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NEWBuildS Tall Wood Building Design Project – Seismic & Gravity Load Analysis and Design Zhiyong Chen University of New Brunswick www.NEWBuildSCanada.ca 1. Introduction 1.1 Customer Demands & Challenges on Structures Taller Buildings Structural systems: Ductile Connection systems: High strength & Ductile Larger Open Space Floor systems: Long span & Vibration We are trying to address these issues !!! 1.2 Flow Diagram Site & Loads (Dead, Live, Wind, Snow and Seismic) Structural System Material, Structural Assembles & Connections Checking on Structural & Fire Issues using FEA 1~3 Iteration s [No] [Yes] Suitable Structural Assembles & Connections Structural Sketch & Report 2. Structural Design 2.1 Concept Design Structural System Post-beam system Possible storey number Shear wall system Shear wall + core system + Shear Wall Construction Platform framing: Easy to be built storey by storey Balloon framing: Reduce the storey joints 2.1 Concept Design Stiffness, Strength & Ductility Shear Wall Steel Beam (1) Core Vertical Joints (2) (Dowel Type) (3) Hold-Down Shear Connector (3) 2.2 Lateral Load Resisting System Hold-Down The typical storey Shear Connector LLRS HSK System (Wood-Steel-Composite) 2.3 Gravity Load Resisting System The typical storey Beams are divided by column / wall GLRS 2.3 Gravity Load Resisting System Floor The typical storey GLRS 2.3 Gravity Load Resisting System Roof The typical storey GLRS 2.4 Design Assemblies and Connections Roof Material CLT panel Type SLT9 HBV-Vario Floor Company STRUCTURALAM Glulam-concrete Floor TICOMTEC (125mm Concrete + 175x532mm GL composite deck beam @ 800mm) GL Beam Glulam D.L.F. 24f-E (215x532mm) Steel Beam Steel G50 (S5x10) D.L.F. 24f-E (730x418=2-365x418, GL Column Glulam 365x418mm) Core & Wall LSL 2.1E LSL (3-19x2.44x0.089m ) TIMBERSTRAND Hold-Down Steel and Glue HSK system TICOMTEC Shear Steel and Glue HSK system TICOMTEC Connector Vertical Steel Dowel type connector Joint 2.5 Sketch List GENERAL G-01: PROJECT DECRIPTION AND SKETCH LIST STRUCTURAL S-01: STRUCTURAL SYSTEM DESCRIPTION S-02: TYPICAL FRAMING PLAN S-03: TYPICAL BUILDING SECTIONS S-04: TYPICAL DETAILS S-05: TYPICAL DETAILS S-06: CONSTRUCTION SEQUENCE DIAGRAMS 3. Structural Analysis 3.1 Massive-Timber-Panel Moment Frame Steel Beam (1) Vertical Joints (2) Hold-Down (3) Shear Connector (3) MTPMF 3.1.1 Influence of Hold-Down 3.1.1 Influence of Hold-Down 60000 40000 Load, N 20000 0 -20000 -40000 -60000 -150 Without ductility With ductility -100 -50 0 50 100 150 Deformation, mm Deformation Hysteresis loops The ductility of the hold-down affects the system ductility. 3.1.2 Influence of Steel Beam 3.1.2 Influence of Steel Beam 600000 500000 Load, N 400000 300000 200000 100000 Small beam section No steel beam 0 0 20 40 60 80 Deformation, mm Deformation Load-deformation curve Steel beam increases the system stiffness and ductility. 100 3.1.3 Influence of Vertical Connections 3.1.3 Influence of Vertical Joint 600 400 Load, kN 200 0 -200 -400 -600 -120 =9 -80 -40 0 40 80 Drift at the top, mm Deformation Load-deformation curve Vertical joint affects the performance of the system. 120 (1) Stiffness of Vertical Joint 3.5 3.0 K/KK con =0 2.5 2.0 1.5 dcon=0.25m 1.0 dcon=1.00m 0.5 -10 -8 -6 -4 -2 10 10 10 10 10 dcon=2.00m 0 10 2 4 10 Kcon,equ/(G//t), m 10 6 10 8 10 10 10 -1 (1) The ratio system stiffness increases with increasing the stiffness of the vertical joint. (2) For a denser fastening case, the system derives a higher stiffness in the rigid case. (2) Strength of Vertical Joint 600 500 Load, kN 400 Fcon=INF Fcon=40kN 300 Fcon=30kN Fcon=25kN 200 Fcon=20kN Fcon=15kN 100 Fcon=5kN Fcon=0kN 0 0 20 40 60 80 100 120 Drift at the top, mm (1) The curves of the two extreme cases form the boundaries of the other intermediate strength cases. (2) The first turning point of the curves from the infinite-connectionsstrength to zero-connection-strength cases increases with increasing the connection strength. (3) Ductility of Vertical Joint - Static 600 500 Load, kN 400 =1 =2 =3 =4 =5 =6 =7 =8 =9 =10 =INF 300 200 100 0 0 20 40 60 80 100 120 Drift at the top, mm The first yield point increases with increasing ductility ratio of the connection. 600 600 400 400 200 200 Load, kN Load, kN (4) Ductility of Vertical Joint - Cyclic 0 -200 -200 -400 -400 -600 -120 =1 -80 -40 0 40 80 -600 -120 120 Drift at the top, mm 600 400 400 200 200 0 -200 -80 -40 0 40 80 120 Drift at the top, mm 0 -200 -400 -600 -120 =5 600 Load, kN Load, kN 0 -400 =9 -80 -40 0 40 Drift at the top, mm 80 120 -600 -120 =INF -80 -40 0 40 80 120 Drift at the top, mm The system ductility and energy dissipation ability are improved by the ductile connections. 3.2 FEA Model of Tall Wood Building Geometrical Model and Elements LSL core, shear wall & diaphragm Shell element – S4R Steel & glulam beams, columns Beam element – B31 Material Models Timber – Elastic Steel – Ideal Elastic-Plastic Stress Stress Strain Strain 3.2 FEA Model of Tall Wood Building Connection Models Vertical joint & shear connector – Ideal Elastic-Plastic with ductility Force Deformation Hold-down connection – Ideal Elastic-Plastic with ductility under tension & without movement Force under compression Deformation 3.2 FEA Model of Tall Wood Building Connection Models Steel beam & GL column – Rigid connections GL beam to beam, column, wall & diaphragm – Hinge connections Contact Models Steel beam to Wall – Tie Panel to panel – Frictionless (in tangential direction) – Hard contact (in tangential direction) Stress Strain 3.2 FEA Model of Tall Wood Building Numerical Simulation Problem • 3-Dimentional • Non-linear Problem Size • Number of elements is • Number of nodes is 154,592 • Total number of variables 585,762 90,834 (Degrees of freedom plus any Lagrange multiplier variables) It is a huge & complex computational task with convergent problems 3.3 Frequency Analysis Sub-Space Method In Y (N-S) direction In Z (rotation) direction In X (E-W) direction 3.3 Frequency Analysis Influence of joint stiffness Rigid Semi-Rigid NBCC T1 T2 T3 1.04 (Torsional) 0.88 (N-S) 0.64 (E-W) 1.66 (N-S) 1.46 (Torsional) 0.94 (E-W) Shear wall: 1.04; Moment Frame: 1.90 Semi-rigid FEA should be used, else the periods of the building would be under-estimated. The fundamental period of this building with semi-rigid joints in the East-West direction is close to that estimated by NBCC. 3.3 Frequency Analysis 1.66S (L=37.3+30.6=67.3m) (1) Wind would control the structural design in the NorthSouth direction, while seismic would control it in the EastWest direction. 0.94S (L=60.5m) 1.46S (2) Some external walls at axis 1 & 7 should be considered to address the torsional issue and the stiffness in N-S direction. 3.4 Gravity Loading Analysis 3.4 Gravity Loading Analysis In X (E-W) direction In Y (N-S) direction The differential shortening is not significant. 3.5 Pushover Analysis Risk method In X (E-W) direction In Y (N-S) direction 3.6 Seismic Analysis Spectral Acceleration, Sa(g) Seismic response of the high-rise wood building is crucial in the ultimate limit state. Investigation method: Nonlinear time history analysis 22 “Far-Field” earthquake records will be scaled at the corresponding fundamental period of the building model to match the spectral acceleration, Sa, of the Vancouver design 10 spectrum. 1 0.1 0.01 Target Spectrum Results Geom. Mean 1E-3 0.01 0.1 1 Period, T(S) 10 3.6 Seismic Analysis 0.25 0.00 -0.25 -0.50 0 3 6 9 t (s) 12 15 S1 S2 S3 S4 S5 S6 0.25 0.00 -0.25 -0.50 0 3 6 9 t (s) 12 15 1.0 Drift ratio (%) 0.50 Input earthquake record Acceration (g) Acceration (g) 0.50 S1 S2 S3 S4 S5 S6 0.5 0.0 -0.5 -1.0 0 3 6 9 t (s) 12 15 Thank you! Yingxian Wood Pagoda Tall Wood Building (66m)