CLT European Experience Properties & Design Research & Testing

Transcription

1 CLT European Experience Properties & Design Research & Testing Prof. G. Schickhofer Institute of Timber Engineering and Wood Technology Graz University of Technology Presentation in the frame of the CLT Forum 2013 in TOKYO Tokyo, 24 nd October 2013 Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 1

2 CONTENT Properties & Design Modification Factors and Characteristic Values Methods of Design Research & Testing Material Connections Structures Conclusions Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 2

3 CONTENT Properties & Design Modification Factors and Characteristic Values Methods of Design Research & Testing Material Connections Structures Conclusions Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 3

4 PROPERTIES & DESIGN Characteristic values of CLT introduction reference cross-section partial factor modification factor deformation factor shrinkage and swelling strength stiffness current regulations national and international technical approvals development of a standard for CLT (pren 16351) approach for determining material properties acc. to EN EN Strength and stiffness parameters: (1)P Strength and stiffness parameters shall be determined on the basis of tests for the types of action effects to which the material will be subjected in the structure, or on the basis of comparisons with similar timber species and grades or wood-based materials, or on well established relations between the different properties. definition of strength classes with consideration of a reference cross section for CLT (similar to GLT) definition of standardized test configurations to compare determined material properties Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 4

5 Characteristic values of CLT selected properties GLT basic material boards CLT basic material boards h CLT,ref CLT GLT PROPERTIES & DESIGN reference cross-section partial factor modification factor deformation factor shrinkage and swelling strength stiffness n = 12 b CLT,ref height/depth/ thickness h GLT,ref = 600 mm t l,glt,ref = 40 mm h CLT,ref = 150 mm t l,clt,ref = 30 mm b t,clt,ref t l,glt,ref bearing models for CLT mostly based on GLT comparability of the demanded reference volumes n top layer 4 for consideration of the system effect width b GLT,ref = 150 mm b l,glt,ref = 150 mm b CLT,ref = 600 mm b l,clt,ref = 150 mm h GLT,ref b GLT,ref n = 15 t l,glt,ref Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 5

6 PROPERTIES & DESIGN Characteristic values of CLT selected properties reference cross-section partial factor modification factor deformation factor Fundamental combinations M Solid timber 1.3 Glued laminated timber 1.25 Cross laminated timber 1.25 LVL, plywood, OSB 1.2 classification like GLT lower dispersion of material data in comparison to basic material (boards) shrinkage and swelling strength stiffness Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 6

7 PROPERTIES & DESIGN Characteristic values of CLT selected properties reference cross-section partial factor modification factor deformation factor shrinkage and swelling Material Standard SC ST GLT EN EN CLT 1) pren k mod - Load-duration class Perm. Long Medium Short Inst ) It is proposed, that the use of CLT in service class 3 is not allowed. classification like GLT strength stiffness Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 7

8 PROPERTIES & DESIGN Characteristic values of CLT selected properties reference cross-section partial factor modification factor deformation factor shrinkage and swelling strength stiffness Material ST GLT EN EN Plywood EN 636 CLT 1) pren Standard type EN type EN type EN k def - Service class > 7s s ) It is proposed, that the use of CLT in service class 3 is not allowed. classification as plywood due to crossed lay-up and stress towards rolling shear consideration of the lay-up is necessary: >7s 7s for simplification: classification as plywood, type 2 Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 8

9 PROPERTIES & DESIGN Characteristic values of CLT selected properties reference cross-section partial factor CLT Material Shrinkage and swelling coef. in % per % change in the m. c. below fibre saturation in plane (IP) out of plane (OP) 0.24 modification factor deformation factor coefficient in-plane is depending on the CLT lay-up ratio of layers in and perpendicular to span with regard to the CLT thickness shrinkage and swelling strength stiffness Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 9

10 PROPERTIES & DESIGN Characteristic values of CLT selected properties reference cross-section partial factor modification factor base material T14 CV [ft,0,l] 25 % ± 5 % 35 % ± 5 % CLT strength class property CL 24h CL 28h f m,clt,k deformation factor shrinkage and swelling strength stiffness Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 10

11 PROPERTIES & DESIGN Characteristic values of CLT selected properties reference cross-section partial factor modification factor deformation factor shrinkage and swelling strength base material T14 CV [ft,0,l] 25 % ± 5 % 35 % ± 5 % CLT strength class property CL 24h CL 28h f m,clt,k f 0,8 m, CLT, k km, CLT ft,0, l, k k m,clt CV [ft,0,l] % ± 5 % % ± 5 % stiffness Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 11

12 PROPERTIES & DESIGN Characteristic values of CLT selected properties reference cross-section partial factor modification factor deformation factor shrinkage and swelling strength stiffness base material T14 CV [ft,0,l] 25 % ± 5 % 35 % ± 5 % CLT strength class property CL 24h CL 28h f m,clt,k f t,0,clt,net,k f t,90,clt,k 0.5 f c,0,clt,net,k f c,90,clt,k 2.85 f v,clt,ip,k 5.5 f T,node,k 2.5 f v,clt,op,k 3.0 f r,clt,k b/t 4: f r,clt,k b/t < 4: research work is needed Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 12

13 PROPERTIES & DESIGN Characteristic values of CLT selected properties reference cross-section partial factor modification factor deformation factor shrinkage and swelling strength stiffness base material T14 CV [ft,0,l] 25 % ± 5 % 35 % ± 5 % CLT strength class property CL 24h CL 28h E 0,CLT,mean 11,000 E 0,CLT,05 9,167 E 90,CLT,mean 300 E 90,CLT, E c,90,clt,mean 450 E c,90,clt, G CLT,mean 650 G CLT, G r,clt,mean 65 G r,clt, research work is needed Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 13

14 CONTENT Properties & Design Modification Factors and Characteristic Values Methods of Design Research & Testing Material Connections Structures Conclusions Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 14

15 Serviceability Limit State SLS Ultimate Limit State ULS PROPERTIES & DESIGN Methods of Design selected verifications Bending e.g.: 5-layered CLT element [assumption : E 90 =0] ES α #5 0 E 0 G 0 t 5 #4 90 E 90 G 90 t 4 #3 0 E 0 G 0 t 3 #2 90 E 90 G 90 t 2 t CLT σ m,edge,d saw tooth - like stress distribution #1 0 E 0 G 0 t 1 m,i 5,edge,d i 5 CLT n M t max,d CLT E K 2 CLT n 2 K J E A e E i i i i i i 1 i 1 m,edge,d f m,clt,d 1.0 normally very low utilization ratio seldom relevant Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 15

16 Serviceability Limit State SLS Ultimate Limit State ULS PROPERTIES & DESIGN Methods of Design selected verifications Shear e.g.: 5-layered CLT element [assumption : E 90 =0] ES α #5 0 E 0 G 0 t 5 #4 90 E 90 G 90 t 4 #3 0 E 0 G 0 t 3 t CLT r,d v,d #2 90 E 90 G 90 t 2 #1 0 E 0 G 0 t 1 (z ) 0 d V z,d A 0 E(z) z da K b(z ) clt 0 v,d (longitudinal) und r,d (transverse) f f v,d v,clt,d r,d r,clt,d Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 16

17 Serviceability Limit State SLS Ultimate Limit State ULS PROPERTIES & DESIGN Methods of Design selected verifications Deflections (loads out-of-plane) 1 1 w ges M M dx V V dx K S CLT CLT single-span beam w(l / 2) 5 q l 4 q l K 8 S CLT Shear Stiffness CLT S S (G b t ) (G A ) CLT tot i i i i i for ratio G 0 /G r = 10 For G 0 /G r = 10 nearly constant and about ¼ of an unidirectional rectangular cross section. Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 17

18 Serviceability Limit State SLS Ultimate Limit State ULS PROPERTIES & DESIGN Methods of Design selected verifications Deflections (loads out-of-plane) Long-term effects due to creep due to the cross layers (rolling shear) higher values than for solid timber or glued laminated timber combinations of actions for instantaneous (t = 0), final and net final (t = ) deflections from EN 1990 and EN combination w lim instantaneous t = 0 w inst w inst,g + w inst,q l/300 final t = w fin w inst + w creep l/150 net final t = w net,fin w fin + w c l/250 w w inst lim,inst 1.0 w w fin lim,fin 1.0 w w net,fin lim,net,fin 1.0 Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 18

19 Serviceability Limit State SLS Ultimate Limit State ULS PROPERTIES & DESIGN Methods of Design selected verifications Vibration verification according to Eurocode 5: EN st natural frequency: f 1 8 Hz YES specification of performance NO special investigation high performance normal performance limits for w and v low performance stiffness: w(1kn) w crit = a YES vibration velocity: v v crit = b (f 1z-1) NO NO YES verification fulfilled verification not fulfilled Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 19

20 Serviceability Limit State SLS Ultimate Limit State ULS PROPERTIES & DESIGN Methods of Design selected verifications Vibration verification according to Hamm / Richter specification of performance limits for f, w and a 1st natural frequency: f1 fcrit NO 1st natural frequency: f1 fmin NO YES YES YES vibration acceleration: a acrit NO stiffness: w(2kn) wcrit NO YES YES verification fulfilled verification not fulfilled Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 20

21 Serviceability Limit State SLS Ultimate Limit State ULS PROPERTIES & DESIGN Methods of Design selected verifications Fundamental natural frequency single span beam æ k f 1,beam = m ö è ç 2p l 2 ø ( EI) l,ef m Stiffness criterion éë Hzù û deflection of a single span girder with a single force F at midspan k m /p % 75 % 50 % 25 % 0 % 25 % 50 % 75 % 100 % degree of flexibility degree of clamping w(f,b F ) = F l 3 48 EI ( ) l,ef b F + F l ( ) ef b F 4 GA effective width b F b F = ( ) b,ef ( ) l,ef l 1.1 EI 4 EI Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 21

22 Serviceability Limit State SLS Ultimate Limit State ULS PROPERTIES & DESIGN Methods of Design selected verifications Vibration acceleration a = æ æ ç è ç è f 1 f f æ F 0 a i,f1 ö 0.4 ç è M gen ø ö ø 2 ö -1 ø 2 æ + 2 z f ö 1 ç è ø f f 2 ém / s 2 ù ë û M gen = m l 2 b é F kg/m2 ù ë û with b F b 2 Fourier coefficient mass and self weight of excitatory person span and effective width frequeny and frequency of excitation damping ratio frequency [Hz] Fourier coefficient α i,f1 [-] frequency of excitation f f [Hz] 4.5 < f f < f f < f 1 < type of floor construction damping ratio ζ supported on 2 sides supported on 4 sides CLT floors with a light or without floor construction 2.0 % 2.5 % CLT floors with heavy floor construction 2.5 % 3.0 % Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 22

23 CONTENT Properties & Design Modification Factors and Characteristic Values Methods of Design Research & Testing Material Connections Structures Conclusions Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 23

24 RESEARCH & TESTING Shear Mechanisms on a RVSE Mechanism I net-shear transfer of shear via board s cross sections τ net = 2 τ 0 Mechanism II torsion torsional shear stresses in gluing interface τ tor = 3 τ 0 (t l / a) RVE and RVSE of a CLT element t CLT nominal shear forces idealised RVSE without checks with edge bonded boards τ 0 mechanism I mechanism II shear forces RVSE with checks or gaps, without edge bonding half system! a = w l a a RVE Y Y Y RVSE Z X a = w l Z X a Z M tor X a t l t l t l t l 2 Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 24

25 RESEARCH & TESTING Shear Strength Test [Mechanism I `Shear ] Master Thesis B. Hirschmann (2011) based on Jöbstl et al. (2008), EN 789 & EN 408 loading in compression or tension (14 angle) no significant influence! F R F R F R shear failure plane F H F V 14 gap cross layer top layers a shear fracture zone t gap F R F R F R Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 25

26 global load F [kn] RESEARCH & TESTING Failure Process Sequence of Fracturing I linear elastic ( 20 to 80 % of F max ) II regressive, non-linear until F max locally mech. I & II III softening, steady state ( 40 to 50 % of F max ) loading in bending & tension shearing parallel to grain & successive dissolution by separation of annual rings MOVIE rgb, 10/150, t gap =0 fgb, 10/150, t gap =5 fgb, 10/150, t gap =5 steady state rgb, 10/150, t gap = global deformation [mm] Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 26

27 RESEARCH & TESTING Failure Process shear forces perpendicular to grain lead to shear failures parallel to grain! F max (1 st peak) governed by interacting mech. I & II confirmed by numerical model tremendous possibilities for load redistribution (steady state) successive dissolution, separation of annual rings at transition zone of early- and latewood fixed-end beams active in bending & tension confirmed by simple engineering model Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 27

28 RESEARCH & TESTING Tests Norway spruce C24 u = 12 % density matched samples top layers w l x t l = 150 x 40 mm² fracture zones free of knots, checks, reaction wood, test parameters (core layers) width w l 150 mm vs. 200 mm thickness t l 10 mm vs. 20 mm vs. 30 mm annual ring orientation AR flat grain (fgb), rift grain (rgb), heart boards (hb) gap width t gap 1.5 mm vs. 5.0 mm vs mm 10 tests per series comparison of configurations EN (Hirschmann, 2011) and CIB (Jöbstl et al., 2008) Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 28

29 RESULTS EN shear strength f v,net,12 [N/mm²] RESEARCH & TESTING f v,net,50,mle setup CIB f v,net,05 setup EN B C D B A H C I C F G thickness t l [mm] width w l [mm] gap t gap [mm] fgb rgb hb AR [ ] constant base parameters w l = 150 t gap = 5 fgb t l = 10 t gap = 5 fgb w l = 150 t l = 20 fgb w l = 150 t l = 20 t gap = 5 ρ mean [kg/m³] f v,net,mean [N/mm²] CV[f v,net ] [%] f v,net,05 [N/mm²] Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 29

30 RESULTS EN shear strength f v,net,12 [N/mm²] shear strength f v,12 [N/mm²] RESEARCH & TESTING f v,net,50,mle setup CIB f v,net,05 setup EN Hirschmann (2011) setup EN ,000 10,000 B C D B A H C I C F G thickness t l [mm] width w l [mm] Brandner et al. (2012) literature survey Brandner et al. (2012) test data Bröker et al. (1987) block shear; clear wood Gaspar et al. (2008) block shear; clear wood shear area A s [mm²] gap t gap [mm] fgb rgb hb AR [ ] constant base parameters w l = 150 t gap = 5 fgb ρ mean [kg/m³] f v,net,mean [N/mm²] CV[f v,net ] [%] f v,net,05 [N/mm²] high significant influence! two reasons size effect on shear strength (+) locking effect (+) decrease with power 0.2 Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 30

31 RESEARCH & TESTING Results significantly influencing parameters lamella thickness t l decreasing f v,net with increasing t l gap width t gap decreasing f v,net with increasing t gap annual ring orientation AR f v,net,rgb f v,net,hb f v,net,fgb not significant parameter lamella width w l 150 mm w l 200 mm Proposed Reference Material and Geometric Parameters t l,ref = 30 mm (t l,st = 20, 30, 40 mm) w l,ref = 150 mm (100 mm w l 240 mm) t gap 5 mm (0 mm t gap 4 (6) mm) AR = fgb Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 31

32 RESEARCH & TESTING Results proposal for test configuration net-shear on single nodes shear perpendicular to grain failure in shear parallel to grain interaction mech. I & II high potential of load redistribution analogies with shear parallel to grain, e.g. AR, t l, w l proposal for net-shear of single nodes for t l 40 mm, w l = 150 mm, AR = fgb, t gap 6 mm assuming CV[f v,net ] = 15 %, f v,net ~ 2pLND f v,net,05 = 5.5 N/mm² latest series 2013 (12 #) 30 x 150 mm², fgb, t gap = 0 mm, ρ 12,mean = 438 kg/m³ f v,net,05 = 6.4 N/mm² Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 32

33 30 mm parallel four RVEs w CLT,ref = 600 mm RESEARCH & TESTING Proposed Reference CLT Diaphragm reference lamella w l x t l = 150 x 30 mm² reference CLT element 5 layers t CLT = 150 mm 4 x 4 nodes w CLT = 600 mm serial one of three gaps n xy parallel two nodes Net Shear in CLT Element net shear failure only if all nodes in x-direction fail (parallel) serial system action in y-direction high potential for load transfer current verification of shear in plane on single nodes judged as reliable! n xy x y n xy w l,ref = 150 mm n xy t l,ref t CLT,ref 150 mm Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 33

34 RESEARCH & TESTING 3 Tests on CLT Elements Norway spruce C24 w l = 105 mm layup mm CLT element 120 x 600 x 1,200 mm³ config. & analysis acc. to Kreuzinger (2013) failure acc. to mechanism I net-shear interaction compression perp. to grain and shear considered F τ gross,12 [N/mm²] f v,net,12 [N/mm²] test test test Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 34

35 RESEARCH & TESTING Shear Strength Test [Mechanism II `Torsion ] Diploma Thesis G. Jeitler (2004) torsional shear stresses in the gluing interface MT 1 3 M a I 2 a T,max 3 P T with J M T J P a P 4 a 6 torsional moment polar sectional moment of gluing interface dimension of RVE test specimen torsional test configuration Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 35

36 RESEARCH & TESTING Shear Strength Test [Mechanism II `Torsion ] Diploma Thesis G. Jeitler (2004) Series A 100 mm Series B 150 mm Series C 200 mm 145 mm 240 mm 145 mm 240 mm 145 mm 300 mm 240 mm 240 mm 300 mm annual ring gradient spruce flat grained boards (SW) edge-grained boards (RB) shear stresses in the gluing interface series annual ring orientation 5%-quantile [N/mm 2 ] A edge grained 3.67 A flat grained 2.79 B edge grained 3.20 B flat grained 2.69 C edge grained 2.98 C flat grained M remark: Value generally accepted! Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 36 T,max 3 ft,clt,k a T 2.5 N / mm²

37 Compression Perpendicular to the Grain Design Value for Compression Stress Perp. to Grain RESEARCH & TESTING Fd c,clt,90,d with: A c,90... contact area A c,90 point supported point supported line supported Picture: DI R. Salzer (AUT) Picture: Architect Reinberg (AUT) Picture: TU Graz (AUT) Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 37

38 characteristic parameters: Compression Perpendicular to the Grain publications regarding CLT: Y. Halili TU Graz, 2008 E. Serrano Linnæus University, 2010 C. Salzmann TU Graz, 2010 f c,clt,90,d cube slab-like specimen k c,clt,90 (`hang-in effect ) E c,clt,90,mean RESEARCH & TESTING Material Resistance against Compression Perp. to Grain (f c,clt,90,d ) specimen formed like a cube slab-like specimen slab-like specimen ( point point ) Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 38

39 Compression Perpendicular to the Grain RESEARCH & TESTING Different Loading Situations Configurations on CLT Elements center load edge load F F `hang-in effect (two sides) corner load edge load F F `hang-in effect (one side) Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 39

40 Compression Perpendicular to the Grain `Framework Model RESEARCH & TESTING CLT cubes failure mode: deformation at defined failure stage F GLT cubes failure mode: e.g. tension perp. to grain F cross layer `reinforcement u y u y 7-layered CLT element F 5-layered GLT element F Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 40

41 Compression Perpendicular to the Grain RESEARCH & TESTING The cross layers cause a `locking effect and therefore a reduction of deformation. comparison of CLT to GLT at the same load level CLT shows reduced deformation perp. to grain (u y ) concentrated on each single layer CLT shows higher stiffness and lower stresses in tension perp. to grain result: lower failure probability at the same load level and higher load bearing capacity perpendicular to the grain Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 41

42 Compression Perpendicular to the Grain RESEARCH & TESTING Strength determined on standardised full-loaded Prismatic Specimen GLT CLT f c,glt,90,k = N/mm 2 [res. publ.] f c,clt,90,k = N/mm 2 f c,glt,90,k = 2.5 N/mm 2 (pren 14080) f c,clt,90,k = 3.0 N/mm 2 (proposal TU Graz) basic value for design Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 42

43 Compression Perpendicular to the Grain Bearing Capacity in Constructions RESEARCH & TESTING GLT CLT edge `line supported centric `point supported GLT k c,glt,90 = 1,0... 1,5... 1,75 f c,glt,90,k k c,glt,90 = 3.75 N/mm 2 proposal TU Graz k c,clt,90 = ~ 1.5 = ~ 2.0 f c,clt,90,k k c,clt,90 = N/mm % + 60 % Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 43

44 CONTENT Properties & Design Modification Factors and Characteristic Values Methods of Design Research & Testing Material Connections Structures Conclusions Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 44

45 RESEARCH & TESTING Transport Assembling storage of CLT elements (production site) charging and transport discharging (building site) mounting parts for roof elements mounting parts for ceiling elements mounting parts for wall elements Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 45

46 RESEARCH & TESTING Mounting Parts for Transport and Assembling for walls: ball-shaped head connected with self-tapping screws textile hanger with high strength and ductility mounting part at the narrow side of a 3-layered CLT element in plane out of plane `shear `pull out `shear tension test configuration failure mode with high deformation [safety factor:7] failure modes Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 46

47 RESEARCH & TESTING Mounting Parts for Transport and Assembling for ceiling and roof elements: tapped blind hole connection with dowel and textile hanger tension test configuration perp. to the grain dowel diameter d = 16 mm failure mode [timber] caused by tension perp. to the grain [rigid] dowel diameter d = 12 mm NOTE: Extension of knowledge regarding the load carrying behavior of mounting parts is required! Research activities are important! failure mode [steel dowel] plastic hinges caused by reaching the yield moment (ductile) Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 47

48 groups and line connections single screws RESEARCH & TESTING Screwed connections in CLT elements 6 main research projects k sys k 90 k gap k 90 k gap ST GLT CLT CLT - side face CLT - narrow face α n ef block shear n ef cyclic behaviour CLT - side face CLT - narrow face CLT - side and narrow face ONGOING ONGOING Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 48

49 CONTENT Properties & Design Modification Factors and Characteristic Values Methods of Design Research & Testing Material Connections Structures Conclusions Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 49

50 RESEARCH & TESTING CLT Lintels Master Thesis A. Reichhart (2013) hinged support (conservative) H L support with springs rigid support (progressive) Kj =? 3-layered CLT elements tests with varying L/H ratio (5 10) proposed degree of clamping: 65% if L/H 7.5 high variance of F max partially very low ultimate loads caused by knots in middle layer therefore: no high stressed lintels in 3-layered CLT elements Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 50

51 RESEARCH & TESTING Seismic Tests 3-steps I connections angle brackets, hold downs and screws CLT/CLT and CLT/concrete/steel shear and tension monotonic and cyclic about 200 tests Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 51

52 RESEARCH & TESTING Seismic Tests 3-steps I connections II walls 5 configurations 17 tests variation of connections, vertical loads and geometries walls with and without vertical joints with and without door opening Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 52

53 RESEARCH & TESTING Seismic Tests 3-steps I connections II walls III building shaking table tests on a three-storey building EU-project SERIES (Seismic Engineering Research Infrastructures for European Synergies) Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 53

54 CONTENT Properties & Design Modification Factors and Characteristic Values Methods of Design Research & Testing Material Connections Structures Conclusions Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 54

55 CONCLUSIONS Conclusions 1. The development of CLT about 25 years ago provides a panel-like product for timber constructions. Combined with one-dimensional GLT members, it was - and still is - possible to open up new markets for timber products. 2. Enhanced by the simultaneously occurring development of screw technology for innovative connection concepts, new possibilities regarding construction and spans were created, increasing the market of timber products. 3. An ongoing trend concerning both solid timber construction with CLT and connection systems with screws is to be expected. 4. An increasing competition for resources, also affecting forest and timber industry, can be noticed too. This will lead to a selective and resourcefriendly use of wood diversity. 5. An intelligent mix of solutions in solid and lightweight construction combined with the use of regionally available wood diversity, will gain more visibility in future timber engineering. Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 55

56 CONCLUSIONS CLTdesigner The software tool for designing cross laminated timber elements (CLT) based on the design concepts of Eurocode 5 and numerous research works built up of modules developed and provided by the Centre of Competence holz.bau forschungs gmbh and the Institute of Timber Engineering and Wood Technology of Graz University of Technology available in DE, EN, FR, IT and ES at Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 56

57 CONCLUSIONS CLTcalculator - First CLT App for iphone and ipad developed by A. Mikara in corp. with the Institute of Timber Engineering and Wood Technology Available on App Store! Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 57

58 THANKS FOR ATTENTION! Contact Univ.-Prof. Dipl.-Ing. Dr.techn. Gerhard Schickhofer Institute of Timber Engineering and Wood Technology Graz University of Technology Inffeldgasse 24/I A-8010 Graz P: Gerhard SCHICKHOFER CLT-Forum 2013 TOKYO Institute of Timber Engineering and Wood Technology TU Graz 58