22. CLT FLOOR DESIGN
Moment Capacity
• Moment Capacity Relative to Member Size
• Increased with Laminated Area
• Increased with Material Area
• Increase with Effective Area & Lever Arm
23. CLT FLOOR DESIGN
Moment Capacity
• Moment Capacities Vary between CLT Products
• Moment Capacity Provided by CLT Supplier
• Importance of Understanding Moment Capacity
– Longitudinal Shear Due to Bending
– Rolling Shear Between Timber Layers
– Effective Bending Stiffness
25. CLT FLOOR DESIGN
Rolling Shear is Dependent on Many Factors
Timber Species; Cross Layer Density; Lamination Thickness; Moisture
Content; Sawing Pattern; Cross Sectional Size and Geometry
Rolling Shear
26. CLT FLOOR DESIGN
Rolling Shear
• Effective Bending Stiffness Dependent on Rolling Shear
• Transverse Layers Modeled as Theoretical Connectors
Between Longitudinal Layers
• ϒ Factor → Effective Moment of Inertia → Effective
Bending Stiffness. ϒ = 0 (No Connection) ϒ = 1 (Fully Rigid)
• Rolling Shear Modulus (GR) Predetermined by Supplier
27. CLT FLOOR DESIGN
Design Capacities
• Rolling Shear Modulus used to Calculate Effective
Bending Stiffness
• Effective Bending Stiffness used to Calculate;
– Moment Capacity
– Shear Capacity
– Deflection
Design Capacities Provided by CLT Manufacturer
28. CLT WALL DESIGN
Two Way Wall & Beam Performance
Beam Configuration Wall Configuration
29. CLT WALL DESIGN
Compression Members
Applicable to both Wall & Column Applications
Pparallel ≤ F’c Aparallel
Pparallel = Load Applied Parallel to the Fibres
F’c = Adjusted Compression Strength
Aparallel = Area of Layers with Fibres Running Parallel to the
Direction of the Load
30. CLT WALL DESIGN
Tension Members
Tension Loads can only be Resisted by the Layers
where the Grain Runs Parallel to the Applied Load
Tparallel ≤ F’t Aparallel
Tparallel = Load Applied Parallel to the Fibres
F’t = Adjusted Tensile Strength
Aparallel = Area of Layers with Fibres Running Parallel to the
Direction of the Load
31. CLT LATERAL DESIGN
Shear Walls & Diaphragms
• Resistance to Wind & Seismic Loadings
• Wall & Floor Panels Designed as Shear Walls & Diaphragms
• Panel Shear Strength will vary based on Fastener Size,
Fastener Spacing, Fastener Location, & CLT Shear Strength
• Deflection Determined by Engineering Principles & Testing
CLT is a Suitable Substitute for Concrete in Lift
Shaft & Building Core Design
32. CLT LATERAL DESIGN
Seismic Design
• CLT Panel Connectors Provide Primary Source of
Yielding while CLT Panel Remains Elastic
• Special Seismic Detailing Required for CLT
– Fasteners Loaded in Shear
– CLT Member Design at Connections
– Nominal Connection Capacity
– Fastener Withdrawal
37. CLT VIBRATION DESIGN
Material Characteristics
• Damping is Approx. 1%
• Area Mass is 50 – 150kg/m2
• Fundamental Natural Frequency > 9Hz
• Footstep Force causes Transient Vibrations which
can be controlled by the Stiffness & Mass of the
CLT Floor Panel
• Span & Slab Depth Dependent
38. CROSS LAMINATED TIMBER
Fire Design
CLT Charring Rate
~ 0.82mm/min
• CLT is NOT Timber Framed Construction
• Fire Plasterboard Solutions Available
43. CLT PROPERTIES & PERFORMANCE
Variation Between Manufacturers
• CLT Design & Material Properties Predetermined
and Provided by CLT Manufactures
• CLT Products Differ in Material Properties and
Design Performance
• Importance of Obtaining Specific CLT Information
from Local Australian Suppliers
• Importance of Early Involvement from Suppliers
44. CLT DESIGN RESOURCES
• Supplier Specific Material Properties
• Spanning & Pre-dimensioning Tables
• Preliminary Design Software (EURO & AUS Codes)
• CADE Systems Engineering Design Software
– New CLT Modeling Component
– Based on the AUS Standards
– Flexible CLT Sectional Analysis
– Design Coordination with other Construction Materials
45. BALANCING ACT
Strength & Serviceability Vs. Fire & Acoustics
Construction Depth Vs. Floor to Ceiling Height
Wall Height Vs. Importation Cost
Panel Optimisation Vs. Construction Time
EARLY CLT SUPPLIER INVOLVEMENT IS VERY IMPORTANT
CLT DESIGN & CONSTRUCTION
What Governs the Design?
46. CROSS LAMINATED TIMBER
Importation Professionals
• Importation Capacity for Manufacture, Storage & Delivery
• Importation Distance & Lead Time Management
• Risk Management & Contingency Plans
