Revision of Eurocode 5 Evolution Group Reinforcement

Transkript

1 Workshop of COST FP September 2013, Trento, Italy Revision of Eurocode 5 Evolution Group Reinforcement Dr.-Ing. Philipp Dietsch Technische Universität München Chair for Timber Structures and Building Construction Univ.-Prof. Dr.-Ing. Stefan Winter

2 Background - Development of Eurocode : CIB-Structural Timber Design Code. CIB Report Publication 66: Conseil International du Bâtiment. Rotterdam 1987: Common Unified Rules for Timber Structures. Eurocode No. 5. Report EUR European Commission. Brussels. 1993: ENV :1993. Eurocode 5, Design of Timber Structures, Part 1-1: General Rules and Rules for Buildings. European Committee for Standardisation CEN. Brussels 2004: EN :2004. Eurocode 5: Design of Timber Structures Part 1-1: General Common Rules and Rules for Buildings. CEN. Brussels. + small corrigendum AC: small amendment A1:2008

3 Background - CEI-Bois Project Revision of EC5 ( ) Objective: establishing a widely harmonised basis for the revision of Eurocode 5 Pan-European survey amongst a multitude of stakeholders List of design rules to be improved or expanded List of additional design rules to comply with the state of the art in timber construction from: [Dietsch, P., Winter, S.; "Eurocode 5 - Future Developments towards a More Comprehensive Code on Timber Structures"; Structural Engineering International, Vol. 21, No. 2, 2012]

4 Background - CEN TC250 SC5 meetings Eindhoven and Verona [ Chairmans Presentation, Meeting 18 in Eindhoven, 2010, Document CEN-TC250-SC5 N0255] Establishment of Group on Reinforcement, Meeting 20 in Verona, 2011, [CEN-TC250-SC5 N0269] Members: Philipp Dietsch, TUM, Germany (Chair); Alfons Brunauer, Wiehag, Austria; Robert Jockwer, ETH, Switzerland; Kjell Arne Malo, NTNU, Norway; (Roberto Crocetti, Lund University, Sweden)

5 Approach to develop design rules for reinforcement Methods shall be backed by scientific evidence, e.g. publications for CIB-meetings Methods shall represent the commonly accepted state of the art and shall be applicable by practicing engineers Methods shall feature record of positive practical application, i.e. through implemented national standards, ETA, etc. from: [Dietsch, P., Winter, S.; "Eurocode 5 - Future Developments towards a More Comprehensive Code on Timber Structures"; Structural Engineering International, Vol. 21, No. 2, 2012] Only applications that practice deems necessary shall be incl. first edition of report shall be based on rules featuring record of national application [CEN-TC250-SC5 N0269]

6 Approach to develop design rules for reinforcement [ Chairmans Presentation, Meeting 18 in Eindhoven, 2010, Document CEN-TC250-SC5 N0255]

7 Report Document CEN/TC 250/SC 5 N0289 [Document CEN-TC250-SC5 N0300]

8 Report Document CEN/TC 250/SC 5 N0289 Draft text for Eurocode 5 Scientific Background [Document CEN-TC250-SC5 N0300]

9 Applications already covered in Report of Evolution Group Reinforcement of double tapered, curved and pitch cambered beams by rods (screwed-in or glued-in) or glued-on plywood, LVL l ad ef l ad max r in Outer Lamella t t r in Amongst others: [Blumer, H., Spannungsberechnungen an anisotropen Kreisbogenscheiben und Sattelträgern konstanter Dicke, Lehrstuhl für Ingenieurholzbau und Baukonstruktionen, Universität Karlsruhe (TH), 1972/1979] [Ehlbeck, J, Kürth, J., Einfluss des querzugbeanspruchten Volumens auf die Tragfähigkeit gekrümmter Träger konstanter Höhe und gekrümmter Satteldachträger aus Brettschichtholz, Forschungsbericht der Versuchsanstalt für Stahl, Holz und Steine, Abt. Ingenieurholzbau, Universität Karlsruhe (TH), 1990] [Mistler, H.L., Querzugbemessung von BSH-Trägern nach EC 5: Ein Vergleich mit Forschungsergebnissen, Holz als Roh- und Werkstoff 56 (1), 1998, pp ] [Blaß, H.J., Ehlbeck, J., Kreuzinger, H., Steck, G., Erläuterungen zu DIN 1052: , Bruderverlag, Karlsruhe, 2004]

10 Applications already covered in Report of Evolution Group Reinforcement of notched beams by screws, glued-in rods or glued-on plywood, LVL f t,90,k f t,0,k 21 [MN/m 2 ] l ad > l ad h h ef h Amongst others: [Möhler, K., Siebert,W., Untersuchungen zur Erhöhung der Querzugfestigkeit in gefährdeten Bereichen, Bauen mit Holz 86 (6), 1984, pp ] [Henrici, D., Beitrag zur Bemessung ausgeklinkter Brettschichtholzträger, Bauen mit Holz 92 (11), 1990, pp ] [Blaß, H.J., Steck, G. Querzugverstärkungen von Holzbauteilen: Teil 1 Teil 3, Bauen mit Holz 101 Issue 3, pp , Issue 4, pp , Issue 5, pp ] l r

11 Applications already covered in Report of Evolution Group Reinforcement of cross-connections by screws, glued-in rods or glued-on plywood, LVL F Pure Compression (F c ) Perpendicular to Grain F c = F l ad,c l ad,t F Tension and Compression Perpendicular to Grain F c = 1-η*F; F t = η*f critical area F F/2 F/2 F Pure Tension (F t ) Perpendicular to Grain F t = F F F/2 F/2 Amongst others: [Möhler, K., Siebert,W., Untersuchungen zur Erhöhung der Querzugfestigkeit in gefährdeten Bereichen, Bauen mit Holz 86 (6), 1984, pp ] [Ehlbeck, J., Görlacher, R., Werner, H., Determination of Perpendicular-to-Grain Tensile Stresses in Joints with Dowel Type- Fasteners, CIB-W18 / , Proceedings of the international council for research and innovation in building and construction, Working commission W18 - timber structures, Meeting 22, Berlin, 1989] [Blaß, H.J., Steck, G. Querzugverstärkungen von Holzbauteilen: Teil 1 Teil 3, Bauen mit Holz 101 (3-5)] l ad,c

12 Applications already covered in Report of Evolution Group Reinforcement of holes by screws, glued-in rods or glued-on plywood, LVL h ro h d h ro l a a h ro t t h ro h d a r a a r a r a a r l r a l r Amongst others: [Kolb, H., Epple, A. Verstärkungen von durchbrochenen Brettschichtholzbindern, Schlussbericht zum Forschungsvorhaben I , Forschungs- und Materialprüfungsanstalt Baden-Württemberg, Stuttgart, 1985] [Blaß, H.J., Steck, G. Querzugverstärkungen von Holzbauteilen: Teil 1 Teil 3, Bauen mit Holz 101 (3-5)] [Blaß, H.J., Bejtka, I., Querzugverstärkungen in gefährdeten Bereichen mit selbstbohrenden Holzschrauben, Forschungsbericht der Versuchsanstalt für Stahl, Holz und Steine, Abt. Ingenieurholzbau, Universität Karlsruhe (TH), 2003] [Aicher, S., Höfflin, L., Glulam Beams with Holes Reinforced by Steel Bars, CIB-W18 / , Proceedings of the international council for research and innovation in building and construction, Working commission W18 - timber structures, Meeting 42, Zürich, 2009]

13 Applications to be covered by Evolution Group PriorityA: all applications covered so far Reinforcement of connections (n = n ef ) Reinforcement of areas with high compressive stresses perpendicular to the grain (support areas) influence of moisture changes on reinforced members (still lacking sufficient knowledge and experience, i.e. research -> validation -> standardization) Priority B: reinforcement against shear stresses reinforcement in areas of high compressive stresses at an angle to the grain

14 State of the art reinforcement methods, not yet covered in report Self-tapping screws as reinforcements in connections with dowel-type fasteners (contents by courtesy of: H.J. Blaß et al., KIT) [Bejtka, I., Blaß, H.J., Self-tapping screws as reinforcement in connections with dowel-type fasteners, CIB-W18 / , Proceedings of the international council for research and innovation in building and construction, Working commission W18 - timber structures, Meeting 38, Karlsruhe, 2005]

15 State of the art reinforcement methods, not yet covered in report Self-tapping screws as reinforcements in beam supports (contents by courtesy of: H.J. Blaß et al., KIT Karlsruhe) Bottom View Bottom View [Bejtka, I., Blaß, H.J., Self-tapping screws as reinforcements in beam supports, CIB-W18/ , Proceedings of the international council for research and innovation in building and construction, Working commission W18 - timber structures, Meeting 39, Florence, 2006]

16 Influence of moisture changes in reinforced members [TUM, TUG] Reduction of timber MC 3-4 % around threaded rods, positioned perp. to th grain, can lead to critical stresses usually one large crack developing [Dietsch, P., Einsatz und Berechnung von Schubverstärkungen für Brettschichtholzbauteile; Dissertation; Technische Universität München; 2012] [Wallner, B., Versuchstechnische Evaluierung feuchteinduzierter Kräfte in Brettschichtholz verursacht durch das Einbringen von Schraubstangen, Master Thesis, Institut für Holzbau und Holztechnologie, Technische Universität Graz, 2012]

17 Workshop of COST FP September 2013, Trento, Italy Revision of Eurocode 5 Evolution Group Reinforcement Thank you for your attention! Dr.-Ing. Philipp Dietsch Technische Universität München Chair for Timber Structures and Building Construction Univ.-Prof. Dr.-Ing. Stefan Winter