Bending and tension strength classes in European standards

• Autorzy: Bacher M. , Krzosek S.

Warianty tytułu

PL

Klasy wytrzymałości tarcicy w normach europejskich oparte na zginaniu i rozciąganiu

• Języki publikacji: EN

Abstrakty

EN

The current strength classification system for softwood in Europe is based on bending properties (C classes). To optimize the efficient use of timber, especially for engineered timber products, an additional strength class system based on tension properties (T classes) was defined and will be included in the next revision of EN 338. The strength profiles of both strength classes are compared. Today there are grading methods available which are optimized for both strength class systems.

PL

Klasy wytrzymałości tarcicy w normach europejskich oparte na zginaniu i rozciąganiu. Aktualny system klas wytrzymałościowych dla drewna iglastego w Europie (klasy C) bazuje na właściwościach drewna przy zginaniu. W celu optymalizacji efektywnego użycia drewna, szczególnie w drewnianych wyrobach inżynierskich, zdefiniowano dodatkowy system klas wytrzymałościowych bazujący na właściwościach drewna przy rozciąganiu (klasy T). System ten będzie uwzględniony w kolejnej nowelizacji normy EN 338. W referacie porównano oba systemy klas wytrzymałościowych. Aktualnie dostępne są urządzenia do sortowania tarcicy według obu systemów klas wytrzymałościowych: C i T.

Słowa kluczowe

EN

softwood; sawn timber; bending property; tensile property; bending strength; tensile strength; elasticity modulus; rupture modulus; mechanical grading; strength grading; strength class; European standard; EN 338 standard

• Wydawca: -
• Czasopismo: Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology
• Rocznik: 2014
• Tom: 88
• Opis fizyczny: p.14-22,ref.

Twórcy

autor

Bacher M.

• MiCROTEC GmbH, Julius Durst Str.98, 39042 Brixen, Italy

autor

Krzosek S.

• Department of Wood Science and Wood Protection, Faculty of Wood Technology, Warsaw University of Life Sciences - SGGW, 159 Nowoursynowska Str., 02-776 Warsaw, Poland

Bibliografia

• 1. BACHER M., KRZOSEK S. 2013: Modulus of elasticity tension/bending ratio for polish grown pine (Pinus sylvestris L.) and spruce (Picea abies Karst.) timber, Ann. WULS - SGGW, For. and Wood Technol. 82.
• 2. BURGER N., GLOS P., 1995: Verhältnis zwischen Zug- und Biege-Elastizitäts- moduln von Vollholz (Relationship between modulus of elasticity in tension and bending for timber), Holz als Roh- und Werkstoff (European Journal of Wood and Wood Products), Volume 53, Issue 2, pp 73-74.
• 3. DENZLER J.K., GLOS P., 2007: Determination of shear strength values according to EN 408, Material and Structures, Volume 40, pp 79-86.
• 4. DEVISSER D.A., GALLIGAN W.L. 2005: Tension/bending ratios for mechanically graded European lumber - Results of tests conducted under the American lumber standard, Proceedings of the 14th International Symposium on Nondestructive Testing of Wood, May 2-4, University of Applied Sciences, Eberswalde, Germany.
• 5. STEIGER R., ARNOLD M., JOCKWER R., 2010, Property relationships used in EN 338 strength grades of Norway spruce structural timber, World conference on timber engineering (WCTE 2010), 20-24 June, Riva del Garda, Italy.
• 6. WCLIB, 2003: Tension/Bending Ratios of Machine Stress-Rated Lumber, Technical Report No. 2, West Coast Lumber Inspection Bureau, Portland, Oregon, USA.
• STANDARDS
• 1. AS/NZS 1748.2:2011: Timber - Solid - Stress-graded for structural purposes - Part 2: Qualification of grading method. Standards Australia/Standards New Zealand.
• 2. AS/NZS 4490:2011: Timber - Solid - Stress-graded for structural purposes - Verification of properties. Standards Australia/Standards New Zealand.
• 3. ASTM D 1990:2014: Standard Practice for Establishing Allowable Properties for Visually-Graded Dimension Lumber from In-Grade Tests of Full-Size Specimens, American Society for Testing and Materials, Pennsylvania, USA.
• 4. DIN 1052:2008: Design of timber structures - General rules and rules for buildings, German Committee for Standardization, Berlin.
• 5. DIN 4074-1:2012: Strength grading of wood – Part 1: Coniferous sawn timber, German Committee for Standardization, Berlin.
• 6. EN 338:2009: Structural timber - Strength classes, European Committee for Standardization, Brussels.
• 7. DRAFT prEN 338:2013 (August 2013): Structural timber - Strength classes, European Committee for Standardization, Brussels.
• 8. EN 384:2010: Structural timber - Determination of characteristic values of mechanical properties and density, European Committee for Standardization, Brussels.
• 9. DRAFT prEN 384:2013 (August 2013): Structural timber - Determination of characteristic values of mechanical properties and density, European Committee for Standardization, Brussels.
• 10. EN 1194:1999: Timber structures - Glued laminated timber - Strength classes and determination of characteristic values, European Committee for Standardization, Brussels.
• 11. EN 1912:2012+AC:2013: Structural timber - Strength classes - Assignment of visual grades and species, European Committee for Standardization, Brussels.
• 12. EN 14080:2013: Timber structures - Glued laminated timber and glued solid timber - Requirements, European Committee for Standardization, Brussels.
• 13. EN 14081-1:2005+A1:2011: Timber structures - Strength graded structural timber with rectangular cross section - Part 1: General requirements, European Committee for Standardization, Brussels.
• 14. EN 14081-4:2009: Timber structures - Strength graded structural timber with rectangular cross section - Part 4: Machine Grading -Grading machine settings for machine controlled systems, European Committee for Standardization, Brussels.
• 15. DRAFT FprEN 16351:2013, July 2013: Timber structures - Cross laminated timber - Requirements, European Committee for Standardization, Brussels.
• 16. INSTA 142:2009: Nordic visual grading rules for timber. National Standardization Bodies in Denmark, Finland, Iceland, Norway and Sweden.
• 17. PN-D-94021:2013: Tarcica konstrukcyjna iglasta sortowana metodami wytrzymałościowymi, Polish Committee for Standardization, Warsaw.
• 18. PN-EN-1991-1-1:2010: Eurokod 5 - Projektowanie konstrukcji drewnianych - Część 1-1: Postanowienia ogólne, Reguły ogólne i reguły dotyczące budynków, Polish Committee for Standardization, Warsaw.