Bardage, S. (2023). Susceptibility of surface-modified superhydrophobic wood and acetylated wood to mold and blue stain fungi. Progress in organic coatings, 182, Article ID 107628.
Open this publication in new window or tab >>Susceptibility of surface-modified superhydrophobic wood and acetylated wood to mold and blue stain fungi
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2023 (English)In: Progress in organic coatings, ISSN 0300-9440, E-ISSN 1873-331X, Vol. 182, article id 107628Article in journal (Refereed) Published
Abstract [en]

The susceptibility of surface-modified wood, surface-modified acetylated wood and acetylated wood to mold and blue stain fungi was investigated. The surface modifications were based on fluorinated and non-fluorinated silicone nanofilaments for increased hydrophobicity. Results showed an increased mold resistance of the surface-modified superhydrophobic wood with mold appearing later or with less intensity on the modified surfaces than on the untreated wood in accelerated mold chamber tests due to the increased water resistance of the samples. All acetylated wood samples exhibited good mold resistance as the available water in acetylated wood was reduced. The surface modifications on acetylated wood had a slightly negative effect on mold resistance due to side effects from the modification. The surface-modified wood showed high blue stain fungi coverage, whereas almost no blue stain fungi were observed on the acetylated wood and surface-modified acetylated wood. The surface-modified superhydrophobic wood showed high mold coverage after conditioning in a high-humidity environment or after exposure to UV irradiation. Meanwhile, the acetylated wood and surface-modified superhydrophobic acetylated wood showed a small amount of mold coverage in these conditions.

Place, publisher, year, edition, pages
Elsevier BV, 2023
Keywords
Mold, Blue stain, Acetylated wood, Superhydrophobic surface modifications, Silicone nanofilaments
National Category
Wood Science
Identifiers
urn:nbn:se:kth:diva-328273 (URN)10.1016/j.porgcoat.2023.107628 (DOI)000989564000001 ()2-s2.0-85153096634 (Scopus ID)
Note

QC 20230607

Available from: 2023-06-07 Created: 2023-06-07 Last updated: 2023-06-07Bibliographically approved
Wang, Y., Wang, T., Ringaby, J., Crocetti, R., Debertolis, M. & Wålinder, M. (2023). Testing and analysis of screw-connected moment joints consisting of glued-laminated timbers and birch plywood plates. Engineering structures, 290, Article ID 116356.
Open this publication in new window or tab >>Testing and analysis of screw-connected moment joints consisting of glued-laminated timbers and birch plywood plates
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2023 (English)In: Engineering structures, ISSN 0141-0296, E-ISSN 1873-7323, Vol. 290, article id 116356Article in journal (Refereed) Published
Abstract [en]

This study presents the feasibility of constructing moment joints using birch plywood plates and glulam beams. Beam-beam joints consisting of birch plywood gussets and glulam beams connected by self-tapping screws were built and tested in the four-point bending regime. Analytical calculations based on the fastener group's torsional moment resistance, the proposed elastic and post-elastic fastener group's load-bearing criteria, and the design formulas given in Eurocode 5, are performed to predict the connection capacity in both elastic and post-elastic stages. Under the four-point bending, all specimens with birch plywood plates with the face-grain orientation of either 0 degrees or 22.5 degrees to the beam length direction, showed brittle failure either in the glulam beam or birch plywood plate. Numerical models are constructed to capture the global load-deflection behavior of all beam specimens. The foundation zone modeling scheme is adopted to consider the influence of the fasteners' embedment on the macroscopic load-deflection curves. As a result of comparison, the analytical calculations give reasonable pre-dictions on both the elastic and post-elastic ultimate beam capacity, and the numerical models give satisfactory predictions on the bending stiffness for all tested beam specimens.

Place, publisher, year, edition, pages
Elsevier BV, 2023
Keywords
Birch plywood, Moment joints, Glued-laminated timber
National Category
Architectural Engineering
Identifiers
urn:nbn:se:kth:diva-331198 (URN)10.1016/j.engstruct.2023.116356 (DOI)001012505000001 ()2-s2.0-85162205550 (Scopus ID)
Note

QC 20230706

Available from: 2023-07-06 Created: 2023-07-06 Last updated: 2023-12-07Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0002-9156-3161

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