Checker Building Structural Analysis and Design Zhiyong Chen 1, Minghao Li 2, Ying H. Chui 1, Marjan Popovski 3, Eric Karsh 4, and Mahmoud Rezai 4 1 Univ. of New Brunswick, 2 Univ. Canterbury, 3 FPInnovations, and 4 Equilibrium Consulting Inc. www.newbuildscanada.ca
>30m 1. Background Wood as a structural material can date back to more than 7000 years. 67.310 65.880 67.31m 50.000 32.25m 40.000 30.000 20.000? f/ρ, materials & technology 10.000 Horyu-ji Temple ±0.000 Yingxian Wood Pagoda Stadthaus 2
20-Storey Mass Timber Building CHECKER 20-storey timber building Design data North Vancouver: high earthquake, wind and rain 20 storeys: 19 standard storeys + 1 podium Total height: about 60m with 3m per storey Plan dimensions: 27m x 27m with 9m grid Wood Materials: structural composite lumber (SCL), cross laminated timber (CLT), and glued laminated timber (Glulam) Connection: Wood-Steel-composite (HSK) system, Wood-Concrete-composite (HBV) system, and dowel-type connection 3
2. Structural Challenges & Solutions No. 1 high wind and seismic load develop a shearwall + core system of high stiffness, strength, and ductility Simplified Lateral load resisting system Schematic diagram of the LLRS 4
2. Structural Challenges & Solutions No. 1 high lateral wind and seismic load establish a high performance connection system HSK system for use as hold-down and shear connections for panel-to-panel and to the concrete podium Dowel type connection with selftapping screws for panel-to-panel 5
2. Structural Challenges & Solutions No. 2 large vertical deformation & complicated horizontal connections balloon framing construction technique Gravity load resisting system 6
2. Structural Challenges & Solutions No. 3 long span floor & roof wood-concrete composite system Glulam-concrete composite floor 7
2. Structural Challenges & Solutions No. 4 No design principles Size Structural Assemblies & Connections Mechanical Theory Code Provisions Numerical Simulation [No] Design Criteria [Yes] Final Design 8
3. Structural Design Size structural assemblies & connections based on 1.6W Step 1 Linear seismic response: (1) Modal analysis & ESFP & (2) RSA [Yes] Step 2 Wind induced-response: (1) Static wind & (2) Dynamic wind [Yes] Step 3 Non-linear static behaviour: Pushover analysis [Yes] Step 4 Seismic response: Non-linear time history analysis [Yes] [No] [No] [No] [No] Final design 9
Design Results Grade 50 Steel beam S5 10 The typical storey Grade 2.1E TimberStrand LSL (19m 2.44m 89mm, 3 layers) Lateral load resisting system
Design Results The typical storey Lateral load resisting system Dowel-type connection (19mm) of LSL with k=25.5kn/mm & P max =32.5kN HSK system, P max =0.8kN, K parallel =7.4kN/mm & K perpendicular =2.5kN/mm for each hole
Design Results Gravity load resisting system The typical storey DLF 16c-E Glulam column (365 418mm & 730 418mm) DLF 24f-E Glulam beam (315 532mm)
Design Results Floor Gravity load resisting system The typical storey HBV Vario system, 125mm concrete + 175 532 mm Glulam beam @
Design Results Floor Roof The typical storey Gravity load resisting system SLT9 (309mm) and SLT3 (99mm) CrossLamTM with single-span
4. Numerical Simulating Solutions Strong assembly - weak connection Macro-element model for connections Force Deformation A (a) Vertical & shear connectors Force B FEM of CHECKER Macro-element model for connector Deformation (b) Hold-down connector Macro-element connectors 15
5. Modeling Structural Performance 5.1 Gravity loading differential shortening (a) In X (E-W) direction The differential shortening is not significant. (b) In Y (N-S) direction 16
5.2 Vibration of Composite Floor Vibration has a great influence on diaphragm design (a) FEM of composite floor f 1 d 1kN 0.44 >18.9 (b) The 1 st mode shape (c) Deformation shape under a concentrated load of 1kN f 1 = 6.0 = 20.1>18.9 0.44 0.44 0.064 d 1kN 17
5.3 Wind-Induced Response Static Procedure: f n > 1.00 Hz Dynamic Procedure: 0.25 f n 1.00 Hz Experimental procedure: f n < 0.25 Hz f n 1 2 n i 1 x i Fi x n x n i xn Mi i 1 x n 2 f n = 0.53 Hz, therefore dynamic procedure is required. 18
5.3 Wind-Induced Response FEA was performed to calculate the lateral deformation of the tall wood building under wind load. P i 19
Number of Storey Number of Storey 5.3 Wind-Induced Response 20 20 15 15 10 10 5 5 Static Dynamic 0 0 10 20 30 40 Lateral Drift, mm (a) Storey drifts Static Dynamic 0 0.0 0.5 1.0 1.5 2.0 2.5 Inter-Storey Drift, mm (b) Inter-storey drifts Under static wind load: the roof drift is 31.2 mm ( h n /1800) and the interstorey drift of each storey is less than h i /500 (=6mm). Under pseudo-static wind load: the roof drift is 33.7 mm ( h n /1700) and the inter-storey drift of each storey is less than h i /500 (=6mm). 20
5.3 Wind-Induced Response The across- and along-wind accelerations, a W and a D (m/s 2 ), were estimated by 2 a r aw fnw g p wd Bg W a f g KF 2 2 S D 4 nd p CeH D Cg Substituting the values of the parameters into equations, a W and a D are 0.9% and 1.1% of g, which are both less than the acceleration limits of 1.5%g for residential occupancy. 21
5.4 Seismic Response (1) Fundamental Natural Period, T a the period of the FEM of the building was 1.97 s. It is almost twice that estimated by NBCC equation. (2) Seismic Force Modification Factor, R d CLT Handbook: R o =1.5 and R d =2.0 for CLT panel system The tall wood report: a higher R d value (3.5) could be used Pushover analysis: R d = 2.03 34 T 0.05 h 1.04s Therefore R o R d = 3.0 (1.5 2.0) was used. (3) Design lateral earthquake force, V, (Equivalent Static Force Procedure) V S Ta MV IEW Rd Ro the specified design base shear is about 4893kN. a n 22
Number of Storey Number of Storey 5.4 Seismic Response Response Spectrum Analysis 20 20 15 15 10 10 5 5 0 X i R d R o /I E 0 100 200 300 400 500 Lateral Drift, mm (a) Storey drifts X i x i x i R d R o /I E 0 0 5 10 15 20 25 30 Inter-Storey Drift, mm (b) Inter-storey drifts The roof drift is 431 mm, and the inter-storey drift is less than 2.5%h s (=75mm). 23
Base Shear, kn Pushover Analysis 5.4 Seismic Response The stiffness, yield strength and deformation, maximum strength and deformation, and failure / collapse deformation, of the building under lateral load. 10000 8000 FEA result EEEP P i 6000 4000 2000 K = 23.7 kn/mm P y = 7430 kn P max = 8140 kn = 2.55 R d = 2.03 4893kN 0 0 200 400 600 800 1000 Lateral Drift at Top, mm 24
Pushover Analysis 5.4 Seismic Response (a) Yield of vertical joints of shear wall (b) Yield of vertical joints of core (c) Yield of connections between core panels (d) Yield of shear connectors 25
Spectral Acceleration, S a (g) 5.4 Seismic Response Non-linear Time History Analysis Seismic response of the high-rise wood building is crucial in the ultimate limit state. Ten (10) Far-Field earthquake records were scaled at the corresponding fundamental period of the building model to match the spectral acceleration, S a, of the Vancouver design spectrum. 10 1 0.1 0.01 Target Spectrum Results Geom. Mean 1E-3 0.01 0.1 1 10 Period, T(s) 26
Base Shear, kn Inter-Storey Drift Ratio, % 5.4 Seismic Response Non-linear Time History Analysis 9000 3.0 8000 2.5 Non-linear Design Criterion 7000 6000 5000 Non-linear P max P y of EEEP Design Value 2.0 1.5 1.0 0.5 4000 0 2 4 6 8 10 No. of Earthquake Records (a) Base shear 0.0 0 2 4 6 8 10 No. of Earthquake Records (b) Inter-storey drift ratio - All the base shears are less than the yield load of EEEP and the maximum capacity derived by Pushover Analysis - All inter-storey drift ratios are less than the design requirement of 2.5%. 27
6. Conclusions Gravity loading analysis the compressive deformation is small Pushover analysis the static load-carrying capacity and ductility is sufficient Wind-induced response analysis the deformation, through & across-wind accelerations are less than the limits Non-linear time history seismic analysis the inter-storey drift ratios are less than limit 20-storey timber building 20-storey timber buildings with the advanced products and connections are possible. 28
The End. Thanks for your attentions! 29