ITW CONSTRUCTION ASIA PACIFIC RESIDENTIAL DIVISION
WoodSolutions Symposium1st December 2016
Session 2E: Lightweight Floor & Wall Design
Presented by:Nick Cui
Pryda Australia
How are current timber buildings designed?
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Most timber structural design systems that are available can readily cope with the
engineering requirements from a design perspective for these types of buildings.
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Design – Architectural /
Engineering
Specification
Fabricator/
Manufacturer
Installation
Compliance
Building concept
Where we currently fit in the process…
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Design – Architectural /
Engineering
Specification
Fabricator/
Manufacturer
Installation
Compliance
Building concept
What about panelisation?
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Keep in mind as we move forward…
Current timber framing
• 3 to 4 storey category widely accepted
• Mostly pre-fab frame, floor & roof
• Panelised floors & walls at infancy
Mid-rise opportunity
• 4 to 5 storey category (more for hybrid)
• Different mind set will be needed
• Panelisation may be key to compete here
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FLOOR TRUSSES & CASSETTES
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Open web floor trusses…
Longreach (timber web)
• Any depth, typically 200–600mm
• Premium performance & stiffness
• Set downs – 35/45mm typical.
• Span up to 7.4m (400mm 90x45 F17)
Pryda Span (metal web)
• 250, 300 & 400mm (nominal)
• Lightweight & economical
• Set downs – 35/45mm typical.
• Span up to 6.9m (400mm 90x45 F17)
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Multiple load areas…
More varied dead & live loads
Engineer to specify on drawings
Load areas drawn on model
Trusses designed for dead/live loads
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Dynamic performance…
Imposed load check(Absolute deflection under Q)
EC5 METHODS:
Footstep induced vibrations(Fundamental frequency > 8 Hz)
Low-frequency effects (UKNA to EC5)(Step frequency effect)
FURTHER CONSIDERATIONS:
Effect of supporting elements…
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Flooring lining options…
Particleboard/OSB/plywood flooring
FC Sheet/concrete for wet areas
Promat/Hebel/INEX Floor
Other materials also accommodated
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Ceiling lining options…
Plasterboard/FC sheet etc…
Insulation/fire/acoustics
Services – within/below floor
Open panel method currently used
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End types…
Many end types available
Only a handful may apply
Consideration for cassette stability
Consideration for crushing etc…
Timber Beam
Pryda Joist
Hanger Supporting
Truss
STANDARD END DETAIL TYPE 6
Waling Plate
Min. Bearing 30mm
on Waling Plate
STANDARD END DETAIL TYPE 8
Skew Nails Preferable Into
Beam to Restrain Bottom Chord
Min. Bearing 30mm
STANDARD END DETAIL TYPE 7
TYPICAL BEAM SUPPORT FIXING
OPTION 1
2/75 x 3.75mm
Dia. Skewed Nails
Self Drilling Screws CSK
Heads
TYPICAL PLATE SUPPORT FIXING
OPTION 2
Pryda Multigrip With Min. 3/35 x
3.15mm Dia. Pryda Nails Per Tab
OPTION 1
2/75 x 3.75mm
Dia. Skewed Nails
Min. Bearing 30mm on
Primary Bearing Point
STANDARD END DETAIL TYPE 11
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Manufacturing…
2.7m wide to 3.5m wide +
9m long to 12m long +
Depends on linings & transport
Designed & supplied by fabricator
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Lifting systems…
Straps & slings
Hooks, chains, load rings
Proprietary lifting systems
Typically 4 point lifting
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WALL FRAMES & PANELS
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Prefab or site framed…
Prefab generally more common
Typically 90mm wide (3–4 storeys)
Cladding/finishes completed on site
Longer overall installation/build time
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Panelised wall frames…
Emerging option but gaining traction
“Open panels” more common. No internal linings, bulk insulation or services
Options: sheathed, breather membrane, external cladding & windows/doors fitted
Faster overall installation/build time
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External cladding options…
Sheathed only with Ply, OSB etc…
Lightweight w/board, foam, FC sheet
Hebel panels, James Hardie claddings
Brickwork & rendered finishes
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Bracing systems…
Higher bracing & tie down demands
Conventional & special systems
Truss brace system built into walls
Trussed portals, moment connections
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Issues to overcome…
Creep, shrinkage, crushing
Lateral stability & connections
Wind & EQ (tie downs, ductility etc…)
Robustness/Disproportionate collapse
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TOOLS & REFERENCES
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Literature & Design Guides…
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Pryda technical support…
• Design office support & advice
• Preliminary truss designs/feasibility studies
• Product support and technical advice
• Links to fabricators – quoting & supply
What to take away from this session
ITW CONSTRUCTION ASIA PACIFIC RESIDENTIAL DIVISION
• 4 to 5 storey “sweet spot” for lightweight timber structure
• 5 to 8 storey – Consider “Hybrid” CLT & light timber
• Panelised solutions very promising but still early stages
• Fabrication & supply chain – Need guidance & confidence
• New systems & techniques – Look to overseas?
• Collaboration between all parties essential to move forward
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QUESTIONS?