The document discusses design considerations for cross-laminated timber (CLT) buildings. It covers optimal CLT designs and applications, material properties, design resources, suitable projects, finishes, floor, wall and lateral designs. It also addresses vibration, fire, acoustic performance, connections, termite control, variations between manufacturers, design software, balancing strength with other factors, importation, and the CLT design and construction process when working with a supplier like SmartStruct.

1. Designing CLT Buildings
Presented By – Robert De Brincat

2. INTRODUCTION
CLT Design Considerations
• Optimum CLT Design & Building Applications
• Strength / Serviceability / Vibration / Fire / Acoustics
• Floor, Wall & Lateral Design
CLT Supply & Design Resources
• CLT Material Properties & Supplier Involvement
• Design Resources Available
• Design, Construction & Importation Process
• SmartStruct & Tilling Timber

3. CROSS LAMINATED TIMBER PROJECTS
• Optimum Slab Span – 4.5m to 5.5m
• Simple Compartment & Wall Layouts
• Minimal Load Transfer Between Floors
• Optimum Building Height – 5 to 8 Levels
• Residential & Commercial Developments
• Lightweight Construction & Poor Foundations
• Speed of Construction
Suitable Applications & Benefits

4. Affordable Housing - Austria

5. Das Post Hotel - Austria

6. Lee Valley Athletics Village

7. Lee Valley Athletics Village

8. Lee Valley Athletics Village

9. Lee Valley Athletics Village

10. Woodlands Trust

11. Woodlands Trust

12. Woodlands Trust

13. Woodlands Trust

14. Woodlands Trust

15. Woodlands Trust

16. CROSS LAMINATED TIMBER
Available Finishes
• Architectural Visual Finish
– Smoothly Edge Glued
– Individual Boards Planned
• Industrial Visual Finish
– Individual boards Sanded or Brushed
• Non-Visual Finish
– Unexposed Panels

17. CROSS LAMINATED TIMBER
Available Finishes

18. CROSS LAMINATED TIMBER
Available Finishes

19. CROSS LAMINATED TIMBER
Floors – Walls – Shafts
Design Considerations

20. CLT FLOOR DESIGN
Two Way Slab Performance

21. CLT FLOOR DESIGN
Two Way Slab Performance
Wall Below CLT

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

24. CLT FLOOR DESIGN
Longitudinal Shear Due to Bending
Longitudinal Shear
Solid Section Non Laminated Section

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

33. CLT CONNECTIONS
Floor Details
Single Surface Spline
Internal Spline
Half Lapped
Double Surface Spline

34. CLT CONNECTIONS
Wall/Concrete Floor Details
Metal Bracket Metal Plate Metal Shoe

35. CLT CONNECTIONS
Wall/Floor Details
Straight Screw
Straight Screw
Angled Screw
Steel Bracket
Steel Bracket

36. CLT CONNECTIONS
Wall/Floor Roof Details
Double Bracket
Bracket & Screw
Bearing Angle
Block & Screw

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

39. CROSS LAMINATED TIMBER
Fire & Acoustic Performance
FRL – 90/90/90
Rw – 57
Thickness – 284mm
FRL – 90/90/90
Rw – 60
Thickness – 290mm

40. CROSS LAMINATED TIMBER
Fire & Acoustic Construction

41. CROSS LAMINATED TIMBER
Fire & Acoustic Construction
Acoustic Layer
Plasterboard Ceiling
Ceiling Insulation
5 Layer CLT
2 x Layers Fire Check
70mm Concrete Topping
Wooden Floor Covering

42. CROSS LAMINATED TIMBER
Termite Control
Termite Management
is dealt with in
accordance with
AS3660.1 – 2000

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

47. What is SMARTSTRUCT?
Design – Fabrication – Supply – Construction
COLLABORATION COLLABORATION COLLABORATION

48. SMARTSTRUCT CLT PROPOSAL SERVICE
Concept
Design
Preliminary
CLT Design
CLT Panel
Optimisation
CLT Supply
Cost
CLT
Construction
Cost
CLIENT
– Architectural Layout
– Material Wastage
– Transport Cost
– Construction Cost

49. CLT DESIGN & CONSTRUCTION PROCESS
CLT Delivery
to SmartStruc
CLT Manufacture
Shop Drawing
Approval
CLT Shop
Drawings
CLT Delivery to
Site & Install
PROJECT
DESIGN
FINISH
CONSTRUCTION
PROJECT
TENDER
START
CONSTRUCTION
Fire Engineered Solution
PCA
Acoustic Consultant
OCCUPATION
CERTIFICATE
Building
Inspections
SmartStruct Engineer
Architect Services
CLIENT