| 1. |
- Blomqvist, Lars, 1962-, et al.
(författare)
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Development of novel structural connections - Inspiration from furniture industry
- 2021
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Ingår i: World Conference on Timber Engineering 2021, WCTE 2021. - Santiago, Chile : World Conference on Timber Engineering (WCTE).
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Konferensbidrag (refereegranskat)abstract
- The presented project aims to develop prototypes for building connections inspired by the furniture and interior industry and explore them with representatives from the timber construction industry. The long-term vision is that actors from furniture and building industry together develop a smart system for assembly of building elements, which provide higher precision, faster and more efficient assembly than what is available today. The prototype connection developed in this project shows that the idea is ripe for full-scale investigation. Laboratory tests showed promising results due to the high failure loads obtained with very high stiffness.
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| 2. |
- Blomqvist, Lars, 1962-, et al.
(författare)
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EXPERIMENTAL AND NUMERICAL ANALYSES OF A CONNECTION FOR CLT STRUCTURES
- 2023
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Ingår i: Proceedings of the 2023 World Conference on Timber Engineering (WCTE). - Oslo, Norway : Curran Associates, Inc.. ; , s. 1154-1159
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Konferensbidrag (refereegranskat)abstract
- Although building systems made of cross-laminated timber (CLT) have become common in Sweden in the past 20 years and they have developed rapidly during the same period, steps remain to be taken to simplify the assembly of such systems, especially at construction sites. Current construction methods, however, remain labour-intensive and thus show room for improvement.This paper describes a novel connection for the assembly of building elements made of CLT. Simple and inexpensive, the connection is fairly insensitive to manufacturing tolerances and enables rapid, more efficient construction than the connections for CLT structures currently used. Test results show the excellent strength and stiffness of the connection, which also allows the replacement of numerous fasteners, including nails and screws, with only a single steel rod.
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| 3. |
- Blomqvist, Lars, 1962-, et al.
(författare)
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Stress distribution in veneers under lamination and simultaneously bending : an experimental and numerical investigation
- 2023
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Ingår i: Wood Material Science & Engineering. - : Taylor & Francis Group. - 1748-0272 .- 1748-0280. ; 18:3, s. 995-1002
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Tidskriftsartikel (refereegranskat)abstract
- Laminated veneer products (LVPs) are veneers glued together into a predetermined shape. Experimental and numerical investigations were performed under lamination and simultaneously bending of veneer laminate to study the stress distribution in the laminate. Laminates of different thicknesses were made of peeled veneers of European beech. The veneers were coated with adhesive, inserted in a mould which had the shape of a semicircle, and finally pressed at 20 degrees C to a laminate. Two Teflon-polymer films including sensors for measurement of the contact pressure were placed on both sides of the laminate to measure the local contact pressure (contact stress) between the laminate and the mould. At the beginning of the bending process, the contact stresses were locally distributed over the laminate in a similar pattern as in a three-point bending; after the laminate was further bent, the stress distribution rearranged to be as in four-point bending. In the end of the moulding, the local contact stresses increased over the entire laminate and reached a 'peak-value' over bent area in the middle part of the mould. A finite-element model was created to study the bending process. Regarding the overall development of the contact stress variations, the experimental and the numerical results agreed.
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| 4. |
- Brandon, Daniel, et al.
(författare)
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High-Fire-Resistance Glulam Connections for Tall Timber Buildings
- 2019
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Tall timber buildings generally require fire resistance ratings of 90 minutes, 120 minutes or more. The vast majority of fire tested structural timber connections, however, did not reach a fire resistance that was relevant for these buildings. Commonly timber connections between glued laminated timber members comprise of exposed steel fasteners, such as bolts, screws, nails and dowels. However, it has previously been concluded that connections with exposed steel fasteners, generally do not achieve fire resistance ratings of 30 minutes and are, therefore, inadequate to be implemented in tall timber buildings without fire encapsulation. The research project presented in this report consists of four connection fire tests that are designed to achieve structural fire resistance ratings of 90 minutes, using different design strategies. This goal was achieved for all tested column-beam connections. A single test of a moment resisting connection did not lead to a fire resistance rating of 90 minutes, due to timber failure at the smallest cross-section after 86 minutes. The low temperature of the steel fasteners and the limited rotation of the connection, however, suggest that the connection would have been capable of achieving a 90 minutes fire resistance rating if larger beam cross-sections would be used.
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| 5. |
- Jockwer, Robert, 1984, et al.
(författare)
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FATIGUE RESISTANCE OF ADHESIVE BONDED CONNECTIONS WITH AND WITHOUT INTERNAL STEEL PLATES IN LARGE TIMBER STRUCTURES
- 2023
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Ingår i: World Conference on Timber Engineering (WCTE 2023). ; 4, s. 2118-2124
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Konferensbidrag (refereegranskat)abstract
- A modular wooden wind turbine tower has been developed by the Swedish company Modvion AB, where the prefabricated modular elements are connected by glued timber-timber edge joints and by hybrid timber joints with bonded-in perforated steel plates. The application of wood-based products in such a demanding application and highperformance structure is challenging and a variety of questions had to be solved to ensure a reliable performance. The fatigue performance of the adhesive bonded connections has been evaluated in a research project and is presented in this paper. Test specimens of the fatigue resistance of the adhesive and the bond line has been developed. Different stress ratios with alternating loads and high numbers of load cycles have been tested. The results of the tests are presented in this paper.
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| 6. |
- Johansson, Carl-Johan, et al.
(författare)
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Sågverksnytt nr 1
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)
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| 7. |
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| 8. |
- Lemke, Ulf, et al.
(författare)
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New Criteria For Visual Strength Grading of Sawn Timber From Birch Grown In Sweden
- 2023
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Ingår i: World Conference on Timber Engineering (WCTE 2023). - : World Conference on Timber Engineering (WCTE). - 9781713873273 ; , s. 740-749
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Konferensbidrag (refereegranskat)abstract
- Today there is no standard for strength grading and CE-marking sawn timber of Birch grown in Sweden, which makes it impossible to use this material as structural timber. Internationally, there are standards for visual grading of hardwood in several European countries. However, these standards may not be used to classify Birch timber grown in Sweden without having been tested and verified to meet the standard's requirements. In a project (BizWOOD) run by RISE, 600 pieces of sawn birch wood from Sweden is visually graded and strength tested. The project aims to result in grading rules for birch, either by using international standards or where international standards will be used as references for the identification of defects that will be included in the grading model. This paper summarizes parts of the BizWOOD project and includes 1) description of sampling and timber origin, 2) visual grading according to international standards, 3) strength testing of the material, 4) evaluation of mechanical characteristics, 5) evaluation of grading techniques.
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| 9. |
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| 10. |
- Lycken, Anders, et al.
(författare)
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Development of a simulation-evaluation program for introducing and using output control in the sawmill industry
- 2010
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Ingår i: Proceedings of the final conference of COST Action E53. - : Edinburgh Napier University.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A computer program for simulating output control has been developed. The calculations in the program follow the standard EN 14081-3:2005, where output control is described. The purpose of the simulator is to make it possible to improve the yield without jeopardizing the safety of the produced boards by testing different approaches in grading. The program is a research tool, as well as a program to use in production where output control is used. In the program is it possible to test e.g. the influence of change of IP-values, number of grades, pre-grading of logs, raw material region, etc. The result of a simulation is shown both as diagrams and numeral. The standard C-grades are pre-programmed with K-, Y- and Z-coefficients according to the standard. Other grades can be added by the user.
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