Recent UBC research activities on CLT and Glulam

Transcription

1 UBC Recent UBC research activities on CLT and Glulam Frank Lam Professor and Senior Chair of Wood Building Design and Construction University of British Columbia August 19, UBC-Tongji-CSRN Symposium, Vancouver 2013 Timber Structures PhD Student Symposium, Vancouver 1

2 Cross Laminated Timber (CLT) Concept bonding on wide surface only Multi-layer plate elements with 3 up to 9 layers Crosswise orientated boards, laths or planks Bonding between layers primarily on the wide surfaces only Maximum dimensions: Length = 16+ m, Width = 3 m, Thickness = 0.5 m 2

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5 CLT European Production European Cross laminated timber (CLT) has moved from a niche market since mid 1990 s to a mass produced product. Production is projected to double (600,000 m³) or triple (1,000,000 m³) by

6 10 Stories CLT Building in Melbourne 6

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10 NSERC Strategic Network NEWbuildS (2010 to 2015) Title Year HQP University Development of evaluation methodology for Rolling Shear in CLT MSc UNB Development of design methods for CLT and application of modal testing Manufacturing Parameters on CLT Floor Performance to resist out-of-plane loading Innovative CLT Building Systems Localized Rolling Shear Reinforcement PhD UNB PhD 1 MSc 1 PDF UBC MASc UBC 3 Master students, 3 PhD students, 1 PDF 10

11 UBC Research on CLT Investigate the influence of manufacturing parameters on CLT production Glue (PU, PRF) Species (SPF, Hem-fir) Grade Pressure Studied the structural performance of as floor or roof plates Computer model and experiments (J. Chen) On going study on the rolling shear performance of CLT under short and long term loading (M. Li and Y. Li) 11

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13 UBC Tests on Shear Bond Pressure Levels: 0.1, 0.3, 0.6 MPa Two Types of Adhesives: PRF and PU Two Species: SPF and SPF/Western Hemlock Shear Strength and Stiffness 13

14 UBC Tests on Shear Bond 14

15 Rotational Modulus (N/mm 3 ) Shear Strength (MPa) UBC Tests on Shear Bond Shear strength of different adhesives PRF 0.1 (20) PUR 0.1 (27) PRF 0.3 and 0.6 (51) PUR 0.3 and 0.6 (54) Maximum Mean Minimum Rotational modulus of different adhesives PRF 0.1 (20) PUR 0.1 (27) PRF 0.3 (26) PUR 0.3 (27) PRF 0.6 (26) PUR 0.6 (27) Maximum Mean Minimum

16 Rolling Shear Failure 16

17 Rolling shear failure mode study Need to study the rolling shear strength in CLT under short and long term loading Need to consider possible reinforcement techniques 17

18 UBC Short term tests Loading setup Ten specimens were cut from each CLT panel in a manner that the face layers were parallel to the span direction. The bending tests were conducted with a small span-depth ratio of 6 in order to promote RS failure mechanism in the cross layers, as shown in Figure. A displacement controlled loading rate of 2 mm/min was used for the specimens 18

19 UBC Short term tests FE Model Rolling shear stress distribution in ANSYS model Maximum stress area is in 2/3 span area Compared with test results 19

20 UBC Fatigue tests Fatigue test setup 25th%-tile capacity is chosen for fatigue test loading control value Load control 20

21 Continuing research Foschi and Yao model (1986) is based the relationship between damage and stress history Wang and Lam Model (2010) is based the relationship between damage and strain history 21

22 NSERC Strategic Network NEWbuildS (2010 to 2015) Title Year HQP University Stiffness and strength of CLT diaphragms (in-plane loading) Seismic response of CLT mid-rise system Force transfer around openings in CLT buildings(lateral load) Innovative Post tensioned CLT Walls Connections in CLT Buildings Systems Stability of CLT wall under vertical load MASc UBC PhD 1PDF UBC MASc UBC MASc 1PDF UBC MSc UNB/Laval PhD UBC 5 Master students, 2 PhD students, 2 PDF 22

23 UBC Project - Stiffness and strength of CLT diaphragms (in-plane loading) In-plane loading connection layout E

24 Stiffness and strength of CLT diaphragms (in-plane loading) Force (KN) 90 Force-Displacement curves for Layout E specimens E1 E2 E3 E4 E5 E6 Average Displacement (mm)

25 Linear springs at the location of shearwalls non-linear springs in X direction

26 Column Behaviour of CLT at UBC Rolling Shear Failure 26

27 Column Behaviour of CLT Rolling Shear Failure 27

28 Column Behaviour of CLT Rolling Shear Failure 28

29 Fire test of CLT Floor system under unfactored design live load 29

30 Fire test of CLT Wall system under unfactored design live load 30

31 Charred specimen Wall tests: average charring rate after about 100 minutes of fire exposure was 0.72 mm/min, which is slightly higher than the one-dimensional charring according to EN The effect of falling off of charred layers is not significant. No significant influence of the support conditions studied in this investigation could be observed on the fire behavior of the CLT wall panels. Floor tests: average charring rate after about 60 minutes of fire exposure was 0.79 mm/min. An influence of the orientation of the layers on the charring behavior was not observed as the SR system carried higher loads compared to the WR system. 31

32 130 mm x 0.91 m x 16.4 m

33 180 mm x 1.2 m x 21.6 m 33

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35 Mean MOR (MPa) Size Effect of 24f Glulam Beam including latest results Test Average ULAG Average CSA based procedures US Based Procedures (k=10) Beam Depth (mm)

36 Log 10 (Mean Bending Strength MPa) 1.8 Size Effect in Glulam Log(Test Data) y = x R² = Log(ULAG Simulation) Linear (Log(Test Data)) Linear (Log(ULAG Simulation)) y = x R² = Log ( Beam Volume mm 3 )

37 Log 10 (Mean Bending Strength MPa) 1.8 Size Effect in Glulam 1.75 y = x R² = Log(US 1990 Test Data) Log(UBC Test Data) Linear (Log(US 1990 Test Data)) Linear (Log(UBC Test Data)) y = x R² = Log ( Beam Volume mm 3 )

38 Research Direction Develop Reliability Based Design information for Connection Behaviour Seismic and Fire Develop Reliability Based Design information for System Response - Seismic and Fire 38

39 The Landing 375 Water Street Vancouver 1905 ca Height m Floors 7 (above ground) and 2 (below ground) Constructed 1905 Renovated

40 Yingxian Wooden Pagoda, China - Tallest Wood Building in the world, 66 m in height, built 1055 ca. 40

41 Contact Information Dr. Frank Lam P.Eng. FIWSc, FIAWS Senior Chair Professor Wood Building Design and Construction Department of Wood Science University of BC 2424 Main Mall Vancouver BC Canada V6T 1Z4 Tel:

42 Thank you for your attention 42

43 SIZE EFFECTS IN GLULAM TIMBER EN 1995 Provisions Reference depth: 600 mm For bending strength of beam with depths less than 600 mm, the characteristic values may be increased by a factor kh, given by k h = min 600 h 1.1 No adjustments for shear strength 0.1

44 SIZE EFFECTS IN GLULAM TIMBER US Code Provisions Reference size:130x305x6400 mm The allowable bending strength is modified by a factor kv as k v = 305 h l w where h = depth (mm); l = length (m); w = width (mm) k = 10 for Douglas fir and 20 for Southern Yellow Pine No adjustments for shear strength 1 k

45 SIZE EFFECTS IN GLULAM TIMBER Canadian Code Provisions Reference size:130x610x9100 mm The specified bending strength of beam deeper than 610 mm is modified by a factor kz as k z = 1.03 bl 0.18 where l = length (m); b = width (m) Adjustments for shear strength

46 Approach Experimental based program is expensive and have limited scope Develop a FEM program ULAG Establish a comprehensive input database Verify ULAG predictions Use ULAG to evaluate a large range of cases